Geomorphology and Geoarchaeology of the Red River Valley, Louisiana 400DPI

Quaternary Geology and Geoarchaeology of the Lower Red River Valley

• A FIELD TRIP •

Trip Leaders

Whitney J. Autin and Charles E. Pearson

Friends of the Pleistocene South Central Cell

11 th Annual Field Conference Alexandria, Louisiana

March 26-28, 1993


• A FIELD TRIP ..

Trip Leaders




March 26-28, 1993


• A FIELD TRIP •

Trip Leaders




March 26-28, 1993

guidebook edited by Whitney Autin and John Snead

© 1993 Friends of the Pleistocene, South Central Cell

COVER PHOTO: A view northwest across the Red River Valley from St. Maurice Bluff in Grant Parish, Louisiana.

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10th 1992

9th 1991

8th 1990

7th 1989

6th 1988

5th 1987

4th 1986

3rd 1985

2nd 1984

1st 1983

Friends of the Pleistocene South Central Cell Field Conferences

Late Cenozoic Alluvial Stratigraphy and Prehistory of the Inner Gulf Coastal Plain, South-Central Texas - Rolfe Mandel and Chris Caran:San Antonio, TX - March 27 - 29

A Prehistory of the Plains Border Region - Brian J. Carter and Phillip A. Ward Ill: Woodward, OK - May 17 - 19

Field Guide to the Mississippi Alluvial Valley, Northeast Arkansas and Southeast Missouri - Margaret J. Guccione and E. Moye Rutledge: Wynne to Blytheville, AR - March 30 - April 1

Geomorphology, Quaternary Stratigraphy, and Paleocology of Central Texas -Michael D. Blum, James F. Petersen, and Rickard S. Toomey Ill: Fredricksburg, TX - April 7 - 9

Late Quaternary Geology of Southwestern Louisiana and Southeastern TexasRichard U. Birdseye and Saul Aronow: Lake Charles, LA to Beaumont, TX - March 25 - 27

Late Quaternary Stratigraphy, Neotectonics and Geoarcheology of Southwestern Oklahoma - C. Reid Ferring, Anthony J. Crone, Stephen A. Hall, Kenneth V. Luza, and Richard F. Madole: Lawton, OK - March 27 - 28

Quaternary Geomorphology and Stratigraphy of the Florida Parishes - Joann Mossa and Whitney J. Autin: Baton Rouge to Hammond, LA - April 18 - 20

Loesses in Louisiana and at Vicksburg, Mississippi - Bobby J. Miller, Joe J. Alford, Will J. Day, and Anthony J. Lewis: Baton Rouge, LA to Vicksburg, MS - April 12 - 14

Elements of the Geomorphology and Quaternary Stratigraphy of the Rolling Plains of the Texas Panhandle - Thomas C. Gustavson: Quitaque,TX - April 6 - 8

Guidebook to the Central Llano Estacado - Vance T. Holliday, Leland GiIe, Eileen Johnson, and Roberta Speer: Lubbock, IX

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Table of Contents

Friends of the Pleistocene South Central Cell Field Conferences (list and map) ............................ iii

Table of Contents .............................................................................................................................. iv

List of Figures ..................................................................................................................................... vi

List of Tables .................................................................................................................................... vii

Acknowledgements ......................................................................................................................... viii

Introduction - ,. Snead ........................................................................................................................ 1

Section I - An Overview

Quaternary Geology of the Lower Red River Valley - W. ,. Autin ......................................... 5

Geoarchaeology of the Lower Red River Valley - C. E. Pearson and D. G. Hunter ................ 25

Section II - The Field Trip

STOP 1 CD Late Tertiary to Middle Pleistocene Evolution of an Upland Erosional Landscape: Review of the Williana and Bentley Area - W. ,. Autin, ,. Snead, P. M. Walthall, D. ,. McCraw, and W. ,. Day ............................................................................................... 45

STOP 2 CD Late Middle Pleistocene Evolution of a Constructional Alluvial Plain: Review of the Montgomery Area and the St. Maurice Section - W.,. Autin, ,. Snead, P. M. Walthall, D. ,. McCraw, and W. ,. Day ........................................................................................... 53

STOP 3 CD Wisconsinan Constructional Alluviation of the Red River: Review of the Aloha Prairie Area - W. ,. Autin, ,. Snead, P. M. Walthall, D. ,. McCraw, and W. ,. Day .................. 61

STOP 4 CD Archaeological Sites Along the Pleistocene Terrace Margin and Red River Floodplain - C. E. Pearson and D. G. Hunter ................................................................................. 69

STOP 5 CD Archaeological Sites Along Bayou Rapides: An Abandoned Red River Course - C. E. Pearson and D. G. Hunter ............................................................................................. 75

STOP 6 CD Hydrodynamics, Flow, and Suspended Sediment Transport of the Lower Red River - ,. Mossa .................................................................................................................... 81

STOP 7 CD Loyd's Hall: Historic Period Settlement and Use of the Bayou Bouef Meander Belt-C. E. Pearson and D. G. Hunter .................................................................................... 93

STOP 8 CD Monda Gap and the Red River Diversion - C. E. Pearson and D. G. Hunter .......... 99

STOP 9 CD Wisconsinan Constructional Alluviation of the Mississippi River: Review of the Avoyelles Prairie Area - W. ,. Autin, A. AsIan, ,. Snead, and D. ,. McCraw ............... 103

ROAD LOG .......................................................................................................................... 116

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Section III - Contributed Articles

Surficial Deposits of Tertiary Age in the Central Louisiana Area - J. E. Rogers .................. 125

The Fate of Fisk's Pleistocene Units in Texas - S. Aronow ........................................... ....... 128

Soil Stratigraphic Units of the Lower Red River Valley - B. A. Touchet ....................... ...... 133

Waddell Bluff and Terrace Stratigraphy in the Lower Red River Valley - J. J. Alford and J. C. Holmes ..................................................................................................................... 135

Allostratigraphy and Geoarchaeology Within the Mississippi Alluvial Valley - P. V. Heinrich .................................................................................................................... 137

Extractions of Engineering Geology on the Lower Red River - P. E. Albertson .................. 143

Characteristics of Cores from the Upland and Intermediate Complex in the Florida Parishes - W. J. Autin, J. Mossa, and B. J. Miller.......... ........................................................... 147

Surface Geologic Mapping in Louisiana - Its Beginnings, Rise, and Recent Decline - R. P. McCulloh ................................................................................................................... 153

Distinctive Patterns in the Areal Distribution of Stream Alluvium in North Louisiana - R. P.

McCulloh .................................................................................................................. 158

Appendix

1993 FOP Guidebook Contributors .................................................................................... 163

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List of Figures

Figure 1- Generalized geology of the Red River Valley ....................................................................................................... 1

Figure 2 - Road map of the field trip area ............................................................................................................................ 3

SECTION I

Figure 3 - Geomorphic landscape positions ........................................................................................................................ 7

Figure 4 - Physiography of Grant and LaSalle Parishes ..................................................................................................... 13

Figure 5 - Generalized and diagrammatic relationships of Pleistocene materials across Red River, in vicinity of Grant Parish .................................................................................................................................................................. 14

Figure 6 - Ideal profile section through the delta showing regional effect of overloading at continental margin .......... 14

Figure 7 - Lower MissiSSippi Valley loess correlations ....................................................................................................... 16

Figure 8 - Cross section of the Red River alluvial valley taken near Zimmerman, Louisiana, showing typical flood plain features and stratigraphy ................................................................................................................................... 30

Figure 9 - The Red River just below the Great Bend in southwestern Arkansas showing the river meander features discussed in the text ........................................................................................................................................................... 35

Figure 10 - Locations of initial occupation sites of the Archaic period and the estimated eastern edge of the Red River meander belt at ca 1000 B.C .............................................................................................................................. 36

Figure 11 - Locations of initial occupation sites of the Fourche Maline period and the estimated eastern edge of the Red River meander belt at ca A.D. 900 ..................................................................................................................... 36

Figure 12 - Locations of initial occupation sites of the Caddoan period and the estimated eastern edge of the Red River meander belt at ca A.D. 1600 ............................................................................................................................. 37

Figure 13 - Geological and cultural features in the vicinity of lYfoncla Gap ..................................................................... 40

SECTION II

Figure 1.1 - Geologic map of the Williana - Bentley area .................................................................................................. 46

Figure 1.2 - Topographic map of the Williana - Bentley area ........................................................................................... 47

Figure 1.3 _ Cross Section of the Williana _ Bentley area .................................................................................................. 49

Figure 2.1- Geologic map of the Montgomery area .......................................................................................................... 54

Figure 2.2 - Topographic map of the St. Maurice area ...................................................................................................... 55

Figure 2.3 - Cross section of the St, Maurice - Montgomery - Waddell area ..................................................................... 58

Figure 3.1 - Geologic map of the Aloha Prairie area .......................................................................................................... 62

Figure 3.2 - Topographic map of the Aloha Prairie area .................................................................................................... 63

Figure 3.3 - Cross section of the Aloha .Prairie area ........................................................................................................... 64

Figure 4.1 - Topographic map of the Zimmerman Hill area ............................................................................................. 70

Figure 4.2 - A portion of the 1971 "Boyce, Louisiana" quadrangle (7.5' series) showing the historic Red River channel chronology, major physiographic features, and known archaeological sites in the vicinity of Zimmerman Hill ....................................................................................................................................................................... 71

Figure 4.3 - A generalized cross section through portions of the Pleistocene uplands and Red River alluvial valley at Zimmerman Hill showing major geomorphic features and locations of known archaeological sites ............. 72

Figure 5.1- Topographic map of the England Air Force Base area .................................................................................... 76

Figure 5.2 - Plan view of the England Air Force Base stop area showing the various relict Red River channels identified in the area by Smith and Russ (1974) and known archaeological sites along Bayou Rapides .............................. 77

Figure 5.3 - A generalized cross section through portions of the Red River alluvial valley showing the major geomorphic features associated with Bayou Rapides and Big Bayou and locations of known archaeological sites ............. 78

Figure 6.1 - Topographic map of the Red River / Fort Buhlow Lake area ......................................................................... 82

Figure 6.2 - Primary tributaries and d~stribut~l!ies of the Red River system in the south-central United States .............. 83

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Figure 6.3 - The drainage system and levees of southern Louisiana ................................................................................. 83

Figure 6.4 - Maximum, mean, and minimum discharges in the Mississippi - Atchafalaya River system ........................ 85

Figure 6.5 - Suspended sediment discharges and concentrations in the Mississippi - Atchafalaya River system ............ 85

Figure 6.6 - Percent flow discharge of the Red River and Old River system to the Atchafalaya ....................................... 86

Figure 6.7 - Percent suspended sediment discharge of the Red River and Old River system to the Atchafalaya ............. 87

Figure 6.8 - Discharge-suspended sediment relationships for the Red River at Alexandria, 1963-91 .............................. 88

Figure 6.9 - Discharge-suspended sediment relationships for the Red River above the Old River Outflow Channel above Simmesport, 1974-87 ......................................................................................................................................... 89

Figure 6.10 - Discharge-suspended sediment time series for the Mississippi - Atchafalaya River system in water year 1968 beginning October I, 1967 ................................................................................................................................ 90

Figure 7.1 - Topographic map of the Bayou Boeuf / Loyd's Hall area ............................................................................... 94

Figure 7.2 - Plan view of the Loyd's Hall stop area showing major geological features and archaeological sites along Bayou Boeuf .................................................................................................................................................................. 95

Figure 7.3 -A generalized cross section through portions of the Pleistocene uplands and Red River alluvial valley showing the major geomorphic features in the vicinity of Bayou Boeuf and Loyd's Hall .............................................. 96

Figure 8.1 - Topographic map of the Moncla Gap area ................................................................................................... 100

Figure 8.2 - Geological and cultural features in the vicinity of Moncla Gap .................................................................. 101

Figure 9.1 - Topographic map of the Avoyelles Prairie .................................................................................................... 104

Figure 9.2 - Meander scars of the Avoyelles Prairie ......................................................................................................... 105

Figure 9.3 - Meander scars of the Ferriday - Vidalia area ................................................................................................. 106

Figure 9.4 _ Comparison of ridge and swale landscape positions ................................................................................... 107

Figure 9.5 - Stratigraphy of a point bar flat ...................................................................................................................... 108

Figure 9.6 - Stratigraphy of the outer bend of a meander ............................................................................................... 109

Figure 9.7 - Landscape geomorphology, lithofacies, and pedogenic properties of Holocene Mississippi River alluvium ........................................................................................................................................................... 110

Figure 9.8 - Conceptual relations of the effects of base level alteration on MiSSissippi River meander belt deposits ... 111

Figure 9.9 - Geologic map of the Avoyelles Prairie .......................................................................................................... 113

List of Tables TABLE 1 - Suggested sources for definitions of Quaternary geologic terms ........................................................................ 6

TABLE 2 - Quaternary stratigraphic chart for Louisiana ..................................................................................................... 8

TABLE 3 - Abbreviations used in stratigraphic tables ........................................................................................................ 12

TABLE 4 - Characteristics of a core from beneath Fisk's (1938) Williana Terrace type locality ...................................... .48

TABLE 5 - Particle size data for Williana core-RR1-Metcalf series ................................................................................ .49

TABLE 6 - Characteristics of a profile from the Williana gravel pit .................................................................................. 50

TABLE 7 - Particle size data for Williana gravel pit-RR22-Smithdale series .................................................................. 50

TABLE 8 - Characteristics of a core from beneath Fisk's (1938) Bentley Terrace type locality ......................................... 51

TABLE 9 - Particle size data for Bentley core-RR11-Glenmora series ............................................................................ 51

TABLE 10 - Characteristics of a core from beneath Fisk's (1938) Montgomery Terrace type locality .............................. 56

TABLE 11- Particle size data for Montgomery core-RR12-Kolin series ........................................................................ 56

TABLE 12 - Characteristics of a vertical profile from the Montgomery Alloformation at the St. Maurice railroad cut ... 57

TABLE 13 - Characteristics of a core from beneath Fisk's (1938) Aloha Prairie Terrace type locality .............................. 65

TABLE 14 - Particle size data for Aloha Prairie core-RR19-Gore series .......................................................................... 66

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Acknowledgements

It takes a large body of individuals to coordinate a trip of this style. Without such help, the task would be impossible. The trip leaders would like to thank the Louisiana Geological Survey (LGS) and Coastal Environments, Inc. (CEI) for their help and support of trip and the guidebook development.

A number of cooperating groups provided support to the projects from which our results are based. The U. S. Army Corps of Engineers must be recognized for the con tributions it has made to the study of archaeology of the Red River Area. A considerable amount of the archeological and geoarchaeological research undertaken in the region in the past 15 years has been funded by either the New Orleans or Vicksburg Districts relative to construction projects along the river. The U.S. Geological Survey's COGEOMAP Program has for 6 years provided support to LGS geologic mapping projects in Louisiana. At LSU, the Center for Coastal, Energy, and Environmental Research (CCEER), the Agricultural Center, and the Department of Agronomy provided cooperative support to LGS. The Louisiana Soil Survey (USDA-SCS) provided data, information, and advice to LGS.

Our thanks go to the landowners who provided access to the field trip sites. They include the U. S. Forest Service, Kisatchie

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National Forest for their cooperation at Willi ana; the Kansas City Southern Railroad at St. Maurice; Mr. Randall Fletcher, Mrs. Theda Fletcher Slaughter, and Mr. Red Slaughter at Aloha; Mr. Lacy Knight at Zimmerman Hill, Mr. Floyd Hebert and Mr. Fern Posey at England Air Force Base, Mrs. Virginia Fitzgerald at Loyd's Hall, and Mr. Ward E. Zischke and the Tunica-Biloxi Tribe at the Marksville State Commemorative Area.

The maps, graphics, and desktop publishing of the guidebook were produced by John Snead and the LGSjCCEER cartographic staff, David McCraw, Lisa Pond, and Robert Paulsell.

Technical comments on the guidebook were graciously provided by David Kelley, Richard Weinstein, and Paul V. Heinrich. Art Bettis provided the set of mystery questions.

The Drillers With Attitudes, e.g., Fred Kring, Andres AsIan, and Rick McCulloh assisted W. J. Autin with collection of cores from the Red River and Marksville areas.

The gourmet jambalaya was organized and prepared by Dru Trahan.

Introduction

John Snead

We1cometothe 11th Annual Field Conference of the Friends of the Pleistocene-South Central Cell, hosted by Whitney Autin of the Louisiana Geological Survey and Charlie Pearson of Coastal Environments, Inc. This year we will revisit Harold Fisk's famous Pleistocene terrace type locations, consider pre-historic archaeological sites in the river valley environment, and look at the behavior and floodplain morphology of the Holocene Red River.

Of course there will be a social get-together at Harold Miles Park on Friday evening featuring beverages and some homemade Louisiana jambalaya. On Saturday evening we will have a seafood banquet and annual meeting at Lea-J's in Pineville where we will discuss next years trip.

The headquarters for the '93 FOP will be at the Best Western Motel on MacArthur Drive in Alexandria - ask for Charlie

102 0 1000 98 0

34 0

100 o 100 200 11M 11M

Kilometers

Pearson's room at the desk. Campers are staying at the Kincaid Lake campground west of Alexandria in the Kisatchie National Forest. Whitney Autin will camp there and will be available for information. Except for our final stop in the Lower Mississippi Valley the entire trip will be within the Lower Red River Valley.

The Red River Evolving from it's small tributaries on the broad plains of the Llano Estacada in the Texas panhandle region, the Red River assumes it's own identity near the one hundredth meridian and wanders some 1,200 miles to it's confluence with the Mississippi River at the apex of the great delta. It drains a diverse outcrop sequence of Paleozoic, Mesozoic, and Cenozoic sedimentary rocks as it flows southeastward to join the Lower Mississippi Valley (fig. 1). Draining a basin of about

96 0 94 0

Generalized Geology of the

Red River Valley

92 0

340

32 0 M~trmt~~ Holocene Alluvium

b;;i(\~·;H Pleistocene Deposits

~~.;!.f.:'i Tertiary Coastal Plain ':~"":'~": Formation

~ ~ ~ §

Cretaceous Rocks

I}.·£J Tertiary Ogallalla Formation

102 0 100 0

Permian to Triassic Rocks

Pennsylvanian Rocks Folded and Faulted Sedimentary and/or Igneous Rocks

98 0 96 0

I

Figure 1 - Generalized Geology of the Red River Valley

94 0

I

90,000 square miles, the river transports significant amounts of the reddish Permian sediment that give the Red it's name. All of the Native American names for the river translate to "red". The wilderness explorers of the DeSoto expedition were the first Europeans to visit the Red River Valley in 1541. As the Indians did, the Spanish called the big stream Rojo or Colorado, or sometimes Vermejo. It was Riviere Rouge to the French who successfully contested them for possession of the lower valley.

In the Quaternary, the Red River has at times joined the Mississippi River as it's last western tributary. At other times it has proceeded directly to the Gulf of Mexico, either independently across the coastal plain or through abandoned Mississippi River courses. The modern course of the Red has now been captured by the Atchafalaya River just short of it's former confluence with the Mississippi at Old River. The Atchafalaya, as if inspired by its successful river piracy, now seems bent upon the capture of the Mississippi itself. When this happens, as it inevitably must, the Red will once again join the Mississippi River in it's new Atchafalaya Delta course.

Geologic Setting The Lower Red River Valley has three major bedrock constrictions; near Texarkana, at Grand Ecore near Natchitoches, and the lowest one at Colfax where the hard Oligocene sandstones of the Kisatchie Wold are cut by the river. South of this constriction the valley is bounded on both sides primarily by terraces and uplands of Pleistocene Red River fluvial deposits. Central Louisiana is an area of confluence between the alluvial Pleistocene deposits of the Red and Mississippi Rivers and their transition to the broad Pleistocene units of the coastal plain.

The Holocene valley of the Lower Red River is characterized by numerous and rapidly switching meander belts. The amount of sediment carried, the narrow valley constrictions, and to an extent, the significant and famous Red River

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Raft have contributed to the intense meander activity of the river. The effect of this meander belt SWitching is of great importance to archaeolOgists and geologists because of the potential for dating human occupancy periods, offering clues for the dating of the meander belt deposits themselves.

Field Trip Features This field conference will take you through the Quaternary landscapes of the Lower Red River Valley and each day the trip will begin in Alexandria (fig. 2). Day 1 of the excursion will focus on erosional and constructional landscapes, soils, and sediments in the type locations where Harold Fisk developed his Quaternary Terrace sequence. It will have 3 stops and covers about 130 road miles. Day 2 will focus on the adaptation of Native American culture to the changing flood plain environment in the Holocene valley, Red River sediment and flow, and how European settlement impacted the region's land use and geomorphic processes. There will be 4 stops on the second day which will cover about 95 road miles. Day 3 will be a half-day look at the Monda Gap diversion of the Red River, the Tunica-Biloxi Indian Reservation, and the Pleistocene MiSSissippi River landscapes and lithofacies of the Avoyelles Prairie and its relation to Holocene analogs. There will be 2 stops over 40 road miles and we'll be done by noon.

The Field Guide This field guide is divided into three parts. Section I is an overview of the Quaternary Lower Red River Valley and contains chapters on Geology by Whitney Autin and Geoarchaeology by Charlie Pearson and Don Hunter. Section II consists of the field trip road log and extensive descriptions of the nine stops. Section III contains related papers contributed by field trip members.

Enjoy yourselves and be careful on the highways. Incidently Dry Prong and Woodworth are notorious speedtraps.

Figure 2 - Road Map of the Field Trip Area. The nine stops are indicated with a 0 symbol.

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M !AJflAO U

I NOIl:>lS

Quaternary Geology of the Lower Red River Valley Implications for Stratigraphic Correlations and Geologic Mapping in the Lower Mississippi Valley and Northern Gulf Coastal Plain

Whitney f. Autin

Introduction In landmark publications of the Louisiana Geological Survey (LGS), H. N. Fisk (1938a,1940) developed a tnodelforthe stratigraphic definition of Pleistocene terraces in the Lower Red River Valley (LRRV) of central Louisiana. Subsequent publication of Fisk's (1944) monograph correlated these units through the Lower Mississippi Valley (LMV) and much of the northern Gulf Coastal Plain (GCP). The concepts developed by this research have been the cornerstone of Pleistocene stratigraphic models that have received world wide recognition by Quaternary geoscientists. The landscape evolution models of Fisk, and other previous models applied to LMV and GCP Quaternary stratigraphy do not coincide with modern Quaternary thinking regarding geologic processes, stratigraphic units, chronology, or causal mechanisms.

Modern geomorphic studies (Saucier, 1974, 1981; Autin et aI., 1991; Mossa and Autin, 1989; Autin, 1992) and geologic mapping (Snead and McCulloh, 1984; Saucier and Snead, 1989; Autin and McCulloh, 1991, 1992; LGS, unpublished file data, LGS-COGEOMAP, 1989 to present) have questioned the validity of Fisk's model and its relevance to modern investigations. However, no one has yet placed Fisk's initial studies in the LRRV into a modern context and related this area to regional Quaternary stratigraphy. New data generated in the past decade has shed light on the acute need for reappraisal of the fundamental concepts of Quaternary landscape evolution in the LMV and GCP. Societal need for accurate scientific data applicable to water and environmental resources,land management, and scientific policy has provided the catalyst for supporting this effort towards revised stratigraphic and geomorphic data on Quaternary landscapes.

The LRRV is an area that has been historically important as a Quaternary type area. This region is the first major field area investigated by Fisk upon his appointment to the LGS and Department of Geology at Louisiana State University (LSU), and resulted in publication of the Geologic Bulletins for Grant and LaSalle (Fisk, 1938a), and Avoyelles and Rapides (Fisk, 1940) Parishes respectively. Prior Quaternary investigations indicate that Fisk's concepts are best evaluated by reassessment of the locations he and others of his time considered important. Mt. Pleasant Bluff (Autin et al., 1988), the Avoyelles Prairie (Stop 9, this guidebook), the Tunica Hills (Delcourt and Delcourt, 1977; Otvos, 1980;

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Alford et al., 1983; Givens and Givens, 1988), and FerridayVidalia (AsIan and Autin, 1992) are other examples.

The Quaternary landscapes of Grant Parish offer the opportunity to model an area with a complex depositional and erosional historyextendingback into the Tertiary. Although the stratigraphic record is obviously incomplete, reappraisal of Fisk's (1938a) Pleistocene stratigraphic type areas of Central Louisiana offer an unique opportunity to delve into some of the questions and observations that influenced the thinking of Fisk during the period when he developed his Qua ternary concepts.

Terminology and Nomenclature Geological investigations in the region have produced a proliferation of informal stratigraphic names and terms used in a variety of contexts. Much of the difficulty in communication centers around the term terrace and the definition of terrace sequences in local and regional correlation schemes. In modern geomorphic studies, a terrace is a geomorphic surface commonly associated with aggradation of a sedimentary sequence that has been preserved as a relict above the level of the current system, but does not include the underlying deposit.

Russell (1938) clearly implied and most subsequent workers have accepted that terraces of the LMV were aggradational surfaces of relict alluvial, deltaic, and/or coastal plains. Each terrace (the surface and its underlying deposits) was related to a given sedimentary cycle and terrace names were synonymous with formation names. Terrace sequences were considered causally related to and were correlated with glacial cycles, with aggradation associated with glacial retreat and its accompanying sea-level rise. The aggradational surface stabilized during an interglacial or interstadial, and the following glacial advance dropped base level to produce a terrace. Each terrace was considered comparable in form and process with the currently developing sedimentary cycle.

The objective and replicable description and definition of Qua ternary landsca pes, sedimen ts, soils, stratigraphic units, and geologic map units require the adoption of succinct and easily understood terminology. Standard usage of scientific terms fosters precise definitions and communication between investigators. The following usage is adopted for this gUidebook and is suggested as a starting pointfor subsequent

refinement of nomenclature (Table 1). Terminology is grouped according to geomorphic, sedimentologic, pedologic, stratigraphic, and chronologic usage. Such terms are of fundamental importance to the definition of geologic map units.

Geomorphic Nomenclature The use of geomorphology in Quaternary investigations require understanding of the relation of the land surface (present day topography) with land surfaces of the past. An ancestral land surface is commonly referred to as a geomor-

phic surface, following the convention of Ruhe (1956) and the modern usage of Daniels and Hammer (1992). Ageomorphic surface mayor may not coincide with the present land surface. There are two fundamental types of geomorphic surfaces, those associated with constructional landscapes and those associated with erasionallandscapes. A constructionallandscape is a landform that owes its origin or general character to the processes of upbuilding, such as accumulation by deposition (Bates and]ackson, 1987, p. 142). In the LRRV and LMV, terraces and presently active alluvial surfaces are the fundamental constructional landscapes. Erasionallandscapes pertain to or are produced by the wearing

TABLE 1 - Suggested Sources for Definitions of Quaternary Geologic Terms.

GEOMORPHIC TERM REFERENCE

terrace Russell, 1938 geomorphic surface Daniels and Hammer, 1992; Ruhe, 1956 constructional landscape Bates and jackson, 1987 erosional landscape Bates and jackson, 1987 landscape position Ruhe, 1969 flood plain Walker, 1984; Reineck and Singh, 1980 channel belt Walker, 1984; Reineck and Singh, 1980 flood basin Walker, 1984; Reineck and Singh, 1980

SEDIMENTOLOGIC TERM REFERENCE

deposit Bates and jackson, 1987 lithology Bates and jackson, 1987 sedimentary facies Bates and jackson, 1987 depositional environment Reinick and Singh, 1980 paleoenvironment Bates and jackson, 1987 paleogeographic reconstruction Bates and jackson, 1987

PEDOLOGICTERM REFERENCE

soil horizon Soil Survey Staff, 1975 surface soils Autin et aI., 1991 soil series Soil Survey Staff, 1975 paleosol Autin et aI., 1991 geosol Autin et aI., 1991

STRATIGRAPHIC TERM REFERENCE

exposure Bates and jackson, 1987 outcrop Bates and jackson, 1987 formation Bates and jackson, 1987; NACSN, 1983 alloformation Auti~1992;NACSN,1983

complex Autin et aI., 1991

CHRONOLOGIC TERM REFERENCE

era Bates and jackson, 1987; NACSN, 1983 system Bates and jackson, 1987; NACSN, 1983 series Bates and jackson, 1987; NACSN, 1983 stage Bates and jackson, 1987; NACSN, 1983 geochronology Bates and jackson, 1987 numerical age Coleman et aL, 1987 correlated age Coleman et aL, 1987 relative age Coleman et aL, 1987 calibrated age Coleman et aL, 1987

6

away of the land (Bates and Jackson, 1987, p. 222). The elements of both constructional and erosional landforms can be described in terms of landscape positions. A landscape is described as the distinct association of landforms, especially as modified by geologic forces ... (Bates and Jackson, 1987, p. 368). A landscape position is a point in this continuum as described by the landscape model of Ruhe (1969) (Fig. 3).

The flood plain environment is the fundamental geomorphic landform for assessment of much of the Quaternary constructional landforms of the LRRV, LMV, and GCP. Deltaic, barrier island/lagoonal, and chenier systems are equally important in coastal areas of the region. The flood plain geomorphic system and its relevance to geomorphic surfaces are summarized as background information to this field trip. Valuable references to recognition criteria for flood plain alluvium and comparable sedimentary deposits and landforms incl ude Reineck and Singh (1980), and Walker (1984).

The channel belt produces the primary area of sand body construction in an active flood plain. Channel bel ts incl ude channel and point bar landforms, scroll bars, chute channels and bars, and typically produce ridge-swale topography, abandoned channels, and abandoned cut off channels. Flood plain over bank areas can be divided into proximal and distal components. Proximal over bank areas include accretionary levee and crevasse splay systems. Levees aggrade from suspended sedimentation in near-channel over bank positions. Crevasse splays form by sedimentation in crevasse channels that avulse from meander belts. Splays aggrade and prograde by sheet flow sedimentation in interchannel areas and areas distal to crevasse channel systems. Distal to the channel belt and proximal over bank areas are flood basins. Backswamps and lakes receive silts and clays primarily by suspension sedimentation.

Sedimentologic Nomenclature Sedimentary deposits and their genetically-related environments have a suite of terms commonly used by sedimentologists and stratigraphers. A deposit is earth material of any type, either consolidated or unconsolidated, that has accumulated by some natural process or agent and is generally considered synonymous with sediment (Bates andJ ackson, 1987, p. 175). Lithology is the description of rocks, especially in hand specimen and in outcrop, on the basis of such characteristics as color, mineralogic composition, and grain size, or more simply stated, the physical character of a rock. (Bates andJackson,1987, p. 384). A sedimentary facies is the aspect, appearance, and characteristics of a rock unit, usually reflecting the conditions of its origin, especially as it differentiates the unit from adjacent or associated units. A facies is a mappable, areally restricted part of a lithostratigraphic body, differing in lithology or fossil content from other beds deposited at the same time and in lithologic continUity (Bates and Jackson, 1987, p. 232). A depositional environment is a geomorphic unit in which deposition takes place. It is characterized by an unique set of physical, biological, and chemical processes operating at a specified rate and intensity which impart sufficient imprint on the sediment,

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Divide

Su - summit Sh - shoulder Bs - backslope Fs - footslope Ts - toeslope

Figure 3 - Geomorphic landscape positions (adapted from Ruhe, 7969).

so that a characteristic deposit is produced (Reineck and Singh, 1980, p. 5). A paleoenvironment is an environment in the geologic past (Bates and Jackson, 1987, p. 476). A paleogeographic reconstruction is a spatial distribution of temporally and genetically related paleoenvironments.

Pedologic Nomenclature Soil classification terminology and horizon designations used are adapted from Soil Survey Staff (1975, 1981). A fundamental criteria for recognition of a soil, regardless ofits type or usage, is the recognition of soil horizons. A soil horizon is a layer that is apprOximately parallel to the soil surface. It has some set of properties that have been produced by soil-forming processes, and it has some properties that are not like those of the layers just above and beneath it (Soil Survey Staff, 1975, p. 14). Soils at the present land surface are identified as surface soils or by soil series name depending on the context. Soil series names are based on local mapping in USDA Soil Surveys. The term paleosol describes a buried soil horizon or horizons developed in the geologic past without reference to a stratigraphic context. The term geosol, a buried soil in a stratigraphic context, coincides with guidelines of the North American Commission on Stratigraphic Nomenclature (1983). However, formal names have yet to be applied to the geosols of the region. They are here treated as informal soil stratigraphiC units.

Stratigraphic Nomenclature Definition of stratigraphic units in Quaternary investigations of the LRRV, LMV, and GCP require the use of geomorphic,lithologic, pedologic, and/or associated boundarycriteria. An exposure is an area of a rock formation or geologic structure that is visible, either na turally or artificially, and is unobscured by soil, vegetation, water, or the works of man

(Bates and Jackson, 1983, p. 229). An outcrop is the part of a geologic formation or structure that appears at the surface of the Earth, also bed rock that is covered by surficial deposi ts such as alluvium (Bates and Jackson, 1983, p. 471). A formation is a body of rock identified by lithologic characteristics and stratigraphic position, is mappable at the Earth's surface or traceable in the subsurface, and is the fundamental unit in lithostratigraphic classification (Bates and Jackson, 1983, p. 255). An alloformation is a three-dimensional body of lithofacies differentiated primarily by unconformities (North American Commission on Stratigraphic Nomenclature, 1983; Autin, 1992). A complexis a geomorphic surface or set of temporally related surfaces with an associated sedimentary sequence that may represent more than one depositional environment (Autinetal., 1991). Modern stratigraphiC thinking suggests that each complex is a group of related alloformations. However, research in the region has not progressed to the point of defining a comprehensive

allostratigraphic sequence, so the term allogroup is avoided until sufficient formal definitions develop.

Quaternary Chronology Perhaps the most interesting and complex aspect of Quaternary geoscience is the development and use of chronologies. A chronology is the arranging events in their proper sequence in time; also, considering or measuring time in discrete units (Bates and Jackson, 1983, p.118). Geochronology is the study of time in relationship to the history of the Earth (Bates and Jackson, 1983, p. 269). The era, system, series, and stage are the fundamental divisions of geologic time.

Coleman et al. (1987) recommend use of the following terms for Quaternary age estimates. Numerical-age methods are those that produce results on a ratio scale, that is, they produce quantitative estimates of age and uncertainty whose

TABLE 2 - Quaternary stratigraphic chart for Louisiana.

SYSTEM

~ ~ ~ §

~ ~ ~

SERIES

HOLOCENE I

~ Z ~ u 0 E-< Uj P-I

~ p...

PLIOCENE

STAGE

LATE2

EARLY 2

lATE WISCONSIN

MIDDLE LATE WISCONSIN

EARLY WISCONSIN

SANGAMON

MIDDLE

EARLY

ALLOUNIT 1

Deltaic and Chenier Plains

Intermediate Complex

Upland Complex9

8

REMARKS

1) Defined and correlated by morophologic expression; each complex consists of one or more alloformations; subdivisions have yet to be defined.

2) Early and late are relative terms; can be differentiated locally in coastal and alluvial settings.

3) Meander belts have been differentiated on the Mississippi and Red rivers; undifferentiated on smaller streams. Natural levee and backswamp facies have been differentiated on Geologic Map of Louisiana.

4) Identified as Braided Stream Terraces on Geologic Map of Louisiana Early Wisconsin unit may include some deposits of middle Plestocene valley trains.

5) Lithologic criteria used in identification.

6) Only recognized as flanking selected valleys.

7) Consists of lowstand shelf margin deltas dO\vndip and highstand shelf phase deltas updip.

8) Equivalent to Beaumont formation of Texas.

9) Equivalent to Citronelle formation of northern Gulf Coast and High Terraces on Geologic Map of Louisiana

ratios can be compared. Correlated-age methods produce ages by demonstrating equivalence to independently dated deposits or events. Relative-age methods provide an age sequence and most provide some measure of the magnitude of age differences between members of a sequence. Calibrated-age methods are process rates that are calibrated by independent age controls.

The Quaternary sequences of the LRRV, LMV, and GCP are largely correlated by relative-age relations. Numerical-age estimates are limited, but where available provide a basis for correlated-age estimates. Time-dependent radiogenic, chemical, and biological methods are presently in their infancy in the region.

The follOWing relative-age relations and time-stratigraphic terminology are in present usage in LGS Quaternary correlations and geologic mapping investigations (Table 2). These definitions are likely to evolve with additional data and continued investigation. The Quaternary is the second period of the Cenozoic era, following the Tertiary; also the corresponding system of rocks. It began two to three million years ago and extends to the present. It consists of two grossly unequal epochs; the Pleistocene, up to about 10,000 years ago, and the Holocene since that time (Bates and Jackson, 1983, p. 544).

The Wisconsinan pertains to the classical fourth glacial stage of the Pleistocene Epoch in North America, following the Sangamonian interglacial stage and preceding the Holocene (Bates andJackson, 1983, p. 741). Late Pleistocene is generally considered synonymous with Wisconsinan. Wisconsinan can be arbitrarily subdivided into early, middle, and late (Richmond and Fullerton, 1986) (Table 2). Sangamonian pertains to the third classical interglacial stage of the Pleistocene epoch, after the Illinoian glacial stage and before the Wisconsinan (Bates and Jackson, 1983, p. 587). Illinoian pertains to the classical third glacial stage of the Pleistocene Epoch in North America, between the Yarmouthian and Sangamonian interglacial stages (Ba tes andJ ackson, 1983, p. 328). Illinoian can be arbitrarily subdivided into early, middle, and late (Richmond and Fullerton, 1986), but ishere considered the middle Pleistocene (Table 2). Pre-Illinoian refers to Pleistocene deposits and the associated time interval older than Illinoian, and is here considered the early Pleistocene (Table 2). The term pre-Illinoian was adopted for the classical glaciated Kansan and Nebraskan tills when definition of stratigraphic complexity resulted in the abandonment of the original glacial stage names (Hallberg, 1986).

Stratigraphic terminology, references to chronology, and attempts at correlation need to remain consistent andobjective. Use of proxy correlation indices, surrogate chronologies introduced via assum ptive reasoning, and acceptance of correlated-ages for stratigraphic units must be applied with great caution. Such techniques produce only tentative correlations that require subsequent testing by rigorous, independent techniques. Failure to apply independent tests of this style of correlation results in concept-driven models, to adapt a term from 1'1. D. Blum (personal communication). This approach genera tes new models from accepted models, but the new models are only based on assumptions. Let us

9

not forget the need for basic data and relevant cross-checking on the correlations we accept. Global perspectives of earth processes are useless if the data and inferences from local case studies are invalid. Examples of poor usage of stratigra phic correlation abound in modern scientific Ii terature, however, one can provided their own examples.

GEOLOGIC MAP UNITS The use of vari able criteria for geologic map unit definitions and a priori definition of causal mechanisms has produced an inconsistent picture of the nature and distribution of Quaternary geomorphic surfaces. The problem results partly from the lack of a predetermined framework for assessing mapping units. Mossa and Autin (1989) recommended a framework that combines geomorphic,lithologic, and pedologic criteria, while conSidering each independently. Such an approach has been successfully applied to differentiating Quaternary deposits in Illinois (Willman and Frye, 1970). Subsequent to the 1986 SCFOP field gUidebook, Mossa and Autin (1989), Autin et al. (1988, 1991), and Autin (1992) adopted an allostratigraphic approach to the definition of constructional alluvial Quaternary stratigraphic units in the LMV and GCP.

To produce regional map revisions, the terrace sequences of many workers are correlated into a revised map legend (Snead and McCulloh, 1984; Saucier and Snead, 1989). To avoid the ambiguity surrounding the term terrace, each of the regional-scale map units is designated a complex. The term terrace is reserved for morphostratigraphic units as they were originally defined in previous works. The term formation is reserved for units defined by lithostratigraphic criteria. The follOWing summary, partly adapted from Autin et al. (1991), describes the principal Quaternary geologic map units of Saucier and Snead (1989) relevant to the LRRV.

The Upland Complex The Upland Complex is the most are ally extensive and oldest Quaternary unit in the LRRV, LMV, and GCP. The unit extends from the apex of the Mississippi Embayment, south to Louisiana, then forms a coast-parallel belt along the northern GCP from east Texas to West Florida. Discontinuous remnants also occur in the LRRV. The deposits are eqUivalent to the Willis formation of Texas, the Lafayette Gravel (Potter, 1955), the Grover Gravel (Mississippi River source), the Mounds Gravel (Ohio River source), and the Citronelle Formation (Matson, 1916). The Geologic Map of Louisiana (Snead and McCulloh, 1984) depicts the Upland Complex as the High Terraces and described the unit as a tan to orange clay, silt, and sand with a large amount of basal gravel. Surfaces are highly dissected and less continuous than the lower terraces, and are composed of terraces formerly designated as Williana, Citronelle, and the Bentley. Most workers consider these terraces as one morpho stratigraphic unit, although Fisk (1944) believed that portions of two terraces occur in the LMV and GCP regions (Mossa and Autin, 1989).

The deposits of the Upland Complex in central Louisiana have not been studied in detail for several decades. A source area to the north and west is suggested (Kesel, 1987; Fisk,

1949). The deposit consists of a few meters to over 100 m of highly oxidized mixtures of chert gravel, fine- to coarsegrained cross-bedded sand, and lesser quantities of silt and clay. Exposed stratigraphic sequences and lithofacies patterns reflect a high-energy fluvial deposit with multiple channels. The sand and gravel commonly display mediumto large-scale planar foreset and trough cross beds, some over 2 m thick. Gravel deposits occur in thick sequences, where gravel may compose over 50 percentbyweight of individual beds~ Rip-up clasts of intraformational mud and older Tertiary sediments are present in some exposures. Channeling and cut-and-fill features are common in many exposures. Multi-colored clayey sequences, possibly marginal flood basin or channel fill deposits, are also exposed in the unit.

The depositional environments of these sediments have been variously interpreted as glaciofluVial, marine, meandering, or braided stream (Mossa and Autin, 1989). The modern consensus is that an alluvial apron was deposited by braided, coalescing streams. Because there is little paleontological data from the sequence, the age of the deposits beneath the Upland Complex is uncertain. Either a Pliocene or Pleistocene age is generally cited for the time of deposition(Fisk, 1945; Stringfield and LaMoreaux, 1957; Isphording and Lamb, 1971; SelC 1986). However, other investigations suggest an age as old as Miocene (Alt, 1974; May, 1981).

The Intermediate Complex The Quaternary history of the Intermediate Complex is almost completely unknown. The Intermediate Complex comprises the Montgomery Terrace of Fisk (1938a) in the LRRV, the Irene Terrace in a small area north of Baton Rouge (Durham etal., 1967), the possibly equivalent Lissie Formation in east Texas, and the Humboldt and possibly the Henderson terraces of western Tennessee (Saucier, 1987). Saucier (1964) mapped a small area in east central Arkansas and along the Ouachita River (Saucier and Fleetwood, 1970).

The Intermediate Complex stems from the original IntermediateTerraces on the Geologic Map of Louisiana (Snead and McCulloh, 1984) and are described as consisting of light gray to orange-brown clay, sandy clay and silt, with much sand and gravel locally. Surfaces show more dissection and are topographically higher than the Prairie. Composed of terraces formerly designated as Montgomery, Irene, and most ofthe Bentley. The Intermediate Terraces in south Louisiana are depicted as mostly coast-parallel on the Geologic Map of Louisiana. However, river-trending Intermediate Terraces were recognized in the LRRV.

Prior workers believed that the Intermediate Complex can be differentiated from the Upland Complex and the Prairie Complex on the basis of lithology, pedologic features, slope, and degree of dissection (Autinetal., 1991). in the LRRVand LMV (Fisk, 1940; Varvaro, 1957), the deposits consists of about 100 to 300 m of red, brown, and buff interbedded sand, silt, and clay associated with constructional geomorphic surfaces. In the coast-parallel trends of southeastern Louisiana, parts of the unit consist of an erosion surface developed on the downdip portion ofthe Citronelle Formation (Autin and McCulloh, 1991,1992). The constructional alluvial deposits of the Intermediate Complex have been

correlated to the oldest unit of the Prairie Complex, and consist of a fining-upward sequence capped by laminated clay overlain by a geosol with a veneer of loess (Autin and McCulloh, 1991, 1992).

The lithologic character of the Intermediate Complex is neither well known nor consistently ascribed to a specific formation. The potential for confusion with adjacent units is great because of limited field mapping and limited documentation of its characteristics. Detailed field stratigraphic studies are necessary to re-evaluate the Intermediate Complex and systematically define and delineate the appropriate geologic map units associated with this landscape.

Approximations ofthe age of the Intermediate Complex are based primarily on the inferred sea level history of the Gulf of Nfexico. Because the significance ofthe Farmdalian Interstadial has been controversial, the surface and its underlying sediments have been considered either Sangamonian (Fisk, 1938a,b, 1939, 1940,1944; Fisk and McFarlan, 1955; Alford and Holmes, 1985), Yarmouthian (Saucier, 1974), or preSangamonian (Otvos, 1982).

The Prairie Complex The Prairie Complex is a widespread sequence of morphostratigraphic and lithostratigraphic units loosely tied together by a single deSignation. In the LRRV, the Prairie Com plex consists of a series of constructional all uvial deposits and associated geomorphic surfaces. In the LRRV, the Prairie Terrace was first recognized and originally defined at Aloha (Fisk, 1938a) as the youngest offourmajor Pleistocene interglacial fluvial stratigraphic units. Fisk (1938a) considered the lithology of the Prairie Terraces as variable. He originally referred to sediments underlying this surface as the "Prairie Member." In 1944, Fisk elevated the Prairie to formation rank without producing a formal lithostratigraphic definition. Several subsequent workers have adopted his terminology (see Mossa and Autin, 1989). The sequence is generally considered to be fining-upward, with its lower limit placed at a basal gravel that grades up into sand, silt, and clay.

The uni t was extended from Central Louisiana to include the broad coast-parallel Prairie surface in southwestern Louisiana, a comparable belt in the Florida Parishes, and isolated fluvial terraces in northeastern Louisiana (Fisk, 1939). Fisk (1940) subdivided the coast-parallel Prairie of southwestern Louisiana into a Mississippi River fluvial/deltaic unit and a similar unit of the Red River. He also correlated the Prairie Terrace of Louisiana with the Beaumont Formation of Texas and the Pamlico and Pensacola Terraces of Florida.

Doering (1956) recognized two Prairie Terrace levels in Louisiana and questioned the correlation of the fluvial terrace in the Red River Valley with the coast-parallel terrace. Doering (1958) called the coast-parallel Prairie Terrace the Eunice Terrace and correlated it with the Beaumont Formation of Texas while proposing the term Holloway Prairie for a lower Red River Valley terrace. Subsequently, the presence of two levels of the Prairie Terrace in the Red River Vall ey has been substantiated (Smith and Russ, 1974).

10

Snead and McCulloh (1984) described the Prairie Terraces as light gray to light brown clay, sandy clay, silt, sand, and some gravel. Surfaces generally show Ii ttle dissection and are topographically higher than the Deweyville. Three levels have been recognized: two along alluvial valleys, the lower coalescing with its broad coastwise expression; the third, still lower, found intermittently gulfward.

Estimatesofthe age of the Prairie Complex are usuallybased on the inferred sea level history of the Gulf of Mexico, specifically with regard to eustatic pOSition and duration of the FarmdaIian Interstadial. Age designations given to the Prairie Complex ranges from Sangamonian to Farmdalian (Autinetal., 1991). Preservation of geomorphic features, soil development, loess, depositional and erosional features, and radiocarbon dates are criteria used in age deSignation. The Prairie Complex consists of a set of correlative sequences of allostratigraphic units. In the LRRV, the Prairie Complex as presently defined may consist of the Aloha Prairie of Fisk (1938a), the Upper Prairie of Russ (1975), and the Montgomery Terrace of Fisk (1938a).

The Deweyville Complex The Deweyville Complex has been mapped in the LRRV only at Pine Island in Caddo Parish, Louisiana. According to Snead and McCulloh (1984) the lithologic and morphologic description is gray mixed with brown-to-red clay and silty clay; some sand and gravel locally. Topographically higher than alluvium and lower than Prairie Terraces found along streams of intermediate size. Stratigraphic and geomorphic data (Snead and McCulloh, 1984; Miller et al., 1985) suggests thatmuchoftheDeweyvilleComplexoftheLMVandLRRV may be topographically lower than its adjacent alluvial counterparts.

Distinctly oversized meander-belt features, including pointbar ridges and swales and abandoned channels, are characteristic of this complex. lvforphometric analyses of features on the Ouachita River indicate paleochannel widths three times those of Holocene analogs and meander radii and wave lengths two times greater (Saucier and Fleetwood, 1970). Changes in the seasonality and intensity of precipitation events, accompanied by vegetation changes, were possibly factors that influenced Deweyville meander morphology. Noexplanationhasyetto be offered as to why only one meander bight has been documented in the entire LRRV. The age of Deweyville meander scars possibly range from 18 ka to terminal Pleistocene (Autin et al., 1991).

Loess Deposits Remnants of as many as four loess sheets have been identified on Pleistocene and older units west of the LMV. Although loess deposits associated with the LRRV have not been identified, thin silty veneers on Pleistocene surfaces of the LRRV may have an origin partly related to LMV loess deposits.

Holocene Alluvium The Geologic Map of Louisiana (Snead and McCulloh, 1984) subdivides the LRRV Holocene alluvium into natural levee

11

and undifferentiated alluvium. Alluvium is described as gray to brownish gray clay and silty clay, some sand and gravel locally. Includes all alluvial valley deposits except natural levees of major streams. Natural Levees consist of gray and brown silt, silty clay, and some very fine sand, shown only on past and present courses of rna jor streams. Deposits of the LRRV typically have reddish or reddish brown colors imparted from the ri ver' s western red bed source area. All uvium of the LRRV was subdivided into a complex meander belt sequence by Russ (1975). This sequence was simplified by Saucier and Snead (1989) in a re-correlation analogous to that adopted by Saucier (1974,1981) and Saucier and Snead (1989) for the LMV.

Methods And Approach Four field locations discussed in this guidebook evaluate landscape morphology,lithofacies, pedogenesis, and stratigraphy in the LRRV (Stops I, 2, and 3) and UvfV (Stop 9). Topographic patterns from 7.5-minute quadrangles, soil survey data, aerial photographs, and field reconnaissance were used to obtain general geomorphic information. Topographic patterns are associated with sedimentary deposits and soils to define and delineate geologic map units at 1:24,000 scale.

Borings of up to 15 m length and 5 cm diameter were collected with a Giddings hydraulic probe and provide most of the subsurface field data. Cross sections were constructed to illustrate geometric relationships between lithofacies, soils,landscapes, and geologic map units. Most transects are oriented to answer speCific questions about selected landforms. Exposed sedimentary sequences along modern stream cut banks, road and rail road cuts, and the walls of sand and gravel pits were used to observe and describe litholOgiC and pedologic properties and the nature of stratigraphic contacts. Field descriptions are based on pedologic and sedimentologic procedures modified from methods established by the Soil Survey Staff (1975, 1981). Vertical profiles are divided into soil horizons and sedimentary units based on field determinations of color, texture, consistence, soil structure, sedimentary structures, patterns of oxide stains and concretions, and the nature of unit boundaries (Table 3).

Sediment samples were collected from typical vertical profiles for particle size analysis. Sand and gravel fractions were sieved and silt and clay fractions were determined by pipette analysis (Soil Conservation Service, 1972). Particle size data were used to verify field estimates of texture, confirm boundaries between lithofacies identified by field criteria, test vertical profiles for the presence of textural discontinuities, and establish soil morphologic properties and horizon designations. ·These data are the basis for interpretation of physical stratigraphy, chronology, and landscape evolution.

The compilation of revised geologic maps utilizes previously published geological reports and maps, available geotechnical data of the U. S. Army Corps of Engineers and La. Department of Transportation and Development, water well records of Federal and State agencies, and published and file data of the U. S. Department of Agriculture, Soil Conservation Service. Geologic interpretations are checked with color-

TABLE 3 - Abbreviations used in stratigraphic tables

HORIZON designations and descriptive terms are adapted from Soil Survey Staff (1975) COLOR notations from Munsell Soil Colors TEXTURE G - gravel; S - sand; Si - silt; C - clay; L - loam; fn - fine; med - medium; cse -

coarse; v - very STRUCTURE ab - angular blocky; gr - granular; pty - platy; sab - subangular blocky; tn - thin; vfn -

very fine; fn - fine; med - medium; cse - coarse; mod - moderate; wk - weak CONSISTENCE 10 - loose; vfr - very friable; fr - friable; fm - firm; slhd - slightly hard; hd - hard; vhd -

very hard; slpl - slightly plastic HORIZON BOUNDARIES ab - abrupt; cI- clear; gr - gradual; df - diffuse COMMENTS abun - abundant; - bur; worm b-urrows; C flm - clay films; char - charcoal; cont C flm -

continuous clay films; conc - concretions; disc C flm - discontinuous clay films; frag -fragments; lam -laminations; lame -lamellae; nod - nodules; plin - plinthite; popores; pock - pockets; rot - rotted; rt - roots; sat - water saturated; scat - scattered; slick - slickensides; st - stains; tb - tubes; tng - tongues; tr - traces wd - wood

PARTICLE SIZE data calculated on weight percent of < 2mm fraction SAND - percent sand (2mm to 0.05 mm); SILT - percent silt (0.05 to 0.002 mm); CLAY - percent clay «0.002 mm)

infrared imagery, color photography, 9 x 9 inch black and white stereo photography, and soil survey data. Field mapping is conducted by inspecting exposures and collecting cores to check the consistency of geologic interpretations and attempt to resolve specific mapping problems not readily evident from the interpretations of eXisting information. Existing and newly collected data are correlated into a stratigraphic scheme consistent with the existing StratigraphiC Column for Louisiana (LGS, 1992) (fable 2).

Compilation of revised maps are on a base of modern 1:24,000 USGS topographic quadrangles. Geologic contacts are drawn directly on an overlay at the base map scale. The initial step is to separate areas of Tertiary Upland, Pleistocene erosional landscapes, Pleistocene constructional landscapes, and Holocene alluvium. Internal subdivisions of these major units provide additional detail as to the character of the landscape and the nature of the underlying sediments. Once the geologic units are compiled on the overlays, the data can be recompiled onto a regional maps at 1:500,000, 1:250,000, or 1:100,000 base scale.

Landscape Evolution Concepts Landscape evolution models applied to the LRRV, LMV, and GCP can be evaluated and compared by summarizing their historical development and usage. Pertinent areas of discussion are the development of 1) previous terrace concepts, and 2) present landform evolution concepts.

Previous Terrace Concepts Investigations into the nature and distribution of the Quaternary deposits of the northern GCP have produced highly diverse interpretations of the number of terraces and the depositional environments of the underlying sediments. Although some of these differences have been resolved, disagreements still persist over the number, nature, and distribution of the various units.

Early naturalists who wrote about the LMV (Carpenter, 1838; Lyell, 1849) were awed by the massive bluffs exposed along the valley walls of the Mississippi River. They recognized loess and the Pleistocene age of exposed sedimentary sequences. The drowned nature of many of the modern valleys were noticed and fluctuation in base level was recognized as responsible for many of the sedimentary deposits and their relative topographic positions.

Hilgard(1860) produced a landmark overview of the surficial geology and soils of the State of Mississippi. In this classic work, he discussed the distribution of the Orange Sand, Bluff Formation, and Yellow Loam. These were the principal Quaternary units of his time. Subsequent investigations in Louisiana (Hilgard, 1869) included the Port Hudson Clays into his Quaternary sequence.

McGee (1891) described a preglaCial highland (Lafayette Formation) composed of coarse-grained sediments and a glacial age lowland (Columbia Formation) consisting of finer grained sediments. Both units were correlated throughout the Gulf and Atlantic coastal plains. This correlation was supported in Louisiana by Clendenin (1896) and Harris and Veatch (1899).

Matson (1916) was the first to map the high-elevation sands and gravels as the Citronelle Formation. He considered the formation Pliocene in age based on faunal evidence from the type locality in southern Alabama. Matson (1916) claimed that in Louisiana, the Citronelle Formation unconformably overliesMioceneandolderformations,andisunconformably overlain by Pleistocene terraces. He considered the Citronelle fluvial in origin and the topography of its outcrop area a set of terraced plains formed in response to a gentle uplift of the land.

Chawner (1936) conducted surficial geologiC mapping of Catahoula and Concordia Parishes in Louisiana. This geo-

12

w

ALLUViAL VALLEYS

rlit\\{\~~ti~~l PRAIRIE TERRACE

F9 HILLS SECTION HIGHER TERRACES

~ MONTGOMERY'

mIIllIfIIIIl] BENTLEY

~ WILLIAN ...

JNrERTERRACE SLOPE: -

PHYSIOGRAPHY OF

GRANT AND LA SALLE

PARISHES SCALE

14ILESL -s= ...... ----= =MILES o Z .. 6 6 10

Figure 4 - Physiography of Grant and LaSalle Parishes (from Fisk, 1938a, p. 70)

100

D,t'-I--=::..::.::.:..::..-! illl!!.D

i . " ~

~ I ....

~

~ CUTi ~

-lOb ~ .... vtL

• 1tlI,_ 1oI0000Tt. -....

~~~ aTAU. \V PotJOtl

ADrE· N(JRqqm'At.. a<:AL£ 19 ()(~tr:

--Figure 5 - Generalized and diagrammetic relationships of Pleistocene materials across Red River, in vicinity of

Grant Parish (from Fisk, 1938a, p.lO).

GEOSYNCLINE

Mingo Po'n' ........

I GEOS~NCL1NE MARGIN I EPEIROGENIC MARGIN I

TRANSITION ZONE

EPEIROGENIC REGION

ZONE OF ISOS1'ATIC UPL.IFT

S\Jac~\Js1P.\.. f~O~ V

Figure 6 -Ideal profile section through delta showing regional effect of overloading at continental margin (from Fisk, 1940, p. 61).

14

logic mapping effort was completed at the same time Fisk began his initial field investigations in Grant and LaSalle Parishes, adjacent to Chawner's area. Chawner (1936) mapped the Citronelle Formation based on the lithostra tigraphic cri teria of Ma tson (1916), recognized loess deposits on the Sicily Island Hills, and considered the southern terminus of Macon Ridge at the town of Sicily Island to be a PleIstocene terrace of the lvfississippi River. Although Fisk (1938a) discusses the ideas of Chawner (1936), his stratigraphic scheme was promptly abandoned by Fisk (1938a) and never again given serious additional consideration.

Fisk (1938a, 1944) correlated the four surfaces he identified in central Louisiana as the Williana, Bentley, Montgomery, and Prairie (Fig. 4). He delineated these as terraces using geomorphic criteria, such as elevation, slope, drainage pattern, and degree of dissection. Each terrace formed in response to cyclic glacio-eustatic shifts in sea level contemporaneous with uplift of the land, producing a sequence of cyclic entrenchments followed by alluviation (Fisk, 1938b, 1944). By the time of his classic monograph, Fisk (1944) extended his Quaternary terrace model from the LRRV to all of the LMV and much of the GCP.

Fisk believed that stream valleys of the coastal plain were entrenched during Pleistocene glaCial stages and that the fill beneath each terrace was deposited during Pleistocene interglacial stages (Fig. 5). He described the terrace sediments as fluvial deposits that presently trend along modern valleys, and deltaic and coastal deposits that apprOXimately parallel the coast. He believed these sediments were largely derived from the glacial deposits of the northern Uni ted States (Fisk, 1944). According to his concept, terrace differentiation was possible because structural activity had influenced the slopes and elevation of the surfaces. He asserted that the terraces had been downwarped in the deltaic portion and uplifted inland from a hinge line (Fig. 6).

Doering (1956) concluded that four surficial coast-parallel Pleistocene formations were present: the Citronelle (Willi an a) , Lissie (Montgomery), Oberlin (Prairie), and Eunice. A fifth formation, the Duck Lake (Bentley), occurred stratigraphically between the Citronelle and Lissie but had no surface exposure. Using topographic criteria, Doering (1956, 1958) reevaluated Fisk's correlations and concluded that the Williana Terrace, which occurred at much lower elevations on the west side of the Mississippi Valley, was actually the Citronelle Formation and preglacial in age. He also indicated that Fisk's (1940) fluvial and coast-parallel terraces might not be correlative, and he considered the fluvial MontgomeryTerrace eqUivalent to the coast-parallel Prairie Terrace.

Leighton and Willman (1950) produced a significant challenge to the Fisk (1944) model. Their correlation of the Midwestern loess stratigraphic model into the LMV was incompatible with the Fisk (1944) terrace model. Leighton and Willman never resolved their differences with Fisk, but they successfully influenced subsequent workers to assess the number and distribution of loess stratigraphic units on adj acent geomorphic surfaces to estimate the age of the subloess alluvium.

Studies of smaller rivers such as the Sabine of LouisianaTexas (Bernard, 1950), and the Brazos of central Texas (Stricklin, 1961) focused on application of the methods and concepts of Fisk (1944) to drainage basins independent of the Mississippi River. Bernard (1950) concluded that the Sabine River terrace sequence was glacio-eustatically controlled, and added the Deweyville Terrace to Fisk's correlation scheme. Stricklin (1961) found a suite of terraces on the Brazos River of Texas above the Balcones Escarpment, but linked terrace development to climatic and sediment supply controls in the upper drainage basin. Stricklin was the first LSU graduate to conclude that processes other than those emphasized by Fisk were significant, thus suggesting a geographic boundary to Fisk's concept.

Present Landform Evolution Concepts Fisk's agnostics. Durham et al. (1967) proposed a concept for the Florida Parishes in southeastern Louisiana that marked a major digression from Fisk's model. In the western Florida Parishes they identified the Citronelle Formation, the Irene Terrace, and the Port Hickey Terrace. The Citronelle was considered a blanket fluvial deposit with an Appalachian source. The Port Hickey was identified as partly fluvial and partly deltaic. They believed the Irene Terrace was older than the Port Hickey but noted that its boundaries were difficult to determine. Isolated remnants of the Irene protrude as inliers through the Port Hickey surface, and faulting has obscured the original morphology of these surfaces. They believed that Doering (1956) had mistaken the escarpment of the Baton Rouge fault as the terrace contact between the Oberlin and the Eunice surface formations.

Durham et al. (1967) made two Significant pOints about Quaternary stratigraphy in the GCP. An en echelon set of growth faults was recognized in the region as having both surface and subsurface expression. According to Durham et al. (1967), Fisk (1938b) followed one of these faults when he mapped part of his Montgomery terrace. They also pointed out that any attempt at extending a local sequence to a regional correlation of Quaternary sediments and landforms is tentative a best. The investigations of Durham and his colleagues reflect a major turning point in thinking on Quaternary geology and geomorphology in the LMV and GCP.Although their field trip (Durhametal., 1967), did not produce a detailed alternate model, this work was a major dissention to Fisk's model.

Multiple causal mechanisms. Saucier (1974,1981; also see Saucier's section in Autin et al., 1991) produced critical overviews and updates of the Quaternary geology of the LMV subsequent to the work of Fisk. The body of Saucier's research to date emphasizes that base level change is responsible for most of the Quaternary landforms and deposits in the LMV. Four processes of base level changes are considered important: 1) variations in the rates and patterns of sediment yield, 2) glacio-eustatic changes in sea level, 3) tectonics, especially subsidence, and 4) climatic changes as they influenced stream discharges and patterns. The relative influence of given processes varies in space and time. This line of reasoning produced a major

15

expansion on the concept of glacio-eustatic control adopted by Fisk (1944). The interrelation of multiple causative mechanisms affecting Holocene fluvial system evolution are discussed by (Autin, 1989, 1993).

Modern loess stratigraphy. Alford and Miller (1985) recognized that glacial advance and retreat alone was inadequate to explain UvfV loess stratigraphy. They proposed a multiple-component model for LMV loess deposi tion and distribution which incorporated glaCial cyclicity with fluctuations in sea level, aggradation and entrenchment of alluvial deposits, the development of coastparallel terraces, and the pedogenesis of subaerial surfaces.

Miller et al. (1985) utilized this model to correlate loesses within the LMV (Fig. 7). Stratigraphic names were proposed for individual LMV loesses (see Miller in Autin et al. 1991). Miller correlated the uppermost LMV loess, deposited 22 to 9 ka, to Peoria Loess of the midwestern United States. His model deviates from previous stratigraphic concepts with the recognition of an early Wisconsinan loess with TL ages of 75 to 95 ka at Vicksburg (Pye and Johnson, 1988). Miller etal. (1985) named this the Sicily Island Loess after a section described in the Sicily Island Hills. The LMV pre-Sangamonian

N

loess, Crowley's Ridge Loess, is the fourth loess on Crowley'S Ridge, found stratigraphically below Peoria, Roxana, and Sicily Island Loess (see Miller in Autin et al. 1991). A fifth loess-like silt on Crowley's Ridge was named the Mariana Loess, but has yet to be documented as a loess.

Miller's model shows a progressive southward pinching out of individual loess sheets. Marianna Loess is found only on Crowley's Ridge. The Roxana Loess thins from Crowley's Ridge to northern MiSSissippi, where it becomes too thin to exceed the thickness of the basal mixing zone between Peoria and Sicily Island Loess at Vicksburg. This is followed by the disappearance of Crowley's Ridge Loess by the vicinity of Natchez, and finally Sicily Island Loess loses its surficial expression in southern Louisiana, leaving only Peoria Loess on the Prairie Complex south of Baton Rouge.

Although many tenets ofthe Miller loess model for the LMV are still disputed, the distribution data and relative stratigraphic sequence provides a powerful tool for correlation and relative age estimation of Quaternary deposits in the LMV. Thin loess veneers, loess-derived and loess-influenced colluvial deposi ts distal to the axis of the LMV are correlated to the thick loess areas (see Autin et al., contributed artcle,

s Sicily Island Turkey Creek Irene

Louisiana Louisiana Louisiana .L.I'V' ..... ..I.0.J.U...l.LQ .J....4vu.~O.1.a.1la.

1I,,<>-5i11 III LG--lil IIlrrJ" I A II ~G-~ II K III lG-Sili Iii" ~ -1111 <:::: III" III 0

10

Peoria Loess 5

, •• I. I •• , '- 20

Sicily Island Loess

30

10 ~ Q.I

(J S 40

15 50

Hmm3 Mississippi River Meander Belt 3

mm LG Loessial Geosols Preloess Geosols

60

20-1 IDEPTII OF SOIL UG Upland Complex DEVELOPMENT IG Intermediate Complex

PG Prairie Complex 70

DG Deweyville Complex

Figure 7 - Lower Mississippi Valley loess correlations (adapted from Autin et 01./ 1991)

16

..... Q.I Q.I

'+-4

this guidebook). Many modern Soil Surveys clearly show surface soils with silty loess-derived parent materials that help to correlate landscape components into geologic maps.

Allostratig raphy. Alloformations, unconformity bounded stratigraphic units (North American Commission on Stratigraphic Nomenclature, 1983), were introduced into the LMV and GCP in recent years (Autinetal., 1988;Autin, 1992). An alloformation is a three-dimensional body of lithofacies differentiated primarily by unconformities (Autin, 1992). Allostratigraphic units provide a convenient method to depict geneticallyassociated, three-dimensional sediment bodies ofheterogeneouslithology as mappable surficial geologic units. The Mt. Pleasant BluffAlloformation (Autinetal., 1988) was defined as Wisconsinan Mississippi River meander belt deposits of the Prairie Complex. Subseq uent investiga tions suggest that the Mt. Pleasant Bluff deposits can be correlated to comparable deposits beneath the Avoyelles Prairie (Stop 9, this guidebook) and along the western valley wall of the Mississippi River in southwest Louisiana. A sequence of Holocene alloformations were defined in the middle Amite River of southeastern Louisiana (Autin, 1989, 1992). This sequence was correlated into Amite River tributaries of East Baton Rouge Parish (Autin and McCulloh, 1991) and the Tunica Hills of southeastern Louisiana (Autin and McCulloh, 1992). Examples of how an allostratigraphic approach can integrate stratigraphic and archaeologic data are provided by P. V. Heinrich in a contributed note to this guidebook. Mapping in the LRRV suggests that constructional alluvial deposits beneath the Montgomery Terrace and Aloha Prairie Terrace of Fisk (1938a) can be considered alloformations (Stops 2 and 3, this guidebook).

The allostratigraphic approach adopted in the LMV, GCP, and LRRV has both similar and dissimilar aspects to current investigations of alluvial deposits in other areas of North America. Bettis (1990) revised the Holocene alluvial stratigra phy of the DeForest Formation ofIowa (Daniels et al. 1963) and established the Gunder, Roberts Creek, and Camp Creek 11embers. The lithostratigaphic members of the DeForest Formation are recognized byvaria tions in lithofacies characteristics of over bank deposits, relative pedogenic expression, and cross cutting geomorphic surfaces and associated unconformities. Hajic (1989) assessed the Late Quaternary evolution of the Illinois River valley by incorporating lithofacies, pedogenic, and geomorphic criteria to define informal landform-sediment associations. Bettis (1992) used landform-sediment assemblages to explain the expected distribution of cultural materials in the Des Moines river valley of central Iowa. These informal stra tigra phic units are analogous to morpho stratigraphic units as defined by Willman and Frye (1970). Blum (1992) defined allostratigraphic units in the Late Wisconsinan and Holocene deposits of the Colorado Ri ver of Texas. Criteria incl ude the nature and character of boundary unconformities, relative expression of geomorphic surfaces, and relative pedogenic development. The allostratigraphic units were related to sequence stratigraphic concepts.

Each of these examples of alluvial stratigraphic units are conceptually related to the Mt. Pleasant Bluff Alloformation and the Amite River alloformation sequence. All approaches

differ slightly in that they are individual attempts to define stratigraphic successions applicable to investigations of a distinct area. All units defined by these studies fall into the lithogenic stratigraphic unit category (Harland, 1992). Formal stratigraphic nomenclature applied to sedimentarysuccessions are intended to foster definitions for the purpose of communication,nottorestrictstratigraphicunitsintoc1asses nor constrain appropriate styles and methods of producing objective, replicable correlation schemes.

Stratigraphy and landscape Evolution of the lower Red River Valley

Initial steps towards revisions of the Geologic Map of louisiana (Snead and McCulloh, 1984) are resulting in modifications of the definitions and delineation of Quaternary map units and refinement of the Quaternary stratigraphic column. Polygons are being drawn on 1:24,OOO-scale topographic maps, some with 5-foot contour intervals in areas of low relief. New geologic units are beingdefinedorredefined, and acceptable pre-existing units are being defined with greater stratigraphic formality. It is anticipated that a defendable time-space correlation of geomorphic surfaces, lithostratigraphic, allostratigraphic, and soil stratigraphic units will evolve. The following summary describes the present status of regionally significant Quaternary geologic units and the prevailing concepts concerning their distribution, origin, and age.

The Upland Complex

17

Evolution of the Upland Complex was initiated by deposition of the Citronelle Formation and its equivalents on a set of Tertiary erosion surfaces. In the GCP, the Citronelle Formation and its equivalents post date the Fleming Group, and a regional unconformity separates the units. The nature of this unconformity is abrupt and easy to recognize in most places, but com plex facies relationshi ps make delineation of this boundary difficult in some areas. It is possible that Citronelle depOSition was locally on uneroded constructional surfaces. The Citronelle Formation and its equivalents were deposited primarily by a set of braided rivers that coalesced to form alluvial aprons during the Pliocene and early Pleistocene. The possible causes for the deposition of this unit are poorly understood. Climatic, eustatic, and tectonic mechanisms have been previously inferred.

A regionally pervasive geosol has been identified within the weathering profile at the upper boundary of the Upland Complex. This geosol has been informally named the Jackson geosol in the Florida Parishes (see Autin et al., contributed note to this guidebook) and the Upland geosol (Autin et al., 1991). This geosol has been recognized from east Texas to west Florida and throughout the LMV. It typically classifies as a Paleudult developed from intense long-duration weathering of sandy to loamy parent materials. Its morphology indicates surface exposure and pedogenic development in an upland forest setting over timescales probably much greater than 1()4 to 105 years. Soil morphology is grossly similar to soils developed in sandyTertiaryandsomeyounger Pleistocene parent materials.

On most stable landsca pes, the Upland Complex is buried by veneers of loess, silty colluvium, and/or cover sands. The patterns of veneer deposits are locally landscape dependent (Washer and Collins, 1988), but they can serve as local recognition criteria where identified. Erosional stripping of the Jackson geosol and burial by a mappable thickness of coIl uvi urn has been considered as recogni tion criteria for the Intermediate Complex in southeastern Louisiana (see Autin et al., contributed note to this guidebook).

In summary, the Upland Complex can be defined as the Citronelle Formation and its equivalents, with an upper bounding geosol that is commonly buried by a veneer of either loess, colluvium, and/or cover sand. The Citronelle Formation and its equivalents unconformably overly the Miocene Fleming Group and older formations of the CGP, LMV, and LRRV. Based on this definition, the Upland Complex occurs from at least east Texas to west Florida, and throughout the LMV.Its evolution probably represents much of early Pleistocene time.

The Intermediate Complex The Intermediate Complex (Intermediate Terraces) was originally defined by Snead and McCulloh (1984) to include surfaces lower and less mature than the Upland Complex (High Terraces) but higher than the Prairie Complex. It generally consists of Fisk's fluvial Montgomery Terrace in valleys and lower Bentley and Montgomery Terraces in coast-parallel areas. Analysis of the distribu tion of the Intermediate Complex as mapped by Saucier and Snead (1989) suggests 1) no clear definition is available to identify the unit's morphologic, lithologic, or pedologic properties; 2) the regional distribution consists of both erosional and constructional surfaces; 3) criteria for correlations beyond local areas into regionally consistent definitions are unclear; and 4) the probable age of landform development is postCitronelle Formation (early Pleistocene) and pre-Sicily Island Loess (early Wisconsinan).

The morphologic properties of the Intermediate Complex were previously discussed byMatson (1916) and Fisk (1938a, 1939, 1940, 1944). The unit has been partly defined and recorrelated in parts of the Florida Parishes (Autin and McCulloh, 1991, 1992), and has been correlated to the Prairie Complex in northeast Louisiana (Saucier and Snead, 1989). The Intermediate Complex is still presently mapped in the Red, Calcasieu, and Sabine River drainage basins as a modification of Fisk's terrace sequence. The sedimentary sequence is described as a fining-upward sequence in the classic literature (Fisk, 1938a, 1939, 1940, 1944), however, prediction of a sediment sequence from local landscape features is difficult. Soil Surveys recognize areas with surface soils common to the Upland Complex and other areas with surface soils common to the Prairie Complex.

Erosion surfaces have been recognized and mapped in the Florida Parishes of southeastern Louisiana and recognized in southwest Louisiana and central Louisiana. The erosion surfaces are probably best expressed along coast-parallel belts. Constructional aggradation surfaces are recognized in the LRRV (Stop 2, this gUidebook).

In summary, the Intermedia te Complex is an enigmatic, but regionally distributed Quaternary unit. Detailed local stratigraphic investigations are needed to systematically redefine its distribution and properties.

The Prairie Complex The Prairie Complex consists of a multiple set of regionally distinctive geomorphic surfaces. The morphology of Prairie Complex geomorphic surfaces are typically constructional and the unit's topographic patterns commonly reflect underlying lithofacies patterns. Burial by loess and other veneer deposits does little to diminish prominent ridge and swale topography (See Stop 9, this gUidebook). Dissection along the edges of escarpments can sometimes subdue or modify topographic patterns, but dissection can also enhance the recognition of original constructional topography.

Soils of the Prairie Complex are lithofacies and source area dependent. Soils formed from point bar and meander belt deposits are commonly sandy to loamy on ridges and may be clayey in swales. Levee soils are silty, whereas, flood basin soils are clayey. The degree of morphologic expression is probably a function of parent material texture, water table history during alluvial aggradation, and weathering subsequent to terrace development. Parent materials derived from the Mississi ppi River are alkaline, and smecti te clay minerals are common. The Red River produces alkaline red bed parent rna terial wi th a mixed clay mineralogy. Coastal plain streams commonly produce acidic parent materials with mixed or siliceous clay mineralogy.

Genetically-associated lithofacies within the Prairie Complex can be mapped as allostratigraphic units where sufficient data is available. Constructional alluvial units of late middle Pleistocene to late vVisconsinan age have been described (Autin et al., 1991). Lithologic heterogeneity resulting from the deposition of alluvial, deltaic, and coastal deposits makes lithostratigraphic definitions impractical. Additional investigations are necessary to define the spatial and temporal distribution of alloformations prior to defining the Prairie Complex as a stratigraphiC group.

Wisconsinan and pre-Wisconsinan units probably correlative with the Prairie Complex have been identified in the marine record of the Gulf of Mexico (Suter et al., 1987; Heinrich, personal comm unication). Marine and subsurface continental units in Louisiana have updip equivalents that have not been accurately defined. General correlations have been offered for Prairie Complex equivalents in the Texas coastal area (Winker, 1991).

Three surface stratigraphic units of the Prairie Complex have been identified in the GCP and LMV. The oldest is the Lower Prairie Facies, Upper Surface (unnamed), a unit apparently equivalent to the Sangamonian Prairie of Saucier (1977) beneath New Orleans and the Upper Prairie of the LRRV (Smith and Russ, 1974). The closest thing to a stratotype for this unit in the LMV are the alluvial beds at Irene beneath the Sicily Island Loess (Milleretal., 1985) and the strata beneath the Lower Paleosol at Mt. Pleasant Bluff (Autin et al., 1988). This unit needs more stratigraphic work to precisely define

18

its stratigraphic distribution and properties.

The Wisconsinan strata of the Prairie Complex are regionally extensive and comprise large areas of the mappable geomorphic surfaces of the Prairie Complex in Louisiana. The Mt. Pleasant Bluff Alloformation has been identified in the western part of East Baton Rouge Parish as part of the Wisconsinan Prairie Complex, lower surface (Autin and McCulloh, 1991). Its correlatives incl ude areas delineated as the Lafayette meander belt (Fisk and McFarlan, 1955), and Pleistocene deposits uplifted by the Five Islands salt dome chain in south-central Louisiana (Autin, 1984; Autin et al., 1986; Autin and McCulloh, 1993). It is also possibly an updip equivalent to Wisconsinan deltas identified on the continental shelf of the Gulf of Mexico (Suter et al., 1987). The Avoyelles Prairie (Stop 9, this guidebook) is correlative to the Mt. Pleasant BluffAlloformationdefined in southeastern Louisiana. No definitive correlatives have been identified upvalley ofthe Avoyelles Prairie. The Aloha Alloformation ofthe LRRVand its apparently equivalent Red River channel belts in southwestern Louisiana west ofthe Lafayette meander belt (Fisk and McFarlan, 1955; Autin et al., 1991) is also a Wisconsinan unit. Other probable stratigraphic equivalents include the Wisconsinan sand sheet of the Florida Parishes (Mossa and Autin, 1989) capped by the PG-1 geosol (Autin et al., 1991), the Wisconsinan Prairie Complex of southwestern Louisiana (Birdseye and Aronow, 1991), the Prairie Complex, Lower Surface (Autin and McCulloh,1991, 1992) of southeastern Louisiana, and the Little River Valley (LGS, geologic mapping file data).

The youngest stratigraphic unit of the continental Prairie Complex appears to be the lowest coast parallel Prairie Terraces surface (Snead and McCulloh, 1984). This unit is capped by the PG-2 geosol (Autin et al., 1991) in coastparallel areas, however, its stratigraphic distribution, properties, age, and origin remain mostly speculative.

In summary, the Prairie Complex is a diachronous set of constructional geomorphic surfaces that likely express a regional distribution of allostratigraphic units. Presently, the distribution and properties of the various alloformations that comprise the Prairie Complex are incompletely defined. Coast-parallel deposits of the Prairie Complex appear to, in part, be glaCio-eustatically influenced. However, the effects of other influences have not been fully identified.

The Deweyville Complex The geomorphic surface of the Deweyville Complex has been mapped at a couple oflocations in the LRRV (Snead and JvrcCulloh, 1984; LGS geologic mapping file data). However, no stratigraphic investigations have been conducted to identify facies patterns, constrain relative age relationships, or define possible causal mechanisms. The Deweyville Complex is a stratigraphic unit that needs considerable work, both on a local and regional scale.

Holocene LRRV Meander Belts HolocenemeanderbeltsintheLRRVwereoriginallymapped by Russ (1975), then updated and simplified by Saucier and Snead (1989). Cross-cutting relationships and evidence for

multiple occupations of channel courses in the LRRVare highly complex. Typical correlation problems associated with Holocene alluvium in the LRRV are discussed in the companion paper of Pearson and Hunter in this guidebook (see also Stops 5, 7, and 8).

Status of the Present Model -A Step Towards a Regional Synthes'is

Strengths of the Model The application of a multiple stratigraphic approach to regional investigations of Quaternary sediments, soils, and landforms provides a way for physical stratigraphic criteria to be cross-correlated. The stratigraphic approach outlined in this guidebook integrates stratigraphic and landscape evolution by considering the integration of correlations at various temporal and spatial scales. Hopefully, this approach will eventually improve stratigraphic definitions and refine the regional Quaternary stratigraphy.

The long term goal of this effort is to produce a formal stratigraphic nomenclature, using definition criteria relevant to acceptable stratigraphic procedures and codes. The purpose is to define map unit criteria and foster precise communication of data, observations, and inferences.

Shortcomings and The Need for Additional Testing There are present geographic gaps ip the LGS geologic mapping data base. The Florida Parishes of southeastern Louisiana, the LRRV, and LMV are areas where new ideas and information are emerging, whereas, southwestern Louisiana needs additional work and new data. The LGS mapping effort needs stronger collaboration with Quaternary scientists in surrounding states in the region.

A relative chronology is emerging, but numerical age estimates are lacking. Most temporal inferences need to be seriously questioned. The best chronologies available are from the LMV delta and Peoria Loess. The emerging conceptual stratigraphic model is producing a physical stratigraphic framework. Paleontological and archeological records need to be closely integrated with physical stratigraphy to address paleoenvironmental questions.

The LRRV stratigraphy is complex, and correlation of units at this time are considered internal to the LRRV region and not automatically applicable to the LMV and GCP. Interregional inferences prOVided in this guidebook are considered tentative and reqUire additional investigation.

The Ideas of Harold N. Fisk The following set of concepts were developed after being posed the idea of creating my "Best of ... " and "Worst of ... " lists regarding the concepts and ideas of H. N. Fisk's body of published work. This is my list, influenced by the cumulative effect of countless conversations since 1977, the timeof my initial viewing of Fisk (1944). It reflects my comprehension of a great man's scientific accomplishments and his

19

lasting influence a couple of generations later. The things I note are partly based on the things I focus on, however, the writings ofH. N. Fisk provide countless additional examples throughout his prolific and profound work.

First the Worst 1. Fisk rejected the mapping of the Citronelle Formation

introduced by Matson (1916) and mapped by Chawner (1936) in Catahoula Parish, adjacent to Grant and LaSalle Parishes. The Citronelle outcrop area became the Williana and Bentley Terraces.

2. Four Pleistocene units were requisite to Fisk's concept, so the LNfV and GCP Quaternary sequences could be correlated to the four continental glaciations of the Midwestern United States.

3. Glacio-eustasy was considered the only causal mechanism regulating cycles of fluvial aggradation and degradation.

4. Fisk thought that all Pleistocene Terraces developed by identical patterns and processes of alluviation under comparable alluvial, deltaic, and coastal regimes.

5. Valid stratigraphic correlations were established locally, but many regional correlations were geographically overextended.

6. Fisk inferred that each aggradational episode was reflected by a fining upward cycle. Sedimentary and stratigraphic anomalies were generally dismissed by calling on post-depositional erosion and/or uplift.

7. Fisk failed to recognize multiple paleosols within nearsurface sequences. Pedogenic mixing zones, colluvial wash layers, and loess was generally considered as part of the fine-grained component associated with underlying coarse-grained alluvium.

8. Fisk failed to recognize the eolian origin of loess and the application of loess stratigraphy as a correlation tool when associated with constructional geomorphic surfaces.

9. Fisk failed to recognize an extensive set of early to middle Pleistocene erosion surfaces developed on the Citronelle Formation and the associated colluvial deposits. The erosion surfaces are especially significant and mappable in the coast-parallel region of the GCP. Many of these areas became the Montgomery and/or Bentley Terraces.

10. Fisk and his colleagues conducted investigations designed to tacitly reject alternate models proposed by others, not test his model against the alternates with objectively designed field studies.

Then the Best 1. The regional delineation of the Prairie Terrace has not

been substantially modified since the 1940's, despite

20

over 50 years of investigation by subsequent researchers.

2. Fisk recognized that the Prairie had a suite of paleoenvironments directly analogous to the distribution of modern depositional systems.

3. Many of the mapping contacts delineated by Fisk, his students, and his colleagues that applied his model are at major, regionally significant geomorphic, stratigraphic, and/or structural boundaries.

4. Fisk recognized that constructional alluvial landforms were associated with specific depositional lithofacies geometries.

5. lvfodern age estimates indicate that Prairie Complex aggrada tion culminated in the Wisconsinan (Peorian to Fisk), and relative age relationships indicate that aggradation of the Red River's Intermediate Complex (Montgomery of Fisk) culminated by middle Pleistocene to Sangamonian time.

6. The distribution of the Montgomery Terrace in the Lower Red River Valley as a constructional geomorphic surface was accurately mapped and interpreted.

7. Recognition of the Red versus Mississippi River origins of Holocene and Late Pleistocene deposits were accurately interpreted and delineated.

8. Fisk locally recognized the Avoyelles Prairie as a MissiSSippi River meander belt and nearby Belle D'eau as the boundary between the MissiSSippi and Red River deposits of the Prairie Complex.

9. Fisk described the hinge line as the position where all uvial sequences expand in thickness due to subsidence to the south and associated uplift to the north.

10. Fisk noted that the Prairie Terraces of the Red, MiSSiSSippi, Calcasieu, and Little Rivers had different lithostratigraphic characteristics associated with sediments derived from different source areas.

References Alford, J. J., Kolb, C. R., and Holmes, J. C., 1983, Terrace

stratigraphy in the Tunica Hills of Louisiana: Quaternary Research, v. 19. p. 55-63.

Alford, J. J., and Holmes, J. C., 1985, Meander scars as evidence of major climate changes in southwest Louisiana: Annals of the Association of American Geographers, v. 75, no. 3, p. 395-403.

Alford, J. J., and Miller, B. J., 1985, Loesses in the Lower Mississippi Valley: I. A multiple -component model for their deposition and distribution: Agronomy Abstracts, p.188.

Alt,D., 1974, Arid climate control of Miocene sedimentation and origin of modern drainage, southeastern United States, in Oaks, Jr., R. Q., and Dubar, J. R., eds., PostMiocene Stratigraphy, Central and Southern Atlantic Coastal Plain: Utah State University Press, p. 21-29.

AsIan, A., and Autin, W. J., 1992, Holocene flood plain soil formation in the Lower Mississippi River Valley: Implica tions for the interpret a tion of all uvial paleosols: Geological Society of America Abstracts with Programs, v. 24, no. 7, p. A228.

Autin, W.]., 1993, Influences of relative sea level rise and Mississippi delta evolution on the Holocene middle Amite River, southeastern Louisiana: Quaternary Research, v. 39, p. 68-74.

Autin, W. J., 1992, Use of alloformations for definition of Holocene meander belts in the middle Amite River, southeastern Louisiana: Geological Society of America Bulletin, v. 104, p. 233-41.

Autin, W.J., 1989, Geomorphic and Stratigraphic Evolution of the Middle Amite River Valley, Southeastern louisiana: Ph.D. dissertation, Louisiana State University, Baton Rouge, 177 p.

Autin, W.J., 1984, Geologic significance ofland subsidence atJefferson Island, Louisiana: Gulf Coast Association of Geological Societies Transactions, v. 34, p. 293-309.

Autin, W.J., and McCulloh, R. P., 1993, Quaternary geology of Weeks and Cote Blanche Islands salt domes: Louisiana Geological Survey, Open File Series No. 93-01, 44 p.

Autin, W. J., and McCulloh, R. P., compilers, 1992, New Roads Geologic Quadrangle: Louisiana Geological Survey, Baton Rouge, scale 1:100,000.

Autin, W. J., Burns, S. A., Miller, B. J., Saucier, R. T., and Snead, J. I., 1991, Quaternary geology of the Lower Mississippi Valley in Morrison, R. B., ed., Quaternary non -glacial geology of the conterminous U ni ted States: Geological Society of America, Geology ofN orth America, v. K-2, p. 547-82.

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Autin, W.J., andlvfcCulloh, R. P., compilers, 1991, Geologic and derivative engineering-geology hazard maps of East Baton Rouge Parish, Louisiana: Louisiana Geological Survey, Open File Series No. 91-01, 1:24,000 scale, 34 sheets.

Autin, W. J., Davison, A. T., Miller, B. J., Day, W. J., and Schumacher, B. A., 1988, Exposure oflate Pleistocene meander-belt facies at Mt. Pleasant, Louisiana: Gulf Coast Association of Geological Societies Transactions, v. 38, p. 375-83.

Autin, W. J., McCulloh, R. P., and Davison, A. T., 1986, Quaternary geology of Avery Island, Louisiana: Gulf Coast Association of Geological Societies Transactions, v. 36, p. 379-90.

Bates, R. L., and Jackson, J. A., editors, 1983, Glossary of Geology: American Geological Institute, Alexandria, Va, 788 p.

Bernard, H.A.,1950, QuaternarygeologyofsoutheastTexas [Ph.D. dissertation]: Louisiana State University, Baton Rouge, 165 p.

Bettis, E. A., III, 1992, Soil morphologic properties and weathering zone characteristics as age indicators in Holocene alluvium in the upper Midwest in Holliday, V. T., ed., Soils in Archaeology: Smithsonian Institution Press, Washington, D. C., p. 119-44.

Bettis, E. A., III, 1990, Holocene alluvial stratigraphy of western Iowa in Bettis, E. A., III, ed., Holocene alluvial stratigraphy and selected aspects of the Quaternary history of western Iowa: Midwest Friends of the Pleistocene, 37th Field Conference, Iowa Quaternary Studies Group Contribution no. 36, p. 1-16.

Birdseye, R. U., and Aronow, S., 1991, New evidence for a young late Wisconsin age for the Prairie Formation in southwestern Louisiana: Geological Society of America Abstracts with Programs, v. 23, no. 5, p. A223.

Blum, M. D., 1992, Modern depositional environments and recent alluvial history of the lower colorado River, Gulf Coastal Plain of Texas [Ph.D. dissertation]: University of Texas, Austin, 286 p.

Carpenter, W.,1839,Accountofthebituminizationofwood in the human era: AmericanJournal of Science, v. 36, p.118-24.

Chawner, W. D., 1936, Geology of Catahoula and Concordia Parishes: Louisiana Geological Survey, Geological Bulletin 9, 232 p.

Clendenin, W. W., 1896, The Florida Parishes of east louisiana and the bluff, prairie, and hill lands of southwest Louisiana: Geological Survey of Louisiana, part 3, Louisiana State University, Experiment Station, Baton

Rouge, p. 186-200.

Coleman, S. M., Pierce, K. L., and Birkeland, P. W., 1987, Suggested terminology for Quaternary dating methods: Quaternary Research, v. 28, p. 314-19.

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Geoarchaeology of the Red River Valley

Charles E. Pearson and Donald G. Hunter

Introduction Archaeologists have long been aware that human cultural systems and the variability observed in these systems are inexorably tied to the natural environment. Thus, the study of the interrelationships between cultural systems, as manifest in the archaeological record, and various aspects of both the abiotic and biotic non-human environment has been an important element in archaeological research. These types of studies, at least as they are currently pursued, are not expressions of strict environmental determinism, but they do reflect the proposition that natural environments offer certain restrictions and choices to human populations and that these populations make certain selections from their environments dependent upon an array of sociocultural and technological factors. The patterns evident in these selections are of particular concern in understanding human adaptation.

The interrelationship between archaeology and geology is particularly evident, and interdisciplinary studies involving the two have been important for many years (cf. Butzer 1971). In recent years, the term "geoarchaeology" has been used to categorize those types of studies that focus on the interface between these two disciplines. The fairly recent introduction of this term, however, does not imply that these types of studies reflect a completely new area of research. Archaeologists, geologists, geographers, and others have long incorporated geoarchaeological approaches in the study of such phenomena as sediments at archaeological sites,lithic source areas, and the distribution of archaeological sites across soil types and landforms. Some of the earliest geoarchaeological studies were conducted in Louisiana. At about the same time that Harold Fisk was involved in his work on Pleistocene terraces in Louisiana, another young Louisiana State University professor, Fred B. Kniffen, workingwith geologist Richard]. Russell, was conducting a study of the distribution of archaeological sites across deltaic landforms in coastal Louisiana (Russell 1936; Kniffen 1936). Kniffen observed that archaeological sites containing different ceramic assemblages, presumably of different ages, were non-randomly distributed across Mississippi River deltaic landforms in Plaquemines and St. Bernard parishes. He used the archaeological site data to suggest a relative chronology of deltaic landforms in the area. Additionally, Kniffen commented on the consistent association of prehistoric sites with natural levee landforms and, further, he took cores at archaeological sites to collect information on subsidence

rates (Kniffen 1936:414). Just a few years later, in 1938, archaeologists, under the direction of]ames A. Ford, also at Louisiana State University, used augers at the Greenhouse site on the Avoyelles Prairie to locate and define deeply buried archaeological deposits (Ford 1951, Stein 1986). Subsequently, numerous researchers have followed these leads, and the study of the interrelationships of deltaic or alluvial landforms and prehistoric site locations, applying geological field techniques, has been one of the dominant themes in archaeolOgical research in the entire Lower Mississippi Valley region (e.g., Butzer 1977; Fisk 1944; Ford and Quimby 1945; Gagliano 1963; McIntire 1958; Phillips et al. 1951; Phillips 1970; Saucier 1963, 1974, 1981; Weinstein 1981; Weinstein and Gagliano 1985). As a result, the reasonably well known archaeological chronology has become an important basis for assigning dates to geological landforms, or, at least, arranging them in relative chronological sequences.

It is no accident that this settlement/landform approach has become important in the region. The current natural setting and past geomorphological history of deltaic and alluvial areas tend to dictate this type of research. Landform development and change in deltaic and alluvial areas occur at a very rapid rate, a rate which is really on a "human"scale, such that the impacts which these changes had on human occupants, in terms of the wide range of adjustments they had to make to these often extensive landscape changes, are observable in the archaeological record. These changes are commonly, and possibly most easily, observed in settlement distributions. Through time and across space, populations

. opted or were forced to shift habitations to more desirable settlement locations, either as new landforms developed or as old ones deteriorated. Other elements of the archaeolOgical record, of course, also express adaptive changes, and thus often can serve as measures of environmental change. Particularly important have been subsistence studies, which examine shifts in patterns of exploitation that can often be tied to areal environmental changes.

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The Red River region has been the object of extensive archaeological and geological research. Descriptions of the area's archaeological remains date from the late-nineteenth century (cf. Neuman 1970), but intensive examination of the area's archaeological sites did not begin until early in the present century with the work of Clarence B. Moore (1912). Traveling on his steamboat Gopher, Moore visi ted 21 prehistoric archaeological sites along the Red, almost all of which

contained earthen mounds, his major focus of interest (Moore 1912). In the 1920s and 30s, archaeological interest centered on the large mound complex found at the Marksville site and, later, at the nearby Greenhouse site (Seltzer 1933; Ford 1951; Fowke 1927, 1928; Toth 1977). Archaeological work at these, and a number of other prehistoric sites in the lower Red River region (e.g., Ford 1936; Ford and Willey 1940), led to the development of a cultural chronology based on ceramic assemblages which has served as the basic framework for the temporal ordering of archaeological sites in much of the lower Mississippi region.

At about this same time, research was focusing on archaeological sites along the Red River above Natchitoches, in the Caddoan cultural area. Clarence H. Webb, a Shreveport pedia trician, has been responsible for a considerable amount of our knowledge of the Caddoan area with his studies of the Gahagan Mound site (Webb and Dodd 1939); theSmithport Landing site (Webb 1963), the Belcher Mound site (Webb 1959), and Mounds Plantation (Webb and McKinney 1975).

Geoarchaeological approaches have often been em ployed in archaeological research along the Red, although the approach has not always been explicitly stated of formalized. For example, muchofthe archaeological work in the al1uvial valley has, at least, considered fluvial processes as important considerations, and many have involved correlating archaeological site distributions with identified channel chronologies. The extreme meander activity of the Red (discussed below) tends to make this approach to archaeological research in the alluvial valley critical, in terms of addreSSing questions about patterns of adaptation as observed in archaeological site distributions as well as in assessing the status of the archaeological record as it exists today. In terms of the latter concern, for example, the extensive reworking of landforms within a given meander belt of the Red River over time, can, and has, resulted in the removal of large portions of the archaeological record.

In the past 20 years, a considerable amount of the archaeological work undertaken along the Red River has been conducted relative to cultural resources management studies, mostly for Federal agencies. Unfortunately, the result of this research resides primarily in the "gray literature," and has been only minimally distributed. The great majority of the these cultural resources management projects, as well as other studies undertaken along the Red, have been spatially restricted, either to a single site, or to a fairly small area. Few have attempted to extend geoarchaeological interpretations over a wide area, and no comprehensive discussion of the geoarchaeology of the Red River has been undertaken. Despite this, the available information is sufficient to permit the development of general propositions about the geoarchaeology of the Red River, particularly as it relates to the distribution of human settlements across the landscape of the alluvial valley. No effort is made to discuss in detail such topics as sedimentary processes or soil characteristics at archaeological sites, which, while of importance, have received less attention in the alluvial valley than have studies dealing with the diachronic distribution of sites across the landscape. Nor is the geoarchaeology of the uplands surrounding the valley considered, since that topic is complex and requires much more space than is available here. In the

following discussions the Red River alluvial valley in both Arkansas and Louisiana is considered. A brief review of the cultural history of the alluvial valley as portrayed in the archaeological record is presented followed by a discussion of geology and geomorphology which emphasizes those factors critical to geoarchaeological research. This is followed by a discussion of two studies which exemplify geoarchaeological research in the Red River.

Prehistoric Archaeological Background

Paleo-Indian Period (10000 B.C-6500 B.C.) Scattered finds of diagnostic fluted, projectile po in ts, including Clovis, Scottsbluff, and Eden, indicate that the prehistoric occupation of the Red River region of central Louisiana began around 10,000 B.C during the Paleo-Indian period (Gagliano and Gregory 1965:Figure 1). It is presumed that these early populations maintained a highly mobile lifestyle, partially in pursuit of herds of now-extinct Pleistocene megafauna. In central Louisiana, the finds of Paleo-Indian projectile points have been confined to the Pleistocene terraces and older terrace remnants in the flood plain. During this time, peoples probably exploited the alluvial valley, but archaeological evidence of their activities wil1 have been buried by Holocene sediments. The Paleo-Indian period possibly lasted as late as 6,500 B.C., by which time post glacial warming trends and subsequent major changes in vegetation regimes and habitat loss saw the demise of Pleistocene fauna (Brain 1971:7; Smith 1986:5). Itis believed that at that time, Paleo-Indian populations shifted to the exploiting smaller game species, as evidenced by the appearance of smaller projectile points, including the San Patrice, Dalton, and Pelican. This shift marked the transition into the succeeding Archaic period.

Archaic Period (6500 B.C.-2000 B.C) In Louisiana, as throughout most of the present Eastern United States, the Archaic period marked a more sedentary lifestyle for North America's native inhabitants. Presumably, this occurred in response to a shift in dependance to local floral and faunal communities in the overall subsistence strategies after the Pleistocene megafauna had become extinct. Many of the stone tool types of the late Paleo-Indian period continued in use during the Archaic, although styles changed and became more diversified and localized through time. Many have argued that the Archaic is characterized by an increase in quantity and variety of ground-stone tools associated with plan t processing (Gregory and Curry 19 78:32-34), however, Smith (1986) indicates that is only apparent and not real, at least during the early portion of the Archaic period. A dramatic increase in the utilization of riverine aquatic species did occur among many Archaic populations occupying the river valleys and coastal areas of the Southeast. Shel1fish, in particular, were heavily utilized, as evidenced by the numerous Archaic Period shell midden sites. Throughout the Archaic period, sites became increasingly larger, indicating population expansion as communities began more efficiently exploiting the local environments. Long distance trade had began to develop by the Middle Archaic as evidenced by the appearance of exotic lithic materials, including galena, hematite, northern cherts, and

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some steatite. With these new materials came a host of new ground and polished stone artifacts, such as boatstones, bar weights, plummets, and stone beads (Gregory and Curry 1978: 33-34).

Sites occupied during the Archaic period along the Red River Valley in central and northwest Louisiana are primarily confined to the Pleistocene uplands bordering the Red River alluvial valley and on older surfaces within the margins of the flood plain. Many of these sites consist of small lithic scatters, possibly representing short-term camp sites or locations used primarily for lithic raw material procurement. Archaic populations surely used the Red River flood plain environments, but much of the evidence for their presence has been buried by sediments or removed by riverine erosion. The deeply buried Conley site on Loggy Bayou in Bienville Parish is one of the few known examples of Archaic occupation in the Red River flood plain.

Poverty Point Period (2000 B.C.-SOD B.C.) Around 2,000 B.C., many parts of the Lower Mississippi Valley witnessed the introduction of monumental earthen architecture, an apparent complex society, geometric earthworks, a microlithic tool assemblage, an elaborate lapidary industry, and earth oven cooking techniques utilizing baked clay balls. This cultural florescence has been labeled Poverty Point culture after the type site in West Carroll Parish in extreme northeastern Louisiana. This cultural development was apparently so rapid and seemingly without precedent in North America that archaeologists initially considered similarities to the cultures of South and Central America to support long-range trade or cultural diffusion. However, in the Red River Valley, the native inhabitants seem to have continued an Archaic lifestyle, little influenced by the cultural florescence transpiring to the east. Occasional Poverty Point "diagnostic" artifacts, including bar weights, plummets, pendants, and stone beads, occur in late Archaic sites in the central Louisiana area, but these seem merely to be a continuation of developments that began earlier during the Archaic period (Gregory and Curry 1978:37).

Tchula Period (500 B.C.-A.D.1) The Tchula Period (Tchefuncte culture) is marked by the appearance of a well-developed ceramic complex into the Lower Mississippi Valley. Although fiber-tempered pottery was utilized to a limited extent during the Poverty Point period, sites throughout most of the region had been basically aceramic. Tchefuncte pottery is fairly complex, manifesting a wide variety of vessel shapes and decorations. With the exception of these new ceramics, Tchefuncte artifacts seem to represent a continuation of older Archaic and Poverty Point types. Stemmed and notched projectile points are frequently found in Tchefuncte sites, as are bone projectile points, antler tools, and wide variety of bone implements. Ground stone tools include boatstones, bar weights, and plummets (Ford and Quimby 1945:52-72).

There are few well documented Tchula period sites in central Louisiana. John House (1972:49) reported several possible "Tchefuncte-related" sherds from the Lake Rodemacher

Basin approximately 10 km northwest of England Air Base. Gregory and Curry (1978:43) have noted a small number of Tchefuncte sites in Natchitoches and northern Rapides parishes. Lumped into what they have designated as Lena phase sites, these are primarily small concentrations or scatters of occupational debris, including several types of pottery, intermixed with occasional projectile points, tubular clay pipe fragments, and tools produced from silicified wood. Known sites are mainly located on the Pleistocene terraces flanking the alluvial valley or on terrace projections into marginal lakes (Gregory and Curry 1978:43).

Marksville Period (A.D. 1 -A.D. 400) Around A.D. I, the Lower MissiSSippi Valley saw the introduction of an elaborate mortuary complex and new ceramic types that bear considerable similarities to those of the northern Hopewellian cultures of Ohio and Illinois. In the Lower Mississippi Valley, this cultural development has been termed Marksville culture, named after the type site in Avoyelles Parish, Louisiana. The mortuary complex centered around interment of individuals in conical mounds, which were usually built in several stages of construction. Paramount individuals were sometimes placed in log tombs in association with platform pipes, quartz crystals, stone prOjectile points, articles made of Great Lakes copper, and ceramic vessels (Neuman 1984:153-163). Occasionally, cremations and secondary burials were placed in the mounds during various stages of construction. The ceramic complex manifested a variety of plain and decorated vessels. Decorative techniques commonly included wide V-shaped incisions, some of which bordered zones of dentate rocker stamping forming geometric or zoomorphic patterns (Neuman 1984:153-154). Numerous Marksville period sites have been reported in Avoyelles Parish situated both on the terrace edge and in the Red River and Mississippi River flood plains. A small number of these sites have been found in the Red River flood plain associated with early meander belt landforms.

Baytown Period (A.D. 400-A.D. 700) Perhaps one of the most poorly understood segments of Louisiana's prehistoric culture sequence is the Baytown period (Gibson 1982). This period is primarily marked by the disappearance of the elaborate Marksville mortuary complex and the appearance of new ceramic types, including Mulberry Creek Cord marked, Larto Red Filmed, and Woodville Zone Red. Apparently during that time, the construction of truncated pyramidal mounds, which became more numerous in the later periods, began. Although the use of the atlatl seems to have persisted into the Baytown period, arrowpoints first appeared during that time, indicating the introduction of the bow.

Numerous Baytown period sites are known to exist east of Alexandria in the Catahoula Lake, Black River, and Little River Drainages and in the vicinity of Marksville. Primarily these occur in alluvial valley settings or the edges of Pleistocene terrace inliers.

Coles Creek Period (A.D. 700-A.D. 1200) The Coles Creek period is marked by the appearance of new

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ceramic types, featuring a wide variety of incised, pinched, punctated, and stamped decorations. It was also during that time that the construction of truncated pyramidal mounds flourished, the mounds themselves serving both for mortuarypurposes and foundations for buildings, such as temples, residences of apparent high-status individuals, or charnel houses. Not only were Coles Creek burials made in mounds but also in cemeteries, and the burials, which were seldom accompanied by grave goods, displayed a wide variety of forms including flexed, disarticulated, extended, and isolated skulls. As with the earlier prehistoric periods, agriculture seems to have played little importance in the overall subsistence strategy of these people, though some cultigens may have been grown in limited quantities (Neuman 1984:213). Moreover, the old subsistence strategies, dating perhaps to the Archaic period, continued to be utilized throughout this entire culture period. Most of the reported Coles Creek sites in central Louisiana are situated in the alluvial valley or on the terrace edge.

Coles Creek sites in the Red River valley extend as far north as the area of Natchitoches, where a cultural boundary seems to have existed after about A.D. 500. Below Natchitoches, prehistoric populations in the Red River valley are cuI turally tied to the lower Mississippi River valley region, while above that point societies exhibiting a quite distinctive material cuI ture emerged.

Mississippi Period (A.D. 1200-A.D.1700) The cultural manifestation transpiring throughout much of the Lower Mississippi Valley during the Mississippi period is termed Plaquemine culture. Plaquemine seems to have developed out of the preceding Coles Creek culture, because Plaquemine ceramics seem to have antecedents in many of the former Coles Creek types (Neuman 1984:258). Like their apparent predecessors, Plaquemine peoples continued to construct extensive mound centers, featuring one or more truncated pyramidal mounds normally arranged around a large central plaza, and their burial patterns were similar to those practised by Coles Creek peoples. Many researchers view the emergence of Plaquemine culture as the result of Mississippian influences from the north and east on resident Coles Creek peoples (VVeinstein 1985). What differentiates Plaquemine culture from Mississippian culture is primarily the lack in the former of shell-tempered ceramics and cult items related to the Southeastern Ceremonial Complex. Apparent Mississippian influence on Plaquemine culture can been seen in the occasional occurrence of shell-tempered ceramics and cult motifs within otherwise typical Plaquemine artifact assemblages. Like their Coles Creek predecessors, Plaquemine peoples seemed to have lived both in the alluvial valley and on the margins of the Pleistocene terrace.

Caddoan Culture Around A.D. 900, Caddoan culture seems to have emerged in northwestern Louisiana wi th the developmen t of the Alto phase. Alto peoples apparently maintained a ranked SOCiopolitical structure governed by a military-religious hierarchy. Ceremonial centers featuring one or more conical mounds, were constructed, and these mounds served as

repositories for the dead social elite. Grave goods, including ceramic vessels, copper ornaments, large and delicately chipped bifaces (Gahagan knives), and massive zoomorphic pipes, were interred with paramount individuals in association with apparent sacrificial retainers (Webb and Dodd 1939; Webb and McKinney 1975). Many of the Alto ceramics are also found in Coles Creek contexts, evidencing an apparent close relationship between the two regions. However, the Alto phase was the time at which many well-made and finely engraved ceramic types appeared in the region along with new vessel shapes, including the long-necked water bottle. Although most of the work conducted at Alto centers has been undertaken at ceremonial centers, one Alto hamlet has been extensively investigated (Thomas et al. 1980). These investigations indicate that Alto peoples continued to utilize hunting and gathering techniques in their overall subsistence strategies, in addition to cultivating maize, squash, and gourd (Thomas et al. 1980:285). Furthermore, these investigations explored the non-social elite of the Alto phase who were probably more representative of the majority of the population at that time.

Arguments have been made that around A.D. 1200, the Caddoan peoples inhabiting much of northwest Louisiana largely abandoned the alluvial valley in favor of the bordering uplands. With this shift, came the abandonment of many of the former ceremonial centers and the evidently highly ranked social structure maintained bytheAlto peoples. Some mound groups continued to be occupied in the valley, but most sites were small and located in the hills along the terrace margin or along small streams. This change is equated with the Bossier phase. These arguments for the abandonment of the alluvial valley may be more apparent than real simply because many sites in the valley are buried by alluvium and have not been found. In recent years, increasing numbers of Caddoan sites of all ages have been found in the alluvial valley and, presumably, the evidence will eventually show a continued and constant use and occupation of flood plain environments.

Although some ofthe oldAlto ceramic types continued to be used during Bossier times, new ceramic types also emerged, and they generally lacked the quality in workmanship that was displayed on examples from the earlier era. Most Bossier burials were made in small, shallow pits at village sites. No large cemeteries or burial mounds are known. The majority of the burials were extended supine, and most Bossier burial associations were utilitarian ceramics. Specifically lacking are the ceremonial objects and artifacts manufactured from exotic materials, which are frequently associated with highstatus Alto burials (Webb 1948; Webb 1983).

An apparent rejuvenation of a highly ranked socioreligious hierarchy, and the introduction of new ceramic types in northwest Louisiana marked the beginnings of the Belcher phase around A.D. 1500. However, mounds were no longer being built to serve solely as repositories for the social elite, but also as foundations for temples and residences of highstatus individuals. Important individuals in the community were buried in mounds, and numerous grave goods accompanied these interments. However, unlike their Alto predecessors, few exotic materials were employed in the mortuary complex. The only non-local goods found in high-status

28

burials include shell ornaments, evidently derived from coastal sources. Several of these items are decorated with what are known as {(Southern cult" motifs, a distinctive iconography spread across the southeast at this time period, suggesting some amount of Mississippian influence (Webb 1959).

Caddoan populations occuppied the Red River region of northwestern Louisiana and southwestern Arkansas when European settlers began to move into the region in the eighteenth century. By the early decades of the nineteenth century, disease and warfare brought about by contact with Europeans had significantly reduced the Caddo population, and in 1835 they were removed from Louisiana by the American government.

Geology and Geomorpology of the Red River Alluvial Valley

Travelers and military men began to provide descriptions of the natural settingofthe Red River, its alluvial valley and the surrounding uplands in the first quarter of the nineteenth century (Darby 1816,1817; Fisk 1938:35-47; Stoddard 1812). Within the past 50 years, numerous professional studies have been conducted on the geology and geomorphology of the Red. Among the most significant of these early investigations were those of Harold Fisk on the geology of Grant and LaSalle parishes (1938) and Rapides and western Avoyelles parishes (1940), both of which are particularly important because of their discussions on the Pleistocene terraces features which border the alluvial valley. Fisk's interpretations are discussed by Autin in the first portion of this Guidebook. A series of other parish studies prOVide information on the regional geology, although they concentrate on the uplands, not the all uvial valley. These include studies for Webster Parish (Martin et al. 1954), DeSoto and Red River parishes (Murray 1948), and Catahoula and Concordia parishes (Chawner 1936).

In his Geological Investigation of the A lluvial Valley of the Lower Mississippi River, Fisk (1944) proVided a regional geological and geomorphic synthesis, which emphasized the chronological sequence of Mississippi River courses, but included the lower Red River region. Fisk's work has been reassessed by Roger Saucier (1974), although on a broader and more general scale. Saucier's access to recent archaeological and radiometric information has resulted in reinterpretation of a number of Fisk's conclusions (Saucier 1981).

Concurrent with Saucier's work, Oscar Abington (1973) described and quantified Red River's meander morphology and examined its hydrology, channel scour and fill processes, and utilized historical information to in terpret recent changes in the river's channel morphology. Later, in 1975, D. P. Russ, and subsequently, John Lenzer (1977) described the fluvial processes and deposits of the lower Red River in Louisiana. One of the most detailed and comprehensive studies of the geology of the Red River is contained within a series of geologic maps published by the U. S. Army Corps of Engineers, Waterways Experiment Station, in Vicksburg, Mississippi (Smith and Russ 1974). The recent geological map of the state of Louisiana has further defined the geological settings ofthe Red River area (Snead and McCulloh 1984)

as do Saucier and Snead (1989). Additionally, a considerable number of archaeological studies conducted for cultural resources management purposes, provide varying types of information on the geology and geomorphology of the Red River,mostparticularlyon thegeomorphologyandgeomorphic history of specific locations (e.g., Commonwealth and Associates, Inc., 1981; Gagliano et al. 1979; Gulf South Research Institute 1975; Pearson and Ducote 1979; Thomas et al 1980; Weinstein et al. 1979).

Frye and Leonard (1963) have presented discussions of Pleistocene geology and formations along the Texas portion of the Red. Their terminology and interpretations of Pleistocene and Holocene formations differ from those of the Louisiana researchers, making correlations difficult. Ludwig's (1972) study deals specifically with water resources, but it also provides maps and some minimal information on the recent geology of the Red River region in Arkansas.

The Geological Setting The Red River is formed in western Oklahoma by the juncture of the Prairie Dog Town Fork and the Salt Fork, which arise in northwestern Texas and northeastern New Mexico, respectively. The Red crosses Texas and, east of the Panhandle, forms the northern boundary of that state. In Arkansas, the river runs south of the Ouachita mountains; at the town of Fulton, the river makes a 90· turn to the south (the Great Bend), flowing south-southeast through Louisiana and eventually joining the MissiSSippi and Atchafalaya rivers.

In Arkansas and Louisiana, the Red River alluvial valley ranges from 5 to 30 km wide. Just north of Natchitoches, the valley is somewhat constricted as it cuts through relatively resistant rock formations of the Sabine uplift. At Natchitoches and just above the town of Boyce the river valley is severely constricted where it is incised through the high, dissected ridge systems known as the Nacodoches Wold and the Kisatchie Wold. Several faults cross the river valley in a general northeast-southwest direction. These are components of the south Arkansas and Rodess fault systems (Gulf South Research Institute 1975:121) and in places have displacements of as much as 65 m.

The river valley is bounded by formations of varying ages. North of Rapides Parish the western valley wall is primarily Tertiary, marine sedimentary rocks. South of Rapides Parish, portions of the western valley wall and most of the river's eastern boundary are uplands and terraces of Pleistocene, Red River fluvial deposits. The southeastern boundary of the alluvial plain is formed by the Teche Ridge, an abandoned, ancestral Mississippi River course (Lenzer 1977).

The uplands bordering the Red River alluvial valley are not of primary concern in the present discussion; they have been considered thoroughly in the foregoing section of this Guidebook. However, they are of interest to any archaeology conducted in the alluvial valley, because during both the prehistoric and historic period these uplands were important to those populations living on the valley flood plain. For example, the often extensive graveliferous deposits found in landforms associated with the early Pleistocene

29

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Figure 8 - Cross section of the Red River alluvial valley taken near Zimmerman Louisiana, showing typical flood plain features and stratigraphy (source: Smith and Russ 1974).

Upland Complex provided an important source of stone, particularly chert, for tools throughout much of the prehis. toric period. Other lithic resources, such as petrified wood and sedimentary quartzite which occur in Tertiary formations in the uplands, were also extensively exploited during the prehistoric period by the occupants of the alluvial valley (Heinrich 1986, 1987).

The alluvial valley slopes to the south at an average rate of less than 3 m per kilometer, and elevations range from 80 m above mean sea level near the Texas border to about 12 m near the mouth of the Black River (Gulf South Research Institute 1975:111). The modern alluvial valley lies ator near the flood level of the Red River and its tributaries. This modern Holocene formation is incised across older Pleistocene and Tertiary formations. Through Arkansas and most of Louisiana, the Red River meanders within its own alluvial

valley. However, about 28 km southeast of Alexandria, the river leaves its alluvial valley through Monda Gap and enters the Mississippi River Valley.

The Pleistocene history of the Red River is unique because it is the only major western tributary of the Mississippi River that was not directly influenced by mountain or continental glaciers (Frye and Leonard 1963:31). Therefore differences existed between the geomorphic processes operating on the Red River and those operating on the lower Mississippi River. For instance, although the typical Pleistocene pattern of episodes of valley deepening followed by valley alluviation occurred along the Red River, valley scourings were evidently more profound than alluviations due to a lack of available alluvial material from glacial outwash.

Available data suggest that the Red River has occupied its

30

present valley for approximately the last 12,000 or 14,000 years. During this period, the shifting river has spread meander belt and backswamp sediments over earlier graveliferous deposits (fig. 8). Approximately 12,000 years B.P., the flood plain of the lower Red River was 4 or 5 m below its present elevation; since that time the flood plain has slowly aggraded to its current level. This aggradation continued until artificial levee construction confined the river along much of its length, preventing overbank flooding and subsequent deposition of sediment.

Red River Alluvial Valley Geomorphology The modern alluvial valley floor is relatively flat, broken only by natural levees, old stream channels and lakes, and occasional erosional remnants of earlier geologic age. The numerous relict stream channels and cut-off lakes attest to the extreme meander activity of Red River in Arkansas and Louisiana, which, in part, appears to be related to the instability of Red River alluvial soils (Abington 1973:24). These characteristically reddish-brown soils tend to expand and shrink greatly when their moisture content changes, often resulting in dramatic and extensive collapse along river cutbanks. This process occurs especiaUywhen the river begins to drop after haVing been at or near a high-water stage. The tremendous number oftrees thrown into the river by this erosional process was partly responsible for the development of the extensive raft of trees and logs (the Great Raft) that partially blocked the Red River in Louisiana until its removal in the late nineteenth century (Abington 1973).

The heavy sediment load carried by the Red also contributes to its meander activity. These sediments, composed of approximately 25% sand and 75% silt, are derived primarily from bank and bed erosion upstream and, secondarily, from tributary streams (Ludwig 1972:34). The large amount of sediment in the river results in the rapid deposition of point bars, which in turn contributes to cutbank erosion (Abington 1973).

The extreme meander activity of the river is, of course, important to archaeologists. The continued abandonment of segments of the channel and their eventual filling, coupled with simple gradual shifts in the river course, result in the constant production of new land surfaces along the river, and the destruction of old surfaces and any archaeological sites they may have contained. No precise estimates are currently available as to the age, extent, or rate of formation of various river-associated surfaces along the entire Red River; however, in southwestern Arkansas itis suggested that at least 50% of the land surfaces within the modern meander belt of the Red River in that area are probably less than 400 years old (Pearson and Ducote 1979).

Another factor of Red River geomorphology pertinent to archaeology relates to several relatively recent events that have altered river gradient and, thus, processes of channel aggradation and degradation. Pearson (1986) suggested that about 1700 years B.P. the Red River diverted its course through the Monda Gap near Marksville, Louisiana, shorteningits course by about 45 km. Abington (1973) has argued that this diversion resulted in entrenchment of the channel and flood plain, the development of natural levees several

31

feet lower than those of the flpre-Moncla Gap Diversion" course, and the creation of channel obstructions in the form of extensive log jams or rafts. In addition, the Monda Gap diversion resulted in the development of a knickpoint (point of change in gradient) at the diversion site. Entrenchment caused the drainage of some former backswam p lakes (Murray 1948). The effect of the knickpoint migration was blocked partiall y by the resistant ridge of Miocene siltstone (Fleming Formation) at Alexandria. This ridge, locally known as the falls or rapids, was removed by the U. S. Army Corps of Engineers in 1892 and 1893, permitting knickpoint migration and entrenchment to continue upstream.

Further contributing to the entrenchment of the river was the final removal of the Red River rafts by the federal government in themid-1870s. These rafts, collectively known as the Great Raft, consisted of a complex of log jams that partially blocked the river above Alexandria, diverting it into numerous courses and causing large backswamp lakes. In the 1830s the raft stretched from north of Natchitoches for more than 100 mi upriver. Between 1828 and 1848, the Federal government undertook a major program of raft removal, and under the direction of Captain Henry Miller Shreve, much of the raft below Shreveport was removed (Mills 1978:21-22). Neglect of raft removal over the next several decades resulted in its reformation. In 1872, the Federal government again began raft removal. By 1873, a channel had been cut completely through the raft, and clearing and maintenance over the next few years essentially removed this obstruction (Mills 1978:54).

Raft clearance has resulted in drainage of many backswamp and /{rim" lakes, confinement of the river to a single channel, and increased entrenchment. During those years that the raft was extan t, aboriginal, as well as historic, settlement and use of the alluvial valley was partially controlled by the location, size and duration ofindividual raft lakes. Additionally, large numbers of archaeological sites are likely to have been covered by lake sediments as lakes formed or expanded (Commonwealth and Associates 1981:32). There is currently no reliable information available on the age, extent or configuration of the rafts or raft lakes prior to the historic period. Many, however, have argued or implied that the formation of rafts along the Red occurred in fairly recent times, possibly just prior to the coming of Europeans in the eighteenth century (Bagur n.d.). Abington (1973) implies raft formation was influenced by the Red's diversion through Monda Gap, which he assumed occurred about 500 years ago. If Pearson (1986) is correct, however, and the diversion took place doser to 1700 years ago, then the formation of rafts may have begun much earlier than is commonly thought. It seems likely that archaeology may prove to be the most useful approach to address questions about the age and extent of rafts, particularly where sites are found buried by raft lake sediments, thus providing a terminus post quem for the lake.

Alluviation is one of the geomorphic processes which must be considered in understanding the archaeology of the alluvial valley. The Red River carries a heavy sediment load, and overbank flooding results in extensive sedimentation in certain areas. Alluviation is not, however, a simple nor a regular process throughout the valley, as exemplified by the

common occurrence of archaeological deposits of widely varying ages at the present ground surface in fairly restricted areas (Pearson and Ducote 1979). Extensive geomorphic and archaeological research is needed before the processes of alluviation and its effects upon the archaeological record are fully understood. Even then, because of the complex array of factors affecting alluviation within the flood plain, it may be that these processes will only be accurately predictable over fairly small areas.

The alluvial flood plain of the Red River and nearby uplands support upland pine forests, tributary bottomland hardwoods, and alluvial backswamp hardwoods (Delcourt 1976). Cultural activities in the historic period have so drastically altered the vegetation in much ofthe study area that modern vegetation occurrences and distributions reflect little of the prehistoric condition. Today much of the valley has been cleared for agricultural development, while forest management activities have reduced the amount of hardwood timber stands in the uplands.

The Holocene Flood Plain: The Archaeological Implications

The Holocene flood plain lies at or near the flood level of the Red River and its tributaries. The valley floor is relatively flat, broken only by natural levees, numerous old stream channels and lakes, backswamps and rimswamp basins, and occasional erosional remnants of earlier geologic age. The purpose of this section is to describe and characterize the major landforms found in the Red River flood plain, briefly review their critical geomorphic characteristics, and, finally, discuss these features in terms of their implications to archaeological and geoarchaeological research.

Tertiary and Pleistocene Inliers Several pre-Holocene erosional remnants stand as inliers within the flood plain of the Red River. Among the most prominent of these are the Tertiary formations known as Buzzard Bluff below Fulton, Arkansas, and the Tertiary and Pleistocene formation, Couchanda Hill, located near Coushatta, Louisiana (Commonwealth and Associates, Inc. 1981:29). Within the area covered by this field trip is a small inlier of Prairie Terrace located along Bayou Boeuf just northwest of th e communi ty of Lecompte. As high, elevated landforms these inliers provide ideal settlement locales, generally removed from the dangers of frequent flooding often encountered on the flood plain, but still near the flood plain resources. Additionally, these inliers often have resources infrequently found in the alluvial valley, such as stone, increasing their importance, particularly to prehiStoric popUlations. Because they constitute the oldest land surfaces within the alluvial valley, they are likely to contain evidence of early human occupation. No systematic archaeological study of inliers wi thin the Red River Valley has been undertaken, however, artifacts dating to the Archaic period (circa 3000 to 8500 BP) and, possibly, Paleo-Indian period (circa 11,000 BP) have been recovered from these features in Arkansas (Pearson and Ducote 1979:2-29), and the Prairie Terrace inlier north of Lecompte is conspicuous by the large number of prehistoric sites it contains, including a fairly large mound group.

Meander Belts Meander belts constitute the most obvious and the most mappable of the Holocene flood plain geomorphic features. Meander belts include all of the elements of a meandering stream system; the river channel, natural levees, point bar landforms, cut offs or oxbows, abandoned channel segments, and crevasse splays and channels. The delineation of meander belts and the development of meander belt chronologies and sequences has been an important aspect of geological research in the Lower Mississippi Valley for 50 years, exemplified in the work of a number of researchers. The use of archaeological data commonly has been used to refine and order portions of these meander belt sequences (d., Fisk 1944 and Saucier 1974, 1981). The meander belt history of the Red River is extremely complex; however, efforts to develop meander belt chronologies for the Red have been undertaken by Russ (1975), Saucier (1974; 1981), and Saucier and Snead (1989). These efforts have relied primarily on the morphology of meander belts and their cross-cutting relationships, plus correlation with geomorphic events in the MiSSissippi flood plain. Little reliance has been placed on archaeolOgical data. Gagliano et al. (1979) used archaeological data to assess the previously identified Red River meander belt sequence at the extreme southern end ofthe Red River alluvial valley, and one study has relied heavily on archaeological data in the development of a meander belt chronology for the Red River in southwestern Arkansas (Pearson 1982; Pearson and Ducote 1979). This latter study is discussed in more detail below.

While channel morphology, meander belt elevations and cross-cutting relationships are the most commonly used criteria for reconstructing meander belts, the geomorphic complexity of the Red River argues tha t these factors have to be used cautiously. For example, the choke points produced by the Nacodoches and Kisatchie wolds reduce to two the number of traceable meander belts through the constrictions. The changes in local base levels created by these constrictions result in different gradients and natural levee elevations above and below these points (Russ 1975). This fact makes it difficult to assume that "similar-appearing, but unconnected courses above and below each constriction were once continuous, and that flow in them was synchronous" (Commonwealth and Associates, Inc. 1981:32). In particular, it is difficult to trace the older meander belts over long distances because of the problems in identifying and delineating them, and because of the often even greater difficulty in reliably distinguishing them from other early meander belts. Despite these difficulties, a number of authors have developed meander belt sequences for the Red River. We would argue, however, that the identity of the earlier meander belts in particular must be viewed with caution until some means of reliably dating and associating spatially distinct segments is employed.

A number of relict meander belts, or more precisely meander belt segments, of the Red River can be seen in the area visited by this field trip. One of these segments is today occupied by Bayous Rapides andJean deJean and is located south ofthe modern Red River extending from the town of Boyce to Alexandria. Relying on its cross-cutting relationships with other channel segments, Russ (1975:169-171) indicated that

32

this is a portion of the youngest of the Red's relict meander belts, abandoned immediately prior to the river's occupancy of its present course. He suggests that the Bayou RapidesJean de Jean course was abandoned about 450 to 500 years ago, after having been occupied for a considerable period of time. Saucier and Snead (1989) follow Russ' identification of this meander belt as the most recent prior to the establishment of the modern channel; however, they do not assign a precise age to it. There is, in fact, little evidence to support Russ's contention about the age of this meander belt. He, in part, implies that the shift was related to the Red's diversion through Moncla Gap about 500 yrs B.P., but this diversion may have taken place as early as 1700yrsB.P. (Pearson 1986).

Archaeological sites along the natural levees of Bayou Rapides or Bayou Jean de Jean would aid in formulating an age for this system; to date few have been found. One recently discovered site may hint at an earlier date than Russ suggests. This site, which represents one of the stops on the field trip, is located on the natural levees of Bayou Rapides on England Air Force Base. It produced aboriginal lithics and a small quantity of ceramics of types normally associated with the Plaquemine culture, which dates from about A.D. 1200 to possibly as late as A.D. 1700. Importantly, these materials were found resting directly on grayish brown silts identified as in situ natural levee deposits. Finer grained sediments, identified as slack water deposits, cover the archaeological materials, indicating that the archaeological site was established after active natural levee accretion had ended along Bayou Rapides. While this could indicate that primary flow in Bayou Rapides had ceased as early as A.D. 1200, the site may have been established at a much later date. Additional archaeological data from along Bayou Rapides, and along the other Red River meander belts, will be needed to develop realistic chronologies for these features.

Natural Levees Natural levees develop as a river overflows and deposits suspended sediments. That portion of the natural levee closest to the river channel is the highest and contains the coarsest sediments, while toward the outer edges of the levee the deposits are finer grained and thinner. Natural levee sediments generally consist of silt, silty clay and some sand, all of which tend to have reddish to reddish brown colors derived from the river's western red bed source area. As the levees develop, they generally provide some of the highest, best drained, and most fertile land within an alluvial valley, a combination of factors that makes them among the most desirable types of terrain for settlement. The accumulation of archaeological data from the Red River, as is generally the case in similar settings elsewhere, indicates that human settlement in alluvial valleys is closely associated with natural levee features. In particular, these landforms became desirable after the introduction of cultigens into the region and the shift to a reliance on these crops. The alluvial valley was certainly used during earlier time periods, although only a fairly small number of sites of great age are known. It is probable that a fairly large segment of the earlier archaeological record has been removed by the meandering Red River or, in some instances, buried by sediments.

33

Crevasse Channels and Splays During periods of extreme high water, the river may scour out channels where the outer edge of a meander bend cuts into the river's own natural levee, and if these channels cut through the levee, they are known as crevasses. If the period of flooding is relatively short then the crevasse channels take on a splayed, fan-shaped form as they deposit sediment on the lower lands beyond the limits of the natural levee. If, however, the crevasse is continually kept open by annual flooding, then it may extend many kilometers into the low lying backswamps, and, possibly c0nverting the crevasse into a distributary/tributary stream, possibly capturing the flow of the original trunk stream. Relatively firm natural levees form along crevasse channels, and ideal habitation locales are developed. This is particularly true at the point of breakout, where the natural levees of both the major stream and the crevasse combine to form a larger than normal habitable land surface where access would have been available to both the major river channel and the extensive, biologically rich backswamp area.

No detailed correlation of archaeological sites with crevasse features has been attem pted for the Red River, but it has been noted elsewhere. For example, a review of prehistoric and historic aboriginal site locations along the Mississippi River below Baton Rouge shows that many of the known sites are situated where crevasses have occurred. The sites are located either on the the river's widened natural levees or on the crevasse features themselves. Similarly, evidence from numerous studies in Louisiana's coastal zone indicates that prehistoric sites on deltaic landforms are commonly located adjacent to or on crevasse features.

Oxbow lakes Oxbow lakes are formed when the river abandons a meander loop and alters its course through a cutoff. Eventually sediments fill the entrances to the former meander loop, and it becomes a lake. Such lakes then pass through successive stages of faunal and floral development and eventually become filled with sediment. During their early life, oxbow lakes are probably the most productive ecosystems in an alluvial valley (Smith 1978:480-489). Particularly productive just after closure when they still receive overflow from the river during periods of flood or high water, they support large populations of fish, molluscs, and turtles, and attract a variety of other wildlife, such as waterfowl. In addition to abundant biotic resources, oxbow lakes offer optimum conditions for human habitation and exploitation along the well drained, high ground of their natural levees.

In the Red River flood plain, settlement along the natural levees of oxbow lakes offers the added advantage of being removed from the banks of the active channel where channel migration can be rapid and the rate of bank line erosion high. This phenomena was certainly recognized by prehistoric occupants of the valley, as it was by historic settlers.

Backswamp drainage areas Land suitable for habitation can also be found along the banks of small streams draining the lower backswamp areas

that are situated between the natural levees of the Red River and the valley bluffs. These streams flow into the larger water courses, but still provide some minor relief by way of their own small natural levees. These lower levees were probably less desirable than those along the higher crevasse and major river channels, but they would have been suitable for short seasonal occupations.

Case Studies in Geoarchaeology

Case Study 1 . Geomorphology and Prehistoric Settlement Patterns in the Great Bend Region of the Red River In 1979 Coastal Environments, Inc., of Baton Rouge, undertook an archaeological assessment of several areas along the Red River in what is known as the Great Bend region in southwestern Arkansas where the Corps of Engineers proposed revetment construction (Pearson and Ducote 1979). To expand the usefulness of the study, information on the area's archaeology and geomorphology was collected to examine the relationships between the geomorphic history of the alluvial valley and prehistoric settlement distributions in the Great Bend region. This effort resulted in the development of a model of prehistoric settlement patterns through time and the establishment of a chronological sequence of landforms in the alluvial valley, both of which represent an initial step in understanding the paleogeography of the Red River flood plain. The following discussion draws from the results of that study presented in Pearson (1982) and Pearson and Ducote (1971).

The Study Area The study area consists of an approximately 50-km-long stretch of the Red River all uvial valley located just below the Great Bend (fig. 9). While geologic and geomorphic data were considered within the entire study area, archaeological data adequate to provide reasonable information on settlement patterns were available only from a small segment just above Garland City, designated Analysis Area in figure 9.

The three principal topographic and geologic features ofthe study area are the Red River alluvial valley itself, the flat to rolling Pleistocene terraces, and the hilly Tertiary uplands bordering the alluvial valley. The upland terraces are of Pleistocene age and represent ancient Red River flood plains (Frye and Leonard 1963; Martin et al. 1954; Smith and Russ 1974). They are of various intermediate elevations, are characteristically level to slightly rolling, and are dissected bymodern water courses and relict Pleistocene-age Red River channels. The hilly uplands are of Tertiary age and provide the highest elevations in the Great Bend region (Ludwig 1972:5). Elevations in the uplands of the northern portion of the study area reach 135 m, and in some areas bordering the alluvial valley there are bluffs rising as high as 60 m above the flood plain.

Flood Plain Landforms An initial effort was made to identify and establish a tentative chronology of alluvial valley landforms within the study area. This effort was necessarily at a broad scale. The landforms consisted of meander belts, or portions of mean-

der belts, and their chronolOgical placement was made on their morphological characteristics and spatial position. What is identified as the modern meander belt consists of the present river course and its recent oxbow lakes. The modern oxbows were identified, in part, by their degree of filling; that is, they generally consist of open water or have only slight amounts of filling towards their ends. Also, the Red River Survey maps of 1886-1887 (U.S. Engineer Department 1886-1892) and various U. S. Geological Survey topographic maps shOWing the 1951 channel were used to identify recent river courses.

Intermediate age channels are those which have been partially filled and contain little or no open water, yet are still easily discernible on the ground and on topographic maps. Often these are cypress swamps which are flooded for portions of the year. These channels also tend to display a patterned'distribution in the river valley (fig. 9). In the northern three-quarters of the study area, with one or two exceptions, the intermediate age channels are confined to the eastern side of the modern meander bel t. In the extreme southern portion of the study area they are found only on the western side of the modern channel.

As figure 9 indicates, the identified intermediate age channels in this area do not form complete meander belts, but rather appear to represent partial or truncated segments of meander belts. Of these channels east of the river, all but one open to the west, suggesting the river has shifted slightly west since it occupied these channels, leaving only those that had formed the eastern portion or, more specifically, the left-hand descending meanders of its former meander belt or belts.

Farther south, the intermediate age former channels all open to the east, suggesting the river has shifted in that direction. These relict meanders represent the truncated remnants of the right-hand descending meanders of the former meander belt of the river.

The oldest class of relict meanders in the valley are those that are completely, or almost completely, filled. These early meander scars are barely discernible on topographic maps, and many can be seen only in infrared aerial photographs. Early meander scars are scattered throughout the valley; however, in most cases they are located farther from the modern river course than are meander segments identified as intermediate age (Fig. 9). The older meander scars generally do not form identifiable segments of meander belts, but appear as isolated loops or channel segments. Erosion and filling over a long time period have obliterated or obscured much of the evidence of these early river courses. Only in one area is a complete segment of a possible early meander belt observable. This belt runs west from a Tertiary age inlier known as Buzzard BIuffin the northern part of the study area and is currently occupied by Finn Bayou (Figure GA-2). The good preservation of the Finn Bayou meander belt is indicative of a sudden abandonment of this portion of the channel, evidently due to an avulsion farther upstream. The continued or subsequent occupancy ofthis relict river channel by Finn Bayou as an underfit stream has probably prevented its filling to the same extent as most of the other early meander scars.

34

\ \~

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1000 B.C. to A.D. 1600

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Figure 8- Cross section of the Red River alluvial valley taken near Zimmerman, Louisiana, showing typical flood plain features and stratigraphy (source: Smith and Russ 1974),

35

Note should be made of one other alluvial valley landform in the study area; the Deweyville Complex. The Deweyville Complex comprises the latest Pleistocene formation in the study area and occurs as small remnants adjacent to the modern alluvial valley. The Deweyville has been recognized along most major streams on the Gulf and Atlantic Coastal Plain (Gagliano and Thorn 1967) and along many major tributaries of the MiSSissippi (Autin et al. 1991). Characterized by distinctly over-sized meander-belt features, the Deweyville Complex is situated stratigraphically between the Prairie Complex and Holocene flood plain. Currently, it is believed that the Deweyville Complex developed in response to climatic change, probably primarily "changes in seasonality and intensity of precipitation events" (Autin et al. 1991:560). Estimates of the age of Deweyville features have ranged from 7,000 yrs B.P. to 30,000 yrs B.P., but the available archaeological evidence suggests it dates prior to about 13,000 yrs B.P. (Autin et al. 1991; Weinstein and Kelley 1984). Smith and Russ (1974) have identified Deweyville Complex surfaces in the southern part of the study area. These are located at an elevation of about 65 m,

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Figure 10- Locations of initial occupation sites of the Archaic period and the estimated eastern edge of the Red River meander belt at ca 1000 B.C. (source: Pearson 1982),

elevations only slightly above the modern flood plain, and have relatively level surfaces with barely observable meander scars.

Given the complexity of alluvial valley geomorphology, this identification of a chronology of meander belts and associated landforms is considered hypothetical, but testable, Information on prehistoric settlemen t distribution was used to examine and date the hypothesized meander belt sequence and to develop generalizations about the the dynamics of prehistoric settlement on the alluvial flood plain (Pearson 1982).

Archaeological Site Distribution and Holocene Meander Belts The site data used here consists of that reported to or recorded by the Arkansas Archeological Survey as of 1979 and presented in Pearson (1982), Only in one part of the study area is there a sufficien t number of known prehistoric

. sites whose age and distribution can be used in the develop-

36

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Figure 11 - Locations of initial occupation sites of the Fourche Maline period and the estimated eastern edge of the Red River meander belt at ca A.D. 900 (source: Pearson 1982).

ment of initial estimates of meander belt ages. These are found on the eastern side of the all uvial valley in northern Lafayette County. This area is referred to as the analysis area in the following discussion. The majority of these sites have been reported byalocalresident andavocational archaeologist, Herschel Kitchens. Presently, there is no reason to assume that prehistoric site concentrations differ to any great extent in other similar portions of the alluvial valley. Recent research in the Red River flood plain below Shreveport seems to suggests high site densities, possibly not unlike those reported here aeff Girard, personal communication 1992). Elsewhere sites simply have not been found or reported.

The locations of sites within the analysis area were plotted according to period of initial occupation, the assumption being that patterned distribution of sites through time may provide information on ages of various landforms. Three broad categories of initial periods of occupation were used: Archaic (ca. 6000B.C. to 1000 B.C.), Fourche Maline (ca. 400 B.C. to A.D. 900), and Caddoan ca. A.D. 900 to A.D. 1780).

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Figure 12 - Locations of initial occupation sites of the Caddoan period and the estimated eastern edge of the Red River meander belt at ca A.D. 1600 (source: Pearson 1982).

As shown in figure 10 initial occupation sites of the Archaic period are confined to the eastern bluff edge and to the alluvial valley floor adjacent to the bluff. This distribution is interpreted not as an avoidance of settlement in the river bottoms, but as an indication of the destruction by the river of any Archaic sites which may have existed farther west. ]udgingfrom the distribution of these sites, the eastern edge of the Red River meander belt at the end of the Archaic period (ca 1000B.C.) would have been as shown in figure 10. The flood plain surfaces available for occupation at 1000 B.C. corresponds almost exactly to the area assigned to the early meander scar category of relict channels.

Initial occupation Fourche Maline sites (Fig. 11) occur farther west onto the flood plain than Archaic si tes, suggesting tha t between a pproxima tely 1000 B. C. and A.D. 900 the Red River meander belt shifted westward with a concomitant shift of settlement. The identified eastern boundary of the Red River meander belt at about A.D. 900 is shown in figure 11. All of the flood plain added to that occupied by Archaic sites falls within the intermediate age channel category.

Initial occupation Caddoan sites are found in the flood plain even farther to the west than are Fourche Maline sites (Fig. 12) , attesting to the continued westward shift of the Red River meander belt in this area. The estimated eastern edge of the Red River meander belt at about A.D. 1600 is shown in figure 12. All of the land surface added since the end of the Fourche Maline period falls within the intermediate age class of relict channel landforms.

The modern meander bel tis loca ted just west of these known Caddo an sites, suggesting the river has occupied its present meander belt for approximately the last 400 years. It is unlikely that the river will continue its westward shift. Extensive levee systems constructed since the nineteenth century have stabilized the meander belt, though meander activity within this modern belt continues to be considerable.

The evidence presented indicates that the land surfaces between the westernmost extent of Archaic period sites and the eastern edge of the modern meander bel t were formed or became suitable for occupation between about 1000 B.C. and A.D. 1600. All relict meander scars in this area fall into the intermediate age category, while the Archaic period initial occupation sites are associated with early meander scar landforms. By extension, it is suggested that elsewhere in this portion of the river valley landforms associated with what have been classified as early meander scars predate 1000 B.C., those associated with intermediate age channels date 1000 B.C. to A.D. 1600, and landforms associated with the modern meander belt postdate A.D. 1600.

At present, it is impossible to further differentiate the ages of the various early meander scars and their associated landforms, though additional si te da ta may all ow for, at least, the dating of specific early meander segments.

The identification of various aged landforms can in turn guide future archeological research and the development of hypotheses about site distributions through time. It appears

37

that landforms associated with early meander scars will contain sites ranging in age from at least the Late Archaic through the present. Presumably, sites of much earlier age will be found in association with some of these early surfaces, though site data are not available which would allow an estimation of how much earlier. It should also be noted that these surfaces have been exposed to alluviation for a long time, and early sites on them may now be covered by considerable amounts of alluvium.

Intermediate age meander belt landforms are expected to contain occupations dating from approximately 1000 B.C. to the present. Those sites used in this analysis that are located on landforms associated with this meander belt are all located at or near the present ground surface. Since these sites represent a considerable time span, it would appear that alluviation has not been generally extensive within the intermediate age meander belt in the analysis area, although in specific locales it may be considerable. Whether or not this holds true for portions of this meander belt outside the analysis area remains to be seen.

The Red River is estimated to have occupied the modern meander belt for approximately the last 400yearsj however, older land surfaces, not yet removed by the meandering river, are still found within this belt. The majority of sites located in the modern meander belt will probably postdate ca. A.D. 1600, but some earlier sites will be found on the older land surfaces still extant within the meander belt.

As emphasized earlier, the Red River is extremely active, is subject to rapid and dramatic changes in course, and is characterized by rapidly eroding cutbanks. There is no doubt that prehistoric inhabitants were cognizant of this and would have hesitated to establish settlements, especially larger, more important ones in places that were in immediate danger of destruction. The most obvious choice for settlement in the alluvial valley would have been along the relatively recently formed oxbow lakes adjacent to the active channel. Settlements along oxbow lakes were removed from the immediate danger of river activity and were located in areas providing the combined advantages of the high, well drained soils of relict levees and the abundant resources (especially fish) found in these lakes (Smith 1978:480-489). It is argued that most of the major sites (e.g., mound sites) associated with relict Red River channels were established and occupied during that period when the channel was a productive oxbow lake.

Archeological site distributions in the Red River alluvial valley appear to be related to and largely dictated by river activity. Prehistoric settlements are more likely to be associated with recently formed oxbow lakes, because of the optimum conditions they offer, in comparison to active river channels. In the study area, it appears that as the meander belt shifted there was a concomitant shift in settlement to take advantage of the newly formed levees and, presumably, recently relict oxbows and channel segments. The prehistoric settlement distributions observed in the valley today are also, in part, a consequence of site destruction brought about by the effects of river meander activity.

Heinrich (1991:320) has recently suggested that the processes oflateral channel migration and alluviation along the active channel of streams can, inherently, produce a pattern of site distribution which only appears to indicate a cultural preference for settlement along relict channel segments and courses. He uses archaeological site data from along the Mississippi River below Baton Rouge to demonstrate that sites of widely varying ages are, in fact, found associated with the levees of the present channel. Heinrich may be correct concerning the lower Mississippi; it is really a unique case. However, importantly, there are no relict meanders or channel segments associated with the modern course of the river below Baton Rouge which would serve to test his hypothesis. We would argue, in general, that where relict channels do occur they offer an array of environmental advantages that attracted human use and settlement, although, no doubt some settlements would be located along active streams. The biological advantages of relict channels are at their optimum during their early life, the period when human use would be at its greatest. Support for this pattern of occupation is found in the soil stratigraphy reported from many archaeological sites in alluvial valley as well as deltaic settings. Cultural remains, particularly in the Red River flood plain, tend to be found stratigraphically above, or intermingled in, the very upper levels of identified natural levee sediments. This suggests that the human occupation occurred after the cessation of, or near the very end of, natural levee accretion and, thus, about the time the channel became relict.

Systematic archeological surveys should be directed at testing the proposi tions concerning the age ofthe meander belts and associated landforms put forth in this study. Archeological surveys of a sample of the recent land surfaces identified in the modern meander belt should provide the data necessary to test the hypotheSis that they are less than 400 years old. Similar work should be directed at selected areas of the intermediate age meander belt for the same reason.

The Finn Bayou meander belt offers an ideal research universe within which to examine the interrelationships between prehistoriC settlements and the Red River. Site data from this area should provide informa tion on the age of the meander belt as well as insight into the nature of site location in relation to the major components of the meander belt system (e.g., oxbow lakes, active channeC crevasse levees, etc.). The erosional remnants in the valley and the identified Deweyville surfaces are areas that should provide evidence on the earliest prehistoric occupants of the valley. Although other early surfaces exist in the valley (e.g., early meander scar landforms), sites located on them are likely to be inaccessible because of alluviation.

Estimating Meander Activity and Site Destruction in the Great Bend Region The extreme meander activity ofthe Red River results in the continuous destruction and redeposition of a considerable percentage of the land surfaces within its meander belt. Since these surfaces contain archaeological sites, it is presumed that the longer the river occupies a given meander belt the more sites will be destroyed.

38

Some insight into the amount and rate of site destruction is provided by data concerning the destruction of historically documented sites in the vicinity of the study area. Of the 49 mounds reported by Moore (1912) and other early sources, only 26 have been relocated; most of the others have been lost to the river (Frank Schambach, personal communication). Therefore, within approximately a 100-year time span, possibly one-half of the prehistoric sites known to have been located in the modern meander belt have been destroyed. If Abington (1973) is correct in assuming that Red River meander activity has lessened since the 1880s, then the possibility that the rate of site destruction was greater in the early historic and prehistoric periods than it was in the past 100 years must be considered. In light of this possibili ty of extensive site loss, the available archeological sample of prehistoric sites within a Red River meander belt, may only be a poor representation of the original population of sites.

This factor is most critically related to assessments of past site populations within meander belts which were active for some period oftime. In those instances where meander belts are abandoned after a short period of activity, or in those where complete meander belt segments or systems are abandoned in toto, then current site distributions and types are presumably more representative of the original population that existed and provide more meaningful information on past settlement systems. The well-preserved Finn Bayou meander belt mentioned above is a case in point. This meander belt contains a number of cu t-offs, suggesting some long period of activity, but it was apparently abandoned suddenly, leaving a full range of meander belt landforms available for settlement. Archaeological site distributions across these landforms should provide inform a tion on how these landforms were utilized. Several well preserved meander belt systems are induded in the present field trip, specifically Bayou Rapides and Bayou Boeuf. The general lack of cut-offs and abandoned meander segments along these two bayous suggests that neither was occupied for a long period of time before abandonment. Thus, thevariabili ty in, as well as sheer number of, preferred landform settings alongthese two meander belts maybe less than will be found along systems like Finn Bayou which were active for long periods of time. It is possible that these geomorphiC characteristics will be reflected in the archaeological record, Le., fewer sites and less variability in types of sites along systems like Bayou Boeuf than along systems like Finn Bayou, but this question has not yet been addressed by archaeologists.

Case Study 2: The Monda Gap Diversion In that portion of the Red River below Alexandria, Louisiana, Fisk (1944) identified several relict courses of the river on the basis of physiographic and topographic evidence. In the same area, Saucier (1974:Fig. 1) has identified four former courses in addition to the present course. The identified relict courses, as shown in figure 13 flowed west, southwest and south of an eleva ted outlier of the late Pleistocene Prairie Complex known as the Avoyelles Prairie. Other earlier courses are presumed to have existed, although physical evidence of their existence has been obliterated by the activities of later streams.

In its final 80 km, the modern course of the Red River flows

within the alluvial valley flood plain of the Mississippi River. This segment became occupied when the river's course diverted through Monda Gap, located at the northern end of the Avoyelles Prairie (Fig. 13). The new northern course reduced from 65 km to 13 km the distance required for the river to descend to the Mississippi River flood plain. In 1986, using archaeological data, Pearson (1986) provided new suggestions on the date of the Red's diversion through 'Nfonda Gap. His findings are summarized here.

Several suggestions as to the date of diversion through Monda Gap had been presented, but none had never been accurately determined. Fisk (1944:Table 6), correlating the diversion with stage 15 of his chronology for the lYfississippi River, suggested a date of about A.D. 1500 to A.D. 1600; Abington (1973:10) and Saucier (1974:Fig. 3), generally accepted this date. Russell (1967:32-33) believed the diversion occurred within the past 1500 years, while Lenzer (1979) argued that the diversion could have occurred 1000 years ago.

All of these estimates relied on geologic and geomorphic evidence. Pearson (1986), relying on information from three archaeological sites associated with the modern Red River meander belt below Monda Gap, was able to bring more precise temporal information to bear on this question. These three sites (Fig. 13) were all initially reported by Clarence B. Moore in connection with his work along the Red River in the early years of this century (Moore 1912). The sites are: mounds near mouth ofL'Eau Noire Bayou (16AV 39),lower mound on Saline Point (16 AV 41), and upper mound on Saline Point (16AV 13). Twoofthesites (16AV13 and 16AV 41) are now on an abandoned segment of the Red River produced when the river was shortened for navigation purposes in the 1930s.

Toth (1977:439-441) reanalyzed Moore's ceramic collections from two of the sites (16 AV 13 and 16 AV 41) and identified the earliest components at each as falling within the early Marksville period. Marksville period and later ceramics have also been recovered from the third site, the mounds at L'Eau Noire Bayou (16 AV39). Excavations at the site have indicated the presence on~/farksville period ceramics, though the most intensive occupation occurred during post-Marksville times (Klinger et al. 1983; Pearson et al. 1983).

Currently accepted dates for the Marksville period in the Lower Mississippi Valley are on the order of 100 B.C. toA.D. 400 (Toth 1977:16; ShenkeI1981). Toth's identification of early Marksville components at 16 AV 13 and 16 AV 41 would argue for occupation occurring at these two sites near the beginning of the period. Where the other site, 16 A V 39, would fall within the time span of Marksville is presently unknown.

All three of the sites are located near the present channel of the Red River and within the meander belt (Smith and Russ 1974). Borings indicate that Red River levee and point bar deposits in the area of the sites are on the order of 10 to 12 m thick (Smith and Russ 1974). C. B. Moore (1912) noted that both of the Saline Point sites were mounds that rose about 3 m above the ground surface and that at 16AV 41 the

39

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Figure 13 - Geological and cultural features in the vicinity of Monda Gap. The archaeological sites used to estimate the age of the modern Red River course are underlined (source: Pearson 1986).

deepest of a number of burials excava ted was only 1 m below the surface. All of these data suggest that these sites are associated with the natural levees of the modern course of the Red, and thus necessarily post da te the appearance of the river in this area (Pearson 1986).

The stratigraphic relationship of cultural deposits to natural levee formations is clearer at the other site, 16 AV 39. Here, excavations located intact cultural deposits containing Marksville period ceramics at a depth of 2.5 m below the present surface. Beneath these cultural materials are Red River levee deposits (Klinger et al. 1983).

Itis argued that the Marksville period occupations identified at these three sites occur on, and in association, with the

naturalleveesofthe Red River. Consequently, theynecessarily post-date the river's occupancy and subsequent levee development in this area. IfToth is correct in his assessment of early Marksville occupations, then diversion through Monda Gap and natural levee formation had to have occurred by approximately A.D. 1 and certainly no later than A.D. 200.

No pre-Nfarksville period sites are reported along the Red River below Monda. Although this may be a reflection of lack of site information, it would seem to indicate that the river diverted through Monda Gap by early Marksville times or, at least, had not developed levee systems suitable for habitation prior to then. The time reqUired to develop such landforms is currently unknown,

40

An early Marksville period date for the Red River below Monda Gap may provide partial explanation for the concentration of Marksville period settlements on the northern and eastern edge of the Avoyelles Prairie near the present course of the river (Fig. 13). Here there are several archaeological sites with Marksville period occupations, induding the rna jor mound center of Marksville. Presumably, Marksville period populations were attracted to the combined resources of the elevated AvoyeUes Prairie, the 1vfississippi River flood plain, and the alluvial flood plain of the active Red River producing the observed site concentrations. The Red River diversion through Monda Gap would have been an important factor in influencing Marksville period, as well as later prehistoric, settlement in the region.

References Abington, O.D., 1973, Changing meander morphology and

hydraulics, Red River Arkansas and Louisiana [Ph.D. dissertation]: Louisiana State University, Baton Rouge.

Autin, W. ]., Burns, S. A., Miller, B. ]., Saucier, R. T., and Snead, ]. I., 1991, Quaternary geology of the Lower Mississippi Valley in Morrison, R. B., ed., Quaternary non -glacial geology of the conterminous U ni ted States: Geological Society of America, Geology ofN orthAmerica, v. K-2, p. 547-82.

Bagur,]., n.d, Before the Raft: Waterwise: The Shreveport to Daingerfield Study Newsletter, U.S. Army COrps of Engineers, Vicksburg District, v.1, p.1-2.

Brain, ]. P., 1971, The Lower Mississippi Valley in North American prehistory: National Park Service, Southeast Region, Atlanta.

Butzer, K. W., 1971, Environment and archeology, an ecological approach to prehistory: Chicago, Aldine Publishing Company, 703 p.

Butzer, K. W., 1977,

Chawner, W. D., 1936, Geology of Catahoula and Concordia Parishes: Louisiana Geological Survey, Geological Bulletin 9,232 p.

Commonwealth and Associates, Inc., 1981, Cultural resources survey of the Red River Waterway from Shreveport to the 1vfississippi River: Commonwealth and Associates, Inc.,]ackson, Michigan, 2 vols., 574 p.

Darby, W., 1816, A geographical description of the state of Louisiana: John Melis, Philadelphia.

Darby, W., 1817, A geographical description of the state of Louisiana, the southern part of the state of Mississippi and territory of Alabama:] ames Olmstead, New York.

De1court, H. R., 1976, Presettlementvegetation of the north of the Red River land district, Louisiana: Castanea v. 41, p.122-139.

41

Fisk, H. N., 1944, Geological investigation of the alluvial valley of the Lower Mississippi River: U.S. Army Corps of Engineers, Mississippi River Commission, Vicksburg, 1vfississippi, 78 p.

Fisk, H. N., 1940, GeologyofAvoyelles and Rapidesparishes: Louisiana Geological Survey Geological Bulletin 18, 240 p.

Fisk, H. N., 1938, Geology of Grant and LaSalle parishes: Louisiana Geological Survey Geological Bulletin 10, 246 p.

Ford,]. A., 1936, Analysis of Indian village site collections from Louisiana and MissisSippi: Department of Conservation, Louisiana Geological Survey, Anthropological Study 1.

Ford,]. A., 1951, Greenhouse, A Troyville-Coles Creek period site in Avoyelles parish, Louisiana: American Museum of Natural History Anthropological Papers, v. 44, pt. 1.

Ford,]. A., and Quimby, G, 1945, The Tchefuncte culture, an early occupation of the Lower Mississippi Valley: Society for American Archaeology Memoir 2.

Ford,]. A., and Willey, G., 1940, Crooks site, a Marksville period burial mound in laSalle Parish, Louisiana: Department of Conservation, Louisiana Geological Survey Anthropological Study 3.

Fowke, G., 1927, Archaeological work in Louisiana: Smithsonian Miscellaneous Collections, v. 78.

Fowke, G., 1928, Archaeological investigations - II: Annual Report of the Bureau of American Ethnology, n. 44, p. 399-540.

Frye,]. C. and, Leonard, A. B., 1963, Pleistocene geology of Red River basin in Texas: University of Texas, Bureau of Economic Geology Report of Investigations, 49.

Gagliano, S. M., 1963, A survey of preceramic occupations in portions of south Louisiana and south Mississi ppi: Florida Anthropologist, v. 16, p. 105-132.

Gagliano, S. M., and Thorn, B. G., 1967, Deweyville Terrace, Gulf and Atlantic coasts: Louisiana State University Coastal Studies Bulletin 1, p. 23-41.

Gagliano, S. M., and Gregory,]r., H. F., 1965, A preliminary survey of Paleo-Indian points from Louisiana: Louisiana Studies, v. 4, p. 62-77.

Gagliano, S. M., Weinstein, R. A., Rader, B., Small, B. A., and McCloskey, K. G., 1979, Culturalresourcessurveyofthe Teche-Vermilion conveyance channel, St. Landry Parish, Louisiana: Coastal Environments, Inc., Baton Rouge, 78p.

Gibson,]. L., 1982, The Troyville-Baytown issue: Louisiana Archaeology, v. 9, p. 31-64.

Gregory, H. F., Jr., and Curry, H. K., 1978, Natchitoches Parish cultural and historical resources: prehistory: Natchitoches, Louisiana, Natchitoches Parish Planning Commission.

Gulf South Research Institute, 1975, Environmental analysis - Red River waterway, Louisiana, Texas, Arkansas, and Oklahoma: Gulf South Research Institute, Baton Rouge, 7 vols.

Heinrich, P.,1986, Petrified wood: Louisiana Archaeological Society Newsletter, v. 13, p. 2-5.

Heinrich, P.1987, Quartzite: Louisiana Archaeological Society Newsletter, v. 13, p. 2-5.

Heinrich, P., 1991, A sedimentolOgical explanation for the distribution of archaeological sites in a meander belt as stated by the "relict channel rule": Gulf Coast Association of Geological Societies Transactions, v. 41, p. 320.

House,J. H., 1972, Archeological salvage in the basin of Lake Rodemacher, Rapides Parish, Louisiana: Gulf South Research Institute, Baton Rouge.

Klinger, T. C., Cande, R. F., Kandare, R. P., and Cochran, R. J., 1983, Cultural resources survey, testing and assessment in eight areas, eleven localities and at eight archaeological sites in Avoyelles Parish, Louisiana: Historic Preservation Associates.

Kniffen, F. B., 1936, Preliminary report on the Indian mounds and middens of Plaquemines and St. Bernard parishes: Louisiana Geological Survey, Bulletin 8, p. 407-422.

Lenzer,J. P.,1977, Geology and geomorphology, in Thomas, Jr. P. M., Campbell, L.J., and Ahler, S. R., The Hanna site: an Alto village in Red River Parish: New World Research, Inc., Pollock, Louisiana, p. 32-50.

Ludwig, A. H., 1972, Water resources of Hempstead, Lafayette, Little River, Miller and Nevada Counties, Arkansas: U. S. Geological Survey Water-Supply Paper 1998.

Martin, J. L., Hough, L. W., Raggio, D. L., and Sandberg, A. E., 1954, Geology of Webster Parish, Louisiana: louisiana Geological Survey, Bulletin 29.

McIntire, W. G., 1958, Prehistoric Indian settlements ofthe changing Mississippi River Delta: Louisiana State University Coastal Studies Series I, 128 p.

Mills, G. B., 1978, Of men and rivers, the story of the Vicksburg District: Vicksburg, U.S. Army Corps of Eng ineers.

Moore, C. B., 1912, Some aboriginal sites of Red River: Journal of the Academy of Natural Sciences ofPhiladelphi a, Second Series, v. 14.

Nfurray, G. E., 1948, Geology of DeSoto and Red River Parishes: Louisiana Geological Survey, Bulletin 25.

42

Neuman, R. W., 1970, Archaeological and historical assessment of the Red River basin in Louisiana, in Davis, H.A., Archeological and Historical Resources of the Red River Basin: Arkansas Archeological Survey Research Series, n. I, p. 3-24.

Neuman, R. W., 1984, An Introduction to Louisiana Archaeology: Louisiana State University Press, Baton Rouge.

Pearson, C. E., 1986, Dating the course ofthe lower Red River in Louisiana: the archaeological evidence: Geoarchaeology, v. I, p. 39-44.

Pearson, C. E., 1982, Geomorphology and prehistoric settlement patterns in the Great Bend region, in Schambach, F. F., and Rackerby, F,. Contributions to the Archeology of the Great Bend Region: Arkansas Archeological Survey Research Series 22, p. 12-29.

Pearson, C. E., and Ducote, G., 1979, Cultural resources survey of four proposed construction projects along the Red River in southwestern Arkansas: Coastal Environments, Inc., Baton Rouge, 165 p.

Phillips, P., 1970, Archaeological survey in the Lower Yazoo Basin, Mississippi, 1949-1955: Harvard University, Peabody Museum of Archaeology and Ethnology Papers, v. 60, pt. 1.

Phillips, P., Ford,J.A., and Griffin,J. B., 1951, Archaeological survey in the Lower Mississippi Alluvial Valley, 1940-1947: Harvard University, Peabody Museum of Archaeology and Ethnology Papers, v. 25.

Russ, D. P., 1975, The Quaternary geomorphology of the Lower Red River Valley, Louisiana [Ph.D. dissertation]: Pennsylvania State University, College Park, 205 p.

Russell, R. J., 1936, Physiography of the Lower Mississippi River: Louisiana Geological Survey Bulletin 8, p. 3-199.

Saucier, R. T., 1981, Current thinking on riverine processes and geologic history as related to human settlement in the southeast: Geoscience and Man, v. 22, p. 7-18.

Saucier, R. T.,1974, Quaternary geology of the Lower Mississippi Valley: Arkansas Archeological Survey, Research Series 6, 26 p.

Saucier, R. T. ,1963, Recent geomorphic history of the Pontchartrain basin: Louisiana State University Coastal Studies Series 9, 114 p.

Saucier, R. T., and Snead, J. I., compilers, 1989, Quaternary geology of the Lower MissiSSippi Valley in Morrison, R. B., ed., Quaternary non-glacial geology: Conterminous United States: Geological Society of America, The Geology of North America, v. K-2, scale 1:1,100,000.

Seltzer, F., M., 1933, Hopewell type pottery from Louisiana: Journal of the Washington Academy of Sciences 23, p. 149-153.

Shenkel, R.]., 1981, Big Oak Island archaeology: prehistoric estuarine adaptations in the Mississippi River Delta: New Orleans, National Park Service.

Smith, B. D., 1978, Variations in Mississippian settlement patterns in Smith, B. D., Mississippian Settlement Patterns: Academic Press, New York, p. 479-503.

Smith, B. D., 1986, The Archaeology of the Southeastern United States: From Dalton to de Soto, 10,500-500 B.P.: Advances in World Archaeology 5: Academic Press, New York, p. 1-26.

Smith, F. 1., and Russ, D. P., 1974, Geological investigation of the Lower Red River-Atchafalaya basin area: U.S. Army Engineer Waterways Experiment Station Technical Report S-74-5.

Snead,]. I., and McCulloh, R. P., compilers, 1984, Geologic map of Louisiana: Louisiana Geological Survey, Baton Rouge, Scale 1:500,000.

Stein, J. K., 1986, Coring archaeological sites: American Antiquity, v. 51, p. 505-527.

Stoddard, A., 1812, Sketches, historical and descriptive of Louisiana: Philadelphia, Mathew Carey.

Thomas,]r., P. M., Campbell, 1.J., and Ahler, S. R., 1980, The Hanna site, an Alto village in Red River parish: Louisiana Archaeology 5, 381 p.

Toth, A., 1977, Early Marksville phases in the Lower Mississippi Valley: a study of culture contact dynamics [Ph.D. dissertation]: Harvard University, Cambridge, Massachusetts.

U. S. Engineer Department, 1886-1892, Survey of Red River and tributaries, Arkansas and Louisiana.

Webb, C. H., 1983, The Bossierfocusrevisited: Montgomery I, Werner and other unicomponent sites in Wyckoff, D. G., and Hofman, J. L., Southeastern Natives and Their Pasts: Papers Honoring Dr. Robert E. Bell: Oklahoma Archeological Survey, Norman, p.183-240.

Webb, C. H., 1959, The Belcher mound: Memoirs of the Society for American Archaeology 16.

Webb, C. H., 1948, Caddoan prehistory: the Bossier focus: Texas Archeological and Paleontological Society 19, p. 100-147.

Webb, C. H., and Dodd, M., 1939, Furtherexcavationsofthe Gahagan mound: connections with the Florida culture: Bulletin of the Texas Archeological and Paleon tological Society, no. 2, p. 29-126.

Webb, C. H., and McKinney, R. R., 1975, Mounds plantation (16Cd12), Caddo Parish, Louisiana: Louisiana Archaeology 2, p. 39-127.

Weinstein, R. A., 1981, Meandering rivers and shifting villages: a prehistoric settlement model in the upper Steele Bayou basin, Mississippi: Southeastern Archaeological Conference Bulletin 24, p. 37-41.

Weinstein, R.A., 1985, Development and regional variation of Plaquemines culture in south Louisiana: 6th MidSouth Archaeological Conference, Mississippi State University.

Weinstein, R. A., and Gagliano, S. M. , 1985, The shifting deltaic coast of the Lafourche country and its prehistoric settlement in Uzee, P. D., The Lafourche Country:

43

The People and the Land: Center for Louisiana Studies, Lafayette, p. 122-48.

Weinstein, R. A., Glander, W. P., Gagliano, S. M., Fulgham, S., Pearson, C. E., and McCloskey, K. G., 1979, Cultural resources survey of five proposed construction projects along the Lower Red River, Louisiana: Coastal Environments, Inc., Baton Rouge, 291 p.

SECTION II

he i ld Trip

44

STOP 1

Late Tertiary to Middle Pleistocene Evolution of an Upland Erosional Landscape

Review of the Williana and Bentley Areas

W. f. Autin, f. 1. Snead, P. M. Walthall, D. J. McCraw, and W. f. Day

liThe Williana Terrace forms the main divides of Grant and La Salle Parishes and is everywhere badly dissected. U. S. Highway 167 (from Alexandria to Winnfield) follows the main stream divide between Little River and Red River drainage, and the typical surface is named from the section crossed by the highway one mile south of Williana. Streams flowing southeast and southwest from the divide in this vicinity have cut through the terrace materials, exposing their unconformable contact with the Tertiary sediments."

liThe Bentley Terrace is best developed in central Grant Parish, where it is preserved as a narrow area at the foot of a fairly well preserved escarpment one mile north of Bentley. The escarpment is only locally preserved in other parts of the area. The extent of the original surface has been reconstructed from the general accordant elevation of ridges."

Location The Williana-Bentley transect (Fig. 1.1), located in northern Grant Parish illustrates the complexity of soil geomorphic relationships of an erosional landscape with multiple geomorphic surfaces and geologic map units. The traverse along U. S. Highway 167 from Bentley to Willian a is on the regional drainage divide between the Red River and Little River valleys. Comparison of the sedimentologic and pedologic features of the Williana core, the Williana pit, and the Bentley core illustrate the effects of differential geosol erosion, burial by a variable thickness of colluvial veneer, and the complexity of using landform and lithologic associations as a guide to geologic mapping.

Topography and geomorphology Elevations along the transect range from over 82 m immediately south of Williana to near S4 m in the upper drainage of the Big Creek valley near Dry Prong. The landscape is moderately sloping, with local gently sloping to nearly level summits and shoulder slopes. Big Creek is the only stream along the transect with a notable size flood plain. The boundary between Fisk's (193a) Bentley and Williana Terraces is marked by a change in the drainage dissection pattern 2 - 3 km north of Bentley (Fig. 1.2). Surface slopes heading north and east (up the stratigraphic dip) to the Little River are greater than surface slopes heading south and west (down the stratigraphie dip) to the Red River. Both of Fisk's (1938) units were grouped into the High Terraces (Snead and

45

- Fisk, 1938, p. 59-60, p. 62

McCulloh, 1984) and the Upland Complex (Saucier and Snead, 1989).

Site characterization The Williana core is from an area near where Fisk (1938) described a typical Willian a Terrace landscape. A 4 m core reveals a sequence of 1.7 m of colluvium over an eroded paleosol developed in the Vicksburg Group (RR1, Tables 4 andS). The colluvium is a 10YRIoamwithanargillichorizon that has 7.SYR mottles and a weakly developed soil structure. Tongues and root fills began at the base of the colluvium, where mixing with the underlying paleosol is evident. The underlying paleosol developed in the Vicksburg Group is truncated, and only the lower 30 cm of its Bt horizon is preserved at this site. Faint laminations of clay, silt, and silt loam were observed in the C horizon.

The Willi ana pit is located 0.8 kmfrom the Willi ana core, but exposes a 3 m sequence of the weathering profile of the Upland geosol (RR22, Tables 6 and 7). A 40 cm thick sandy loam to loam A-E-B\E horizon sequence is interpreted as colluvium. The primary lines of evidence for this inference are the lithologic similarity of the surface horizons in the pit to colluvial deposits of other landscape positions, and the thickening of this horizon set in a downslope direction across the pit exposure. The profile of the geosol consists of a red 2.SYR sandy clay loam argillic horizon with moderate subangular blocky structure and heavy clay films on ped surfaces. Pockets, tubes, and lamellae of 10YR bleached sand

~ Hu Alluvium

(U ndifferen tia ted) Tej Prairie Complex

~ Ppl (Lower Surface)

~ Prairie Complex Ppu (Upper Surface)

Pu Upland Complex

~ Toe Catahoula Formation

< Vicksburg Group g Tov (U ndifferentia tea)

~ Jackson Group ~ Tej (Undifferentiated)

\ Loca tion of Williana -Bentley Cross Section

• RR 1 Core Location

0 5

Kilometers

Pu

N

Figure 1.1 - Geologic Map of the Williana - Bentley Area. The transect of the WillianaBentley Cross Section is indicated.

46

are the primary C horizon properties. Rotted chert gravel occur throughout the weathered interval. The reticulate mottled and tongue pattern common in the Upland geosol through its regional extent can be observed in a lenticular clay loam channel fill lateral to the sampled soil profile.

The Bentley core is from an area near where Fisk (1938 ) described a typical Bentley Terrace landscape. A 6 m core revealed a sequence of 1.6 m of colluvium overlying a truncated weathering profile of the Upland geosol (RR11, Tables 8 and 9). The colluvium has a 10YR clay loam argillic

horizon with platy structure, plinthite, and gray tongues of silt loam and silty clay loam. Theunderlyinggeosol is eroded down to its BC horizon. Tongues from the overlying colluvium terminate in the upper .horizon of the geosol. The C horizon texture varies from sandy loam to medium sand and the horizon has oxide stains and mottles.

Stratigraphy of sediments and soils The Tertiary formations occur beneath a regionally-extensive unconformity that separates the units from the Quater-

Figure 7.2 - Topographic Map of the Williana - Bentley Area. The stop 7 site is indicated.

47

TABLE 4 - Characteristics of a Core From Beneath Fisk's (1938) Williana Terrace Type Locality

Location: Grant Parish, Louisiana; 31 0 39'26" N, 92 0 33'27" W (Sec 22 T8N R2W); Williana, LA 7.S-minute quadrangle; LGS core locality RR-1; site is on an upper sideslope along Forest Service Road 165; elevation is 82.3 m; slope is 1 to 3 percent; surface soil classifies as Metcalf Series (Aquic Glossudalf).

DEPTH, em HORIZON MATRIX COLOR MOTTLE COLOR TEX STRUCTURE CONSIST BDY COMMENTS

0- 20 2.5YR 5/8 LS fr ab fill; rt; G

TOP OF COLLUVIUM

20 - 30 Ap 1 OYR 5/2 SL wk fn ab fr cI rt

30 - 40 E 1 OYR 6/4 10YR 5/2 L wk fn ab fr ab rt; 10YR 5/2 SL burfills

40 - 70 Btl 10YR 7/8 L wkmed ab hd gr rt; disc C flm on peds

70 - 90 Bt2 10YR 7/8 7.5YR 6/6 L wk med sab hd gr disc C flm on peds

90 - 130 Bt3 10YR 7/8 7.5YR 6/6 L wk med sab hd cI C flm & 10YR 8/3 SiL flm on peds

130 - 170 Bt&2Bt 1 OYR 6/8 2.5YR 4/8 SCL mod med sab fm gr 10YR 7/2 SiCL tng & rt fills

TOP OF TRUNCATED PALEOSOL DEVELOPED IN OLIGOCENE VICKSBURG GROUP

170 - 200 2Bt 10YR 7/2 7.5YR 5/8 CL mod med sab fm df 10YR 7/2 SiCL tng & rt fills

200 - 260 2BC 5Y 6/3 SiCL wk med ab fm df 10YR 6/8 & 7.5YR 5/8 st 260 - 400 2C 2.5Y 7/3 L fm 10YR 6/8 & 7.5YR 5/8 st; faintlam

TABLE 5- Particle SIze Data for Williana Core- RR1- Metcalf Series HORIZON DEPTH, cm VCS CS MS

Ap 20 - 30 1.0 1.3 4.8

E 30 - 40 0.6 0.6 3.2

Btl 40- 70 0.6 0.3 1.8

Bt2 70 - 90 0.2 0.2 1.8

Bn 90 - 130 0.1 0.2 1.5

Bt&2Bt 130 - 170 0.0 0.1 1.7

2Bt 170 - 200 0.0 0.1 1.3

2BC 200 - 260 0.0 0.1 0.4

2C 260 - 400 0.0 0.1 0.2

nary Upland Complex. The local distribution of Tertiary and Quaternary geologic units are illustrated in Figure 1.2. In the area of the Willian a-Bentley transect, Tertiary formations range in age from the middle Eocene Jackson Group to the upper Miocene Fleming Group. Surface soils that develop in the outcrop area of the Tertiary Formations along the Williana-Bentley transect are mostly Cadeville and Metcalf soils (Hapludalfs and Glossudalfs) (USDA, 1986).

The Upland Complex is mapped as a blanket deposit of sand and gravel across the area mapped as Williana and Bentley of Fisk (193a). The sand and gravel blanket, mapped as the Citronelle Formation by Chawner (1936) on correlative landsca pes in neighboring Catahoula Parish, was deposited on an irregularly dissected Tertiary landscape. The deposit is continuous across much of what Fisk (1938) considered the Bentley Terrace, and is distributed as discontinuous hilltop caps or is absent from some areas originally considered the Williana Terrace. Observations indicate that the formation is generally greater than 10 m thick in the areas originally mapped as Bentley Terrace. Surface soils that develop in the

FS VFS TOTAL SAND TOTAL SILT TOTAL CLAY

13.3 38.4 58.8 36.1 5.1 20.9 26.3 51.5 41.0 7.5 12.1 20.2 34.9 40.2 24.9 18.6 23.8 44.7 40.7 14.6 19.3 24.3 45.3 38.6 16.1 19.4 30.3 51.5 27.8 20.7 15.6 15.4 32.4 39.2 28.3

3.5 12.2 16.2 52.0 31.9 1.8 27.5 29.5 46.6 23.8

outcrop area of the Upland Complex along the WillianaBentley transect are mostly Smithdale, Ruston, Malbis, and Glenmora soils (Paleudults and Paleudalfs) (USDA, 1986).

The yellowish loamy colluvium drapes most upland landscapes of the Tertiary formations and the Upland Complex. In southeastern Louisiana, a similar lithology occurring in the same stratigraphic position is termed the Montpelier Colluvium where it overlies a truncated geosol in the Citronelle Formation (Autin et al., contributed notes, this guidebook). Both deposits may be part of a family of colluvial deposits that veneer landscapes as young as the Intermediate Complex, Montgomery Alloformation (Stop 2, this guidebook).

The cross section along the Williana-Bentley transect (Fig. 1.3) illustrates the geometry of the landscape, the distribution of formations, and variations in lithology within map units. Colluvium is the first unit beneath the land surface at all locations investigated. The thickness of the colluvium varies, but the landscape pattern of thickness variations in

48

Williana - Cross Section North

o 2 4 6 8 10 South 861 ____ ~ ____ ~ ____ L_ __ ~ ____ _L ____ ~ ____ L_ __ ~ ____ _L ____ ~ __ _=22~k,m

84

82

80

78

76

74

72

70

68

66

64

62

60

58

56

Williana

Vicksburg Group Upland Complex

86

84

82

80

78

76

74

56

54-!..-------------------------------------~------~------~ 54

Lithofacies of Williana - Bentley Cross-Section

Iiii Silty Clay Loam, Clay Loam, Clay

~ Silt Loam, Loam, E:..::::::J Loamy Sand Loam,

Loamy Sand

~U Topography

Figure 1.3 - Cross Section of the Williana - Bentley Area.

this area has not yet been determined. Tertiary clay and clay loam was identified in the Williana area in the northern 5 km of the cross section. To the south, weathering profiles of the Upland geosol were identified. The modern land surface is in tensely dissected, however, the upper surface of both the Tertiary formations and the Upland geosol form complex geomorphic surfaces whose forms do not correlate directly with the present landscape.

n:::.1 Sand ~

I'1iJ Sand & Gravel

D Colluvium

- Base of Colluvium

~ Unconformity

Geologic mapping Tertiary geologic units locally mapped are the Vicksburg and Jackson Groups, the Oligocene Catahoula Formation, and the Miocene Fleming Formation. Vicksburg and Jackson lithologies are primarily fine-grained silty and clayey deposits. The Jackson outcrop area is delineated on upland summits by broad, low relief nearly level landscapes. The Vicksburg Group and Catahoula Formation have erratic to saw-tooth shaped topographic contours and dissected den-

49

TABLE 6 - Characteristics of a profile from the Wlliana gravel pit.

Location: Grant Parish, Louisiana; 31 °39'23" N, 92°32'52" W (Sec 23 T8N R2W); Williana, LA 7.5-minute quadrangle; LGS locality RR-22; site is in a gravel pit on an upper sideslope along Forest Service Road 127; profile is on the eastfacing wall ofthe pit; elevation is 76.2 m; slope is 3 to 5 percent; surface soil is mapped as Smithdale Series (Typic Paleudalf).

DEPTH, em HORIZON MATRIX COLOR MOnLECOLOR TEX STRUCTURE CONSIST BDY COMMENTS

0- 30 10YR 3/3 SL fr ab filii rti soil clasts

TOP OF COLLUVIUM 30 - 45 A 1 OYR 6/3 SL wk vfn gr vfr ab rti Wdi chari bur 45 - 60 E 1 OYR 6/3 5YR 5/8 SL wk vfn ab vfr cI rti bur; some rt & bur filled with

1 OYR 3/3 LS 60 - 70 B\E 5YR 5/8 L wk fn ab fr cI rt; bur

GEOSOL DEVElOPED IN CITRONELLE FORMATION OR ITS EQUIVALENT 70 - 120 2Bt1 2.5YR 4/4 SCL mod med sab fm gr C flmi scat 4 - 8 mm G; rot G

120 - 155 2Bt2 2.5YR 4/6 SCL mod med sab fr df C flm; scat 4 - 8 mm G; rot G

155·230 2BC 2.5YR 4/8 SCL wk med sab fr df scat 8 • 16 mm Gi rot Gi tb of 7.5YR 6/8 & 1 OYR 8/2

230 - 270 2C1 2.5YR 4/8 GSL vfr gr abun 8 • 16 mm G; rot G; pock & tb of 7.5YR 6/8 & 1 OYR 8/2 GS

270 - 330 2C2 2.5YR 4/8 SL vfr scat 4 - 8 mm G; rot G; pock, tb, & lame of 7.5YR 6/8 & 10YR 8/2 S

TABLE 7 - Particle Size data for Williana gravel pit-RR22-Smithdale series.

HORIZON DEPTH, cm VCS CS MS FS

A 30 - 45 1.2 6.6 34.0 14.0 E 45 - 60 0.5 5.3 29.9 21.5 B\E 60 - 70 0.4 4.5 24.1 16.0 2Btl 70 - 120 0.7 3.9 24.3 18.0 2Bt2 120 - 155 0.3 3.9 26.1 18.5 2BC 155 - 230 3.7 15.6 40.6 4.6 2C1 230 - 270 5.7 10.3 48.1 13.1 2C2 270 - 330 0.2 4.2 66.9 10.4

dritic drainage networks. Rounded to elongated sloping shoulder slopes and summits indicate isolated, discontinuous outcrop areas of Upland Complex alluvium and/or colluvium covering the Tertiary formations. When the Tertiary units outcrop in side slope to foot slope positions, their geomorphic recognition is considerably more difficult.

The Upland Complex consists of predominantly sand and gravel deposits of what has been previously considered the Citronelle Formation (Matson, 1916; Chawner, 1936). The upper boundary of the fluvial deposit is marked by the Upland geoso!. At most places, the geosol is truncated and buried by younger colluvium. Geosol erosion is more severe in areas originally mapped as Williana Terrace than in the areas mapped as Bentley Terrace.

VFS TOTAL SAND TOTAL SILT TOTAL CLAY

14.6 70.4 26.4 3.1 6.5 63.8 30.2 6.0 8.0 53.0 29.9 17.1 5.7 52.6 20.0 27.4 8.9 57.8 13.5 28.7 5.8 70.4 3.5 26.1 1.1 78.3 2.2 19.5 0.6 82.3 1.1 16.6

Significance of relationships The Upland Complex has been called by a multitude of names (see Mossa and Autin, 1989; Autin et al., 1991 for summaries). Citronelle is the name commonly applied to the eastern GCP, Citronelle or Lafayette is typically applied in the LMV, and Willis and/or Lissie is generally applied west of the LRRV. The LGS geologic mapping program has yet to determined if a boundary exists between these formation names, or if the synonymy implied by Matson (1916) and Rosen (1972) is applicable. Regional petrologic variations as a function of source area differences have not been fully evaluated (see Potter, 1955). Such variations might provide reasons to adhere to traditional formation names that are presently considered provincial (Autin et al., 1991).

The Upland Complex was deposited on a Tertiary erosion surface with a complex landscape history. The modern

50

TABLE 8 - Characteristics of a core from beneath Fisk's (1938) Bentley Terrace type locality

Location: Grant Parish, Louisiana; 31°30'04" N, 92°31'44" W (Sec 5 T6N R1W); Dry Prong, LA 7.5-minute quadrangle; LGS locality RR-11; site is on a topographic flat along the right of way of US Hwy. 167; elevation is 73.2 m; slope is 0 to 1 percent; surface soil is mapped as Glenmora Series (Glossaquic Paleudalf).

DEPTH, em HORIZON MATRIX COLOR MOTTLE COLOR TEX STRUCTURE CONSIST BDY COMMENTS

0- 50 10YR 7/3 L fr ab filii rti G; soil clasts

TOP OF COLLUVIUM 50 - 75 B\E 1 OYR 6/8 10YR 7/2 L fr cI po filled with 10YR 7/3 L; 2.5YR 4/

8plin 75 - 11 0 Bt 1 OYR 6/8 10YR 7/2 CL md med pty fr gr rt; disc 10YR 5/4 C flm on peds; 2.5YR

5/6 plin; 10YR 7/2 SiL tng 110 - 190 BC 1 OYR 6/8 2.5YR 5/6 CL md tn pty fr gr 1 OYR 7/2 SiCL tng 190 - 210 BC&2BC 2.5YR 5/6 1 OYR 6/8 SC wk tn pty fr cI 10YR 7/2 SiCL tng

TOP OF TRUNCATED GEOSOLIN CITRONELLE FORMATION OR ITS EQUIVALENT 210-295 2BC 2.5YR 4/6 7.5YR 6/6 SCL wk tn pty fr gr 10YR 7/2 SiCL tng 295 - 325 2Cl 7.5YR 6/6 2.5YR 5/6 SL vfr cI 2.5YR 4/8 st on rt tr 325 - 370 2C2 10YR 7/8 10YR 7/3 SL fr cI 2.5YR 5/6 st 370 - 395 2C3 2.5YR 5/8 10YR 7/8 SL fr gr 395-415 2C4 2.5YR 5/8 SL fr ab 7.5YR 7/8 st 415 - 485 2C5 5YR 6/6 med S 10 df 485 - 500 2C6 10YR 7/8 med S 10 df 500 - 600 2C7 5YR 6/6 fn S 10

TABLE 9- Particle Size Data for Bentley Core- RRll- Glenmora Series

HORIZON DEPTH, em VCS CS MS FS

B\E 50 - 75 0.5 0.4 1.6 1.6 Bt 75 - 110 0.1 0.1 0.9 7.6 BC 110 - 190 0.0 0.1 0.5 9.2 BC&2BC 190 - 210 0.0 0.1 0.4 4.5 2BC 210 - 295 0.0 0.0 0.4 16.9 2C1 295 - 325 0.1 0.1 0.7 20.5

2C2 325 - 370 0.0 0.0 2.6 7.3 2C3 370 - 395 0.0 0.1 3.3 18.2

2C4 395-415 0.0 0.0 2.7 14.2

drainage network was probably not established and many of the Upland Complex streams crossing the LRRV in Central Louisiana may not be directly related to the LRRV. Field observations support the inferences of Kesel (1987) that paleocurrents were primarily from a set of NE to SW flowing braided stream alluvial aprons. These alluvial aprons were part of a regional set of aprons across the northern GCP. Upland Complex deposits to the NW ofthe Bentley-Williana area were likely associated with an ancestral Red River Valley. Reconnaissance observations suggest that the red jasper content of the granule gravel fraction may increase in the LRRV to the northwest. Source sediments were primarily coarse-grained siliciclastics. The red color of the sediments appears to be derived from weathering of iron bearing minerals. A set of erosion surfaces developed after deposition of the alluvial aprons. The erosion surface complex has a mantle of colluvium that locally veneers the Intermediate Complex, Montgomery Alloformation and older landscapes.

VFS TOTAL SAND TOTAL SILT TOTAL CLAY

32.6 36.5 42.1 21.4 23.6 32.3 37.1 30.6 30.7 40.5 29.6 29.8 46.4 51.5 12.6 36.0 42.9 60.2 11.3 28.5 48.5 69.8 12.1 18.1 60.4 70.3 14.1 15.5 42.2 63.9 10.9 25.2 51.8 68.8 12.7 18.4

51

Pimple Mounds Several miles north of Montgomery, on your way to FOP stop #2 pimple mounds can be seen in a pasture on your right. The leveling effects of agriculture and mechanized logging have eliminated the pimple mounds in much of the area, but these are unmodified classic examples. These natural hillocks exist on both Tertiary and Quaternary deposits in Louisiana, Arkansas, Texas, Missouri, and Kansas, but have never been reported east of the Mississippi (Murray, 1948).

Pimple mounds occur on hilltops, sideslopes, and valley bottoms, but seem to be best developed on sandy terrace flats. Owen (1860) was probably the first to describe them and his origin theory was that of differential weathering. Subsequent writer's theories have included mud lumps, hydrostatic pressure, vegetation clumping, indian mounds, whirlwinds, ant hills, sand dunes, indian agricultural practices, ground squirrels, pressure, artesian waters, soil horizon thickening, and poor drainage. There is increasing evidence in recent years that "all features referred to as pimple mounds were not formed by the same agent" (Holland, 1943).

-John Snead

52

STOP

Late Middle Pleistocene Evolution of a Constructional Alluvial Plain

Review of the Montgomery Area and the St. Maurice Section

W. J. Autin, ,. I. Snead, P. M. Walthall, D.'. McCraw, and W. J. Day

"The Montgomery Terrace is so named because of its typical development on the southern outskirts of the town of Montgomery, near the intersection of U. S. Highway 71 and State Highway 162. The terrace forms the divide between small streams flowing west into Red River and those flowing east into Nantaches Creek, which follows the base of an escarpmen t marking the eastern limit of the terrace. Although marginal erosion has destroyed much of its initial flatness, enough of the Montgomery surface is preserved to reveal its original character./I

Location The St. Maurice-Montgomery-Wadell transect (Fig. 2.1), located in northwestern Grant and southwestern Winn Parishes, illustrates the soil geomorphic and stratigraphic characteristics of what is likely the oldest preserved Pleistocene meander belt of the LRRV. The traverse along U. S. Highway 71 from the St. Maurice railroad cut, through the town of Montgomery, to Wadell Bluff follows a nearly contiguous outcrop of the ancestral alluvial plain. Locally, this landform produces the drainage divide between the Red River Alluvial Valley and N antachie Creek, a tributary of the Red River. Sedimentologic and pedologic features of the Montgomery core (RR12) and the St. Maurice railroad cut illustrate common stratigraphic relations observed in the area. This stop highlights the lithofacies patterns of an ancestral LRRV meander belt with red bed source area sediments, burial of the alluvial deposit by a veneer of colI uvi urn, and the effects of drainage network development on the morphology of a constructional geomorphic surface. Historically, investigators have commonly discussed the stratigraphy at St. Maurice (Harris and Veatch, 1899), and Nfontgomery Landing and Wadell Bluff (Fisk, 1938; Alfordet aI., 1985; Alford and Holmes, contributed note to this guidebook). However, reconnaissance visits have shown that Montgomery Landing and vVadell Bluff are poorly exposed at present and provide limited information on the sedimentary sequence beneath Fisk's (1938) Montgomery Terrace.

Topography and Geomorphology Elevations along thetransect range from about 55 m north of Montgomery to less than 31 m in local gullies near vVadell. Topographic highs, reflecting the geomorphic sur-

-Fisk~ 1938~ p. 56-57

face preserved by the upper limits of alluvial aggradation, typically range from 52 to 44 m in the transect area. The landscape is mostly level to gently sloping, except for locally steep slopes near local gullies and escarpments. Small streams that dissect the edges of the geomorphic surface commonly headwater on alluvial flats to form weakly-expressed dendritic networks. Constructional alluvial landforms, such as abandoned channels, point bar and natural levee ridges, and ridge and swale topography cannot be readily identified without soils or sedimentologic data. Pimple mounds locally occur along the transect between Montgomery and St. Maurice. Fisk's (1838) Montgomery Terrace was correlated to the Intermediate Terraces (Snead and McCulloh, 1984) and the Intermediate Complex (Saucier and Snead, 1989).

Site Characterization The Montgomery core is from an area near where Fisk (1938a) described a typical Montgomery Terrace landscape. A 12.1 m core reveals a sequence of 1.3 m of colluvium over a paleosol developed in the Montgomery alluvial fill (RR12, Tables 10 and 11). The colluvium is a 7.5YR mottled loam. A surface soil with a 2.5YR argillic horizon developed through the colluvium and the upper sandy clay loam cap of the underlying alluvium. The surface soil has weak to moderately developed soil structure and clay films on peds. The B horizon grades to a C horizon developed in the upper part of a point bar facies. The core terminated on a water saturated loamy sand with gravel. A distinct lithologiC discontinuity can be identified in the core within the B horizon. This discontin uity marks the stratigraphic boundary between the colluvium and the underlying alluvium. Total silt percent drops substantially along with a sharp increase in total clay per cent across this boundary (fable 11). The colluvium has a higher silt content than the underlying alluvium.

53

~ Hrm Red River Ppl Prairie Complex (Lower Surface)

\ Location of

Meander Belts Ppu Prairie Complex (Upper Surface) Montgomery

~ Red River Cross Section Hri

Natural Levee Pi Intermediate Complex ~ • RR 12 Core Location ~ Hb Backswamp Pm Intermediate Complex-

g Hu Alluvium Montgomery Surface (Undifferen tia ted) Pu Upland Complex N

~ Tej Jackson Group (Undifferentiated) 0 5

t Claiborne Group I I ~ Tee (Sparta and Cook Mountain Formations Kilometers ~ Undifferentiated) ~ Teee Claiborne Group (Cockfield Formation)

Figure 2 .1 - Geologic Map of the Montgomery Area. The transect of the Montgomery-Waddel Cross Section is indicated.

54

The St. Maurice rail road cut exhibits facies patterns and stratification typical of the bed load sediment preserved in channel belt lithofacies. Three exposures combine to produce a 1000 m long view of the stratigraphy along the bluff adjacent to the alluvial valley (Fig. 2.2). The elevation of the railroad grade is at 40 to 41 m. The southern end of the exposures are where a local dirt road heads into the flood plain of the Red River towards St. Maurice Lake. The 1000 m point of the transect is at the railroad bridge across Saline Bayou.

Exposure I, at the northern end of the exposure set, has a 4 m vertical cut into Tertiary beds along the east wall of the cut. Exposed is a reddish brown (SYR 5/3) clay with thin silt laminations, reddish yellow and brownish yellow (7.SYR and 10YR 6/8) stains, and paper thin iron stained and indurated silt beds. This lithology grades laterally to a light gray and white (SY 7/2 and 8/2) lens of clay and silty with yellow (2.SY 7/8) mottles and very dark brown and yellowish red (10YR 2/2 and SYR 5/8) stains.

Exposure 2 is a continuous cut of up to 7 m thick and about 150 m long. Exposures of Pleistocene sand and gravel and Tertiary beds are on both the east and west walls. The upper part of the alluvium has been eroded from dissection near the terrace escarpment. The cut reveals a 4 m thick red sandy lithofacies that is the lower part of the weathering profile. A 1.5 m thick gravelly facies marks the base of the alluvium. The upper 60 em of the gravelly facies is a set of matrix supported lenticular gravelly sand beds with a small-scale fining upward cycle. The lower 90 em is a mostly clast supported sandy gravel, with individual clasts up to 8 mm diameter, and the basal bed having even coarser clasts. The lowest lithofacies in the cut is a 1.5 m sequence of the Eocene Cockfield Formation, a bedded sand with abundant clay rip clasts and iron stains on beds.

Exposure 3 is a continuous cut of up to 12 m thick and about 350 m long. The general stratigraphie sequence reveals that the Montgomery alluvium has an upper reddish sandy

Figure 2.2 - Topographic Map of the St. Maurice Area.

55

TABLE 10- Charcteristics of a Core from Beneath Fisk's (1938) Montgomery Terrace Type Locality.

Location: Grant Parish, Louisiana; 31°39'SO" N, 92°S3'OS" W (Sec 21 T8N RSW); Montgomery, LA 7.S-minute quadrangle; LGS locality RR-12; site is on a topographic flat in a yard of an abandoned home west of US Hwy. 71; elevation is 48.8 m; slope is 0 to 1 percent; surface soil is mapped as Kolin series (Glossaquic Paleudalf).

DEPTH, em HORIZON MATRIX COLOR MOTTLE COLOR TEX STRUCTURE CONSIST BOY COMMENTS

TOP OF COLLUVIUM 0-10 Ap 10YR 7/4 SL fr cI fill; rt; G 10- 45 A\E 10YR 7/4 7.5YR 6/6 SL fr ab overwash; rt; 5YR 5/8 cone 45 - 70 E\B 7.5YR 5/8 L wk fn ab fr cI rt; po; bur; disc 5YR 5/8 C tim in po&

on peds 70 -100 B\E 5YR 5/8 7.5YR 5/6 L wk med ab sl hd gr po & bur, some filled with 10YR 8/1 fS;

7.5YR 7/6 L tng 100 - 130 Bt 2.5YR 5/8 7.5YR 7/6 SCL wk med sab sl hd cI po; 5YR 5/4 & 7.5YR 5/4 C flm on ped;

tng 1 OYR 8/4 LS

TOP OF THE INTERMEDIATE COMPLEX, MONTGOMERY ALLOFORMATION, POINT BAR FACIES 130 - 190 2Bt1 2.5YR 5/8 7.5YR 8/6 SCL mod med sab sl hd df 2.5YR 4/6 C flm on peds; 5YR 5/4 &

7.5YR 5/4 C flm on peds, po, & rt tr; 1 OYR 8/3 LS tng

190 - 230 2Bt2 2.5YR 5/8 SCL md med sab sl hd cI po; rt tr; 2.5YR 4/6 C flm on peds; 10YR 7/2 LS tng

230 - 320 2BC 2.5YR 5/8 SCL md med pty fr cI 2.5YR 4/6 C flm on peds & rt tr 320 - 350 2C1 5YR 6/6 SL wk tn pty vfr gr 350 - 440 2C2 5YR 7/4 LS 10 df 440 - 750 2C3 5YR 8/4 fn S 10 df 5YR 6/8 & 10YR 7/8 st 750 - 880 2C4 7.5YR 7/4 fn S 10 df

880 - 940 2C5 7.5YR 7/4 LS 10 cI 5G 7/1 C clasts at 920 em 940 - 995 2C6 7.5YR 7/4 LS 10 cI sat; 1 OYR 2/2 & 1 OYR 6/8 st at top of

water table 955 -1210 2C7 7.5YR 7/4 LS 10 sat; G

TABLE 11 - Particle Size Data for Montgomery Core-RR 12 -Kolin Series

HORIZON DEPTH, em VCS CS MS FS VFS TOTAL SAND TOTAL SILT TOTAL CLAY

Ap 0- 10 2.6 7.2 12.2 18.0 26.7 66.8 28.7 4.5

A\E 10- 45 1.5 2.1 4.0 13.3 38.3 59.2 35.0 5.8

E\B 45 - 70 0.8 0.4 0.5 7.5 30.2 39.3 40.4 20.3

B\E 70 - 100 0.6 0.1 0.2 0.2 50.8 51.9 33.7 14.5

Bt 100 - 130 0.1 0.1 0.2 8.5 41.6 50.5 27.5 22.0

2Bt1 130 - 190 0.0 0.0 0.1 12.7 42.3 55.1 12.8 32.1

2Bt2 190 - 230 0.0 0.0 0.2 10.9 51.1 62.2 12.6 25.2

2BC 230 - 320 0.0 0.0 0.3 13.2 54.5 67.9 11.1 20.9

2C1 320 - 350 0.0 0.0 0.2 44.4 37.2 81.8 7.7 10.5

2C2 350 - 440 0.0 0.1 0.6 39.8 46.3 86.8 11.2 2.1

2C3 440 - 750 0.0 0.2 2.5 47.4 39.8 90.0 6.1 4.0

2C4 750 - 880 0.0 0.1 1.1 52.5 36.9 90.6 5.0 4.4

2C5 880 - 940 0.1 1.4 7.5 33.7 44.1 86.7 8.0 5.3

2C6 940 - 995 0.8 5.6 21.6 40.4 18.0 86.5 8.6 4.9

2C7 995-1210 0.2 4.1 16.8 42.0 21.1 84.3 8.8 6.9

56

TABLE 12- Characteristics ofa Vertical Profile From the Montgomery Alloformation At the St. Maurice Railroad Cut.

Location: Winn Parish, Louisiana; 31 °45'27" N, 92°57'24" W (lrreg Sec 37T9N R6W); St. Maurice, LA 7.5-minute quadrangle; LGS locality RR-38; site is at a railroad cut a about 1 km west of the village of St. Maurice; elevation is 49.2 m; slope is 5 to 8 percent; surface soil is disturbed.

DEPTH, em MOTTLE COLOR TEX STRUCTURE CONSIST BOY COMMENTS

0-200 DISTURBED COLLUVIUM, MIXED WITH SPOIL

TOP OF THE INTERMEDIATE COMPLEX, MONTGOMERY ALLOFORMATION, POINT BAR FACIES

200 - 300 2Bt 2.5YR 4/6 7.5YR 8/6 SL wk med sab fr df rt; C tim on peds; overgrown

and poorly exposed

300 - 440 2Cl 5YR 5/6 LS

440 - 600 2C2 5YR 5/6 7.5YR 8/4 S

600 - 750 2C3 5YR 5/6 1 OYR 8/2 S

750 - 950 2C4 5YR 5/8 SG

COCKFIELD FORMATION, EOCENE CLAIBORNE GROUP

950 -1250 5Y 8/1 S

weathering profile, an underlying bedded yellowish sand that grades to gravelly sand, then a basal gravel lag deposit. The gravel lag rests on an unconformity with the underlying Eocene Cockfield Formation, a fine to medium sand with common to abundant clay chips, no gravel, and intricate patterns of iron staining. The thickest vertical profile of the exposure is at 290 m on the west wall. This profile, which illustrates most of the common features observed in exposure, is summarized in Table 12.

The continuity of the Montgomery alluvium in the St. Maurice railroad cut is disrupted by two distinct channel fills. At 180 m, a 4 m thick channel fill sequence consists of a light gray (10YR 7/2) silt loam Bt horizon with red (lOR 4/ 8 and 2.5YR 5/6) mottles, moderate angular blocky structure, and hard consistence. The underlying white (2.5Y 8/2) BC and Chorizonshaveyellowishred (5YR5/6) mottles, and texture grades from a friable loam to sandy loam. A loose sand and basal gravel rests beneath the erosional scour surface at the base of the channel fill. A second 4 m thick channel fill at 380 m cuts through the Montgomery sands and thin basal gravel into underlying Cockfield sand beds. The channel fill sequence is lithologically similar to the profile at 180 m, however the cross sectional dimension of the lens is wider, and also appears to be slightly siltier. Both of these lenses have smaller dimensions than a modern Red River channel cross section, cut into and through the Montgomery alluvium, and have lithologies and geometries that suggest an origin as local gully fills that formed subsequent to Montgomery aggradation.

Stratigraphy of sediments and soils Along the St. Maurice-Montgomery-Wadell transect, the Montgomery alluvium rests unconformably above the Ter-

vfr

10 10

10

10

cI bur; G clasts 4 - 8 mm; pock

7.5YR 8/3 S

ab 2.5YR 4/8 lame of LS

ab scat G up to 8 mm; 2.SYR 5/8

st; 1 OYR 8/2 bleached zones

ab fabric is mostly clast supported;

8 -16 mm G

bedded with complex stain

zones

tiary stratigraphic sequence (Fisk, 1938a; Smith and Russ, 1974). Units outcropping in the area range from the Eocene Claiborne Group to the Miocene Fleming Group (Snead and McCulloh, 1984). The local Tertiary outcrop pattern is illustrated on the geologic map of the area (Fig. 2.1 ). The lithologic character of the lowermost facies in the St. Maurice rail road cut is similar to sediments mapped as the Eocene Cockfield Formation exposed along U. S. Highway 84 west of Winnfield, about 25 km north of St. Maurice. Data from U.S. Army Corps of Engineers investigations (Smith and Russ, 1974) and LGS field localities suggests that the thickness of a complete vertical profile of the Montgomery aggradational sequence should be on the order of 15 m.

The character of the Montgomery geomorphic surface, lithologic and geometric properties of lithofacies, and the unit's distinctive basal and lateral boundaries suggest that the unit can be considered as an alloformation. The Montgomery Alloformation has facies variations that indicate a tendency for fining upward vertical profiles with sandy and loamy facies grading down to sandy and gravelly facies in and near channel belts, and localized areas of clayey backswamp facies in flood basin areas away from channel belts. The St. Maurice rail road exposure of bedded sands and gravels grading upwards into sandy and loamy sediments indicates meander belt aggradation. The Montgomery core has similar properties (Tables 10 and 11), with a distinct fining upward profile of a point bar facies grading upward to an upper point bar/natural levee facies. Surface soils that develop in the outcrop area of the Montgomery Alloformation along the St. Maurice-Montgomery-Wadell transect are mostly Gore, Kolin, Malbis, and Glenmora soils (Paleudalfs) (USDA, 1986). The Kolin is the only surface soilofthis group with a lithologic discontinuity defined within its soil profile (USDA, 1986).

57

Montgomery Cross Section North

o South

26km 561-----~----~--~----~----~----~----L---~-----L----~----~----~----+56

4 6 8 10 2 12 14

54

52

50

48

46

44

42

40

38

36

34

St. Maurice

rn Tn TTl TI'J-r, Eocene Cockfield Formation"""" r-r-,. /"

Montgomery Wadell 54

52

50

48

46

44

42

40

38

36

34

32

30

28 Lithofacies of Montgomery Cross-Section

32

30

28

26

24

Red River ~ Silty Clay Loam, ~ Sand

Oay Loam, Oay 26

24 m Sand & Gravel

Silt Loam, Loam,

22

~ Loamy Sand Loam, D Colluvium Loamy Sand 22

lQQI Covered Interval -- Base of Colluvium

20~---------------------------------------------------------------------------L20

Figure 2.3 - Cross Section of the St. Maurice - Montgomery - Waddell Area.

The colluvium drapes the Montgomery Alloformation as a veneer deposit, covering the Montgomery constructional geomorphic surface. The colluvium generally is a loam with a total silt content higher than the underlying alluvium (Table 11). The colluvial veneer over the Montgomery Alloformation is probably a facies of the colluvium identified on higher landscape positions (Stop 1, this guidebook). An alternative interpretation is that the colluvium on the Montgomery Alloformation inherits much of its lithologic character from reworking of the colluvium from higher landscapes and deposition on lower landscape positions.

The cross section along the St. Maurice-Mon tgomery-Wadell transect (Fig. 2.3) illustrates the geometry of the landscape, the stratigraphie relation between the Montgomery Alloformation and the overlying colluvium, and variations in Montgomery Alloformation lithofacies. The colluvium is the first unit beneath the land surface at all locations investigated, except where local gully fill sequences were encountered. The thickness of the colluvium varies slightly, but the pattern of thickness variations in this area appears to be related to post depositional sheet erosion and terrace edge gully dissection. Clay to silty clay loam lithofacies of the

upper Montgomery Alloformation reflect deposition in backswamp environments, whereas loamy to sandy lithofacies reflect deposition in a channel belt environment. Vertical profiles typicall y become sandy with depth, grading to loamy sand and sand with occasional gravel. A basal gravelly channellagfacieswas observed everywhere the base of the Montgomery Alloformation has been confidently identified.

Geologic mapping Fisk (1938) initially mapped the area of the St. MauriceMontgomery-Wadell transect as his Montgomery Terrace. The LGS revision of the type area distribution of the Montgomery Alloformationis illustrated in the geologic map (Fig. 2.1). Subsequently, Smith and Russ (1974) and Russ (1975) correlated the southern part of this transect (Fig. 2.3, 20 to 26 km) as part of their Prairie Terrace. Alford et al. (1985) revisited the Wadell Bluff locality described by Fisk (1938) and obtained 23 to 30 ka radiocarbon age estimates from organic deposits from greater than 20 m below the top of Wadell Hill. An update of the age estimates at Wadell Bluff is provided as a contributed note to this guidebook (see

58

Alfoi'd and Holmes). The LGS core collected from Wadell Hill (Fig. 2.3, RR 37) did not penetrate the lithology with the preserved organic debris reported by Fisk (1938) and Alford et al. (1985).

This apparently incompatible set of observations produces the following set of alternate possibilities to explain the stratigraphic significance of Wad ell Bluff. 1) IfWadell Bluff is Wisconsinan as inferred by Alford et al. (1985), then this is the likely age of the Montgomery Alloformation. However, tentative regional correlations suggest that the Montgomery Alloformation and the Prairie Complex, Upper Surface predate the Sangamonian interglacial. 2) The regional distribution of colluvial veneers and Sicily Island Loess, plus Sangamonian and pre-Sangamonian TL dates for deposits beneath the Prairie Complex, Upper Surface (Harrelson and Smith, 1988) support a middle Pleistocene age for the Montgomery Alloformation. 3) Wadell Bluff does not correlate to Aloha, since Wadell Hill is 7 m higher in elevation than Aloha, the Red River Prairie Terrace type locality of Fisk (1938) (Stop 3, this guidebook). Wadell Hill is also veneered by colluvium, whereas none of the Aloha cores are veneered by this colluvium. 4) Regional stratigraphic projections suggests that Aloha is correlative to the Mississippi River lithofacies of the Avoyelles Prairie (Stop 9, this guidebook). The A voyell es Prairie has an inferred middle to late Wisconsinan age, based on the local relation to the Prairie Complex, Upper Surface at Holloway, a 27 ka radiocarbon age at the correlative Mt. Pleasant Bluff type locality (Autin et al., 1988), and regional distribution of Peoria Loess that buries the paleosol on the Avoyelles Prairie and at Mt. Pleasant Bluff.

Present geologic map revisions correlate the Montgomery Alloformation to the a constructional alluvial fill of the Intermediate Complex. The Montgomery Alloformation is differentiated from the Upland Complex by its lower topographic elevation, preservation of a constructional landscape, and preservation of a fining upward alluvial fill with channel belt and flood basin lithofacies identifiable in ancestral LRRV deposits. The Montgomery Alloformation is differentiable from younger Prairie Complex stratigraphic units based on its higher topographic elevation, greater degree of stream dissection, and better developed gullies near escarpments. Constructional landform features are also distinctly definable on the younger surfaces of the Prairie Complex. Mappable thicknesses of colluvium are absent from vVisconsinan Prairie Complex units such as at Aloha (Stop 3, this guidebook), the Avoyelles Prairie (Stop 9, this guidebook), and other Prairie Complex Wisconsinan equivalents.

Correlating the Montgomery Alloformation from the main axis of the LRRVintolocal tributary streams is tenuous. Local correlatives are absent to rare in tributaries because 1) some tributaryvalleysmaypostdatetheMontgomeryalluviation, and 2) older fills of the Prairie Complex are readily discernible only where they are preserved adjacent to younger Prairie Complex deposits. Differentiating multiple Prairie Complex surfaces and their deposits is possible only with detailed morphologic data such as projections of alloformation slopes,lithofacies patterns, and soils geomorphic comparisons.

Significance of relationships The Montgomery Alloformation is apparently the oldest constructional meander belt alluvium in LRRV. The alluvial fill associated with this unit has differentiable channel belt and flood basin lithofacies. The alloformation reflects the initiation of sediments derived from a red bed source area in the Southern Great Plains (Gustavson et al., 1981).

The Montgomery Alloformation is the alluvial fill associated with Fisk's (1938) Montgomery Terrace. The Montgomery Alloformation is a valid LRRV stratigraphic unit, however the regional extent inferred by Fisk (1939, 1944) has yet to be verified. The Montgomery Alloformation is presently considered a regionally correlative to the Intermediate Complex. An alternative interpretation is that the Montgomery Alloformation is a Red River alluvial fill regionally correlative to the Prairie Complex. Through much of the coastparallel Pleistocene of the northern GCP, the Intermediate Complex is a set of erosion surfaces developed on the Citronelle Formation (Autin et al., contributed note, this guidebook). The erosion surface complex has a mantle of colluvium that veneers the Montgomery Alloformation locally in the LRRV. Either the Montgomery Alloformation is part of what is elsewhere mapped as the Prairie Complex, Upper Surface (Autin and McCulloh, 1991, 1992), or it represents an alluvial fill that has not yet been recognized outside of the LRRV.

59

Fossil Flora in Pleistocene Gravel

In some Pleistocene gravel deposits there is a high percentage of petrified wood among the pebbles. Petrified palmwood is a common find on gravel bars in Louisiana rivers and also in the bedded deposits of the Pleistocene streams and is oneofthetwo official Louisiana State Fossils by Legislative decree (the other is Senator B.B. "Sixty" Rayburn -11m serious!).

The Eocene Claiborne Group of North Louisiana is rich in petrified wood and is the closest source area although some well-rounded specimens may have traveled much farther. Occasionally rather large pieces including whole petrified tree stumps can be found in Pleistocene basal deposits.

The angular 1 O-pound Petrified Wood specimen pictured was collected from the base of the Pleistocene at the St. Maurice railroad cutl the FOP stop #2 location.

-John Snead

60

STOP 3

Wisconsinan Constructional Alluviation

Review of the Aloha Prairie Area

W. J. Autin, J. 1. Snead, P. M. Walthall, D. J. McCraw, and W. J. Day

"The name Prairie Terrace is proposed for a surface typically developed near Aloha, sec. 16, T. 7 N., R. 4 W., Grant Parish and at Nebo School, irregular sec. 40, T. 7 N., R. 3 E., La Salle Parish. This surface is characteristic of the most distinctive terrace in central Louisiana. Along the western border of the Mississippi valley, in this general region, the identical surface has been known since earliest settlement as "Prairies." Locally, it has been referred to as the Catahoula Prairie (at Nebo School), Holloway Prairie, and Avoyelles Prairie (Hills)."

Location Th e Aloha Prairi e transect (Fig. 3.1), I oca ted in western Gr an t Parish, illustrates the soil geomorphic and stratigraphic characteristics of a Wisconsinan age LRRV meander belt with distinct remnants of constructional topography(fig.3.2). Aloha is a terraced remnan t in the LRRV along U. S. Highway 71 about 10 km northwest of Colfax. Across section through Aloha (Fig. 3.3) to an equivalent remnant on the valley wall north of Bayou Grappe illustrates common stratigraphic relations and variations in sedimentologic and pedologic features observed in the area. The Aloha Prairie provides a good example ofLRRVWisconsinan meander belt lithofacies with preservation comparable to Holocene deposits. Its relation to surrounding geomorphic surfaces is a good example of the difficulties in subdividing the Prairie Complex into components. Its internal architecture provides an example of how allostratigraphy can help to define and delineate Quaternary deposits. Fisk (1938) described the area at Aloha Cemetery as an example of the general character of the Prairie Terrace in the LRRV. Reconnaissance data indicates that the preservation of this unit in the LRRV is of limited areal extent relative to Fisk's (193a) Montgomery Terrace and the Upper Prairie Terrace of Smith and Russ (1974) and Russ (1975).

Topography and geomorphology Elevations on the Aloha Prairie range from about 36 to 37m in the channel belt to slightly less than 34 m in the distal flood basin. Elevations are less than 28 m in the abandoned Holocene Corefine Bayou-Bayou Grappe channel belt. Topographic highs reflect the preserved upper limits of point bar aggradation in the transect area. The landscape is mostly level to gently sloping, except for locally steep slopes near local gullies and escarpments. Constructional alluvial landforms, such as abandoned channels, point bar and natural levee ridges, and ridge and swale topography can be identified. However, their delineation is easier in areas with

61

-Fisk, 1938, p. 51-52

greater con tiguous areal exten t preserved. Drainage network developmen t is minimal, with small surface streams occupying abandoned Pleistocene channels.

Site Characterization The Aloha core is from where Fisk (1938) described a typical Prairie Terrace landscape for the LRRV. Other relevant Prairie Terrace localities described by Fisk (1938, 1940) include Nebo in the Little River valley, and Holloway and Avoyelles Prairies of the LMV. The Avoyelles Prairie is discussed in Stop 9 of this gUidebook. A 10.5 m core (RR18, Tables 13 and 14) reveals a sequence of interbedded backswamp and natural levee facies of the Red River. The surface soil is a paleosol developed in backswamp facies of the alluvial fill. The thin 25 cm silt loam Ap-E horizons are considered to be partly developed by surface sheet wash, but may also result from pedogenic eluviation at the top of the alluvial deposit. The paleosol has red silty clay Bt-BC horizons with light gray mottles and stains on peds and root traces, blocky structure, and slightly hard consistence. The silty clay C horizon is structureless, has discontinuous stains on root traces, and has occasional slickensides. In the Aloha core, backswamp facies are differentiated from naturallevee facies primarily by texture. Backswam ps typically have clay, silty clay or silty clay loam texture, whereas, natural levees have loam, silt loam, or silty clay loam textures. Natural levee facies are typically less than 2 m thick, whereas backswamp facies are of variable thickness.

Stratigraphy of sediments and soils The Aloha Prairie has facies variations from flood basin backswamps to channel belt point bars and channel fills. The variability across the Aloha area is illustrated by the cross section (Fig. 3.3). Channel belt facies have a tendency for fining upward vertical profiles with sandy and loamy facies grading down to sandy and gravelly facies. Backswamp facies are mostly clayey, with silty interbeds representing

~ Hrm Red River P~ Prairie Complex (Lower Surface) 0 5 Meander Belts

Prairie Complex (Upper Surface) ~ N

~ Red River Ppu

Kilometers i Hrf Natural Levee PI Intermediate Complex

~ Toc Catahoula Formation

~ Hb Backswamp Pm Intermediate Complex- \ Location of Cross Sections

§ Alluvium Montgomery Surface Hu (Undifferentiated) Pu Upland Complex • RR 18 Core Location

Figure 3.1 - Geologic Map of the Aloha Prairie Area. The transect of the Aloha Prairie Cross Section is indicated.

pulses of levee sedimentation into flood basin areas away from channel belts. The predominant surface soil of the Aloha Prairie is the Gore series (Paleudalfs) (USDA, 1986). The Gore series is associated with Cahaba and Bienville soils (Hapludults and Paleudalfs) on correlative geomorphic surfaces in nearby Rapides Parish (USDA, 1980). The surface A and E horizons across the Aloha Prairie are considered to have developed as a sheet wash deposit of silt loam. Although the texture of the surface horizons is fairly uniform across the Aloha transect (Fig. 3.3), the thickness of the surface horizons are greater over the meander belt facies than over backswamp facies. Pedogenic eluviation is likely to have been a significant process of surface horizon development, and the characteristics of these surface horizons does not appear to have stratigraphic significance.

Geologic mapping Fisk (1938) initially mapped the Aloha area as the Prairie Terrace in the LRRV. All subsequent geologiC map compilations have correlated this area to the regional Prairie Terrace (Smith and Russ, 1974; Russ, 1975; Snead and McCulloh,

1984; Saucier and Snead, 1989). The relationship between its geomorphic surface and lithofacies suggests that the Aloha Prairie can be considered as an alloformation. Regional stratigraphic projections suggests that the Aloha Alloformation is correlative to the Avoyelles Prairie (Stop 9, this guidebook).

The Aloha Alloformation is situated topographically above geomorphic surfaces correlated to the Deweyville Complex and Holocene Alluvium. It is lower than geomorphic surfaces associated with the Prairie Complex, Upper Surface, the Montgomery Alloformation, the Intermediate Complex, and the Upland Complex. Soils of the Aloha Alloformation are typically Alfisols and Ultisols and have argillic horizons, distinguishing them from soils developed in Holocene Alluvium. The Aloha Alloformation has readily identifiable meander belt lithofacies and its geomorphic surface has preserved distinct constructional alluvial landforms identifiable on most modern topographic maps, soils maps, and aerial photographs. Soil development is comparable to older units of the Prairie Complex. However, the

62

Aloha Alloformation lacks a distinctly mappable veneer of yellowish colluvium, diagnostic to older surfaces.

Correlating the Aloha Alloformation from the trunk of the LRRV into local tributary streams is complicated, but sometimes possible. Local correlatives are easiest to define in larger valleys like the Little River and in areas where they are preserved adjacent to older Prairie Complex deposits.

Significance of relationships The Aloha Alloformation is apparently the youngest constructional meander belt alluvium of the Prairie Complex in the LRRV. The alluvial fill associated with this unit has differentiable channel belt and flood basin lithofacies. Sediments associated with this unit were derived from a red bed source area in the Southern Great Plains.

The Aloha Alloformation is the alluvial fill associated with Fisk's (1938) Prairie Terrace in the LRRV. The Aloha Alloformation appears to be a valid LRRV stratigraphic unit, however the regionally extensive uni t inferred by Fisk (1944) has variable lithologic, morphologic, and pedologic properties. These variations reflect different source areas, different styl es of fl uvial archi tecture, and deposi tional environments associated with other than fluvial systems. Detailed regional paleogeographic reconstructions of the LRRV, LMV and GCP have yet to be produced.

The term Aloha Alloformation should be restricted to middle to late Wisconsinan meander belt alluvium of the LRRV. Stratigraphically equivalent Red River channel belts in southwestern Louisiana west of the Lafayette meander belt (Fisk

Figure 3.2 - Topographic Map of the Aloha Prairie Area.

63

Aloha Prairie Cross Section

West

Elevation a (m)

56

54

52

50

48

46

44

42

40

38

1 2 3 4 5

Road Cut Prairie Complex RR 20 I

36

34

32

30

28

26

24

22

Holocene Red River Alluvium

Lithofacies of Aloha Alloformation

~ Silty Clay Loam, ~ Clay Loam, Oay

Silt Loam, Loam, Q ~ Loamy Sand Loam,

Loamy Sand

I :: .;.:) Sand

~ Sand & Gravel

E: Unconformity

Figure 3.3 - Cross Section of the Aloha Prairie Area.

64

6

East

7km Elevation (m)

56

54

52

50

48

46

44

42

40

38

36

34

32

30

28

26

24

22

TABLE 13 - Characteristics of a Core from Beneath Fisk's (1938) Aloha Prairie Terrace Type Locality.

Location: Grant Parish, Louisiana; 31 °34'43" N, 92°48'30" W (Sec 16 T7N R4W); Aloha, LA 7.S-minute quadrangle; LGS locality RR-18; site is on a topographic flat in a barn yard next to Aloha Cemetery west of US Hwy. 71; elevation is 33.S m; slope is 1 to 3 percent; surface soil is mapped as Gore Series (Vertic Paleudalf).

DEPTH, em HORIZON MATRIX COLOR MOTTLE COLOR TEX STRUCTURE CONSIST BOY COMMENTS O· 10 Ap 1 OYR 4/2 SiL wk fn ab fr abr overwash; rt; 1 OYR 4/6 st 10- 25 E 10YR 7/4 1 OYR 5/2 SiL wk vfn ab fr cI rt; 7.5YR 6/6 st; 1 OYR 4/2 SiL in po

&: rt tr TOP OF PRAIRIE COMPLEX, ALOHA ALLOFORMATION

BACKSWAMP FACIES 25 - 45 E&:2Bt 5YR 5/6 1 OYR 6/4 SiCL mod med sab fr cI rt; 10YR 6/4 C flm in po &: rt tr 45 - 70 2Bt 2.5YR 4/8 2.5Y 7/2 SiC mod med sab slhd cI rt; disc 2.5Y 7/2 st on peds 70 - 115 2BC 2.5YR 4/8 2.5Y 7/2 SiC wk fn ab slhd cI rt; disc 2.5Y 7/2 st on peds &: rt tr

115 ·130 2Cl 5YR 5/6 2.5Y 7/2 SiC slhd slpl gr disc 2.5Y 7/2 st on rt tr; slick 130 - 150 2C2 2.5YR 5/6 SiC slhd slpl ab disc 2.5Y 7/2 st on rt tr

NATURAL LEVEE FACIES 150·230 3Cl 5YR 5/6 SiL vfr cI lam; beds of SL &: S; 7.5YR 6/8 st on

lam 230 - 255 3C2 5YR 5/6 SiCL mod med sab fr gr po; rt tr; 5YR 4/4 C flm &: 1 OYR 2/2

st on peds 255 - 305 3C3 5YR 6/6 SiL vfr ab 1 OYR 2/2 st on rt tr; lam; SiCL &: LS

beds

BACKSWAMP FACIES 305 • 335 2.5YR 3/6 C hd ab 10YR 7/8 &: 2.5Y 7/2 st; 1 OYR 2/2 st

on slick &: in rt tr; lam; CaC03 nod 335 - 375 5YR 5/6 SiCL mod cse sab slhd ab po; 5YR 4/4 C flms on peds; 10YR

2/2 st on rt tr; SL bed 375 • 530 2.5YR 3/6 5Y 6/2 C hd df 1 OYR 2/2 &: 10YR 7/8 st on slick &: rt

tr; CaC03 nod 530 - 600 2.5YR 3/6 C hd df 1 OYR 2/2 &: 1 OYR 7/8 st on slick; I

am; CaC03 nod

NATURAL lEVEE FACIES 600·640 5YR 5/6 10YR 7/6 SiCL wk med ab slhd cI 5YR 4/4 C flm on peds &: rt tr; 10YR

8/1 C bodies 640·670 5YR 5/6 L vfr gr 1 OYR 2/2 st on lam &: rt tr

BACKSWAMP FACIES 670 - 750 5YR 4/4 C vhd gr 1 OYR 2/2 st; CaC03 nod

750 - 840 2.5YR 3/6 C hd gr 1 OYR 2/2 st; lam; slick; CaC03 nod

NATURAL LEVEE FACIES 840·870 5YR 6/6 SiL vfr gr lam; 2.5YR 3/6 lam C beds with

1 OYR 2/2 st

BACKSWAMP FACIES 870·900 2.5YR 3/6 C hd gr 1 OYR 2/2 st; Si lam; CaC0 3 nod

900·975 2.5YR 3/6 C hd cI 1 OYR 2/2 st; 2.5Y 8/3 st on Si &: LS lam

975 ·1010 5YR 7/4 SiCL vfr cI 2.5YR 6/3 lam with 1 OYR 2/2 st

1010 ·1050 2.5YR 3/6 C hd 1 OYR 2/2 st; Si lam

65

TABLE 14. - Particle size data for Aloha Prairie - CORE RR19- Gore Series

HORIZON DEPTH, em VCS CS MS FS

Ap 0- 10 1.4 1.3 1.4 3.8 E 10- 25 0.3 0.8 1.0 2.0 E&2Bt 25 - 45 0.3 0.2 0.4 1.7 2Bt 45 - 70 0.1 0.2 0.2 1.3 2BC 70· 115 0.0 0.1 0.2 0.0 2C1 115· 130 0.1 0.1 0.2 0.9 2C2 130 - 150 0.0 0.0 0.1 0.7 3C1 150 - 230 0.0 0.0 0.1 0.4 3C2 230 - 255 0.0 0.1 0.1 0.2 3C3 255 - 305 0.0 0.0 0.1 0.3 BACKSWAMP 305· 335 0.0 0.0 0.1 0.6

335· 375 0.0 0.0 0.0 0.3 375· 530 0.0 0.0 0.0 0.0 530 - 600 0.0 0.0 0.0 0.2

NATURAL LEVEE 600 - 640 0.0 0.0 0.1 0.6 640 - 670 0.0 0.0 0.1 0.6

BACKSWAMP 670 - 750 0.0 0.0 0.0 0.0 750 - 840 0.0 0.0 0.0 0.0

NATURAL LEVEE 840· 870 0.0 0.0 0.0 0.1 BACKSWAMP 870 - 900 0.0 0.0 0.0 0.0

900· 975 0.0 0.0 0.0 0.0 975 ·1010 0.0 0.1 0.0 0.1

1010- 1050 0.0 0.0 0.1 0.1

and McFarlan, 1955; Saucier and Snead, 1989; Autin et al., 1991) are also likely candidates for inclusion into this unit. The Aloha Alloformation is inferred to be stratigraphically correlative to the Avoyelles Prairie of the LMV and its equivalents (Stop 9, this guidebook). Other probable strati· graphie equivalents include the Mt. Pleasant Bluff Alloformation in East Baton Rouge Parish (Autin et al., 1988), the Prairie Complex, Lower Surface (Autin and McCulloh, 1991, 1992) of southeastern Louisiana,the Wisconsinan sand sheet of the Florida Parishes (Mossa and Autin, 1989) capped by the PG-1 geosol (Autin et al., 1991), the Wisconsinan Prairie Complex of southwestern louisiana (Birdseye and Aronow ,1991), and the Little River Valley (LGS, geologic mapping file data). The Aloha Alloformation is likely to be older than the lowest coast parallel Prairie Terraces surface (Snead and McCulloh, 1984), and the PG-2 geosol (Autin et al., 1991).

Alford et al. (1985) inferred a Wisconsinan age for the LRRV Prairie Complex based on radiocarbon ages from the Wadell Bluff locality of Fisk (1938a) (Stop 2, this guidebook). As previously discussed, the relation between this age assignment and the inferred stratigraphie position of the organic deposits are enigmatic. Is it possible that a remnant of the Aloha Alloformation was adjacent to the base of the Wadell Bluff locality? Elsewhere in the LRRV, Harrelson (1990) reported radiocarbon ages of 36 to 23 ka for deposits that are apparent correlatives to the Aloha Alloformation.

VFS TOTAL SAND TOTAL SILT

18.1 25.4 67.2 19.2 23.3 64.7 8.5 11.2 53.2 6.2 8.1 42.4 8.8 9.1 44.0 8.5 9.7 44.2 12.9 13.7 44.1 26.6 27.1 61.6 13.4 13.7 56.9 17.6 18.0 60.8 5.0 5.7 38.6

17.5 17.9 48.6 0.3 0.3 34.2 0.4 0.7 39.5 17.2 17.9 43.4 37.7 38.5 45.3 0.2 0.3 33.5 0.1 0.2 31.2 1.1 1.3 74.7 0.2 0.2 32.9 0.1 0.1 34.8 0.6 0.9 61.3 0.2 0.4 39.5

66

TOTAL CLAY

7.4 11.9 35.6 49.5 46.9 46.1 42.1 11.3 29.4 21.2 55.8 33.5 65.5 59.8 38.7 16.3 66.2 68.6 24.0 66.9 65.1 37.9 60.2

Fisk's Cartographic Error Fisk's 1938 report "The Geology of Grant and LaSalle Parishes" established his famous terrace sequence. It is a much-quoted work but it contains a small but significant cartographic error which may have mislead some subsequent investigations.

On the plate entitiled Physiography of Grant and LaSalle Parishes Waddell bluff is mislocated, either by Fisk or his cartographer, upstream to a bluff mapped as Montgomery. The true location of Waddell bluff on this map is mapped by Fisk as Prairie. On the Geologic Map of Grant Parish plate in the samevolume, Waddell bluff is correctly located but the Quaternary terraces are undifferentiated. So, did Fisk work on an incorrect base map and consider Waddell to be Montgomery? Or did Fisk's cartographer mislocate Waddell Bluff after Fisk had mapped it as Prairie?

Many writers who have studied Fisk believe that he considered Waddell bluff to be Montgomery- (Alford, et aI., 1985). Indeed Fisk did describe a Waddell bluff section in his chapter on the Montgomery but may be suggesting that the Montgomery Formation is only exposed in the lower part of the section, leaving the possibility that he consid ered the top of the bluff to be a Prairie surface as mapped. Others have considered the bluff to be Prairie (Smith and Russ, 1974) also citing Fisk.

-John Snead

SECTION

TERRACE SECTION

67

STOP 4

Archaeological Sites Along the Pleistocene Terrace Margin and Red River Flood Plain

C.E. Pearson and D.G. Hunter

location Zimmerman Hill is located just west of 1-49 approximately 29 kmnorthwest of Alexandria in irregular Section 61, T.5 N., R.3 W (Fig. 4.1). The site has been selected because numerous geomorphological features relating to the modern alluvial valley can be viewed in association with archaeological remains at a single locale at the edge of the Pleistocene terrace. River channel chronologies reconstructed from cartographic sources dating to 1803 demonstrate the dynamic nature of the Red River in this locale over the past 200 years (Fig. 4.2).

Geomorphology The stop is located on the western margin of the Red River alluvial valley. The exposed escarpment here is Pleistoceneaged fluvial deposits relating to the Prairie Complex. Elevations range from apprOximately 43 m above mean sea level (msl) in the nearby uplands to about 30 m msl at the toe of the escarpment. Zimmerman Hill, itself, is a remnant of a terrace projection into the alluvial valley which has been bisected by a railroad cut made during the 1890s.

To the north, east, and south of Zimmerman Hill is the Red River flood plain. In this locale, elevations range from approximately 30 m msl at the toe of the escarpment to 18 m msl along the water's edge of the recently cutoff channel lying directly to the east. One of the more obvious geomorphological features of the flood plain can be seen directly north of Zimmerman Hill. Locally known as the Mill Pond, this feature is an excellent example of a largely unfilled, Red River oxbow lake. The recent channel of the river lies directly to the east. It was artificially cut by the U. S. Army Corps of Engineers in the 1980s as part of the development of the Red River Waterway. Across the river is the point bar, which has been prograding westerly for at least the past 200 years.

Cultural History The earliest settlers in this area during the historic period were Apalachee Indians who were originally from Florida and who moved to Mobile in 1704 to escape repeated raids by English allied Indians. At the conclusion of the French and Indian War, the Apalachee requested that the French allow them to move into Louisiana. The Apalachee formed their village here in the fall of 1763, and other immigrant tribal groups, including the Pascagoula, Taensa, Coushatta,

Alabama, and the Mobilians, would soon follow. Throughout the remainder of the eighteenth century, there was little European settlement in this area of central Louisiana.

In the last decade of the eighteenth century, more Europeans began to move into central Louisiana. Some purchased lands form the local Indians and created small plantations devoted toward the production of tobacco and indigo. The Indian presence in the region continued, but it was soon to be overshadowed by the increasing American population that was entering Louisiana under Spain's liberal immigration policies. After the United States purchased Louisiana, more Americans started to move into the region, and after the introduction of steam powered boats and cotton gins in the second decade of the nineteenth century, large plantations sprang up along the entire length of the river as they did throughout the rest of the South.

Isaac Baldwin acqUired the property around 1820 and established his Village Plantation. The Indians were still living on the land as late as 1834 when forced off the property by continued encroachments and depredations committed by Baldwin and his overseer. Baldwin was one of the largest cotton planters in the area, and by 1833 he had some 200 slaves. His main plantation complex, slave quarters, and fields were on the opposite (east) side of the river.

Throughout the remainder of the nineteenth century, this land was owned by various individuals who continued to plant primarily cotton on the east side of the river. After the Civil War, tenant farming and share cropping by blacks replaced the former slave-based labor system. Still, the agricultural use of the land continued as it does today.

In 1895, the property just north of Zimmerman Hill was acquired by the ]. A. Bentley Lumber Company. A large sawmill, which cut primarily southern yellow pine, was constructed on the other side of the oxbow lake which was used as the mill pond. The mill continued in operation until 1961. At that time its production exceeded the availability of usable timber, primarily because the company had not established a reforestation program in its earlier years.

Archaeological Sites Previous archaeological research has identified 15 archaeological sites near Zimmerman Hill. For convenience, these have been grouped into three basic categories: prehistoric

69

/ \ ./ ,- '. \J@

\ ..

':i .~

-------

Figure 4.1 - Topographic map of the Zimmerman Hill Area.

(prior to A.D. 1540), historic Indian (1763-1834), and latenineteenth- to early-twentieth-century Euro-American (Fig 4.2 ).

There are three locales in the immediate vicinity of Zimmerman Hill which have produced prehistoric Indian artifacts. The ages of two of these are not precisely known, but both have produced artifacts similar to those found in Late Archaic contexts (ca. 2000 B.C. to 500 B.C). Both of these are situated on the edge of the Pleistocene terrace overlooking the alluvial valley. The third prehistoric site is within the confines ofthe flood plain and situated justto the west of the mill pond. Research has indicated that this site has an occupation dating to the Coles Creek period (A.D. 900-A.D. 1200). Test excavations have also indicated that it may have earlier components.

Three locales have produced historic Indian artifacts. One

of these is at Zimmerman Hill where diagnostic artifacts have been recovered from both the Pleistocene terrace remnant and the edge of the cutbank overlooking the recent Red River channel. This location corresponds with the position of the principal Apalachee village depicted on an 1803 survey. On the opposite side of the recent channel, two additional areas have produced historic Indian artifacts. These are situated on point bar deposits associated with the Red River and are presumed to have been associated with individual Apalachee houses that were known to have once occupied this point.

Nine archaeological sites in this locale were occupied in the late nineteenth or early twentieth century. On the east side of the river, there are three sites of this age that are presumed to have been associated with tenant quarters on the Thompson Plantation. There are two similar sites si tuated just to the north of the old Zimmerman mill, which were probably

70

J.A. Bently Lumber Co. , Zimmennan Saw Mill (1895-1961)

\ \ , \

- ~ .. ,,-~ .... I "./ I

\'.

• Prehis toric Indian

.A Historic Indian

Late 19th to Early 20th Century Euro-American

" \ ~.\ ~ " '\-L-----.1--________ . ______ --'_ .... _ .. _, __ -L..c:::: __ ,~

Figure 4.2 - A portion of the 1971 USGS "Boyce, La." quadrangle (7.5' series) showing the historic Red River channel chronology, major physiographic features, and known archaeological sites in the vicinity of Zimmerman Hill.

71

workers housing. One additional site of this age is located east of the old mill, while another is just northwest of Boyce. All of these are situated in alluvial settings on either Red River point bar or natural levee formations. Only two latenineteenth- to early-twentieth-century sites are located in the uplands, both near the edge of the valley wall.

Geoarchaeological Implications Figure 4.2 also shows the Red River channel chronology for this area reconstructed from a series of historic maps dating between 1803 and 1971. Developing this type of channel model in the extremely dynamic Red River flood plain is a prerequisite for determining the ages of different land surfaces and, thus, predicting possible site locations. This reconstruction indicates that Zimmerman mill pond was a part of the active channel of Red River in 1803. Around 1820, this hard bend in the river began to be cut off.

Interestingly, the small prehistoric site located on the west side of the mill pond appears to be situated on Red River natural levee deposits. Apparently, however, this natural levee remnant was not associated with the mill pond, because the cultural material from the site indicates it is at approximately 1200 years old. This seems entirely too long for this channel to have been occupied, considering the dynamic nature of the river. This natural levee feature is somewhat higher than the other portions of the levee along mill pond, and it is believed to be associated with an earlier channel that once flanked the western valley wall in this locale. The small stream entering the west side of the mill pond may occupy a portion of the now largely filled abandoned course with which this site was associated.

There are four archaeolOgical sites situated in the uplands along the margin of the valley wall (Figs. 4.2 and 4.3). Two are prehistoric, two are late-nineteenth- to early-twentieth-

merman Pre- Mill Pond ! Pre-

I Post- I Post- Post-Pleistocene Terrace 1820 Pre-1820 ·1820 I 1820 ! 1820 1820

Natural Channel, !Natural' Natural !Channel Point Levee Natural Levees, Levee Levee I Bar

c c 0 0

5'~-S~ e e e -0 ~~~~ .3 3 3 fd ~ .... .": :I: >,:I: ~ ::J ~ fd""§ ~ ~ ~ -Sfd3 I U .~ «J ~ V V v 5~'~ ~ :I:.- W v 0'1 .... -i: QJ ·c cv

~ I "'C u -0 .... i: <3 0'1 .... 0'1 .... !\S .§ '5~ E ~:G <3 <.3 ~ -tf E-o I 0 ~:G ~:G ex: .~'§~~ :JQ. ~ :B]1~fd +J-o :JQ. :JQ.

0

I ~~-g~ c C "--0 "'-0 ..0 ~:::;~ ~~ ~ fd ~ lij E c.~ W 3! Q.:I:.,w u", u", .,

.~ 3 ~u. 5~ £31 £31 ~

]]~~ ~~ ~~ VI NU. ~ u'-cu ....... 3 'c O'Iu:; c 2~£.~ v u .!!! cO 0'1 :I:.,N< £ 0'1

Figure 4.3 - A generalized cross section through portions of the Pleistocene uplands and Red River alluvial valley at Zimmerman Hill showing major geomorphic features and locations of known archaeological sites (Note: arrows indicate archaeological sites).

72

century site, and one is historic Indian site (related to the Apalachee occupation of the area). Although the prehistoric sites may have been utilized to some extent for procuring lithic raw materials, their placement along the edge of the valley wall and their size may indicate that they were occupied for relatively short periods of time when the Red River was at flood stage. Similarly, the historic Indian and Euro-American sites may have been so located to avoid flood waters. Elevated lands, such as those provided by the nearby Pleistocene terrace, near water or a flood plain, are usually considered by archaeologists as having a high potential for site occurrence.

Two historic Indian sites have been located on the point bar of the recen t channel. These were the locations of A palachee houses during the 1820s. The coarse deposits of the point bar were elevated, well drained and naturally suited for growing crops.

73

What Happened to Zimmerman?

A look at the series of 7.5' and 15' Boyce quadrangles through the years shows a common occurence in early 20th century Louisiana, namely the ascent and decline of a "company town". The Bentley Lumber Company established a mill here in 1895 and soon builta company store and residences for the mill workers.

The community of Zimmerman on the 1932 quad contains 58 buildings including the saw mill and two schools (separate but equal?), plus 4 railroad sidings connecting with the Texas and Pacific mainline and to the logging railroad which connected the lumber mill with its piney woods raw materials. The main highway to Shreveport passed by the front gates.

By 1945 a ring levee had been constructed around the main mill and town site to protect it from Red River flooding. 65 buildings are depicted including two large mill structures. The two schools are not indicated but a church is.

The 1971 map shows what is left 10 years after the mill closed. The large mill is gone, only 4 residential and 4 non-residential structures still stand. The logging railroad is long abandoned and the sidings are gone from the T & P tracks. The main highway has moved a mile to the west leaving the much diminished "community" of Zimmerman on a deadend, unmaintained segment of the old highway. An Interstate highway now leapfrogs the area completely (1991 map revision, page 70).

In a few more years there wit I likely be little trace of the lumber town of Zimmerman other than the mill pond, the levee, and perhaps a name on the map designating a country intersection.

-fohn Snead

74

STOPS

Archaeological Sites long Bayou Rapides: An Abandoned Red River Course


Location. England Air Force Base is located between Louisiana Highways 1 and 28 approximately 6 kIn west of Alexandria. The specific stop location is situated in irregular Section 34, T. 4 N., R. 2 W. Bayou Rapides, which flows just south of England Air Base, is.an abandoned Red River course (Fig. 5.1). Several archaeological sites have been recently located in the immediate vicinity of this locale which contribute toward an understanding of past Euro-American land use and provide some information concerning the age of this abandoned course.

Geomorphology This stop is located in the approximate center of the Red River alluvial valley. Bayou Rapides is one of the most pronounced geomorphic features in this locale. Elevations range from about 27 m msl on the highest segments of the natural levee of Bayou Rapides to about 24 msl in the backswamp areas. A number of relict courses of the Red have been identified in this area by Smith and Russ (1974) and are shown in Figure 5.2. Approximately 1 kIn north of this locale is Big Bayou, another abandoned and largely filled Red River course. Judging from the amount of channel fill in Big Bayou, its course appears to be earlier than that occupied by Bayou Rapides, plus it appears to be cross cut by Bayou Rapides (Smith and Russ 1974). Still further north is the modern channel of Red River, which is located approximately 2 kIn from this stop location. It should be noted that the existence of some of the meander belts shown in Figure 5.2 must be considered tentative; the identification of the earlier meander belts, in particular, is based on speculative topographic evidence (Smith and Russ 1974).

Cultural History Historic settlement of this portion of central Louisiana seems to have commenced during the late eighteenth century in the last years of Spanish rule. Although some of the early settlers were French, most of the families to settle on this portion of Bayou Rapides were Anglo-Americans. Rapid development along the banks of the bayou probably began during the early American period with the introduction of steam powered mills for processing cotton and, to a somewhat lesser extent, sugarcane. During the plantation era, Bayou Rapides served the local planters as a navigable water body to transport crops to the river and, thence via the Red, to markets in New Orleans. At low water stages of the river,

Bayou Rapides could have served as an route in circumnavigating the rapids, a set of siltstone shoals which blocked the river at Alexandria. This feature gave Rapides Parish its name. Except for the development of the air base, the area along Bayou Rapides has remained basically rural and agricultural throughout its known history.

Archaeological Sites Until recently there were no known archaeological sites in the immediate vicinity of England Air Force Base. Environmental assessments made in relation to base closure operations have located three sites which contribute an understanding to past settlement patterns and land use activities (Fig. 5.2). One is located at the present stop location. Known as Oak Isle Plantation, this site was initially occupied at the turn of the nineteenth century. In later years, it became a relatively large plantation, probably producing both cotton and sugarcane. During the Federal invasion of central Louisiana in the spring of 1864, this plantation, which belonged to Dr. John Seip, was burned along with several others along the bayou. After the war, the Seips rebuilt, and the property apparently was utilized for agricultural purposes and a family residence until acquired by the government in the 1940s.

A second archaeological site is located apprOXimately 1.4 kIn southwest of the stop locale and, again, is situated on the natural levee of Bayou Rapides. Known as the McNutt Plantation, this site seems to have been initially occupied during the 1870s probably as a small Reconstruction period plantation. little is known about the specific history of this plantation; however, some of the buildings were still in use in the early 1940s when the military acquired the property.

Adjacent to the McNutt Plantation is a site that was a black quarters area dating to the turn of the twentieth century. Known as the Wei! site, this location served to house workers on Clio Plantation located on the opposite of the Bayou. This site is also situated on the natural levee of Bayou Rapides.

Geoarchaeological Implications The three sites discussed above are all nineteenth- and twentieth-century Euro-American sites related to plantation developments along Bayou Rapides (Fig.S.3). The natural levee feature on which they are situated provided the high-

75

// --.- ~~ " I' II :1 I{

ii i;

Figure 5.1 - Topographic map of the England Air Force Base area.

est lands locally available for habitation. The elevation of the natural levee provided some degree of protection during flooding, especially before extensive levee construction commenced along Red River during the late 1800s. There are no known sites in the backswamp areas to the north of Bayou Rapides or along Big Bayou. This would be expected, as these areas are relatively low lying and generally not suited for habitation. Although some prehistoric sites could be expected along the natural levee features of Big Bayou, they might be buried by alluvial sediments.

One of the most important geoarchaeological implications comes from the Oak Isle site. limited test excavations there have revealed the presence of a minor prehistoric component. The aboriginal materials include lithics and ceramics. A preliminary analysis of these artifacts indicates they date to the Plaquemine period, or between A.D. 1200 and A.D. 1700. This suggests this abandoned course could date as

early as 800 B.P. Additional archaeological research along Bayou Rapides will likely locate other archaeological sites which can be used to more precisely date this relict channel course. Our current interpretation is that the Bayou Rapides course predates the historic period by some considerable period of time.

76

'. . . . . . . . . . . . --" ............. 1 r.~.""1'';'' .... ::' •••••••••• 'f} r.·.·.·.\ :-:-:-:-:.j "'::-:-:·:-1 • • • • .J ,. • • • • J I

:- :- :- :- • ( ':-:-:-:-: ~ J • ....... ~ ~'.'.'.'.'.I J.'.

• D ••••••••••• . . . . . . . . . . . . IfJth Ctmttu"y Pl9Inbticns

Abcrigin9l1 Sites

••• D •••••••••••••••••••••• . . . . . . . . . . . . . . . . . . . . . . . . . • • • • • • • • • • • • • • • • • • • D •••••• . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...........................

. . ./ /. .... Jr· . . ':"-. ..........---'-.....".." ............... ...r ...... ( r············I"'·,..,.~· .... '. . . . . . . . . . .. . ........... . 1::::..::::::.,' ·.·.1 l.·.·.·.·.·. i" r.("'"> ... \. .............................. r ........... ~ ...................... .

• 1 L ••••• / ...... y ....... ."............. . . . . . .. ...... 1 ••••••••••• \ 1·.·.·.·.;..- I.·.·.·~ ........... ,.~ --.. . ..... .. l.., '.. ...................... . ...... .:... :.- ....- ./. • • • J, ~. • • • ."/ ,..,. .- r- 0:- ...... ". • • i/f'l ,. . l 1 ......... .

..... \ \>:- :;'>'/'-: -: -: -:. >. ~~\: -:./ / > >: \ l>. -: . -: -:.:-:-:- >:-'\' -:..:.,. ./............... ..........:. ~ 1········\ '\ '~ ... '. .' ........ .

-"':--:-"-:-':':':':':':':':':'. ~""''''.':':':':' \\~.:.:.: .. ':"";":":': ..................... ':-., \'" ...... ......... .......................................... l. .-..:.: .... .-.. '.'

.... ::::::::::::::::::::::::::::::::::::. >~~::: .,J~

- -- - -

Figure 5.2 - Plan view of the England Air Force Base Stop area showing the various relict Red River channels identified in the area by Smith and Russ (1974) and known archaeological sites along Bayou Rapides.

77

England Air Force Base

Backswamp Natural Levee and Point Bar

Bayou Rapides,

Abandoned Course

Natural Levee Backswamp

h~t!!~!!!~~~~~~·~·~·~·~· .~. . '. '. '. '. '. ............. . ....... . .............. . . .................. .......... . .................. . ••••••••••••••••••••••••••••••• •••••••••••• • •••••••••••••••••••••••••••• I"

Big Bayou, Abandoned

Course

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• •• ' • • • • • • • • • • • • ••••••••••••••••• • • I •••••••• I ••••••••• I ••• " •••••••••••• " .... , ......... ' ........ ,"- .....

:-:.:. Holocene Deposits .:.:-:.:-:.:.:.:-:.:-:.:-:.:.:.:. ::.:.:.:.:.:.:-:.:-:.:.:.:-:-:.:.:-:.:-:.:-:.:-:.:-:.:-:.:-:.:-:.:-:.:-:.:r ................ " ..... '- ........ ~·'" • • 0 •••••• I I •••••• I • • • •••••• I ••••••• I ••••••••••••• I ••••••• V" ..... ""'"' ... / .... ,,,J0 ..................................... ,......... ., ................ ' ................... , ....... ', ........ , ..... ", .... ...., • •• ' ••••••••• I • '. '.' I •• ' I •••• ' ••• '. '. '.' • '. '. I • • .' ••• I .' • I. I ••••• I ••••••• ' I '. '. I • '. ' • • v .... ,· ........ , ......... ,"- .... . •••• '.' I'. I •• I •••••• • .. • •••••••••••• I ••••••• I.... • ••••••• I ••••••••••••••••••••••••••••• • \j .... ,' .... /',/'Io,..I ..... J

...... ' .. >.: .. ,.:.'.: ...... >.: ...... : .. : .... : ... : ...... : ... : .. : .. : : ... :.: ... :: ... : ... :.: .. : .... : ... , ...... :.'.: .. , .. > .. :.:.: ... :.:.: ..... : .. >.: '.: -:.' .. ' '.> : ... : ... : ... : ... : ..... : .. : .. : .... : ... : .... :.'.: .... :.' ........ :. '. . :.: . :.: I :.: • :.: 1 •• : 1 •• : 1 •• : 1 • ': ••• : I ' ••••••••• ' ••••••••••••• '. '. I ••••••••• ' •• I ••

',,, I ••• ' • I,: I I,: • I. I" I, .. I ', •• I '1 I' • I.: I I. ,I • I, I' , I ... I I. I' • I, I' I ... 1. II I' 0 II " I I. I' I I. I' I I. I' • I. ,I • I, I' I '. I' • I,.' , ., .. I •• ' I I, " I I. I" • I ::: :.1::: :.1:.'::,'::: :.'::: ~.::: :11::: :.,:,~ :.':'': ::::: ::.::: ::,::::::,~ :.;.:: :,:,:: :,:,,': :,:,:: :1:':: :.:.:: :'::'::'=1:: :,',"',': .f •• ' 'V" ..... , 'A I I " I '.'. ' ••

~:::::~ ~:::::~ ~:::::~ ~:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ~~:::~ ~:::::~ ;:~::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:} ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;::::~ ;/~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:::::~ ;:':::~ ;:::::~ ;::::.~ ;:::::~ ;:::::~ ;:::::~ ;/~ ;/~ ;:::::~ ;:::::~ ;::::.~ ;:'::': ::.::~ ;:::::~ ;:::::~ ;:::::~ ;

·m~::t~~~~;~!:~~~{J,~~t:~~!~l~~li~~~j{l~~]~;j~~:t::~~~~!;~lt~l~~!~l~~I;ijl;{ll~l~~lr:~:;,~~~~~;~$.~~;.~~~~:~::t:lrt~~1ij{1!;~fijl !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!G I I 1

0 •• to ~I I, II 't II II'I 0, I I 10 ' 0 I, •• 10 ' 0 't tt ' 1 '1 II '. I, Ie eo I. '0 t. °t .... °, • 0 10 '. to eo to 0 , °t I, '0 'I '0°' .0., °, I I to I. to I. 00 O. 10 '0 't' I I, .... 0 .. 't eo e l " ' o °1 ' I 10 " I 10 'I °0 tl eo" I t.' I I, ". '0 I, I, I. " I, eo ee 10 I, It I .. °

1 •• 10 I I °

0 I. 1

0 •• 0, I, '0 I. II I I 10 I I 1

0• 1 "0 tl 'e'

Figure 5.3 - A generalized cross section through portions of the Red River alluvial valley showing the major geomorphic features associated with Bayou Rapides and Big Bayou and locations of known archaeological sites (Note: arrows indicate archaeological sites).

78

Flying Tigers The last aircraft left England Air Force Base last summer as the base was closed in the post-cold war military reductions. For the last twentyyears the base was hometo the 23rd Tactical Fighter Wing, the descendent unit of the WWII American Volunteer Group, better known as the Flying Tigers.

Led by Louisiana native General Claire Chenault, the Flying Tigers in their famous shark-mouthed P-40 fighters, fought the Japanese in China before America's official entry into the war. The unit became the 23rd Fighter Group after Pearl Harbor and later became the 23rd Fighter Wing in the postwar TactIcal Air Command. The wing flew several types of tactical fighter in the 50's and 60's in both attack and air defense roles.

Atthe close of the Vietnam Warthe unitwas assigned to England Air Force Base and began conversion from A-7 attack aircraft to the tank-busting A-l 0 close support attack fighter. Two of the 23rd TFW's three squadrons were deployed to Saudi Arabia and earned distinguished unit honors during the Gulf War in 1991. Upon their return the wing was inactivated, the planes transferred or retired, and the base was closed.

England Air Force Base itself was constructed by the Army Air Corps during World War II as a B-17 bomber training base. Briefly closed after WWII, it was reactivated during the Korean War and housed several different Tactical Air Command units during the Cold War. The base trained F-' 00 Super Sabre and F-4 Phantom units during most of the Vietnam War, rotating several squadrons overseas and was also home to an Air Commando Group during this period. The base was permanently closed by the military in 1992.

-John Snead

79

STOP 6

Hydrodynamics and Suspended Sediment Transport of the Lower Red River

Joann Mossa

location This stop is near the great rapids of the Red River(FIg.6.1). The Red River, which drains about 90,000 mF (233,000 km2) of five states including Louisiana, Arkansas, Texas, Oklahoma, and New Mexico (Fig. 6.2) is appropriately named being that the river has a reddish color from the significant quantities of sediment that it transports which are derived largely from the Permian red beds in the upper part of the basin. Originating in the semi-arid plains region of eastern New Mexico, comprising the boundary between Oklahoma and Texas, and flowing towards the southeast, the Red River is a major tributary of the Atchafalaya River. The Old River Outflow Channel where flow is controlled from the Mississippi River through various structures of the Old River control project is also a major contributor to the Atchafalaya, and infrequent contributions are funneled through the Morganza Floodway during extreme floods (Fig. 6.3).

Throughout its length, the Red River is a shallow unstable river. Even in the lower reaches where it becomes deeper and more stable below Alexandria, the Waterways Experiment Station (1950, p. 3) has noted that controlling depths at low water are something less than four feet. At this site(Fig. 6.3), the modern processes of the river are briefly discussed, with the emphasis being on the suspended sediment dynamics, and the importance of this river for supplying sediment to southern Louisiana where vast quantities of coastal wetlands are being transformed into open water. Current rates of wetland loss in Louisiana, for example, are apprOximately 30 mF/yr (77.7 km2/yr) (May and Britsch, 1987; Britsch and Kemp, 1990). This characterization regarding hydrology and suspended sediment in the Red River is confined to the LO'wer Red River, especially the reach between Alexandria and Simmesport, Louisiana (Fig. 6.3). In order to understand the role ofthe Red River in the Mississippi-Atchafalaya river system, it is important to evaluate hydrology and sediment transport at other locations in the system.

Hydrology: Discharge Means, Extremes and Trends

In contrast with the MissiSSippi, the Lower Red River at Alexandria shows highly variable maximum, mean, and minimum discharges from year-to-year, with means fluctuating about seven-fold over the period of record (Fig. 6.4). Because the drainage area is smaller and precipitation in the Red River basin is not as regular or abundant as the Missis-

81

sippi, the Red River lacks the sustained baseflow of the Mississippi and floods are more episodic. Also unlike the Mississippi, the years with high mean discharges are not often the same as years with high maxim urn discharges. In some years, with numerous events, mean flows may be high although no single event stands apart from the remainder. Conversely, a single large event of short duration might not significantly increase the mean discharge during a year of otherwise below-normal flow quantities.

Flow in the Mississippi River below the diversion, in contrast, is fairly consistent, and fluctuates only two-to threefold from extremes of maxima, means, and minima (Fig. 6.4). The regularity of flow is related to the large basin size, the humid climate with precipitation throughout the year, and its ability to store groundwater. Years with high annual mean discharges typically coincide with high annual maximum discharges. Overall, the discharges on the Mississippi are dominan t in the system and strongly affect discharges on the Old and Atchafalaya rivers (Fig. 6.4). Mean discharges on the Mississippi below the diversion are about twice those on the Atchafalaya, about three times that of the Old River system, and generally over ten times that of the Red River. The Red River discharges consequently do not strongly influence quantities and time series patterns of discharge on the Atchafalaya in most years.

Suspended Sediment Means, Extremes and Trends

Declining trends in suspended sediment load and concentration since 1950 are characteristic of the Red River and other rivers in the Mississippi-Atchafalaya system (Fig. 6.5). Factors that may contribute to this decrease include cumulative effects of dams and reservoirs, bank revetments, other engineering structures, and land use and land manangement changes upstream in the basin. Most trends are significant at the 5% Significance level for both suspended load and concentration. The four rivers in the system show differences in quantities of sediment supply reflecting climatic and geologic differences of the drainage area, and differences in timing that reflect the differing sequences of process phenomena in each region (Fig. 6.5). The Red River has highest concentrations for every year over the period of record, generally exceeding the MissiSSippi and Old rivers by two to five times. The differences are attributed to the greater sediment yields insemi-arid as compared to humid climates because of differences in vegetation and soil erosion poten-

Figure 6.1 - Topographic map of the Red River / Fort Buhlow Lake area

tial (Langbein and Schumm, 1958; Fournier, 1960; Douglas, 1967; Walling and Kleo, 1979; Dunne, 1979; Hadleyet al., 1985). Mean annual suspended sediment concentrations are typically lowest in Old River, but in some years are lowest in the lYfississippi. The Atchafalaya, receiving some flow from the Red River and most from the Mississippi through Old River, shows mean suspended sediment concentrations intermediate to both rivers but generally closer to the Mississippi and Old rivers than the Red River.

The Role of the Red River in the Mississippi-Atchafalaya System: Examples

of Annual Discharge and Suspended Sediment Contributions

Part of why the the Red River may have received little attention in terms of its contribution to the Atchafalaya River is possibly because some researchers believe that a large river as the Mississippi (1,124,000 mil or 2,910,000 krnZ) would likely drown out sediment contributions from the much smaller the Red River (90,000 mF or 233,000 kmZ). Indeed, on the average the bulk of the flow comes from the Old River, although the year-to-year scenario and the sediment scenario are more complicated. The Old River system

has provided from about 39 to 84% of the flow of the Atchafalaya River at Simmesport for various water years between 1966 to 1991, with the flow discharge averaging about 67.3% over this period (Fig. 5). The remaining smaller proportion is provided by the Red River, which accounts for 16 to 61 % of the Atchafalaya River flow and averages 32.7% over this period (Fig. 6.6).

The annual suspended load contribution of Old River system presently ranges from about 25% to 97% of the annual suspended load of the Atchafalaya at Simmesport, and therefore shows a wider range than the flow (Fig. 6.7). That of the Red River above the Old River Outflow Channel, computed as the remainder, provides about 3% to 75% of the Atchafalaya's load (Fig. 6.7). Thus, because the contributions provided by the Red River are highly variable, in some years the Red River provides only a minor contributions of suspended sediments in the Atchafalaya, whereas in other years it is the dominant component of the suspended sediment load. On the average for the period between 1966 and 1991, the annual suspended load provided by the Old River system is 54.7%, whereas that provided by the Red River is 45.3%. Thus, while the Red River provides less than one-third of the flow in the Atchafalaya it provides nearly one-half of its sediments because of its high suspended

82

o 100 200 kilometers

I I I I I I

o too 200 miles

Figure 6.2- Primary tributaries and distributaries of the Red River system in the south-central United States (Arkansas, Louisiana, Oklahoma, and Texas). A small portion of the basin also falls in New Mexico (data simplified from the u.s. Geological Survey 1 :2,000,000 scale Digital Line Graph).

OLDRNER 'LOW CHANNEL

RIV'ER-;:;~~L--_,;. .... .:....:..L_~ding ___ M~I~SIS~I:~ _____ -,

FLOIQDlVAY'-~I--'\'\l l._..-:R~i:-ve.rh Laroncnd7AinN9,ZA n~::~:IANA ( \

\

Figure 6.3 - The drainage system and levees (dotted lines) of southern Louisiana. Stations discussed in this paper include: 1) the Red River at Alexandria; 2) the Red River above the Old River Outflow Channel near Simmesport; 3) the Mississippi River below diversion (Red River and Tarbert Landing); 4) the Old River Outflow Channel near Knox Landing; and 5) the Atchafalaya River at Simmesport (from Mossa, 1990).

83

(X) ~

~;i~u~I~~~ a~J M~~:~~~C~~!~S\ Discharge in thousands of cIs

5001

450

400

350

300

250

200

1966 1970 1976 1980 1985 WATER YEAR

- Maximum ~ Mean 0 Minimum -<>- Moving Mean

ATCHAFALAYA RIVER AT SIMMESPORT Maximum, Mean, and Minimum Discharges

Discharge in thousands of cfs 1000~,~~~------~~--------------------------~

900 - ,-_ .. -"--'-"~-' .... -.- .. - .~ _ .. -.•. -~.- .. _._ ....

800

700

600

500

400

300

200

100

0 1950 1966 1960 1966 1970 1976 1980 1985 1990

WATER YEAR

- Maximum ~ Mean 0 Minimum -<>- Moving Mean

MISSISSIPPI RIVER BELOW DIVERSION / Maximum, Mean, and Minimum Discharges

Discharge in thousands 01 cIs 2000

1 1800

1600

1400!

1200, 1

1000 1

800'

800

400

200 ,miU~U~~~mml~tl~~~~~m~m~~mml~~ID~t_, , , , ,I 1956 1960 1965 1970 1975 1980 1986 1990

WATER YEAR

- Maximum ~ Mean 0 Minimum -i>- Moving Mean

OLD RIVER SYSTEM Maxim:Jm, Mean, and Minimum Dischsrges

Discharge in thousands 01 cIs 1000

1 900

800

700

600

600

400

300

1955 1980 1966 1970 1975 1980 1985 1990 WATER YEAR

- Maximum ~ Mean 0 Minimum -e- Moving Mean

Figure 6.4 - Maximum, mean, and minimum discharges in the Mississlppi-Atchafalaya River system (Red, Mississippi, Atchafalaya and Old rivers) (from Mosso, 1990).

00 l.I'I

RED RIVER AT ALEXANDRIA Susp. Sed. Discharge and Concentration

SSO (t/day X 1000) and SSC (mgll) 2000

1 1800

1800

1400

1200

1000

800

800

400

2°~III~WijmIftW~,1 I I 1" " ,I 1960 1965 1980 1985 1970 1975 1980 ,985 1990

~TER YEAR

_ssa ~SSC -Mow.M •• nSSa -- .. CI'I.I .... nSac

ATCHAFALAYA RIVER AT SIMMESPORT -----+----! Suep. Sed. Discharge lind Concentration

SSO (ttday X 1000) and SSC (mg/l) 2000

1 1800

1800

1400

1200

1000

1955 1980 10S5 1970 1976 1980 1985 1990 ~TER YEAR

_ssa ~8SC ---Mov. M ... n S80 --"CI'I ..... " SSC

)

MISSISSIPPI RIVER BELOW DIVERSION / Suap. Sed. Dillch8f911 and Concentration

SSO (I/day X 1000) lind SSC (molt) 2000

1 1800

1800

1400

1200

1000

- sao ~ 88C _ Mow. M •• n 880 -- "CI'I. M" ... SSC

OLD RIVER OUTFLOW CHANNEL NEAR KNOX lG. Sulll). Sed. Discharge and Concentration

SSO II/day X 1000) and SSC (mgll) 2000

1 1800

1800

1400

1200

1000

600

800

400

200

0 1950 1955 1960 1965 1970 1975 1960 1965 1990

~TER YEAR

- sso ~ SSC ..... "ow ..... " ssa -- Mo.o ..... n sac

Figure 6.5 -:- Suspended sediment discharges and concentrations in the Mississippi-Atchafalaya River system (Red, Mississippi, Atchafalaya and Old rivers) (from Mossa, 1990).

sediment concentrations. Assessment of discharge-sediment relationships in the Atchafalaya are thus incomplete without examining the spatial and temporal variations of these parameters in the Red River.

Discharge-Suspended Sediment Relationships in the Red River

Red River at Alexandria

Suspended sedimen t and silt-clay concentrations on the Red River at Alexandria show strong linear relationships (Fig. 6.8), with maxima in excess of 5000 mg/I. Total suspended sediment, suspended silt-clay, and suspended sand concentrations generally increase rapidly throughout the range of discharges, with the suspended sand concentration showing more scatter and a lower correlation coefficient than the total suspended sediment and silt-clay concentration relationships with discharge. Because of the high suspended sediment concentrations, the Red River at highest discharges has suspended sediment loads comparable to that on the Mississippi River below the diversion. The percentage of sand in suspension shows tremendous scatter throughout the discharge range (Fig. 6.8), with most scatter in the intermediate discharges and no apparent increase with increasing discharges. Since both silt-clay and sand concentrations show similar increases with discharge as manifested

by similar slopes of the regression equations, the proportions manifest by the percentage sand in suspension show much scatter but no consistent relationship with discharge.

Red River above Simmesport (above Old River Outflow Channel)

Further downstream on the Red River above Simmesport above the Old River Outflow Channel, the discharge-suspended sediment relationships are somewhat different than upstream. Although both suspended silt-clay and sand concentrations on the Red River above Simmesport increase as discharge increases, they have very different slopes and intercepts (Fig. 6.9). The graph of total suspended sediment concentration with discharge strongly resembles that of its major constituent, the suspended silt-clay concentrations. The suspended sand concentration is minimal at low flows but considerable at high flows, whereas the suspended siltclay concentration and total suspended sediment concentrations show much smaller slopes. Thus, in contrast with the upstream station, the percentage sand in suspension shows a fairly good relationship with discharge, increasing as discharge increases especially above a threshold level of 50,000 cfs or 1500 m3/s (Fig.6.9).

A Sample Daily Time Series Despite the relatively small contributing flow of the Red

ATCHAFALAYA FLOW DISCHARGE Percent contributed by Red & Old rivers

Percent of Q at Simmesport 100~-------------------------------------------------------------------------~

8 0 ..................................................................... -.......................................................... __ .......... __ ................................................................................................. --........ _ ......... __ .-...... _ ................................ .

60

40

20

o 20

40

60

80

100~-L-L-L-L~~~~~-+~~~~-4~~~~~~~~~~+-~

1965 1970 1975 1980 1985 1990 WATER YEAR

.. Q, RED ~Qp OLD

Figure 6.6 - Percent flow discharg~ of the Red River and Old River system to the Atchafalaya. In most years, th.e Red River contributes between 20 and 40% (mean is 32.7%) of the flow to the Atchafalaya, as contrasted WIth 60 to 80% (mean is 67.3%) contributed by the Mississippi River through the Old River Outflow Channel (data source: U.S. Army Corps of Engineers, New Orleans District, 1992).

86

River to the Atchafalaya as compared to the Mississippi contribution through the Old River system, the Red River has an important influence on the sediment time series of the Atchafalaya. Evidence discussed above shows that in terms of annual contributions, the Red River provides an average of 45.3% and maximum of 75% of the suspended sediment load in the Atchafalaya River. High suspended sediment concentrations, which exceed 1000 mg/l during high flows, are also characteristic of the Red River. Since the Red River comprises a large component in selected years, it may strongly influence the sediment time series or signature of the Atchafalaya over smaller timescales as well. Wateryear 1968 (Fig. 6.10), when 34.8% of the flow and 58.9% was provided by the Red River, is indicative of this phenomena where the Red River is the dominant influence on the sediment time series or signature of the Atchafalaya. This is evidenced by the numerous large peaks that occur on the Atchafalaya that do not occur on the Mississippi but instead can be traced to the Red River. Several other years show similar phenomena, even if the flow in the Red River flow is not particularly high, one or a few large events may be noted on the Atchafalaya River time series with no apparent relation to the Mississippi River system. Thus, even though the flow time series strongly resembles the Old River or the 1tfississippi River, the sediment time series is a hybrid of the Red River and Mississippi River sequence.

Summary and Conclusions The Red River, which has low discharges throughout much of the year, is periodically the major contributor of suspended sediment supply the Atchafalaya and thus coastal Louisiana. As the suspended sediment concentrations of the Mississippi River have declined because of reservoirs and bank protection by revetments and improved soil conservation measures, the relative contribution of sediment in the Red River system has become increasing important for supplying sediments for wetland accretion in the Atchafalaya basin. In fact, the Red River strongly influences the sediment time series signature of the Atchafalaya, comprising in excess of 70% of the suspended sediment in the Atchafalaya in some years. Recent projects involving construction of several locks and dams on the Red River should consider that any changes in sediment regime related to these and associated engineering projects such as revetment construction, mayim pact the suspended sediment loads in the Atchafalaya basin to a considerable extent and thus that available for deposition in the coastal wetlands of southern Louisiana.

ATCHAFALAYA SUSPENDED SEDIMENT LOAD Percent contributed by Red & Old rivers

Percent of as at Simmesport 100r---------------------------------------------~

8 0 ......................................................................................... _ ..................................... _ ............................ _ ..................................... _ ..... _ ....................... _ ....... _ ... _ .. _ ........................ _ ................................ ..

60

40

20

o 20

40

60

80

1980 WATER YEAR

.. Qs, RED _as, OLD

1985 1990

Figure 6.7 - Percent suspended sediment discharge of the Red River and Old River system to the Atchafalaya.ln most years, the Red River contributes between 20 and 70% (mean is 45.3%) of the suspended sediment to the Atchafalaya, as contrasted with 30 to 80% (mean is 54.7%) contributed by the Mississippi River through the Old River Outflow Channel (data source: U.S. Army Corps of Engineers, New Orleans District, 1992).

87

--o CI) CI)

-""-0)

E -z 0 :3 0 I-C/')

1963-91

Q (~ /s)

10 100 1000 10000 10 100 1000 10000

1OO0m.~. --1°OH.~ i 40 -t--+-t-++++-ItI--'~+IP 1°mam.mllfil D..

1-t--t-I-H-1I+tH--+-+-f-+++!-H--+-I--++J~-+++-u.uu

100 1000 10000 100000 1000000

Q (cfs)

10, 100 1000 10000

1000

100

10

1+--+--I-++1H-H+---+-+4-H+1-H--~-+-H-HU--4--'-'-~

100 1000 10000 100000 1000000

Q (cfs)

-""-t:D E -z 0 0 0

~

o -r-++~~-+--100 1000 10000 100000 1000000

Q (efs)

10 100 1000 10000

1000

100

10

1+-~~~-+~~~++~~~~~

100 1000 10000 100000 1000000

a (efs)

Figure 6.8 - Discharge-suspended sediment relationships for the Red River at Alexandria, 1963-91. Discharge (Q) is shown in cubic feet and cubic meters per second on the x-axis, whereas suspended sediment concentration (SSC), percentage sand in suspension (PCTSAND), suspended silt-clay concentration (STCLCON), and suspended sand concentration (SANDCON) are shown on the y-axis. Suspended sediment concentrations above 1000 mg/I are not unusual during high flows. Percentage sand in suspension does not show a good relationship with discharge (data from U.S. Geological Survey and U.S. Army Corps of Engineers).

'88

-.......

10 100

RIVER OUTFLOW CHANNEL ABOVE SIMMESPORT, LA

1974-87

1000 10000 10 100 1000 10000 10000 1111111 I 11111111 I 11111111 I /1111 ~ 100 1111111 I I 1111111 I I 1111111 11111

~y O. 1 9 x ·0. ()-g r O. h Iy o ·0.82 0] III At.

80 .. 1ooom.31 •• - A~

~ 100 ----~ 60 a

~ ~ J

!~~ -o en en

....... 0)

E -z 0 g ~ fI)

1°gm'·.Rmme. 1+-~H*~~~~~+#~~~~

100 '000 1 oro:) 100000 1000000

a (cfs)

10 100 1000 10000

10000 1111111 I I 1111111 I I 1111111 I I 1111111

ft

''1000

100

10

1 100

, .. "

O.57x· ·0.57 r 0.6 III

!A!!

f.:

"

1000 10000 100000 1000000

Q (c1s)

t5 D...

40

20

- .. o 100

' ..

10

~ :.'

J f-

I

1000 10000 100000 1000000 Q(cfs)

100 1000 10000

10000 1111111111111111111111111 111111 :fy

1000

-....... ~ _ 100 z § ~ 10

1 100

Ox 1.48 r -0.7

.& 11

16 ~ ~ l

14-

~: ~ ~~

rll lA'

1 11111111

1000 10000 100000 1000000

Q(cfs)

Figure 6.9- Discharge-suspended sediment relationships for the Red River above theOld River Outflow Channel near Simmesport, 1974-87. Discharge (Q) is shown in cubicfeet and cubic meters per second on the x-axis, whereas suspended sediment concentration (SSC), percentage sand in suspension (PCTSAND), suspended silt-clay concentration (STCLCON), and suspended sand concentration (SANDCON) are shown on the y-axis. Suspended sediment concentrations above 1000 mg/I are not unusual during high flows. Percentage sand in suspension does not show a good relationship with discharge (data from U.S. Geological Survey and U.S. Army Corps of Engineers).

89

MISSISSIPPI RIVER AT TARBERT LANDING ATCHAFALAYA RIVER AT SIMMESPORT, LA

5.00 i .... tar y.oor 19611 _~'N :: r --.-,- > '"

2.20 J 4.00 110

i -, i 2.00 i I It .. 110

~ ~ UO-l ~ ~ I ~ 3_00 60 ~ 1.60 -1, r; a 60 ~ ~ :l 1.40 1 r; ~ t. t. ~ F 1.20 -1 i } 2.00 t. 40 ~ } 1.00~ t. t. 40 ~ U I t.A .\ A .. u I .. ~ A A A A A t5 ~ 0.

110 1 A 2i :If A A A A e :If Q '. 1.001 ~A ZO ~ ~ A zo :z; ~ 41 I. 11 W1 ~ ;

C7 ~~ _. III C7 A III

0.00 , •• i 0 - '- u 0.00 ,.. .... -_---_ ..... -_---,;;p..-........... ---...... ---....;;;;;;;; ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

u.,... D..".. -- Q - sse 3I!IIQ L IIISAMI -- ill - -- sse SSQ t.!IIS.lND

RED RIVER AT ALEXANDRIA OLD RIVER NEAR KNOX LAKDi:f.':C _tar Jeer lMe _tar Jeer 1966

5.00 2.60 I ---------~ 100

2.40 ~ i 5.00 100 2.20

~ .... 2.001 }-IICI " z :If A ~ 4.00 IICI ~ } 1.11C1

t ... . ' .. I ! ::~ .. ~ if . • r:. 1.20 ~ fa ! .1 t. \ ~} 1.001- t. A 40 ~ ..:. 2.00 I 40; U ..

:; A:' .:l 0..80 I, 2i ~ ..... • A 41: '\. 41 A ~ .. ~ • ;r 0.60 ~ " J \ t. 1'\ A :: 20 :: .\ I \ I \ I '. 20 .; 1.00 .; 0.40 " r\ \ .1 t. ! ",\ _ ~/ \~ _ A:

0.20

0.00 0.00

50 100 150 ~ ~ 300 3'lO 50 100 150 zoe ~ 300 3'lO

lJe7a lJe7a -- II - sse -- S!IQ t. IIS.I.NO -- CII -- - - sse S!IQ 1. lISL'ID

figure 6.10 _ Discharge-suspended sediment time series for the Mississippi-Atchafalaya river system in water year 1968 beginning October 1, 1967. Discharge (Q) is expressed in millions ofcfs for the Mississippi, Atchafalaya, and Old rivers, and in hundred-thousands cfs for the Red River. Suspended sediment discharge (SSQ) is expressed in millions of tons/day and suspended sediment concentration (SSe) in grams/liter. Percentage sand in suspension is shown as a triangle following the right Y-axis. The differences appear to be related to contributions from the Red River. Although the Mississippi andAtchafalayashowsimilar discharge (dark line) signatures, theyshowverydifferentsignaturesforsuspendedsedimentdischarge(light line), and suspended sediment concentration (dashed line). Such patterns are most pronounced during years in which the Red River discharge is relatively high whereas the Mississippi River discharge is relatively low, which can be approximated using the data in figure 3 (from Mossa, 1990).

Acknowledgements Jan Coyne ofUF produced the diagram ofthe Red River basin and Beth Wilder of UF generated the graphs of dischargesuspended sediment relationships. Individuals in the LGS Cartographic Section drafted the diagram of southeastern Louisiana and integrated the time series graphs of the lvfississippi-Atchafalaya river system. Early portions of this research were supported by NASA (Grant No. NAGW-1SS2) and the Louisiana Department of Natural Resources (Contract 21940-88-02). Funding was also provided by the U.S. Army Corps of Engineers, Waterways Experiment Station (DACA39-92-M-4918) project (fom Richardson, Coastal Engineering Research Center, project manager) which assesses suspended sediment fluxes to the Gulf of Mexico. Data were willingly provided by the New Orleans District, U.S. Army Corps of Engineers (Nancy Powell, Hydrologic Engineering Section).

91

Bedload Much gravel in Louisiana occurs as lentils in the basal deposits of Pleistocene units. They contain pebbles averaging less than 1" in diameter although boulders of up to 24" have been recorded. Lemon and baseball sized gravels are fairly common in the deposits of the Upland Complex and the occasional grapefruit-sized rock wi" be found.

Coarse sediment usually travels as bedload, its journey characterized by rolling, bouncing, and sliding along the bed surface, the biggest pieces remaining immobile within the channel for long periods. A stream of high competence is needed to transport the heaviest sediment particles.

The specimen pictured is a 94-pound quartzite boulder found atop the Miocene contact among the basal gravels of the Pleistocene. It was collected from the railroad cut on the east side of Buhloh Lake that you pass when you enter and leave FOP stop #6. The closest source area for such material is the Catahoula Formation 20 miles to the north.

-John Snead

92

STOP 7

Loyd's Hall: Historic Period Settlelllent and Use of the Bayou BoeufMeander Belt


location Loyd's Hall, a nineteenth-century plantation home, is located on the natural levees of Bayou Boeuf about 33 km south of Alexandria and just east of Highway 71 (Fig. 7.1). Generally considered to be the youngest of the relict Red River meander belts in the region, Bayou Boeuf exhibits modestly well-preserved natural levees and a reasonably open channel. These natural levees rise about 3 m above the surrounding backswamp and provide the area's highest and most arable land. During the late eighteenth and early nineteenth centuries Indian and white immigrants into the region began to settle and cultivate these natural levees. Additionally, they exploited and used the nearby Pleistocene uplands for a variety of purposes. The Loyd's Hall location typifies the characteristic use of the higher natural levees of relict Red River courses in the region.

Geomorphology This stop is located on the natura~ levee on the south side of Bayou Boeuf. As a relict course ofthe Red River, Bayou Boeuf extends about 89 km from Alexandria in the north to near the town of Washington in the south, where it enters Bayou Teche. An extension of the Bayou Boeuf system below vVashington, known as Bayou Little, again enters Bayou Teche about 11 km south of the upper entrance. Near Alexandria, the Bayou Boeuf course occupies present-day Bayou Robert. Through almost all of its length, the Bayou Boeuf meander belt occupies the western side of the Red River flood plain, often impinging on the adjacent Pleistocene and Tertiary up lands, as it does just west of Loyd's Hall. The natural levees of the Bayou Boeuf meander belt are on the order of 2 to 4 km in width and rise only about 2 to 3 m above the surrounding flood plain. The age of the Bayou Boeuf meander bel t is not precisely known, but it is generally assumed to be among the youngest of the relict Red River courses that extended south of Alexandria prior to the diversion through Moncla Gap. Just west of Loyd's Hall, the Bayou Boeuf course cuts through an earlier north-south trending relict Red River course identified by Smith and Russ (1974) (Fig. 7.2). This earlier course is not discernable at the surface in the vicinity of Loyd's Hall, but several kilometers to the north its natural levees are fairly obvious and the old course is occupied by several streams, including Cross Bayou and Bayou Latanier.

Today the channel of Bayou Boeuf is only partially open,

blocked along much of its length by numerous trees. In the nineteenth century, however, the channel was cleared of trees and snags along much of its length and it served as an important regional waterway for the transport of produce, merchandise and people. A variety of vessels used Bayou Boeuf, including keelboats, flatboats and small steamboats.

About 3.5 km west of Loyd's Hall lie Pleistocene terrace uplands which rise 7 to 8 m above the all uvial flood plain. A number of small swamps (rimswamps) are found at the base of the Pleistocene terrace, where water is impounded by the natural levees of Bayou Boeuf.

Cultural History Little is known about the prehistoric use of Bayou Boeuf, since few early sites have been found along it. In the historic period, many of the early settlers in the region settled along the banks of Bayou Boeuf, attracted by its fertile and elevated levees. The earliest settlements known in the vicinity of Loyd's Hall were made by several immigrant tribes, who moved to Bayou Boeuf in the late 1700s. Among these aboriginal groups were the Biloxi, Yowini, Pascagoula, and Choctaw. Their settlements were made on the west side of Bayou Boeuf, either adjacent to or in the Pleistocene uplands. These villages extended for a distance of about 12 km up the bayou from Loyd's Hall, and two of the village locations are shown in Figure 7.2. These groups cultivated fields in the flood plain adjacent to Bayou Boeuf, and also hunted and trapped in the wooded uplands. In 1802, these tribes became indebted to the merchants William Miller and Alexander Fulton and, subsequently, the two were able to acquire all of the Indian lands, some 46,800 arpents, at a cost of about 3 cents per acre (Whittington 1970:21-22). A small number of these Indian peoples remained in the Bayou Boeuf area well into the present century, but with the loss of their lands most of them left the area.

Subsequently, a number of Americans acquired property along Bayou Boeuf, in what was the new American Territory of Orleans. Many of these early immigrants came from states like Virginia and South Carolina on the eastern seaboard, anxious to acquire cheap and fertile land. Soon, these newly-arrived Americans overshadowed the earlier French and Spanish settlers of the region. Among these early settlers was James Bowie, who acquired a tract of land along Bayou Boeuf just a short distance above Loyd's Hall. These early settlers established their homes, fields and outbuildings on

93

n

\

11 1\ " " " ~~ \~======9"":="~;;; II "

II \ 11 11 11 '

:\./1\ 1\ i I l"\JI~. ~~ t ill' II '

, " , " : II .

" I II II

" 11

" Figure 7.1 - Topographic map of the Bayou Boeuf / Loyd's Hall area.

the natural levees of Bayou Boeuf and, because these levees are fairly narrow, buildings tend to be concentrated close to the banks of the bayou, on the crest of levee (Fig. 7.3).

Sugarcane became the most important agricultural crop in the region in the decade of the 1820s (Whittington 1970:66). Soon most of the arable lands along Bayou Boeuf were planted in sugarcane, and sugar houses for processing the cane were constructed on almost every major plantation. These sugar houses, like most other buildings, were situated on the high natural levee lands and, generally, close to the bayou where there was easy access to water transport (Fig. 7.2). Sugarcane cultivation fluctuated, depending upon market conditions and, particularly, weather, since Bayou Boeuf lies near the very northern range for successful cane cultivation. When sugarcane was not profitable, the planters turned to cotton, and this periodic fluctuation between major crops has continued to this day.

Many Bayou Boeuf planters had second homes in the adjacent pine-covered Pleistocene uplands, where they often resided in the summer months. Additionally, these uplands were exploited for their timber and game, just as the Indian populations had done previously, and many established their family cemeteries there (Fig. 7.2).

Loyd's Hall itself was apparently constructed by James D. Loyd who acquired the property in 1840, having moved into the area from Tennessee. The house, probably built in the 1840s, is constructed of brick made on the property with cypress and pine used for framing and flooring. Loyd's Hall, in its style, size, and construction, is somewhat more refined than were most of the planter houses along Bayou Boeuf. Little is known about the use of the land under Loyd's ownership which lasted until his death in 1864. Interestingly, no sugar house was located on the property in 1861, although many of the adjacent properties had them (Fig. 7.2). In 1851 there were 25 planters producing sugar along Bayou Boeuf in Rapides Parish, but James Loyd is not listed among them, nor does his name appear for other years during this period (Champomier 1852). If sugar cane was grown on Loyd's property, it may have been processed atone of his neighbor's sugar houses.

94

Zkm I o 1m! ----.... ---.---:-

19th Century Sugar Houses

18th Century Indian Sites

RELICT CHANNEL

Lloyd's Hall

Figure 7.2 - Plan view of the Llody's Hall Stop area showing major geological features and archaeological sites along Bayou Boeuf. The relict channel data are obtained from Smith and. Russ (1974).

95

Bayou Boeuf

Pleistocene Terrace Marginal Lake Natural Levee

Natural Levee and Point Bar

Backswamp

Figure 7.3 - A generalized cross section through portions of the Pleistocene uplands and Red River alluvial valley showing the major geomorphic features in the vicinity of Bayou Boeuf and Lloyd's Hall (Note: arrows indicate archaeological sites).

Archaeological Sites and Geoarchaeological Implication

Relatively few archaeological sites have been reported along the natural levees of Bayou Boeuf. This may in part be due to its fairly young age, but it is also related to the lack of extensive archaeological survey of the Bayou Boeuf meander belt. Gagliano et al. (1979:66) report only a single prehistoric site along the lower end of Bayou Boeuf, near where it joins Bayou Teche. This site was initially occupied during the Coles Creek period, suggesting a pre-700 yrs B.P. age for the natural levees here. How much older the meander belt may be is not known.

Several archaeological sites are known in the vicinity of Loyd's Hall, but these are either prehistoric sites located in the adjacent Pleistocene uplands, or are late prehistoric and historic sites located on the na turallevees of Bayou Boeuf. As noted above, however, these sites do provide information on the settlement patterns of the historic period, patterns which were closely tied to the physiography of the available landforms.

96

Ralph Smith Smith's Railroad The railroad that you followed from Alexandria and crossed under near Loyd's Hall is now a Union Pacific mainline. But the portion from Alexandria to Lecompte is using the original rightof-way of the Red River Railroad, also known as Ralph Smith Smith's Railroad which was built in 1837 and was reportedly the first railroad west of the Mississippi River. The broad Red River natural levee flanking Bayou Robert was utilized to keep the tracks on high ground.

The railroad connected Bayou Boeuf with the Red River and gave the Bayou Boeuf planters a quicker route to the markets of New Orleans via big steamboats on the Red, Atchafalaya, and Mississippi Rivers. Formerly cotton and sugar moved by wagon north to the Red or south byflatboat and a few small steamboats via Bayous Boeuf, Teche, and Courtableau.

Of course the railroad was demolished by the Union Armyin the Red River Campaign of 1864. They also burned the towns of Alexandria and Campti as well as over 70 plantation homes after being defeated at Sabine Crossroads by a Confederate army a third it's size. Fortunately Loyd's Hall and a few others in the Bayou Boeuf country were spared, probably because the main retreat followed the Red to Simmesport.

Esther Wright Boyd, wife of LSU president David French Boyd, wrote of the railroad,

"The 'train' consisted of a locomotive, a baggage car and a passenger car. When the Yankees destroyed the road they 'laughed until they cried' over the 'loco' which was so antique that they had never seen the like "(7 906)

-John Snead

98

STOP 8

Monela Gap and the Red River Diversion

C.E.Pearson and D.C. Hunter

Location Monda Gap is located about 10.5 km northwest of the town of Marksville (r3N, R3E, Sec. 54-58). The Red River cuts through Monda Gap, passing from its alluvial flood plain into that of the Mississippi River. At the narrowest pOInt of the gap, approximately 2 km eastofthe Highway 107 bridge, the valley of the Red is less than a kilometer wide (fig.8.1). South of the gap is the elevated Prairie Terrace (Qtp) feature known as the Avoyelles Prairie (Snead and McCulloh 1984). Bounding Monda Gap on the northwest is a small segment of Prairie Terrace (Qtp), and on the north is an extensive Pleistocene-age braided stream surface produced by glacial outwash of the ancestral Arkansas River.

Geomorphology Prior to its diversion through Monda Gap, the Red River flowed west and south of the Avoyelles Prairie, tributary to either an early course of the Mississippi River or to the Teche course of the Mississippi. Several relict courses of the Red River have been identified in the alluvial valley west and south of the Avoyelles Prairie (Russ 1975; Saucier 1974, Saucier and Snead 1989). These are the Wauksha course, believed to be tributary to the Teche-Mississippi and dating circa 5400 to 3900 years B.P; the Petite Prairie course, dating circa 4000 to 2200 years B.P., the Huffpower course, circa 1500 to 2200 years B.P., and the Boeuf course, dating circa 1500 until 500 years ago These dates must be considered very tentative, and, in fact, recently Autin et al. (1991:562) have sidestepped the question of dating individual Red River meander belts because of inadequate chronologic information and the complexities of channel morphology. However, Gagliano et al. (1979) have presented some archaeological data that, at least, supports the dates suggested for the Petite Prairie course.

When the Red River cut through the northern end of the A voyelles Prairie and diverted its flow toward the east, it reduced from 65 km to 13 km the distance required for the river to descend to the MissisSippi River floodplain. This reduction in length disrupted the equilibrium of the system and effectively increased the gradient of the Red, initiating a wave of entrenchment up the alluvial valley above Monda Gap (Commonwealth Associates, Inc. 1981:28; Russ 1975). Abington (1973) suggested that the gradient of the river continues to increase, although Russ (1975:173) argued that channel degradation along the Red is not uniform and, at

least in areas above Natchitoches, is probably more dosely related to the removal of the rafts and tectonics than to the diversion through Monda Gap. It has been generally agreed, however, that the diversion resulted in channel shifts and abandonments above the diversion.

Several suggestions as to the date of diversion through Moncla Gap have been presented. Fisk (1944:Table 6), correlating the diversion with st'.lge 15 of his chronology for the Mississippi River, suggested a date of about A.D. 1500 to A.D. 1600; Abington (1973:10), Russ (1975) and Saucier (1974:Fig. 3), generally accepted this date, although Saucier and Snead (1989) assign no date to the modern Red River course which passes through Moncla Gap. Russell (1967:32-33) believed the diversion occurred within the past 1500 years while Lenzer (1979), argued that the diversion could have occurred 1000 years ago.

Archaeological Evidence and Geoarchaeological Implications

A number of archaeolOgical sites are known from the vicinity of Monda Gap(Fig.8.2). Relying on data from several of these sites, Pearson (1986) has been able to bring more precise temporal information to bear on the question of the date of the Monda Gap diversion. Three sites, in particular, have proven useful in addreSSing this question. The sites are: mounds near mouth of L'Eau Noire Bayou (16 A V 39), lower mound on Saline Point (16 AV 41), and upper mound on Saline Point (16 AV 13) (Fig. 8.2), all of which are located 12 to 15 km west of this stop. Two of the sites (16 A V 13 and 16 AV 41) are now on an abandoned segment of the Red River produced when the river was shortened for navigation purposes about 60 years ago. All of these sites were initially examined by Clarence B. Moore early in this century (Moore 1912).

The aboriginal ceramic collections from two of the sites, 16 AV 13 and 16 AV 41, indicate the earliest components at each falls within the early Marksville period (Toth 1977:439-441). Marksville period and later ceramics have also been recovered from the third site, the mounds at L'Eau Noire Bayou (16 A V 39) (Klinger et al. 1983; Pearson et al. 1983).

The currently accepted dates for the Marksville period in the Lower Mississippi Valley are on the order of 100 B.C. to A.D. 400 (roth 1977:16; Shenkel 1981). The identification of early Marksville components at 16 AV 13 and 16 AV 41

99

Figure 8.1 - Topographic map of the Moncla Gap area.

would argue for occupation occurring at these two sites near the beginning of the period. Where the other site, 16 A V 39, would fall within the time span of Marksville is unknown.

All three of these sites are located within the modern meander belt of the Red River below Monda Gap (Smith and Russ, 1974). Red River levee and point bar deposits in the area of the sites are on the order of 10 to 12 m thick (Smith and Russ, 1974). Moore's (1912) information on the Saline Point sites and excavations at the other site, 16 AV 39, indicate the Marksville cultural deposits are associated with Red River natural levee deposits. Consequently the sites necessarily post-date the river's occupancy and subsequent levee development in this area. If the identification of early Marksville occupations at two of the sites is correct, then diversion through Monda Gap and natural levee formation had to have occurred by approximately A.D. 1 and certainly no later than A.D. 200.

An early Marksville period date for the Red River below Monda Gap may provide a partial explanation for the concentration of Marksville period settlements on the northern and eastern edge of the Avoyelles Prairie near the present

course of the river (Fig. 8.2). Here there are several archaeological sites with Marksville period occupations, induding the major mound centers of Marksville and Greenhouse. It can be argued that Marksville period populations were attracted to the combined resources of the elevated Avoyelles Prairie, the Mississippi River floodplain, and the alluvial floodplain of the active Red River, producing the observed si te con centra tions. The Red River diversion through Monda Gap seems to have been an important factor in influencing Marksville period, as well as later prehistoric, settlement in the region.

100

/\./

MONCLA GAP

16 AV 41

o 6 10 H H H I

kllomehu

UNDIFFERENTIATED PLEISTOCENE 'TERRACES

LATE PLEISTOCENE TERRACE SURFACES

PRESENT RED RIVER COURSE

RELICT RED RIVER COURSES

ARCHAEOLOGICAL SITES WITH MARKSVILLE PERIOD COMPONENTS

Figure 8.2 - Geological and cultural features in the vicinity of Monda Gap. Those archaeological sites used to estimate the age 6f the modern Red River course are underlined (source Pearson 1986).

101

The Monela Cultural Gap When passing from the uplands across Monda Gap to the Avoyelles Prairie, one notices a difference in landform and natural vegetaion. It takes a doser look but you also cross a cultural boundary at Monda Gap - the boundary between North and South Louisiana.

North of Monda you will find the "upland south" culture, that is English speaking and mainly Protestant with Anglo-Saxon surnames. South of Monda one finds the "Acadian" culture that is primarily Catholic with French surnames and the Acadian French language survives although many no longer speak it fluently. Still, one can detect a remarkably swift accent change from the drawl of the "redneck" to the patois of the "cajun" when traveling from Rapides to Avoyelles Parish.

Geographers have noted and drawn demarcation lines between North and South Louisiana using criteria as varied as house types, cuisine, type of burials, historic voting trends, "blue" laws, agricultural practices, and settlement patterns. The lines break out different areas in some parts of the state, but they all pass through Monda Gap showing the Avoyelles Prairie as the northernmost part of "Acadiana."

-John Snead

102

STOP 9

Wisconsinan Constructional Alluviation of the Mississippi River

Review of the Avoyelles Prairie Area

W. ,. Autin, A. AsIan, ,. I. Snead, and D. ,. McCraw

"Stream behavior and development within the comparatively unstable modern meander belts provide a basis for reconstruction of older meander belts, and by connecting arcuate streams on the Prairie surface it is possible to show the position of channels on the Prairie Terrace belt. That rivers with similar volume-gradient ratios formed both meander belts is indicated by the marked similarity between reconstructed Mississippi River meander belt of Prairie time (fig. 13) and its modern counterpart in northeastern Louisiana and west-central Mississippi (fig. 14). The width of channels on the Prairie Terrace is comparable to that of modern cut-off channels of the Mississippi River, and the average cut-off meander loop has a radius of approximately three miles on both surfaces."

Location The Avoyelles Prairie (Fig. 9.1), located in western Avoyelles Parish, illustrates the soil geomorphic and stratigraphic characteristics of a Wisconsinan age ancestral meander belt of the Mississippi River. The preservation of constructional ridge and swale topography in this area and correlative areas to the south in the Opelousas and Lafayette areas, are unsurpassed in the LMV. The Avoyelles Prairie is an isolated terrace remnant surrounded by the Red River Alluvial Valley to its north and west, and the Mississippi River Alluvial Valley to its east and south. Cores collected from selected landscape positions illustrate lithofacies dependent variations in sedimentologic and pedolOgiC features, and common stratigraphic relations observed in the area. Fisk (1940) used the Avoyelles Prairie as an example of how the constructional morphology of the Prairie Terrace in the LMV compared directly to Holocene meander belts, and concl uded that similar fluvial regimes existed during both times (Fig. 9.2). Lithofacies characteristics of the Avoyelles Prairie are compared and contrasted to the Holocene meander belts of the Ferriday-Vidalia area (Fig. 9.3), presently mapped as meander belts 1 and 3 by Saucier and Snead (1989). Pedologic and sedimentologic characteristics of point bar ridge and swale and natural levee deposits of the Wisconsinan Mississippi River will be examined in cores and compared with data from Holocene alluvium of similar depOSitional environments. This comparison illustrates the effects of shallow burial and base level lowering on lithofacies and pedogenesis of an originally aggradational flood plain setting. Stratigraphic similarities between the Wisconsinan and Holocene meander belt depOSits also suggest that at least two, and perhaps three, meander bel ts existed in the A voyelles Prairie during the Wisconsinan. Lastly, the morphology of Wisconsinan meander belt deposits, paleosol development,

- Fisk, 1940, p. 7S

and age correlations provide insight on the geologic history of the area as well as on possible influences of glacio-eustasy and relative sea level change on Mississippi River sedimentation patterns.

Topography and geomorphology Elevations on the Avoyelles Prairie range from slightly over 25 m on point bar ridges and outer bend natural levees to about 15 m in modern streams that occupy abandoned channel courses (Fig. 9.1). Elevations are less than 13 min adjacent Holocene swamps. The Mississippi River alluvium is buried by a veneer of Peoria Loess up to 4 m thick along the eastern escarpment of the terrace. The loess veneer does not substantially mask the constructional morphology of the meander belt, which is characterized by complex and crosscutting ridge and swale sets and abandoned channel courses (Fig. 9.1). Ridges are represented by broad and linear, level to slightly elevated areas. Swales have been slightly modified by the development of small gullies that have eroded the edges of the escarpment and drain abandoned trunk and splay channels of the meander belt.

Site Characterization Eight cores, ranging from 7.5 to 12.5 m in length were colleCted and used to study the effects of landscape position and depositional environment on sediment and paleosol types (Fig. 9.1). Landscape, lithofacies, and paleosol comparisons include adjacent ridge and swale pairs (Fig. 9.4), a high and a low on a nearly level point bar flat (Fig. 9.5), and proximal to distal natural levee variations on an abandoned channel cut bank (Fig. 9.6).

The ridge-swale pair (Fig. 9.4) is separated by about 500 m

103

I

- · of the Avoyelles Prairie area. 9 7 Topographic map Figure . -

104

0&'

PRAIRIE TERRACE

MEANDER 'BELT

's

Figure 9.2. - Meander scars of the Avoyel/es Prairie (from Fisk, 1940).

105

10'

10'

0$'

LEGEND

D ALLUVIAL VALLEY , COVERED BY BACK

,~ WATER or 1929,

~~~~: UPLAND ON MARGIN "",\~ or ALLUVIAL VALLE '(

1

[illJ,: ALLUVIAL VALLEY ',::: ,:':. NOT COVERED BY

: ' .. ',::::::. BACKWATE.A OF 1929,

TAKEN FROM 41ISS, RIVER COMA/.

SURVEYS

91"Jo'

Figure 9.3 - Meander scars of the Ferriday Vidalia area (from Fisk, 1940).

106

31'00'

meters 25

Swale __________________________ IDdge

MV2 25.0m meters

MVl 22.9m

A

Btx

BC

-25

A-Bw 2E 2Bt 2BC

Peoria Loess C

2Bw 20

2C~!l!!!l!!ll!PlII'!II'J!II!!~_~ -20

3Bw 2C ------

3C 3C

------15

-15 Point Bar Facies

Levee Facies

E1 Silt Loam

Point Bar Facies

1;\1f~ ~~~~~~~ Loam,

D ~ ~

Peoria Loess

Silt Loam

Swamp Facies

Clay, Silty Clay Loam

Figure 9.4. - Comparison of ridge and swale landscape positions.

and has about 2 m vertical relief. The top of the sandy point bar facies has relief identical to that of the overlying land surface. The ridge has a 2.5 m thick natural levee facies that does not appear beneath the swale. Both ridge and swale positions have a clayey backswamp facies draping the lateral accretion and proximal over bank natural levee facies, but the clay has greater than twice the thickness in the swale. Peoria Loess is slightly thicker in the swale, butthis thickness includes a surface horizon that may in part be of cumulic origin due to surface sheetwash.

Cores from the nearly level point bar flat (Fig. 9.5) are separated by about 1250 m and have about 1.5 m relief. The top of the sandy point bar facies is about 1 m lower beneath the landscape low than the landscape high. The loamy upper point bar facies are draped by a clayey swamp facies that drapes the lateral accretion facies. The clay has greater than twice the thickness on the landscape high. Peoria Loess

is slightly thicker beneath the landscape low, here again probably due to a cumulic surface horizon.

Cores from the natural levee of the abandoned channel outer bank (Fig. 9.6) are separated by about 950 m and have about 1.5 m relief. The top of the sandy point bar facies is at an identical elevation beneath both locations, but is over 2 m lower than the lowest sand body elevation on the inner bend of the abandoned channel. The sandy upper point bar facies are draped by a clayey backswamp facies 2 to 2.5 m thick that covers the lateral accretion facies. Above the swamp facies is a natural levee facies. Proximal to the abandoned channel, the levee is 3.7 m thick, has a silt loam to sandy loam texture, and has a buried Bw horizon developed at the top of the facies. Distal to the to the abandoned channel, the levee is 1.6 m thick, has a silt loam texture, and has a buried weak Bt horizon developed through its entire

107

meters 25

MVl0 22.9m

MV12 24.4m

meters -25

A Bt

BC A-Bwg

2Btg

2Cg

Peoria Loess C

20 2C -20

3Bt

3C Point Bar Facies

15

3C

Swamp Facies

E:::~:::l Clay, Silty ---- Clay Loam

Peoria Loess

D SiltLoam

Figure 9.5 - Stratigraphy of a point bar flat.

thickness. A clayey swamp facies 1. 7 to 2 m thick caps the entire alluvial sequence. Peoria Loess thickness is identical at both locations.

Stratigraphy of sediments and soils All surface soils of the Avoyelles Prairie are developed in Peoria Loess (USDA, 1986). Variations in soil morphology reflect differences in topography, drainage, loess thickness, proximity to escarpments, and to a lesser degree, t?e und~rlying constructional alluvial morphology. Two soIl aSSOCIations are present on the Avoyelles Prairie. The Memphis and Loring soils, representing well-drained profiles, occur along the eastern terrace escarpment where loess thickness is greatest and on elevated landscapes such as point bar ridges and natural levee crests. The Calhoun, Coteau, and Loring soils occur in areas not affected by escarpments. Calhoun and Coteau soils are poorly drained soils associated with landscape depressions of point bar swales and abandoned channels. All loess soils of the Avoyelles Prairie are Udalfs, except the Calhoun, which is an Aqualf.

Basal loess mixing zones occur at the contact between Peoria

. Point Bar Facies

L?')l Sand, Loamy Sand, Sandy Loam, Sandy Clay Loam

-15

Loess and the underlying Mt. Pleasant Bluff Alloformation. Pedogenic mixing incorporates surface horizons of the paleosol developed in the underlying alluvium into the base of the overlying loess. Pedogenic mixing zones are recognized in the field by one or more of the following criteria: 1) marked increases in selected particle size classes, 2) transitional textures of lithologically different deposits, 3) mixture of pedogenic properties identified in overlying and underlying horizons, and 4) vestigial properties of surface horizons where no distin~t surface horizon is preserved. Mixing zone properties in loess deposits are largely a function of loess thickness and underlying sub-loess texture (Schumacher et al., 1987, 1988; Miller et al., 1986). Thicker mixing zones are associated with thinner loess deposits and sandy to loamy sub-loess material. Thinner mixing zones are associated with thicker loess deposits and clayey sub-loess material.

Paleosols developed in Wisconsinan Mississippi River alluvium were distinguished from the overlying Peoria Loess by the occurrence ofafirm yellowc1ayor silty clay below the silt loam mixing zone. In general, the alluvial paleosols are weakly developed and are characterized by B or C horizons

108

Proximal ________________ Distal

meters 25

A E

Bt

MV13 24.4m

MVll 22.9m

meters 25

C Peoria Loess A E

20

3Bw -' '-' -' :-' . '. -=- .. ::r::

.... ~.: ...

Btx

20

2Bt

3C .... ~ .. : .... Levee Facies

3Bt

15 15 4C Swamp Facies

5C Point Bar Facies

Peoria Loess

D SiltLoam

Levee Facies

Point Bar Facies

B(j ~:~~~ L~l:;i:~d, Swamp Facies

~ ~

Silt Loam, Silty Clay Loam, Loam, Sandy Loam

g=~ Clay

Figure 9.6 - Stratigraphy of the outer bend of a meander.

with common color mottles, iron nodules, occasional root traces, and slickensides. The abundance and distribution of these features varies between profiles representing different depositional environments.

Paleosols developed in point bar ridge deposits generally consist of an upper clayey unit that overlies sandy units (Fig. 9.4). The upper clayey unit is commonly represen ted by 2 to 4 m of yellow or yellow-brown, acidic clay with common reddish-brown mottles, large iron nodules, and occasional root traces. The clayey unit represents Bw or C horizons that grade downward into weakly laminated, fine to medium brown sands with silty interbeds and occasional iron nodules.

In comparison to ridge profiles, paleosols developed in

swales are characterized by a thicker upper unit of clay and complex interfingering of sands, silts, and clays in the lower half of the profile (Fig. 9.4). The upper clayey unit is commonlyrepresented by 1 to 4 mofyellowand gray, acidic clay or silty clay with common reddish-brown mottles and few iron nodules. The clayey unit is interpreted as C or Cg horizons, which grade downward into the complex interbedded brown sands, silts, and clays. These interbedded units increase in sand content with depth.

Paleosols developed in natural levee deposits consist of an upper clayey unit that overlies sandy loams to loamy sands (Fig. 9.6). The upper clayey unit consists of 1 to2m of yellow, acidic day to silty clay loam with common reddish-brown mottles and large iron nodules. Clay and silt films occur occasionally within root pores and along ped faces in the

109

A Point Bar

Ridge

500m

Natural Levee'

D Sandy Silt

~ Silty Sand, Sand ~ Clay, Silty Clay

N Buried Point Bar

SOOm

Buried Natural Levee

CJ Sandy Silt

rn Silty Sand, Sand ~ Clay, Silty Clay

Figure 9.7 - Landscape morphology, lithofacies, and pedogenic properties of Holocene Mississippi River alluvium.

silty units. Slickensides filled with silt derived from the overlying loess also were observed (Fig. 9.6, core MV13). The upper clayey unit is interpreted as B or BC horizons, which thicken away from the channel cut bank and towards the margin of the natural levee (Fig. 9.1). The yellow clay grades downward into 1 to 3 m of brown, acidic, sandy loams to loamy sands with common reddish- and yellow-brown mottles, iron nodules, and occasional roottraces. The brown silts are either structureless or exhibit a weak angular blocky structure associated with few, thin clay films along pores and ped faces. The silts are interpreted as 2Et, 2BC, and/or 2C horizons, which thin away from the channel cut bank and towards the margin of the natural levee (Fig. 9.6).

The brown silt grades downward into 2 m of reddish-brown clay with many gray and yellow-brown mottles, iron nodules, root traces, and occasional sil t-filled slickensides, which are the same as the slickenside fills in the upper yellow clay. The slickenside fills and clayey texture suggest that these deeper clays probably represent the upper part of an older paleosol developed in backswamp deposits. The mottled reddish-brown clay grades downward into brown sand, which occurs at a depth approximately 2 m below the sands of the point bar ridge and swale profiles.

Holocene meander belt deposits Comparison between Wisconsinan and Holocene meander belt deposits of the Mississippi River provides an unique opportunity to assess the effects of base level lowering on soils developed in an originally aggradational floodplain setting. Information on Holocene lithofacies and soils come from cores of meander belts 1 and 3 (meander belt designations from Saucier and Snead, 1989), which represent presentlyactive and middle Holocene all uviation in the VidaliaFerriday, LA area (Fig. 9.3). Soils were sampled from point bar ridge and swale, natural levee, and backswamp environments of each meander belt.

Meander belt 1 « 2.8 ka) deposits of the Mississippi River are characterized by thick, weakly developed soil profiles with multiple parent materials, abundant color mottles, iron and carbonate nodules, and slickensides. These characteristics reflect the dominance of flood plain sedimentation and soil hydromorphy on pedogenesis. Soil morphology and texture, however, varies among depositional environments.

Point bar ridge soils are relatively well-drained, up to 7 m thick, alkaline, and typically consist of sandy loam in the upper half of the profile and fine to medium sand towards

110

the base (Fig. 9.7). The sandy loams are generally brownishgray and contain abundant root pores, earthworm burrows, and yellow-brown and gray mottles. The loamy units form Bw, BC, and BCg horizons, which grade downward into sands that are weakly laminated and/or interbedded with sil t and form 2C and 2Cg horizons. The base of the profile is commonly marked by well-laminated, dark gray sands.

In comparison to ridge soils, swale soils are generally more clayey and exhibit more complex interbedding, which reflect the episodic infilling of these landscape depressions. Swale profiles are poorly drained, alkaline, and typically consist of clay in the upper half of the profile and silt and sand towards the base (Fig. 9.7). The clay is generally 1 to 2 m thick, gray, mottled, rooted, and contains occasional

slickensides. The clayey units are Bg horizons that grade downward into complexly interbedded Cg horizons of gray sand, silt, and clay which become increasingly sand-rich and iron nodule-poor with depth.

Natural levee soils are moderately well drained, alkaline, and are 1 to 3 m thick (Fig. 9.7). Profiles typically consist of brownish-gray and gray silt loam, sandy loam, and silty clay loam with common gray mottles, root pores, earthworm burrows, and occasional iron nodules. The silty levees are typically Bw and BCg horizons. Gray matrix and mottles colors increase in abundance in the lower half of the profile, and weakly laminated Cg horizons commonly occur towards the base of the profile. The base of natural levee profiles are marked by either a sharp and erosional or diffuse

l: :::,·:1 Sandy Silt

l?:::?J Silty Sand, Sand

~ Clay, Silty Clay

Figure 9.8 - Conceptual relations of the effects of base level alteration on Mississippi River meander belt deposits.

111

and bioturbated con tact with underlying clays of backs warn p environmen ts.

Backswampsoils are poorly drained, up to 10 min thickness, alkaline, and typically contain common yellow-brown mottles, iron and carbonate nodules, and slickensides of Bg and Bkg horizons (Fig. 9.7). The abundance of mottles, nodules, and slickensides commonly decreases with depth and proximi ty to the water table and the B horizons grade to Cg and Ckg horizons. The base of backswamp soils are commonly marked by uniformly gray and well-laminated clays oflake or poorly-drained backswamp environments, or by sands of crevasse splay origin.

Meander belt 3 (3.8 to 6 ka) deposits of the Mississippi River differ primarily from alluvium by the occurrence of 1 to 2 m of pedogenically-modified clay, which overlies silty and sandy soil horizons and represent the upper clay-rich portion of cumulic soils developed in point bar ridge, swale, and natural levee deposits (Fig. 9.7). Additional differences between young and old meander belt soils include the occurrence of acidic horizons in the upper 1 m of older profiles and clay accumulations (Bt and Btg horizons) in relatively well drained or moderately well drained soils developed in old point bar ridge and natural levee deposits.

Mapping of Holocene meander belt deposits and their stratigraphic relationships in the Vidalia-Ferriday area suggests that the clay veneer over the older silt- and sand-rich meander belt 3 deposits represents conditions of renewed over bank sedimentation following meander belt abandonment and relocation. Thus, cumulic soils that consist of upper clayey horizons that overlie silty and sandy horizons record histories of meander belt avulsion.

Comparison of the Avoyelles Prairie to the Vidalia-Ferriday area

Holocene and Wisconsinan soils developed in Mississippi River meander belt deposits suggest that paleosol profiles of the Avoyelles Prairie reflect two stages of pedogenic developmen t. The first stage was characterized by soil hydromorphy accompanied by sedimentation in an aggradational floodplain setting, which produced cumulic profiles with abundant mottles, nodules, and slickensides. The second stage of pedogenesis was characterized by oxidation and leaching. This stage of pedogenic development was associated with regional base level lowering and erosion, accompanied by loess deposition.

The ini tial stage of paleosol developmen t in an aggradational flood plain setting is confirmed by the association of these paleosols with an ancestral meander belt of the Mississippi River and by the similar occurrence and distribution of color mottles, iron nodules, and slickensides in both the Holocene and Wisconsinan meander bel t soils. Furthermore, the stra tigraphic similarities between the Holocene and Wisconsinan meander belt deposits suggest that they have experienced similar depositional and pedogenic histories. For example, the vVisconsinan Avoyelles Prairie and the middle Holocene meander belt 3 are both veneered by several meters of clay. Because the clay unit associated with the middle Holocene deposits reflect renewed over bank sedimentation following

meander belt abandonment and relocation, a similar sequence of events can be inferred for the origin of the yellow and gray clays that veneer the Wisconsinan meander belt beneath the Avoyelles Prairie. Thus, the brown silts and sands that occur in the lower half of the paleosols of both the Wisconsinan and middle Holocene meander belts reflect concurrent sedimen tation and pedogenesis during meander belt occupation. In comparison, the yellow and gray clays that grade downward into the silts and sands, reflect renewed sedimentation and pedogenesis following meander belt abandonment and relocation that produced cumulic paleosol profiles. Because the paleosols are cumulic and weakly developed, they suggest that the amount of time represented by meander belt abandonment, relocation, and renewed over bank sedimentation and pedogenesis was too brief to produce distinct, vertically stacked profiles.

Followingtheperiodofpedogenesisin an active Wisconsinan flood plain environment, an episode of regional base level lowering and erosion, accompanied by loess deposition, initiated the second stage of paleosol developmen t (Fig. 9.8). This stage of development represents a transition from saturated and reducing to well-drained and OXidizing soil conditions associated with the development of the Avoyelles Prairie terrace. The weak development of the paleosols beneath the loess suggest that the loess deposits were thick enough and/or deposited quickly enough to arrest pedogenic development. Preliminary observations suggest that the change in soil-forming conditions did however, cause changes in matrix and mottle colors, pH, and iron nodule size and hardness. For instance, the yellow (2.SY) hue of the Wisconsinan clays that occur beneath the loess is absent from clayey Holocene meander belt soils, which have a gray (SY) hue. The yellow color of the clays may have occurred during a period of surficial weathering following the development of the Avoyelles Prairie terrace and prior to loess deposition. Alternatively, the yellow color of the clay might be attributed to the present-day oxidation and soil development beneath Peoria Loess.

The Wisconsinan paleosols are also more acidic and well drained in comparison to the alkaline and water-logged Holocene meander belt soils. Acidic and well-drained conditions, which developed during the second stage of paleosol development, may have also altered the original mineralogy and chemistry of the paleosols, but no laboratory data are presently available to support this idea. Lastly, iron nodules in the paleosols are larger and harder than in the Holocene soils, suggesting that oxidizing conditions have favored the precipitation and dehydration of iron compounds during the second stage of paleosol development.

Although this analysis of the AvoyeUes Prairie has delineated only one Wisconsinan meander belt of the Mississippi River, core data and comparison with Holocene meander belt deposits suggest that at least two and perhaps three Mississippi River meander belts were present in the area during the Wisconsinan. The presence of a second and younger meander belt in the area can be inferred from the yellow and gray clays, which have buried the silt- and sandrich deposits of the underlying meander belt. The exact position of this younger meander belt has not been determined, but could have been located west of the area in the

112

Hb

Hmrrla

Hrl

Ppl

MV

Hb 10· 1 • Mansura.

Hrl

Hrl

;>-t 0 5 ~ Hmm Mississip~i River Hb Backswamp N

Meander elt Alluvium I

i z Red River Hu (Undifferentiated) Kilometers ~ Hrm

~ Meander Belts Red River

Ppl Prairie Complex (Lower Surface)

::> Hri Natural Levee Ppu Prairie Complex (Upper Surface) MV Core Location a ·11

Figure 9.9- Geologic map of the Avoye/les Prairie.

113

vicinity of Monda Gap or to the east within the present Holocene alluvial valley (Fisk, 1940).

Evidence of a possible third and older meander belt in the area is represented by the sands that occur beneath the natural levee and backswamp deposits along the cut bank side of the abandoned channel (cores MV11 & 13, Fig. 9.6). The top of these sands are several meters below the tops of the sands inside the abandoned channel, and could be associated with an older meander belt.

Geologic mapping The Avoyelles Prairie (Fig. 9.9) represents an ideally preserved set of Wisconsinan MisSissippi River meander belt deposits of the Prairie Complex that have a regional extent and reflect multiple cross-cutting channel belts. Comparable fluvial lithofacies and stratigraphic position, burial by Peoria Loess, and elevation and slope relations allow for correlation to the Mt. Pleasant Bluff Alloformation (Autin et al., 1988; Mossa and Autin, 1989), and the Prairie Complex, Lower Surface of the Florida Parishes of southeastern louisiana (Autin and McCulloh, 1991, 1992). The Avoyelles Prairie also correlates to the Opelousas to Lafayette meander belt (Fisk and McFarlan, 1955) of the Prairie Complex. Wisconsinan Mississippi River meander belt deposits also have been uplifted by the Five Islands salt dome chain in south-central Louisiana (Autin, 1984; Autin et al., 1986;

Autin and McCulloh, 1993). The Wisconsinan deltas identified on the continental shelf of the Gulf of Mexico (Suter et al., 1987) are also possibly downdip equivalents. A Little River Prairie Complex, Lower Surface correlative to the Avoyelles Prairie is preserved at nearby Big Island. Portions of the Prairie Complex at Kolin, Holloway, and Buckeye are part of a topographically higher, LRRV part of the Prairie Complex that possibly correlates to the Upper Prairie (Smith and Russ, 1974; Russ, 1975) and Prairie Complex, Upper Surface of the Florida Parishes of southeastern Louisiana (Autin and McCulloh, 1991, 1992).

No definitive Wisconsinan Mississippi River meander belts have been identified upvalleyofthe Avoyelles Prairie. There is no data to substantiate or refute the possibility that part of the Wisconsinan valley trains (Saucier and Snead, 1989) could be a braid belt equivalent to the Avoyelles Prairie and its correlative meander belt deposits. The Avoyelles Prairie's likely equivalent in the LRRV is the Aloha Alloformation (Stop 3, this guidebook). The Aloha Alloformation is in a the same relative stratigraphic position, has similar degree of lithofacies and paleosol preservation, and appears to be graded to the Avoyelles Prairie.

114

The Rival Diversion We have seen at Monda Gap that the Red River departed its alluvial valley and cut through a Pleistocene highland to find a swifter route to the Mississippi even though it could (and previously did) go around. Of course, the river could not have dim bed up over the terrace to begin its cutting . Rather, a minor, nameless stream cut it's own small valley in that area until the Red was able, during floods, to discharge water through the small gap. A succesion of floods made the gully wider and deeper until, during a major flood event, the tiny stream captured the main channel of the Red River.

The small Prairie inliers at Evergreen and Goudeau are detached portions of the Avoyelles Prairie thatsuggestthatthis event may have occured previously in the continuing process of adjustment between the alluvial fan at the mouth of the Red River valley and the valley plain of the lower Mississippi River.

Until the Corps of Engineers built levees along the Red, the same process was being repeated across the middle of Avoyelles Prairie. Just a few hundred yards south of FOP stop # 9, Coulee des Gruesflows eastward to empty into Old River. Living people can still recall seeing a boiling red torrent pouring through Coulee des Grues during high floods on the Red River. Without modern flood control, the Red might have someday flowed through a gap south of Marksville. Perhaps it may anyway! (Newton, 1987).

-John Snead

HOLaWAY PRAIRIE

115

FOP Stop References Abington, O. D., 1973, Changing meander morphology and hydraulics, Red River Arkansas and Louisiana [Ph.D. dissertation]: Louisiana State University, Baton Rouge.

Alford, J. J., Kolb, C. R, and Holmes, J. c., 1985, Terrace stratigraphy along the Lower Red River, Louisiana: Southeastern Geology, v. 26, no. I, p. 47-51.

Autin, W. J., 1984, Geologic significance of land subsidence at Jefferson Island, Louisiana: Gulf Coast Association of Geological Societies Transactions, v. 34, p. 293-309.

Autin, W.J., and McCulloh, R. P., 1993, Quaternary geology of Weeks and Cote Blanche Islands salt domes: Louisiana Geological Survey, Open File Series No. 93-01, 44 p.

Autin, W. J., and McCulloh, R. P., compilers, 1992, New Roads Geologic Quadrangle: Louisiana Geological Survey, Baton Rouge, scale 1:100,000.

Autin, W. J., Burns, S. A., Miller, B. J., Saucier, R. T., and Snead, J. 1., 1991, Quaternary geology of the Lower Mississippi Valley in Morrison, R B., ed., Quaternary non-glacial geology of the conterminous United States: Geological Society of America, Geology of North America, v. K-2, p. 547-82.

Autin, W.J., and McCulloh, R. P., compilers, 1991, Geologic and derivative engineering-geology hazard maps of East Baton Rouge Parish, Louisiana: Louisiana Geological Survey, Open File Series No. 91-01, 1:24,000 scale, 34 sheets.

Autin, W. J., Davison, A. T., Miller, B. J., Day, W. J., and Schumacher, B. A., 1988, Exposure oflate Pleistocene meander-be-lt facies at Mt. Pleasant, Louisiana: Gulf Coast Association of Geological Societies Transactions, v. 38, p. 375-83.

Autin, W. J., McCulloh, R. P., and Davison, A. T., 1986, Quaternary geology of Avery Island, Louisiana: Gulf Coast Association of Geological Societies Transactions, v. 36, p. 379-90.

Birdseye, R. U., and Aronow, S., 1991, New evidence for a young late Wisconsin age for the Prairie Formation in southwestern Louisiana: Geological Society of America Abstracts with Programs, v. 23, no. 5, p. A223.

Britsch, 1. D., and Kemp, E. B., 1990, Land loss rates: 1vfississi ppi River del taic plain: U. S. Army Corps of Engineers vVaterways Experiment Station, Geotechnical Laboratory, Technical Report GL-90-2, Vicksburg, MS.

Champomier, P. A., 1852, Statement of the sugar crop made in Louisiana in 1851-52: Cook, Young & Company, New Orleans, 48 p.

Chawner, W. D., 1936, GeologyofCatahoula and Concordia Parishes: Louisiana Geological Survey, Geological Bulletin 9, 232 p.

Commonwealth and Associates, Inc., 1981, Cultural resources survey of the Red River Waterway from Shreveport

to the Mississippi River: Commonwealth and Associates, Inc., Jackson, Michigan, 2 vols., 574 p.

Douglas, 1., 1967, 11an, vegetation and the sediment yield of rivers: Nature, v. 215, p. 925-28.

Dunne, T., 1979, Sediment yield and land use in tropical catchments: Journal of Hydrology, v. 42, p. 281-300.

Fisk, H. N., 1944, Geological investigation of the alluvial valley of the Lower Mississippi River: U.S. Army Corps of Engineers, Mississippi River Commission, Vicksburg, Mississippi, 78 p.

Fisk, H. N., 1940, Geology of Avoyelles and Rapides Parishes: Louisiana Geological Survey Geological Bulletin 18,240 p.

Fisk, H. N., 1938, Geology of Grant and LaSalle Parishes: Louisiana Geological Survey Geological Bulletin 10, 246 p.

Fisk, H. N., and McFarlan, Jr., E., 1955, Late Quaternary deltaic deposits of the MiSSissippi River: Geological Society of America Special Paper 62, p. 279-302.

Fournier, F., 1960, Debit solide des cours d'eau. Essai d'estimation de la perte en terre subie par l'ensemble due globe terrestre: International Association of Scientific Hydrology Publication 53, p. 19-22.

Gagliano, S. M., Weinstein, R. A., Rader, B., Small, B.A., and McCloskey, K. G., 1979, Cultural resources survey of the Teche-Vermilion conveyance channel, St. Landry Parish, Louisiana: Coastal Environments, Inc., Baton Rouge, 78 p.

Gustavson, T. V., Finl~y, R. J., and Baumgardner, Jr., R W., 1981, Retreat of the caprock escarpment and denudation of the Rolling Plains in the Texas panhandle: Bulletin of the Association of Engineering Geologists, v. 18, no. 4, p. 413-22.

Hadley, R. F., Lal, R., Onstad, C. A., Walling, D. E. and Yair, A., 1985, Recent developments in erosion and sediment yield studies: UNESCO Technical Documents in Hydrology, Working Group of the ICCE on IHP-II Project A.1.3.1, Paris, France, 125 p.

Harrelson, D. W., 1990, Deposition of a Prairie Terrace sequence, Red River Parish, Louisiana: Geological Society of America Abstracts with Programs, v. 22, no. 4, p. 17.

Harrelson, D. W., and Smith, 1. M., 1988, Thermoluminescence age dates from a Red River terrace sequence, Red River Parish, Louisiana: Geological Society of America Abstracts with Programs, v. 20, no. 4, p. 268.

Harris, G. D., and Veatch, A. C., 1899, General geology in Geological Survey of Louisiana: Louisiana State University Experiment Station, Geology and Agriculture, Section 2, p. 45-138.

Kesel, R. H., 1987, Quaternary depositional surfaces of western Louisiana: Louisiana Geological Survey, Open-File Series No. 87-02, 16 p.

116

Klinger, T. C., Cande, R. F., Kandare, R. P., and Cochran, R. ].,1983, Cultural resources survey, testing and assessment in eight areas, eleven localities and at eight archaeological sites in Avoyelles Parish, Louisiana: Historic Preservation Associates.

Langbein, '\tV.B. and Schumm, S.A., 1958, Yield of sediment in relation to mean annual precipitation: Transactions of the American Geophysical Union, v. 39, p. 1076-84.

Lenzer,]. P., 1979, New data on the date of the Monda Gap diversion: tvfs. on file, New World Research, Pollock, Louisiana.

Matson, G. C., 1916, The Pliocene Citronelle Formation of the Gulf Coastal Plain: U.S. Geological Survey Professional Paper 98, p. 167-92.

May,]. R., and Britsch, 1. D., 1987, Geological Investigation of the Mississippi River deltaic plain: Land loss and accretion: U. S. Army Engineer Waterways Experiment Station, Technical Report GL-87-13.

Miller, B.]., Lewis, G. C., Alford,].]., and Day, W.]., 1985, Loesses in Louisiana and at Vicksburg, Mississippi: Friends of the Pleistocene, South-Central Cell Field Trip Guidebook, 126 p.

Moore, C. B., 1912, Some aboriginal sites of Red River: Journal ofthe Academy of Natural Sciences of Philadelphia, Second Series, v. 14.

Mossa, ]., 1990, Discharge-Suspended Sediment Relationships in the Mississippi-Atchafalaya River System, Louisiana [Ph.D. Dissertation]: Louisiana State University, Baton Rouge, 190 p.

Mossa, ]., and Autin, W. ]., eds., 1989, Quaternary geomorphology and stratigraphy of the Florida Parishes, southeastern Louisiana: A field trip: Louisiana Geological Survey Guidebook Series No.5, 98 p.

Pearson, C. E., 1986, Dating the course ofthe lower Red River in Louisiana: the archaeological evidence: Geoarchaeology, v. 1, p. 39-44.

Potter, P. E., 1955, The petrology and origin of the Lafayette gravel: Journal of Geology, v. 63, p. 1-38, p. 115-32.

Rosen, N. C., 1969, Heavy mineral and size analysis of the Citronelle Formation of the Gulf coastal plain: Journal of Sedimentary Petrology, v. 39, p. 1552-65.

Russ, D. P., 1975, The Quaternary geomorphology of the lower Red River Valley, Louisiana [Ph.D. dissertation]: Pennsylvania State University, College Park, 205 p.

Russell, 1967,

Saucier, R. T., 1974, Quaternary geology of the Lower Mississippi Valley: Arkansas Archeological Survey, Research Series, v. 6,26 p.

SaUcier, R. T., and Snead,]. I., compilers, 1989, Quaternary geology of the Lower Mississippi Valley in Morrison, R. B., ed., Quaternary non-glacial geology: Conterminous United States: Geological Society of America, The Geology of North America, v. K-2, scale 1:1,100,000.

Schumacher, B. A., Miller, B. ]., and Day, W. ]., 1987, A chronotoposequence of soils developed in loess in central Louisiana: Soil Science Society of America Journal, v. 51, p. 1005-10.

Schumacher, B. A., Lewis, G. C., Miller, B.J., and Day, W.J., 1988, Basal mixing zones in Louisiana and Idaho: I. Identification and characterization: Soil Science Society of America Journal, v. 52, p. 753-58.

Shenkel, R.]., 1981, Big Oak Island archaeology: prehistoric estuarine adaptations in the Mississippi River Delta: National Park Service, New Orleans.

Smith, F. 1., and Russ, D. P., 1974, Geological investigation of the Lower Red River-Atchafalaya basin area: U. S. Army Engineer Waterways Experiment Station Technical Report S-74-5.

Snead,]. I., and McCulloh, R. P., compilers, 1984, Geologic map of Louisiana: Louisiana Geological Survey, Baton Rouge, Scale 1:500,000.

Suter,]. R., Berryhill, Jr., H. 1., and Penland, S., 1987, Late Quaternary sea-level fluctuations and depositional sequences, southwest Louisiana continental shelf: Society of Economic Paleontologists and Mineralogists Special Publication 41, p. 199-219.

Toth, A., 1977, Early Marksville phases in the Lower Mississippi Valley: a study of culture contact dynamics [Ph.D. dissertation]: Harvard University, Cambridge, Massachusetts.

U. S. Army Corps of Engineers, New Orleans District, 1992, Summary of Measure Suspended Sediment Loads at Main River Stations (Lower Mississippi RIver at Tarbert Landing, Atchafalaya River at Simmesport, and Old River Outflow Channel at Knox Landing), Reports Control Symbol DAENCWE-12.

United States Army Waterways Experiment Station, 1950, Geology of the Lower Red River, Waterways Experiment Station, Technical Memorandum No, 3-319, Vicksburg, MS, 72p.

United States Department of Agriculture, 1986, Soil survey of Avoyelles Parish, Louisiana: United States Department of Agriculture, 162 p.

United States Department of Agriculture, 1986, Soil survey of Grant Parish, Louisiana: United States Department of Agriculture, 140 p.

United States Department of Agriculture, 1980, Soil survey of Rapides Parish, Louisiana: United States Department of

117

Agriculture, 86 p.

~Na1ling, D. E., and Kleo, A. H. A., 1979, Sediment yields of rivers in areas of low precipitation: A global view: The Hydrology of Areas of Low Precipitation, Proceedings of the Canberra Symposium, International Association of Hydrological Sciences Publication Number 128, p. 479-493.

Whittington, 1970,

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The accompanying road log is designed to provide trip participants with route information. The log is also supplemented with scientific and general information about the areas between trip stops. Each day's log begins in the Alexandria area near the trip headquaters and ends at the final field stop of the day. We will try to mark backwoods intersections with a FOP arrow sign, look for them!

DAY 1 TIME MILE FEATURE

8:00 0.0 Assemble in Pizza Hut parking lot across MacArthur Drive from the FOP motels. The highway is under construction in this area. Be careful, adhere to all detour information, and stay with the caravan. Leave the parking lot and head north, following US 71 and US 165.

1.7

2.5

3.7

5.0

9.7

11.0

17.5

18.6

22.5

23.0

28.2

9:00 29.4

11 :00 30.5

31.5

32.0

37.1

42.0

48.8

50.0

54.0

Cross Red River bridge. Notice exposure of Miocene strata in the channel banks if the water is low. This is a remnant of the historic rapids, from which Rapides Parish obtained its name.

Pass Ft. Buhlow Lake.

Junction of US 71 and US 165. Continue to the right on US 165N.

Junction of US 165 and US 167. Turn left onto US 167N.


Enter Grant Parish. From this point to Bentley, we will traverse the typical landscape of Fisk's Bentley Terrace.

Bentley. Continue north on US 167.

site of Bentley Core - RR 11 on left off Brister Loop road. Continue on US 167N.

Town of Dry Prong.

Cross LA 123. Continue north on US 167.

Turn right on Forest Service Road 122 (gravel road). Cross RR tracks and veer right.

STOP 1 at Williana Pit, site of Williana core- RR 22. This site is National Forest property.

Return to US 167 and turn right (north) to Wi"iana.

Town of Willian a, turn left before caution light at abandoned store.

Bear left at Liberty Chapel Road. Stay on main road. Look for FOP arrows!

Turn right (west) onto LA 122 at Faircloth.

Bridges crossing latt Creek.

Junction with LA 471. Veer right and stay with LA 122.

Village of New Verda. Stay on LA 122 to Montgomery.

Village of Hargis.

119

55.5

56.5

57.1

58.3

62.1

63.2

66.5

67.4

67.7

73.2

12:00 73.4

Upland Complex contact with Prairie Complex.

Cross Nantachie Bayou.

Ascend Intermediate Complex, Montgomery surface.

Junction with US 71 at Montgomery. Turn right (north) on US 71 . Montgomery core site-RR 12 is on left side of road across RR after making turn.

Enter Winn Parish. This is the typical Montgomery Terrace landscape of Fisks' type area.

Classic, unleveled pimple mounds can be seen in the pasture on the right side of the road.

St. Maurice, junction with LA 477. stay on US 71 N to Clarence.

Descend onto Holocene flood plain.

Cross Saline Bayou.

Clarence, junction with US 84. Stay on US 71 N.

LUNCH STOP AT GRAYSON'S BBQ. Lunch on your own here, there is a dining room inside or you can tailgate outside. There is also a convenience store close by.

1 :00 73.4 After lunch, head south on US 71 back to St. Maurice.

79.9 Turn right on LA 477 to St. Maurice RR cut. Look for FOP arrows on gravel roads.

1 :15 80.6 STOP 2 at St. Maurice exposure. This site ison the private right-of-way of the railroad.

3:00 81.3 Return to US 71 and turn right (south).

84.7 Pimple mounds in pasture.

86.0 Grant Parish line.

89.0 Town of Montgomery.

96.5 Pass Wadell.

97.3 Cross Nantachie Bayou spillway.

99.0 Turn right on gravel road and cross RR. Head to Aloha Cemetary.

3:30 99.5 STOP 3 at Aloha Prairie. This site is private property.

5:00 100.0 Return to US 71, turn right (south).

104.0 The Rock at Junction of LA 158 and US 71. Behind Rock Garden Exxon is a classic exposure of the Oligocene Catahoula Sandstone. You can return directly to the Alexandria motels by continuing south on US 71. Or you can go directly to the social at Harold Miles Park by following LA 158 to Colfax, joining with LA 8, and crossing the Red River to Boyce. From Boyce, follow LA 1 south towards Alexandria to the park which is on your right about six miles south of Boyce. Either route is less than 30 miles.

END DAY 1 LOG

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DAY 2

TIME MILE FEATURE

8:00 0.0 Assemble in Pizza Hut parking lot across MacArthur Drive from the FOP motels. The highway is under construction in this area. Be careful, adhere to all detour information, and stay with the caravan. Leave the parking lot and head north, following US 71 and US 165.

0.8 Head north on LA 1.

3.9 Junction with 1-49 and Air Base Road. Stay on LA 1.

4.8 Harold Miles Park on left. Stay on LA 1.

8.4 Stop light at Rapides. Stay on LA 1.

12.5 Cross over 1-49.

13.6 Town of Boyce. Continue on LA 1 north.

14.9 Pass junction with LA 121.

16.8 Turn right to Old Highway 1 at Texaco station. Proceed to stop sign and turn right.

17.7 Gate to Zimmerman Hill.

8:30 18.0 STOP 4 down the road beyond gate. This site is private property.

10:00 18.3 return up Old Highway 1 and turn left to LA 1

18.6 Junction with LA 1, turn left (south) onto LA 1 .

20.5 Turn right on LA 121 and follow Bayou Jean de Jean.

25.8 Junction with LA 1200 west at Hot Wells. Stay with LA 121.

27.5 Junction with LA 1200 east to Boyce. Stay with LA 121. Antebellum home at junction.

30.2 Junction with LA 1202 at McNutt. Take LA 1202 towards England Air Force Base.

32.2 Cross Bayou Rapides at Lamonthe Bridge. LA 496 joins route.

35.7 Junction of LA 1202 and LA 496 at Weil. Stay with LA 496.

37.6 Back gate to England Air Force Base. Enter base and go to STOP 5.

10:30 38.0 STOP 5 England Air Force Base. This site is now municiapal property.

12:00 39.7 return to La. 496 and head east towards Alexandria.

40.8 Pass Kent House Antebellum Home.

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12:05 41.0 Junction with US 165 (MacArthur Drive). LUNCH BREAK. Fast Food is available south on MacArthur Drive from this point. Grab a quick bite or pick up a bag lunch then follow US 71 N towards the Red River bridge. Stop 6 is ten minutes away and has picnic tables.

1:00

2:00

42.4

43.6

44.6

45.4

46.7

48.8

54.6

57.7

62.5

69.0

Construction area. Veer north on US 71 to Red River Bridge.

Top of bridge. Cross Red River.

Turn left on to Ft. Buhlow Airport Road. Be careful, crossing traffic!

Turn right and cross RR. Enter Fort Buhlow Recreation Area. Picnic facilities are here.

STOP 6. Red River Landing.This site is public property.

Return to US 71. turn right and follow US 71 S towards Alexandria.

Traffic Circle. Stay on US 71 S (MacArthur Drive) through the city.

Cross 1-49. Stay on US 71 S.

Pass LSU at Alexandria campus.

Town of Lecompte (Lea's Diner is known for it's fine pies (one of two Louisiana restaurants to get the highest rating from The Underground Gourmet), you can stop here on your return to Alexandria in a couple of hours if you wish and grab a slice of pie and coffee).

72.0 Junction with US 167S at Meeker. Continue on US 71 S.

73.8 Turn right onto Lloyd's Bridge Road (sic). Pass under RR trestle.

2:45 74.5 STOP 7. Loyd's Hall. This site is private property, tourists are welcome.

4:30 75.00 You can return to Alexandria via US 71 (the route the caravan took) or follow the old road along Bayou Bouef to see flood plain topography and historic plantation agricultural areas. The direct route is less than 25 miles to the motels. Don't forget the lemon pie at Lea's!

END DAY 2 LOG

122


8:00 0.0 Assemble in Pizza Hut parking lot across MacArthur Drive from the FOP motels. The highway is under construction in this area. Leave the parking lot and head north, onto the construction traffic cirde following US 71 and US 165. Watch for a quick right turn.

0.5

1.9

2.1

2.9

4.1

9.3

15.7

17.8

19.5

23.0

24.4

25.5

9:00 26.0

10:00 26.6

27.4

30.0

35.0

35.5

36.0

37.0

10:30 37.1

12:00 37.5

Turn right (south) on LA 1 S (Bolton Avenue). Follow Bolton Ave.into midtown Alexandria.

Veer left towards Pineville on LA 28 and US 165.

Turn left (south) on LA 28 and LA 1 (Overton St).

Cross Red River, enter Pineville.

Exit LA 107 (to Marksville). Turn right (south) on LA 107 and cross RR.

Junction with LA 3128. This is the highest point on the Day 3 road log at 160 ft elevation. Continue on LA 107 and cross the Intermediate Complex landscape to Kolin.

Junction with LA 454 at Ruby. Stay with LA 107. Landscape is the Holloway Prairie.

Enter Avoyelles Parish.

Town of Center Point.

Junction with LA 115. Follow LA 115 towards Marksville.

Turn left on LA 1196 towards US Army Corps of Engineers Lock and Dam.

Turn right and cross levee. Enter Ben Routh Recreation Area. This site is a public park.

STOP 8- Monda Gap.

Return to LA 115. Turn left (south) to Marksville.

Cross Red River bridge.

Pass Monda Community center Road. Stay on LA 115.

Domestic buffalo in pasture on right.

Veer to left of Chevron Station on to S. Washington st.

Junction with LA 1. Turn left (south).

Turn left into the Tunica-Biloxi Indian ReseNation. Property of the tribe.

STOP 9 - Avoyelles Prairie. Park at The Marksville Commemorative Area museum.

This is the end of the 1993 FOP field trip. LA 1 North will return you to Alexandria and 1-49. LA 1 South will take you to Baton Rouge and 1-10 via New Roads and US 190E. If the weather is nice try taking the St. Francisville Ferry at New Roads across the Mississippi River and south via US 71 to Baton Rouge.

END DAY 3 LOG

123

S CTIO III

ontri uted Articles

124

Surficial Deposits of Tertiary Age in the Central Louisiana Area

lames E. Rogers

The Sabine uplift is one of the dominant geologic features in northwest Louisiana. This uplift extends into northern Sabine Parish and into northwestern Natchitoches Parish in central Louisiana. Older deposits (Paleocene) of Tertiary age overlie the uplift and dip gently toward the east and more steeply toward the south-southeast. Successively younger deposits of Tertiary age occur to the east and south-southeast of the uplift. These deposits crop out in the hill lands between major river valleys except in areas blanketed by deposits of Pleistocene or Holocene age.

West of the Red River Valley in Natchitoches Parish, in Sabine Parish, in the northern three-fourths of Vernon Parish, and in northwestern Rapides Parish deposits of Tertiary age are well exposed. Relatively fresh outcrops of some units are in road cuts along Interstate 49 or other highways and secondary roads. Farther south in southwestern Rapides Parish and in the southern one-fourth of Vernon Parish nearly all of the area is blanketed by deposits of Pleistocene age. Much of central Louisiana (about 70% of Grant, LaSalle, Rapides, and southern Winn Parishes) east of the Red River Valley is blanketed by deposits of Pleistocene age. In part of this area, erosion has exposed narrow outcrops of deposits of Tertiary age along some streams. Other outcrops in the northern and northeastern part of this area are more continuous-being interrupted by deposits of Pleistocene age and Holocene age along stream courses. Some of the small outcrops east of the Red River Valley are classic, definitive sites for the geologic units. Many of the outcrops are nonfossiliferous and their stratigraphiC position was determined by data from nearby test holes or wells.

The deposits of Tertiary age are composed mostly of unconsolidated sand, silt, clay, and shale. Some outcrops, especially of the Oligocene (?) and Miocene, are indurated sandstone and siltstone. Several marine deposits made up largely of clay and shale form widespread marker beds within the sediments of Tertiary age. Some of the fossils within the marine parts of these beds are used to date the sediments and to provide an indication of the age of overlying or underlying nonfossiliferous deposits.

Deposits of Paleocene age and Eocene age are exposed along Interstate 49 in Natchitoches Parish. Deposits of the upper Eocene and the Oligocene are blanketed by Holocene alluvium along Interstate 49. Deposits of Oligocene age probably are best exposed in the Rosefield area of northwestern Catahoula Parish. Deposits of lower Miocene age crop out

along Interstate 49 in northwestern Rapides Parish. A more extensive section of outcrops of Miocene age occur along U.S. Highway 171 from a short distance north of the Sabine Parish-Vernon Parish line to about 9 miles south of Leesville. Generally, the more definitive exposures of Tertiary deposits are located along secondary roads, local roads, and stream banks.

The geologic units of Tertiary age in central Louisiana as shown on the State Geologic map are (from north to south) the Wilcox Group (undifferentiated) of Paleocene and Eocene ages; The Claiborne Group of Eocene age; the Jackson Group (undifferentiated) of Eocene age; the Vicksburg Group (undifferentiated) of Oligocene age; the Catahoula Formation of Oligocene or Miocene age; and the Fleming Formation of Miocene and Pliocene ages. The Claiborne Group of Eocene age as shown on the map is made up of the Cane River Formation, the Sparta Formation, the Cook Mountain Formation, and the Cockfield Formation. The other unit in this sequence that is subdivided on the map, the Fleming Formation, is made up of the Lena Member, the Carnahan Bayou Member, the Dough Hills Member, the Williamson Creek Member, the Castor Creek Member, and the Blounts Creek Member. The Blounts Creek Member may be partly Miocene age and partly or all Pliocene age. Some of the high terrace deposits also may be Pliocene age. The following sections are a brief discussion of the geologic units.

Wilcox Group The Wilcox Group was divided by H. V. Andersen on his Geologic Map of Natchitoches Parish (1992) into 10 formations. Most were an extension of his work in Sabine Parish. These units are lithologically heterogeneous, and the formations appear to be time units more than mappable rock units. Some of the features on outcrops are related to weathering and cementation or dissolution and redeposition. Several miles north of Natchitoches on the west side of Interstate 49 near the edge of the Red River Valley are very large concretions 6 ft or more in diameter. Occasionally "hard layers" are encountered in the drilling of wells in the Wilcox. These layers may represent concretions in some places and siltstone or sandstone in other places.

An examination of geologic logs and electrical logs does not indicate extensive marker beds in the Wilcox. Thus, the formations would be difficult to trace in the subsurface. The Wilcox in the area has been identified as a deltaic sequence

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which accounts for the occurrence of marine beds (clay) and nonmarine beds of sand, clay, and lignite. Under deltaic conditions some of the marine deposition was simultaneous with nonmarine deposition. The active delta accounts for much of the heterogeneity of the deposits and the lack of definitive marker beds over large areas. For example, in DeSoto Parish (north of Sabine Parish) lignite is mined from a bed below a massive sand bed, the Dolet Hills. This lignite bed and the overlying sand are traceable over a relatively small area.

The description for Wilcox (undifferentiated) on the State geologic map is as follows:

({Gray to brown lignitic sands and silty to sandy lignitic clays, many seams of lignite, some limestone and glauconite. Incl udes small Carrizo Sand (Claiborne Group?) outcrops."

lvfany workers consider the Carrizo to be the basal unit of the Claiborne Group. Exposures of the Wilcox occur in road cuts along Interstate 49 from the valley edge northwest of Natchitoches to about one-quarter mile north of the interchange with Louisiana Highway 6.

Claiborne Group The Claiborne Group of Eocene age is made up of the Carrizo Sand, the Cane River Formation, the Sparta Formation, the Cook Mountain Formation and the Cockfield Formation.

Carrizo Sand The Carrizo Sand is a massive bedded quartz sand. In some areas minor amounts of interbedded silt and clay occur. In addition, thin beds oflignite may occur in some areas. Sandy intervals along Louisiana Highway 6 from about 2 miles east Of the intersection of Interstate 49 to about 2 miles west of the interstate are Carrizo. The sand generally is medium to very fine and ranges in thickness from 30 ft to 150 ft or more. The sand generally is less silty than those in the Wilcox.

Cane River Formation The formation is predominantly gray to brown clay and shale with a few thin beds of silt and lignite. Marl occurs in parts of the interval. Glauconite occurs in the clays and shales and parts of the interval are fossiliferous. This unit is a distinct marker bed in the subsurface. Outcrops that occur along Interstate 49 from the intersection with Louisiana Highway 6 for about 2 miles to the south-southeast are Cane River. Extensive outcrops of the Cane River occur in northeastern Natchitoches Parish-in part overlain by small outcrops of Intermediate and High Terraces.

Sparta Formation The Sparta is an alternating sequence of sand beds, silt beds, clay beds, and a few lignite beds. The sand generally is fine to medium and well sorted. In some places near the base of the Sparta and near the top thin, very fine glauconitic sand beds occur. The lower beds represent the transitional zone from the Cane River and probably should be considered part of the Cane River Formation. The upper glauconitic sand beds probably should be considered part of the Cook Moun-

tain Formation. Generally the Sparta is made up of more than 50% sand-in some places massive and in other places thin bedded. The Sparta crops out along Interstate 49 from 2 miles southeast of the intersection of Louisiana Highway 6 to about4.2 miles southeast of the intersection. The Sparta also crops out in northeastern Natchitoches Parish in the Readheimer area northward to Bienville Parish. In Winn Parish the Sparta crops out to the east of Saline Bayou (east of the Holocene and Pleistocene deposits). The width of the outcrop is about 3 to 5 miles.

Cook Mountain Formation The Cook Mountain is made up of glauconitic clay and shale with beds of fine and very fine green sand. On the outcrop the glauconite weathers to brown ironstone. In places the Cook Mountain is mostly clay (150-200 ft) whereas in other places the large number of silt and sand beds makes the unit difficult to identify on electrical logs. The Cook Mountain crops out along Interstate 49 about 1.2 miles north of the first exit south of Louisiana Highway 6 (local road) and the outcrop extends about a half- mile southeastward along the interstate. The local road is built on the Cook Mountain from about one mile east of the interstate to the edge of the Red River Valley. In Winn Parish a classic outcrop of part of the Cook Mountain is by the railroad bridge· across Saline Bayou atSt. Maurice. In the winter and spring, high water on the Red River generally covers the outcrop.

Cockfield Formation The Cockfield is an alternating sequence of sand beds, silt beds, shale beds, and some lignite beds. The sand generally is fine to medium. Some sand intervals are massive; some are thin bedded. The Cockfield crops out along Interstate 49 from a half mile north-northwest of the first exit south of Louisiana Highway 6 to about 1.2 miles south-southeast of this exit. About one-half of the Cockfield to the southsoutheast is covered by deposits of Pleistocene and Holocene ages.

Jackson Group (undifferentiated) The Jackson Group of Eocene age is made up of light gray to brown clay, some ironstone layers; and minor amounts of very thin sand. The unit is fossiliferous in part. Formations in the Jackson are defined by fossils more than lithology except for the basal Moody's Branch Formation (marl). One of the classic localities for basal Jackson is the bluff on the Red River near Montgomery. Until re-channeling, the river impinged on the bluff and kept it clean. Pictures from early in the century looked very similar to those taken 60 or 70 years later. Now some silting has occurred and during the winter and spring high water covers most of the outcrop. At one time, the con tact with the Cockfield was exposed. Along Interstate 49 the Jackson is concealed by Red River alluvium.

Vicksburg Group (undifferentiated) The Vicksburg Group of Oligocene age is mostly clay in central Louisiana. In western Louisiana there is a basal sand which pinches out down dip and eastward along the outcrop. The clays are gray or brown, calcareous, and fossiliferous. The Vicksburg does not crop out along Interstate 49-

126

the beds are blanketed by the Red River alluvium. Between Rosefield in northern Catahoula Parish and Ouachita River Valley there are fossil beds, calcareous concretions containing fossils, and gypsiferous inclusions. Erosion on both the Jackson and Vicksburg have reduced most of the outcrop to lowlands and distinctive outcrops often are hard to find.

Catahoula Formation The Catahoula is considered by some to be Oligocene age; by others, to be Miocene age. The formation is made up predominately of sand with lesser amounts of silt and clay. Some of the sand is very coarse and has been referred to by some drillers as "rice grain sand". At many places along the outcrop the sand is cemented into sandstone and the silt, into siltstone. A short distance downdip or laterally the sandstone may grade into loose sand. Petrified wood, including palm wood, occurs in the formation. The narrowing of the Red River Valley in northwestern Rapides-western Grant Parishes is a result of the resistance of the indurated beds of the Catahoula. The Catahoula is exposed along Interstate 49 south of the intersection with Louisiana State Highway 499 (Chopin exit). The hilly land rising to the south ofthe flat alluvium is Catahoula. Some of the Catahoula occurs to the north beneath the alluvium. Test holes at Lock and Dam 3 penetrated Catahoula beneath the Red River alluvium.

Indurated beds of the Catahoula are exposed along U. S. Highway 71 northeast of Colfax, in the hill lands west of Interstate 49 southofCloutierviile, and in northem Catahoula ParishnorthwestofHarrisonburg.AbouthalfoftheCatahoula outcrop in the hill lands of Catahoula and LaSalle Parishes is blanketed by high terrace deposits. Between the Red River Valley and the Little River about 80% of the outcrop is blanketed by High Terraces.

Fleming Formation The Fleming Formation is of Miocene age in the lower part and of Pliocene age in the uppermost part. The formation is divided into six members. Each member has been traced either in the outcrop or in the subsurface from near the Sabine River to near the Mississippi River-a distance of more than 100 miles. The members have been traced 20 to 30 miles downdip (some even farther). The Lena, Dough Hills, and Castor Creek members are predominantly clay with occasional thin sand beds interspersed through the intervals. In many areas the surficial clay weathers to a black soil underlain by khaki-colored day. Calcareous concretions are common. At some places thicker sand beds make the intervals difficult to distinguish in the subsurface from the overlying and underlying members. Parts of the Castor Creek contain fossils that paleontologists have dated as Miocene age. For the most part the other members have few fossils-most of which are not a diagnostic indicator of age.

The Carnahan Bayou, Williamson Creek, and Blounts Creek 11embers are an alternating sequence of sand beds and clay beds. The clay may be blue, gray, or green. The sand beds may be thick (100 ft or more) or thin (~few,inches to ~ few tens of feet). Sand may be fine to very fIne, fme to medlUm, or medium to coarse or very coarse. In parts of the area black

gravel (granule to pebble) occurs. The black gravel appears to be deposited along old stream courses active during the Miocene.

The Lena crops out south of the Catahoula along Interstate 49 north of Lena. A small outcrop occurs along U. S. Highway 71, northwest of Bagdad in Grant Parish. Two outcrops occur on the west side of Catahoula Lake at Big Point and Indian Bluff. High terraces blanket most of the Lena in Grant Parish but test holes show that the unit is continuous through the area.

The Carnahan Bayou Member crops out in the Sunk Hill area north of Flatwoods. Flatwoods is about 8 miles west of Interstate 49 on Louisiana State Highway 8. Sunk Hill is about 2 miles north of Flatwoods on a local road (car trail). Large amounts of petrified wood, including palm wood, have been found in the area. Many road cuts in northern Vernon, southern Natchitoches, and southeastern Sabine Parishes show parts of the Carnahan Bayou. Most of the Carnahan Bayou is blanketed by high terrace deposits in Grant Parish. Some small outcrops occur along the Little River and tributaries in south Grant Parish.

The Dough Hills occurs in the Dough Hills area of Rapides Parish. However, this area generally is inaccessible. The Dough Hills crops out at Esler Field about 12 miles northeast of Alexandria. Part of the area about one mile southeast of Kingsville that was mapped as high terrace was shown to be Dough Hills by test holes at Pinecrest State School. The topography in this area is rounded and no cuts were observed, but Dough Hills was penetrated from the soil zone to SO ft. Calcareous material found in the south river bank at the O.K. Allen bridge in Alexandria may be Dough Hills. Much of the Dough Hills in Ra pides Parish is covered by the High Terraces and the Prairie Terraces.

Outcrops of the Williamson Creek are small in Rapides Parish. Outcrops ofindurated sandstone and siltstone in the Pineville area are Williamson Creek. The rapids near the O.K. Allen Bridge on the Red River (currently drowned by the navigation pool) are the reason for the name Rapides Parish. Identification of the unit in this area usually is based on tracing the unit using test holes. East of the outcrops in the Pineville area the Williamson Creek is blanketed by Pleistocene deposits and by Holocene deposits to the Mississippi River.

The Castor Creek Is well exposed in Vernon Parish. To the east in Rapides Parish more than 95% of the unit is blanketed by deposits of Pleistocene age and Holocene age. The fossils in the unit have been found only in the subsurface. Although the unit does not crop out east of the west wall of the Red River Valley test drilling has shown that the unit occurs in central Rapides Parish, in Avoyelles Parish, and in Concordia Parish.

The Blounts Creek Member is well exposed in Vernon Parish. The unit crops out at Blounts Creek in Rapides Parish and near the Red River Valley wall in southeastern Rapides Parish. The unit is blanketed by Pleistocene and Holocene deposits to the east in Rapides Parish and in Avoyelles Parish.

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The Fate of Fisk's Pleistocene Units in Texas

Saul Aronow

Pleistocene Mapping Units in the Gulf Coast of Texas Prior to Fisk

The two major sources of mapping units and stratigraphic terminology for the Pleistocene of the Gulf Coast of Texas in the 1930's and 1940's were

(1) the text (Plummer, 1932) and accompanying highly generalized small-scale map (1:2,000,000) of "3232,11 as it was familiarly known, and

(2) the U. S. Geological Survey map of Texas (Darton and others, 1937).

Plummer (1932, p. 780-795) sets up a Pleistocene System restricted to one group, the Houston Group which is divided into two formations, an older lissie sand [sic] and a younger Beaumont clay [sic]. Underlying the lissie is the Citronelle Group of the Pliocene System. The Citronelle consists of an older Goliad sand formation [sic] and a younger Unnamed Pliocene? sand [sic] (Plummer, 1932, p. 749-763).

The larger-scaled (1:500,000) geologic map of Darton and others (1937) uses the Beaumont clay and the Lissie formation for its Gulf Coast Pleistocene units. The Pliocene (?) Willis sand unconformably underlies the Lissie. In the time interval between "3232 11 and the USGS map, Doering (1935, p. 660-668) had introduced and defined the Willis which he assigned to the late Pliocene or early Pleistocene. The USGS map, in terms of mapping units, essentially follows Doering's 1935 usage.

Fisk's Pleistocene Units in Texas Fisk's concept of four interglacial eustatic high sea-level regressive units for Louisiana,

Prairie Montgomery Bentley vVilliana,

was firmly established by two regional-scale papers (Fisk, 1939, 1944) after undergoing a gestation in several local parish reports (e. g., Fisk, 1938).

Fisk's terminology was possibly first used in Texas in a formal published paper by Price (1947, Figure 1) who equates

the Montgomery with an "olderll Beaumont; the Prairie, with a "youngerll Beaumont (cf. Doering, 1956, p. 1830).

Later it was carried into Texas by his collaborators and/or students. The first of these was H. A. Bernard (1950) who remapped the area between the Sabine and Neches Rivers in southeast Texas Among the many contributions of this unpublished but much referred to Ph.D. dissertation was the first description of the early Holocene (?) to late Pleistocene Deweyville terraces along the Sabine and Neches Rivers. What may be the first formal published map depicting the Deweyville was in Kane's (1959, Figure 1) paper on Sabine Lake which shows the terraces flanking "late Recent ll floodplain deposits of the Sabine and Neches rivers just north of the lake. Kane uses a Prairie "terrace deposits" (= Beaumont in Texas) unit for both the Louisiana and Texas parts of his map. Kane's map is also shown in a guidebook (Gulf Coast Association of Geological Societies, 1959, Plate 6).

More or less contemporaneous with Bernard's investigation of the extreme southeast corner of Texas was a masters thesis by Cox (1950) covering about 21 counties in the drainage basins of the lower Brazos and Colorado rivers in Texas. The area along the Brazos extended from about Waco to the Gulf of Mexicoj along the Colorado from about Columbus to the Gulf. The thesis contains some highly generalized maps of the outcrop of the four coast-paralleling Fiskian units as well as some of their stream-paralleling inland extensions.

Following the work of Bernard and Cox, neither Fisk (1959) in his paper on Padre Island and Laguna Madre nor LeBlanc and Bernard (1954) and LeBlanc and Hodgson (1959) in their coastal studies-which penetrate into a Texan Pleistocene substrate or impinge on a landward Texan Pleistocene upland-use any of the Fiskian units.

References are made to "late Pleistocene deposits" and "a buried eroded Pleistocene surface" (Fisk, 1954), "an inland late Pleistocene plainll (LeBlanc and Bernard, 1954, p. 186), and "late Pleistocene undifferentiatedll (LeBlanc and Hodgson (1959, Figure 12).

Thefirstpublishedattempt-otherthanFisk(1939,p.187)to correlate the Texas Pleistocene with Fisk's four units probably was made in a field trip gUidebook for southeast Texas (Bernard, LeBlanc and Major, 1962, Figures 2 and 3):

128

Prairie = Beaumont Montgomery = Unnamed 2nd terrace Bentley = Lissie Williana = Willis.

The Willis is thus interpreted to be Pleistocene.

Bernard and LeBlanc (1965, Figures 9a and 9b) in whatis still the most useful introduction and guide to the subaerial western Gulf Coast Pleistocene revise the 1962 correlations to

Prairie = Prairie, or Beaumont Montgomery = Montgomery, or Upper Lissie Bentley = Bentley, or Lower Lissie Williana = Williana, or Willis.

This is similar to the an early Louisiana-Texas correlation by Fisk (1939, p. 187).

The high point in the" official" recognition in Texas of Fisk's four-fold Pleistocene scheme was in some early sheets of Texas' Bureau of Economic Geology's Geologic Atlas of Texas. In the first editions of the Beaumont and Houston Sheets (Barnes, 1968a, 1968b) the Quaternary section consisted of

Recent Alluvium

Recent or Late (?) Pleistocene Deweyville Formation

Pleistocene Beaumont Formation Montgomery Formation Bentley Formation Willis Formation,

a mixture of Louisiana and Texas stratigraphic units, similar to the correlation of Bernard and LeBlanc (1965).

On later sheets of the Geologic Atlas the Montgomery and Bentley were phased out and finally abandoned in favor of the Lissie. Thus the Austin, Seguin and Beeville-Bay City sheets (Barnes, 1974a, 1974b, 1975a) have a "Lissie Formation undivided" but note that within the areas of the respective sheets "the Montgomery and Bentley Formations (upper and lower units of the Lissie) are essentially indistinguishable and for that reason are not separately mapped .. "

The subsequent Corpus Christl (Barnes, 1975b) and Brownsville - McAllen sheets (Barnes, 1976a) use a "Lissie Formation undivided;" the Laredo Sheet (Barnes, 1976b), a "Lissie Formation."

Among the several revised second editions of the sheets the Seguin (Barnes, 1979) and Beeville - Bay City (Barnes, 1987) do appear with a "Lissie Formation undivided;" the Houston (Barnes, 1982) and Beaumont (Barnes, 1992) sheets, with just a "Lissie Formation."

About the only remnant of the possible "plurality" of the

Lissie-the smile on the face of the disappearing Cheshire cat-is in the Explanations of the latest versions of Beaumont and Houston Sheets where lithologic and pedologic differences are noted between "upper" and "lower" parts of the Lissie.

This brings us back full circle to the 1937USGS Geologic Map of Texas (Darton and others, 1937) and to Doering's 1935 paper. The major difference is the unequivocal placing of the Willis in the Pleistocene on the Geologic Atlas Sheets.

Rival Classifications Doering (1956, 1958)-who established the Willis-published for an area extending from the Rio Gr ande in Texas to the Vicinity of the Apalachicola River in Florida a widely cited alternative scheme to Fisk's. The coast-paralleling mapping units are derived from localities in southwestern Louisiana. Doering (1956, p. 1837) mapped five Pleistocene units vs. Fisk's four.

With reference to Doering's 1935 units and the later USGS map his new Pleistocene classification is

Holloway Prairie = Recent post-Beaumont Eunice = "upper Beaumont" Oberlin = "lower" Beaumont Lissie = Lissie Citronelle = Willis.

In his 1956 and 1960 papers the Citronelle and the Willis in Texas are considered pre-Nebraskan or pre-glacial Pleistocene; in the 1958 paper a late Pliocene age or early Pleistocene age for the Citronelle are equally plausible.

With reference to Fisk's coast-paralleling terraces in southern Louisiana Doering's units are thusly correlated (Doering, 1958, Table III):

Holloway Prairie = [no unit] Eunice = Prairie Oberlin = Montgomery Lissie = Bentley Citronelle = Williana

Doering (1956, p. 1832 and Figures 3 and 4) strongly suggests that the coast paralleling terraces of southern Louisiana are miscorrelated with the Red River area terraces from which the standard four-fold Fisk section was derived. Doering (1958, Table III) would correlate his southern Louisiana units with Fisk's Red River area units as follows:

Holloway Prairie = Prairie Eunice = Montgomery Oberlin = Bentley Lissie = Williana

Doering believes that the Citronelle is absent from the Red River area.

As noted previously Price was an early user of Doering's units and applied them to Texas. He remained somewhat undecided and eqUivocal about them. He notes in his classic south Texas paper that

729

((In this paper [Price, 1958], the writer returns to Doering's names used in the writer's article: 'Qua_ ternary deltaic plains and strand terraces' in the Corpus Christi Geological Society's FIeld Trip book for 1956, pp. 1-3. In the [guide] book for 1958, Fisk's terms were used ... The writer made this last change in his usage after Doering again discussed the Louisiana correlations in his paper of 1958."

Van Siclen (1972, 1985, 1991) has developed an assemblage of Pleistocene mapping units for the Houston area of Texas which, though not explicitly deSignated, might be considered allostratigraphic units. They are largely fluvial and del taic d eposi ts and related landforms of a PI eistocen e pal eoBrazos River and are mainly confined to the outcrop areas of the Beaumont, Lissie and Willis formations as shown on the Houston and Beaumont Sheets (Barnes, 1982, 1992). He discusses in his 1991 paper eight ((coastal terraces" with names derived from the early USGS-Doering classification, from Doering's (1956, 1958) papers, and from local geographiC localities. None of the Fisk's units survive; the Bentley of an earlier version (Van Siclen, 1985) was dropped.

Though I do not necessarily agree with Van Siclen's specific choice of mapping units, I think this kind of Pleistocene unit /ldeconstruction" is needed for further progress in deciphering the Pleistocene history of the Gulf coast. In some sense the lumping the of Montgomery and Bentley into the Lissie was perhaps an unavoidable backward step but needed to set up a viable lithostratigraphic unit. Snead and McCulloh (1984) avoid any lithostratigraphic /ltraps" by calling their Pleistocene mapping units ((terraces," most of which have several levels.

The multiplicity of interglacials, well beyond the four assumed by Fisk, is suggested by Beard and others (1982) and by Richmond and Fullerton (1986a, 1986b). Some of these generated high sea-level stand regressive deposits but factors (see Mossa, 1991; Saucier, 1991, p. 552-554) other than simple eustatic controls and later coastal downwarping make for a more complex picture with more than four or five depositional units.

A recent map shOWing part or all of the Texas Gulf Coast Saucier and Snead (1989) show three Pleistocene /lcom-plexes" in Texas (and Louisiana), from oldest to youngest: an Upland, an Intermediate, and a Prairie. The Prairie complex is ((equivalent to the Beaumont formation [sic] in Texas; three levels are recognized but not mapped." The Intermediate complex includes the Lissie; the Upland complex, identified as Plio-Pleistocene in age, includes the Willis. These units are discussed in detail in an accompanying text by Saucier (1991, p. 558-59) who comments that

((The essence ofthe Prairie Complex stratigraphic problem is that more than one Significant allostratigraphic unit is represented. Using the terrace criteria of Fisk (1939) and Russell (1940), it has been acceptable to assign a single designation to a variety of depositional sequences. However, continuation of this practice will only cause further confusion. Perhaps it is advisable to assign

new designations .... A more practical approach maybe to define subunits of the Prairie Complex as alloformations, defined on the basis of their boundary relations, especially discontinuities .... Future studies should be directed toward separating the Prairie Complex into Wisconsin and preWisconsin com ponen ts."

Another recent map by Winker (1991b) depicts the Gulf Coast west of the Mississippi floodplain into northern Mexico in morphostratigraphic units (MSUs,seetext, Winker,1991a), a unit not recognized in the latest North American Stratigraphic Code. The MSUs are

Holocene deposits and post-Beaumont terraces Beaumont surface IngleSide beach plain ((intermediate" surface Lissie pre-Lissie surface(s).

These are carried across the Sabine River into Louisiana, and also southward into Mexico. Winker (p. 585) believes

1I ... that only two units are sufficiently continuous and uniform to justify regional nomenclature; these are the Beaumont and Lissie for reasons of priority ... Other surfaces are classified here by their relation to these two regional MSUs (Le., postBeaumont, intermediate and pre-liSSie). As a note of caution, ages and temporal correlation of these surfaces have not been established, and the MSUs should not be assumed to be time-stratigraphic ... "

This is an ironic note on which to end this discussion: the Beaumont of Texas, first named in 1903, invading Louisiana and having priority over Fisk's Prairie which, to some, is the sole surviving unit.. ..

References Barnes, V. E., project director, 1968a, Geologic atlas of Texas,

Beaumont sheet [first edition]: Austin, University of Texas Bureau of Economic Geology, scale 1:250,000.

Barnes, V. E., project director, 1968b, Geologic atlas of Texas, Houston Sheet [first edition]: Austin, Texas, University of Texas Bureau of Economic Geology, scale 1:250,000.

Barnes, V. E., project director, 1974a, Geologic atlas of Texas, Austin sheet: Austin, University of Texas Bureau of Economic Geology, scale 1:250,000.

Barnes, V. E.,projectdirector,1974b, Geologic atlas of Texas, Seguin sheet [first edition]: Austin, University of Texas Bureau of Economic Geology, scale 1:250,000.

Barnes, V. E., projectdirector,1975a, Geologic atlas of Texas, Beeville-Bay City sheet [first edition]: Austin, University of Texas Bureau of Economic Geology, scale 1:250,000.

Barnes, V. E.,projectdirector,1975b, Geologic atlas of Texas, Corpus Christi sheet: Austin, University of Texas Bureau of Economic Geology, scale 1:250,000.

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Barnes, V. E., project director, 1976a, Geologic atlas of Texas, McAllen-Brownsville sheet: Austin, University of Texas Bureau of Economic Geology, scale 1:250,000.

Barnes, V. E., project director, 1976b, Geologic atlas of Texas, Laredo sheet: Austin, University of Texas Bureau of Economic Geology, scale 1:250,000.

Barnes, V. E., project director, 1979, Geologic atlas of Texas, Seguin sheet [second edition]: Austin, University of Texas Bureau of Economic Geology, scale 1:250,000.

Barnes, V. E., project director. 1982, Geologic atlas of Texas, Houston sheet [second edition]: Austin, Texas, University of Texas Bureau of Economic Geology, scale 1:250,000.

Barnes, V. E., project director, 1987, Geologic atlas of Texas, Beeville-Bay City sheet [second edition]: Austin, University of Texas Bureau of Economic Geology, scale 1:250,000.

Barnes, V. E., project director, 1992, Geologic atlas of Texas, Beaumont sheet [second edition]: Austin, University of Texas Bureau of Economic Geology, scale 1:250,000.

Beard,J. H., Sangree,J. B., and Smith, L. A., 1982, Quaternary chronology, paleoclimate, depositional sequences, and eustatic cycles: American Association of Petroleum Geologists Bulletin, vol. 66, p. 158-169.

Bernard, H.A., 1950, Quaternary geology of southeast Texas: Baton Rouge, unpublished PhD dissertation, Louisiana State University.

Bernard, H. A., LeBlanc, R.J., and Major, C. F., 1962, Recent and Pleistocene geology of southeast Texas, in Rainwater, E. H., and Zingula, R. P., Geology of the Gulf Coast and central Texas and guidebook of excursions: Houston, Houston Geological Society,p. 175-224.

Bernard, H. A., and LeBlanc, R. J.,1965, Resume of the Quaternary of the northwestern Gulf of Mexico province, in Wright" H. E., and Frey, D. G., editors, The Quaternary of the United States: Princeton, Princeton University Press, p. 137-185.

Cox, C. L., 1950, Pleistocene terraces of the lower Brazos River, Texas: Baton Rouge, unpublished master's thesis, Louisiana State University.

Darton, N. H., Stephenson, L. W., and Gardner,J. A., 1937, Geologic map of Texas: Washington, D. C., U. S. Geological Survey.

Doering, John [sic], 1935, Post-Fleming surface formations of coastal southeast Texas and south Louisiana: American Association of Petroleum Geologists Bulletin, Vol. 19, p. 651-688.

Doering,J. A.,1956, Review of Quaternary formations of Gulf coast region: American Association of Petroleum Geologists Bulletin, Vol. 40, p. 1816-1862.

Doering, J. A., 1958, Citronelle age problem: American Association of Petroleum Geologists Bulletin, Vol. 42, p. 764-786.

Doering,J.A., 1960, Quaternary surface formations of southern part of Atlantic Coastal Plain: Journal of Geology, Vol. 68, p. 182-202.

Fisk, H. N., 1938, Geology of Grant and LaSalle Parishes: Louisiana Geological Survey Bulletin No. 10.

Fisk, H. N., 1939, Depositional terrace slopes in Louisiana: Journal of Geomorphology, Vol. 2, p. 181-200.

Fisk, H. N., 1944, Geologic investigations of the alluvial valley of the lower Mississippi River: Vicksburg, Mississippi River Commission.

Fisk, H. N., 1959, Padre Island and the Laguna Madre flatscoastal south Texas, in Russell, R. J., editor, Coastal Geography Conference, Coastal Studies Institute, LouisianaState University: Washington, D. C., U. S. Office of Naval Research, Geography Branch, p. 103-152.

Gulf Coast Association of Geological Societies, 1959, Field trip guidebook-Recent sediments of the north-central Gulf Coastal Plain: Houston, Gulf Coast Association of Geological Societies.

Kane, H. E., 1959, Late Quaternary geology of Sabine Lake and vicinity, Texas and Louisiana: Gulf Coast Association of Geological Societies Transactions, Vol. 9, p. 225-235.

LeBlanc, R. J., and Bernard, H. A., 1954, Resume of late Recent geological history of the Gulf Coast: Geologie en Mijnbouw, Nr. 6, Nw. Serie 16e, p. 185-194.

LeBlanc, R. J., and Hodgson, W. D., 1959, Origin and developmen t of the Texas shoreline: Gulf Coast Association of Geological Societies Transactions, Vol. 9, p. 197-220.

Mossa,Joann, 1991, Geomorphology of south Louisiana, in Goldthwaite, Duncan, editor, An introduction to Central Gulf Coast geology: New Orleans, New Orleans GeologicaL Society, p. 123-134.

Plummer, F. B., 1932, Cenozoic Systems in Texas, in Sellards, E. H., Adkins, W. S., and Plummer, F. B., The geology of Texas, Vol. 1, Stratigraphy: University of Texas Bulletin No. 3232,p.519-818

Price, W. A., 1947, Equilibrium of form and forces in tidal basins of coast of Texas and Louisiana: American Association of Petroleum Geologists Bulletin, Vol. 31, p. 1613-1663.

Price, W. A., 1958, Sedimentology and Quaternary geomorphology of south Texas: Gulf Coast Association of Geological Societies Transactions, Vol. 8, p. 41-75.

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Richmond, G. M., and Fullerton, D. S., 1986a, Introduction to Qua ternary glaciations in the United States of America, in Sibrava, V., Bowen, D. Q., and Richmond, G. M., editors, Quaternary glaciations in the Northern Hemisphere: New York, Pergamon Press, p. 3-10.

Richmond, G. M., and Fullerton, D. S., 1986b, Summation of Quaternary glaciations in the United States of America, in Sibrava, V., Bowen, D. Q., and Richmond, G. M., editors, Quaternary glaciations in the Northern Hemisphere: New York, Pergamon Press, p. 183-196.

Russell, R. J., 1940, Quaternary geology of Louisiana: Geological Society of America Bulletin, Vol. 51, p. 1199-1234.

Saucier, R. T., and Snead, J. 1., compilers, 1989, Quaternary geology of the Lower Mississippi Valley, scale 1:1,100,000, in Morrison, R. B., editor, Quaternary nonglacial geology: conterminous U. S., The geology of North America, Vol. K-2: Boulder, Geological Society of America, Plate 6.

Saucier, R. T., 1991, Geomorphology, stratigraphy, and chronology, in Morrison, R. B., editor, Quaternary nonglacial geology: conterminous U. S., The geology of North America, Vol. K-2: Boulder, Geological Society of America, p. 550-564.

Snead, J. I., and McCulloh, R. P., compilers, 1984, Geologic map of Louisiana: Baton Rouge, Louisiana Geological Survey.

Van Siden, D. C., 1972, Correspondence of coastal terraces with inland surfaces in Texas, lower Brazos and Colorado valleys [abstract]: TexasJournal of Science, Vol. 23, p.415-416.

Van Siden, D. C., 1985, Pleistocene meander-belt ridge patterns in the vicinity of Houston, Texas: Transactions of the Gulf Coast Association of Geological Societies, Vol. 35, p. 525-532.

Van Siden, D. C., 1991, Surficial geology of the Houston area: a offlapping series of Pleistocene (& Pliocene?) highest-sealevel fluviodeltaic sequences: Gulf Coast Association of Geological Societies Transactions, Vol. 41, p. 651-666.

Winker, C. D., 1991a, Northwestern Gulf Coastal Plain, in Morrison, R. B., editor, Quaternary nonglacial geology: conterminous U. S., The geology of North America, Vol. K-2: Boulder, Geological Society of America, p. 585-587.

Winker, C. D., compiler, 1991 b, Qua ternary geology, northwestern Gulf Coast, scale 1:2.000,000, in Morrison, R. B., editor, Quaternary nonglacial geology: conterminous U. S., The geology of North America, Vol. K-2: Boulder, Geological Society of America, Plate 8.

132

Soil Stratigraphic Units of the Lower Red River Valley

B. A. Touchet

Soil scientists utilize the term soil stratigraphic unit to define a particular soil series in a particular parent material. If a soil series occurs on a stable landscape} that particular soil stratigraphie unit may actually be a time stratigraphic unit. The Lower Red River Valley is paralleled by soil stratigraphic units which can be traced below the loess stratigraphic units along the Lower Mississippi Valley proper and coast parallel units to the south and west.

Along the Red River Valley wall and the Mississippi-Arkansas River Valley wall (Bastrop Ridge) there is a soil stratigraphic unit that superposes both the Ruston soil stratigraphic unit and the Beauregard-Malbis soil stratigraphic unit. This unit is known as the Forbing soil stratigraphic unit. This is a very extensive soil stratigraphic unit that occurs in a terrace position along the Red River} Arkansas River} Brazos River} and the Colorado River in Texas. It also occurs below the loess on the Bastrop Ridge} the Holloway Prairie in Rapides Parish} and the Bayou Chicot Ridge in Evangeline Parish. The Red River Valley is incised in Tertiary continental and

marine deposits. Superposed on these deposits are loamy Plio-Pleistocene fluvial deposits of the Upland Complex. These deposits appear truncated by the Red River Valley. The soil stratigraphie unit recognized in the Plio-Pleistocene deposits is the Ruston soil stratigraphic unit. This unit correlates to Fisk's Williana and Bentley Terraces. The Beauregard-Malbis soil stratigraphic unit occurs on less sloping topography and correlates to Fisk's Montgomery Terrace.

Other soil series that occur in the Forbing soil stratigraphic unit includes the Acadia and Wrightsville series of the flatwoods areas and the Gore (Hortman), McKamie, Morse and Muskogee on the sloping landscapes along the valleys. Comparable soils with different names occur along the Brazos and Colorado Rivers in the ustic moisture regime of Texas.

SUMMARY CHART

SOIL STRATIGRAPHIC UNIT LANDFORM\STRATIGRAPHIC RELATIONSHIP

PLEISTOCENE UNITS Ruston Fisk's Williana and Bentley Terraces Beauregard-Malbis Fisk's Montgomery Terrace Forbing Between Fisk's Montgomery and Prairie Terrace Pre-Prairie Loess Superposes the Forbing, but dips under the Pine Island unit Pine Island Superposes the Pre-Prairie Loess, but dips under the Crowley unit Crowley Superposes the Pine Island unit

Memphis Superposes all of the above units, but dips under the Kaplan unit Kaplan Superposes Crowley and Memphis units, but dips under the Gueydan unit Bienville-Guyton seemingly the oldest unit in the Red River flood plain, dips under the Gallion unit

HOLOCENE UNITS

Gueydan The Chenier Plain Marsh Rilla-Sterlington Arkansas River unit that dips under the Dundee unit

Dundee Mississippi unit that dips under the Gallion unit

Gallion Red River unit that dips under the Norwood unit

Norwood Holocene Red River unit that interfingers with Commerce unit

Commerce Holocene Mississippi River unit that interfingers with Norwood unit

133

The Forbing soil stratigraphic unit is very important because it is very easy to trace, and therefore other units can be correlated as either older or younger than this unit. For example, this unit superposes the soil units in Fisk's Williana, Bentley, and Montgomery Terraces which in turn superposes the Tertiary deposits and their soils. Conversely, the Forbing unit is buried by the Pre-Prairie-Post Montgomery loess on the Bastrop Ridge, Holloway Prairie and the Bayou Chicot ridge. Both the Forbing soil stratigraphic unit and the PrePrairie-Post Montgomery loess soil stratigraphic unit dips under the Pine Island soil stratigraphic unit in Jefferson Davis Parish. There is also an exposure of the Pine Island unit in the Bayou Chicot area. There is no Pre-Prairie age loess on the Pine Island soil stratigraphic unit. The Pine Island unit is reddish brown like the Forbing unit, but the Pre-Prairie loess separates these two units in Evangeline, Acadia, and Jefferson Davis Parishes. This unit is superposed by the Crowley soil stratigraphic unit of the coast prairie (Fisk's Prairie Terrace of southwest Louisiana).

Both the Pine Island and the Crowley units are superposed by the Memphis soil stratigraphic unit developed in Peoria Loess on the Macon Ridge, Marksville Ridge, and the Grand Coteau Ridge. The Memphis unit dips under the Kaplan soil stratigraphic unit as does the Crowley unit when it is not superposed by Peoria Loess. The Kaplan soil stratigraphic

unit, in turn, dips under the Gueydan soil stratigraphic unit which is the Chenier Plain Marsh soil. The Kaplan unit may be related to the development of the Chenier Plain, since it infills local drains of the southern edge of the firm Prairie s9ils and superposes the Crowley unit. The Gueydan unit is still forming, but becomes progressively older inland away from the coast.

The soil stratigraphic units of the Red River Valley includes the Bienville-Guyton Soil Stratigraphic unit in the Oil City area of Caddo Parish. This seems to be the only exposure of the "Deweyville" in the Red River Valley of Louisiana. The Gallion Soil Stratigraphic Unit occurs on older Holocene meander scars in the Red River Valley. The more recent natural levees of the Red River are easily recognized by the Norwood soil stratigraphic unit. The Rilla-Sterlinton soil stratigraphic unit is an Arkansas River unit dominating the area between the Bastrop Ridge and the Macon Ridge and along the Ouachita River. The Dundee soil stratigraphic unit occurs on older meander scars of the Mississippi River. The younger natural levees of the Mississippi River are recognized by the Commerce soil stratigraphic unit.

134

Waddel Bluff Terrace Stratigraphy in the Lower Red River Valley

John J. Alford and Joseph C. Holmes

A key to understanding the terrace stratigraphy in the lower Red River Valley lies in the correct dating of organic sedimen ts that are exposed at the low water base of Waddel Bluff. Located in Sec. 8, T7N, R4W, Fisk (1938) described Waddel Bluff as the "best" exposure of the Montgomery member in the type area. Although the upper portion of the section is characterized by oxidized sand, silts, and clays, som e 10m below the surface lies a rich, 6m thick fossiliferous horizon.

In the words of Fisk (1938): "The base of the section is composed of bluishgray clays and contains many upright stumps and knees of cypress trees. The sediments surrounding the stumps contain leaf impressions, coprolites of large animals, fresh water ostracodes, a few pelecypods, and many gastropod shells of small size."

Intrigued by this description, and eager to collect datable material, the authors took advantage of the unusually low water of the summer of 1979, and investigated the site. The exposure was as Fisk (1938) described it and excellent samples of datable material were collected.

Three samples were analyzed at the L.S.U. radiocarbon lab. (Table 1). The firsttaken from a well preserved sturn p located about 13m below the surface yielded a date of 30,700 ± 4,900 B.P. Wood fragments 11.5m below the surface produced a

date of 21,800 ± 2100 B.P. A meter and a half higher in the profile, well preserved wood taken from a stump in growth position yielded a date of 26,200 ± 1700 B.P.

These dates were surprisingly young considering that Fisk (1938) and later Russ (1975) believed these deposits to be pre-Wisconsinan in age. Because of this and the fact that the dates, had large margins of error it was decided to have a comerciallab redate the best two samples. These determinations confirmed the earlier findings. Wood from the lower stump gave an age of 30,370 ± 400 B.P. while the upper stump was dated at 22,860 ± 235 B.P. Evidentally the fossiliferous blue-gray clays underlying Waddel Bluff are late Altonian to earliest Woodfordian in age.

Further support for this conclusion resulted from channel stabilization work done by U.S. Army Corps of Engineers. Over the winter and spring of 1979-80 they cut the face of Waddel Bluff back a substantial distance. Low water in May of 1980 revealed that the fossiliferous clay layer was still present some 60m back from the original face (Fig. 1). Wood samples taken from an elevation about a meter below that of the upper stump produced a date of 28,975 ± 425 B.P. (Fig. 1). This date and its position well back from the original face indicates that the Wad del Bluff sediments are a rather substantial fill and not merely a smear of younger sediment against an older surface.

TABLE 1 - Red River Radiocarbon Dates

Site Lab No. Date Material Dated Source Waddel LSU I 30,700 ± 4,900

Waddel LSU II 21,800 ± 2,100

Waddel LSU III 26,200 ± 1,700

Waddel Beta 1220 22,860 ± 235 Waddel Beta 1221 30,370± 400 Waddel Beta 1856 28,975 ± 425

odra Beta 1858 2,890 ± 90

odra Beta 1859 1,430 + 80

stump 0.3m above low water

wood fragments 1.8 m above low water

stump 3 m above low water

stump 3 m above low water stump 0.3 m above low water wood 1.2 m above low water approximately 50 m back from face shell 7.5 m above low water stump 7 m above low water

135

unpublished report, Institute for Environmental Studies, LSU unpublished report, Institute for Environmental Studies, LSU unpublished report, Institute for Environmental Studies, LSU Alford et 01./ 1985

Alford et 01., 1985

Alford et aI., 1985

This paper This paper

In an effort to determine the extent of this fill we travelled 9.6km upstream to where the river next impinged on a terrace that had been mapped as either Montgomery by Fisk (1938) or upper Prairie by Russ (1975). Located in the S.W. 1/4 of irreg. Sec. 86, T7N, R5W this site (informally named the Odra site after the nearby hamlet) presented a clean bluff face that rose some 12m above low water level. Careful examination of the 200m long section revealed no sign of the blue-gray fossiliferous zone. The exposed sediments are indistinguishable from the oxidized upper portion of the Waddel Bluff section.

Datable material was collected from a shell bed situated about 6m below the surface. Some 150m away at about the same level well preserved wood taken from a stump in growth position. The shell produced a date of 2890 -90 B.P. while the wood was dated at 1430 - 80 B.P. Evidentally the surface at Odra is qUite young.

Discussion The array of dates associated wi th Waddel Bluff and the Odra Section raise several interesting points. First, it is clear that the "best" Montgomery (or upper Prairie) exposure in the type area is not Sangamonian but is late-Altonian to vVoodfordian in age. Secondly, the vegetation representing

this time period is dominated by cypress indicating a climate not too dissimilar to what prevails today.

The dates from Odra are surprisingly young. They indicate that a cycle of aggradation and down-cutting took place in this portion of the Red River Valley in the fairly recent past. Certainly, the contrast in the ages of the sediments at Odra and Waddel Bluff show the difficulty in attempting to correlate and map surfaces based primarily on elevation and appearance. Finally, at this time it is uncertain as to how the low Prairie and the Deweyville surfaces relate to the fills at Odra and Waddel Bluff.

References Alford, J. J., Kolb, C. R., and Holmes, J. C., 1985, Terrace

stratigraphy along the lower Red River, Louisiana: Southeastern Geology, V. 26, pp. 47-51.

Fisk, H. N., 1938, Geology of Grant and LaSalle Parishes: Louisiana Departaent of Conservation, Geologic Survey Bull. no. 10, 246 pp.

Russ, D. P., 1975, The Quaternary geomorphology of the lower Red River Valley, Louisiana, Ph.D. Dissertation: The Pennsylvania State University, University Park.

WADDEL BLUFF

GENERALIZEO --------....... -------------------------_ ! ~o~~~t~ .............. -.. ........ ......

GENERALlzeo NEW PROFILE OF EAST BANK

(Material Removed By Corps)

....... ..... ........ ...... ....... ....... ...... ...... ....... ....... ....... ..... o~:;'t

~!;,

~------__ ----------------~.~mlp ________________________________ ~

Figure 1 - Waddel Bluff Cross Section.(from Alford et 01./ 1985).

136

Allostratigraphy and Geoarchaeology Within the Mississippi Alluvial Valley

Paul V. Heinrich

The alluvial plain of the MisSissippi River is a composite geomorphiC surface composed of smaller, morphostratigraphic units - geomorphic surfaces that lie within an incised valley (Saucier 1974; Autin et al. 1991), Five types of geomorphic surfaces, namely, meander belts, backswamps, braid plains, fluvial terraces, and lacustrine terraces, exist within the Mississippi Alluvial Valley and its tributaries. First, a meander belt is a surface that consists of the geomorphic surface and constructional landforms created by the lateral migration of a river while occupying a single course. Second, the backswamp, also called a "flood basin", is the portion of an alluvial plain associated with meander belts consisting of swamp, lakes, or combination of both. Third, the braid plain is an alluvial plain exhibiting the intricately interconnected channels of braided streams or rivers which created it. Within the Mississippi Alluvial Valley, they exist only as fluvial terraces. Fourth, a fluvial terrace is a relict fluvial plain bounded by erosional escarpments and parallels an adjacent, modern stream or river. They occur along the wall of the incised valley and as outliers within it. They are the erosional remnants of other geomorphic surfaces, e.g., braid plains, meander belts, or backswamps. Finally, a lacustrine terrace is an erosional remnant of a plain that once formed the bottom of a slackwater lake within the valleys of rivers and streams tributary to the MiSSissippi River (Shaw 1915; Saucier 1974, 1987; Autin et al. 1991).

Allostratigraphy According to the North American Commission on Stratigraphic Nomenclature (1983),an allostratigraphic unit is a mappable body of sedimentary rock or unconsolidated sediments that is defined and identified on the basis of bounding discontinuities. In case of an incised valley, erosional unconformities and the previously described geomorphic surfaces are bounding discontinuities that can be used to define and map allostratigraphic units (Fig. 1). Two distinct types of fluvial allostratigraphic units, depending whether the geomorphic surface is either fluvial terrace or meander belt, can be recognized.

First, the type of fluvial alloformation associated with a fluvial terrace has three different bounding disconformities (Fig. 1). First, the basal disconformity of this alloformation is a fluvial erosion surface, typically an undulating surface, cut by either the entrenchment, lateral migration, or both of a river channel. This unconformity is related to the deposi-

tion of the overlying fluvial sediments. Second, the scarp that defines a fluvial terrace is the exposed edge of an younger erosional surface which truncates the sediments which comprise a fluvial terrace. As a result, a scarp, as reflected by differences in surface morphology, soil development, and thickness of overbank deposits, separates geomorphic surfaces and fluvial deposits of differing ages. Finally, the upper boundary consists of a geomorphic surface, previously defined as a "fluvial terrace" (Autin 1992).

After its formation, the fluvial terrace can be altered by postdeposi tional processes. Fluvial terraces are frequen tly buried by younger sediments after their formation. These sediments may consist of either overbank deposits, eolian sands, loess, or colluvium. Where buried intact, a fluvial terrace might be detectable by either laterally persistent paleosols or truncated weathering horizons and abrupt changes in sedimentary facies. With prolonged subaerial exposure, erosion of a fluvial terrace will eventually obliterate and obscure constructional landforms and pedogenesis will form progressively thicker paleosols.

Stratigraphic, radiocarbon, and archaeologic data from the Richard Beene Site (41BX831) illustrates the association between fluvial terraces and allostratigraphic units (Fig. 2) (Mandel and Caran 1992). The modern floodplain and the Walsh, Leona, and Miller Terraces are associated with fluvial unconformities that clearly define allostratigraphic units of alloformation rank. Because of the presence of apparent erosional topography associated with it, differing fluvial regimes on either side of it, and significantly older radiocarbon dates beneath it, the truncated Somerset paleosol is interpreted to be the surface of another alloformation. Because of the lack of significant temporal hiatuses, changes in fluvial regime, and erosional unconformities, associated with the other paleosols, they are considered to lie within the same alloformation of which the Applewhite Terrace forms its surface (fig. 2). Within this valley, vertically accreted overbank sediments containing numerous paleosols bury the Qc alloformation instead of the hypothetical backswamp deposits illustrated in Fig. 1 (Fig. 2).

Finally, the meander belt is the surface of an allostratigraphic unit consisting of a basal bounding discontinuity, an upper bounding discontinuity, and a body of fluvial sediments that lies between the bounding discontinuities (Fig. 3). Typically, the upper bounding' discontinuity consists of either an exposed or buried meander belt. In case of a

137

meandering system, the fluvial sediments lying between the unconformities consist of a lower part composed of point bar sands and gravels, overlain by finer-grained and vertically accreted natural levee and overbank sediments. The basal bounding discontinuity is an erosional unconformity formed by scour at the channel bottom and, at the edges, by cutbank erosion. Outside of the meander belt natural levee deposits extend into and interfinger with the adjacent backswamp sediments (Fig. 3) (Fisk 1947; vValker and Cant 1984; Autin 1992).

Unfortunately, the allostratigraphy of the sediments underlying the backswamps that lie between the meander belts of the Mississippi River and its tributaries incised into braided fluvial terraces is uncertain. For example, the backswamps associated with meander bel ts within the Western Lowlands appear to fill narrow alluvial valleys cut into braided fluvial terraces (fig. 4). The lack of detailed boring logs for drillholes penetrating these presumed en trenched valleys prevents the resolution of the, if any, allostratigraphic units underlying these backswamp deposits and the nature of the basal contact of the backswamp deposits. Similarly, the actual base of the allostratigraphic units underlying the braided fluvial terraces cannot be determined because of the lack of contrast between their sediments and the underlying valley fill and the lack of undisturbed cores through them (Fig. 4).

Origin of Fluvial Allostratigraphic Units The origin of fluvial complexes and alloformations has been explained by two general models. First, the classic model of Fisk (1944) concludes that a terrace is the result of fluvial aggradation followed by a period of fluvial entrenchment. His model implies that a floodplain is constructed by the aggradation of a fining-upward sequence in response to a rising base-level, typically a relative rise in sea level. A terrace is created when a floodplain is abandoned by the fluvial system as a resul t of entrenchment in response to a dropping base-level, typically a relative drop in sea level. According to this model, each fluvial terrace and its associated allostratigraphic unit represents the fluvial response to a single rise and fall in base level, which is commonly assumed to be sea level (Autin 1992).

However, Autin (1989, 1992) and BlUm (1992) demonstrate that geomorphic processes more complex than simple changes in base levels create fluvial terraces and alloformations. Autin (1989) found that a temporal clustering of cutoffs initiates a period of meander belt instability within the Amite River Valley of Louisiana. This response results from changes in one or more geomorphic influences, e.g. climate, base-level, etc., which cause an imbalance between river hydrology and sediment delivery. Because of the increased rates of channel cutoffs, the channel pattern locally straightens which favors channels avulsion over lateral accretion. Avulsion creates a new channel which truncates the older alluvium and produces the initial lateral boundaries of a new alloformation. A new stable meander belt is established with a channel pattern and slope in equilibrium with the new conditions of river hydrology and sedimen t delivery after a few decades to cen turies of instability (Autin 1992). Significantly, Autin (1989, 1992) and Blum (1992) demonstrate that to simply interpret all fluvial ter-

races and their alloformations solely as the result of rises and falls of sea level is a grossly simplistic explanation that can be wrong as often as it is right (Heinrich 1992).

lacustrine Terraces A lacustrine terrace is an erosional remnant of a plain that once formed the bottom of a slackwater lake. These lakes were created by the blockage of the mouths of tributary valleys by the aggradation of Mississippi River valley trains. These terraces are highest at the mouth of the tributary and drop in elevation to a flat surface upstream within the tributary valley. Rarely, they exhibit either beach-ridge or river mouth bar like landforms (Shaw 1915; Heinrich 1982; Saucier 1987).

Each lacustrine terrace is the surface of a well-defined allostratigraphic unit. The base of this allostratigraphic unit consists of an erosional unconformity which represents an incised valley cut during interglacial - interstadial times when the tributary valley was unblocked by a glacial valley train. Lying between this lower unconformity and the lacustrine terrace surface is a sequence of nonglacial fluvial sediments overlain by glacial slackwater lake and loessial sediments. The lacustrine terrace forms the upper bounding disconformity of this allostratigraphic unit (Heinrich 1982).

Geoarchaeology The application of allostratigraphy to Late Pleistocene and Holocene sediments and geomorphic surfaces within the Mississippi Alluvial Valley can be used to understand its archaeology. Allostratigraphy can be used to define, correlate and map, genetic depOSitional sequences of sediments within what otherwise appears to be heterogeneous fluvial deposits. Unlike simple terrace mapping, allostratigraphic units formally tie geomorphic surfaces to the three dimensional packages of sedimentary deposits associated with them. A properly defined allostratigraphic unit consists of a set of landforms and depOSitional sequence that formed during a discrete period of time, by specific set of sedimentary processes, and in response to a specific set of environmental conditions. As a result, by combining sedimentological and archaeological data for individual alloformations, generalized, regional predictions can be made for the occurrence, visibility, preservation, and cultural affiliation of archaeological deposits upon landforms and within sediments that form an alloformation. In addition, educated guess can be made about the age and, thus, the cultural affiliation of the archaeolOgical deposits which would have been destroyed by the formation of a fluvial allostratigraphic unit.

For example, because the braided fluvial and lacustrine terraces predate the human occupation of the Mississippi Alluvial Valley, they represent stable features of the landscape that were available for the accumulation of archaeolOgical deposits since Paleo-Indian times (Morse and Morse 1983; Saucier 1987; Autin et al. 1991). As a result, archaeological deposits will have a high visibility on these geomorphic surfaces because in situ archaeological materials of all ages and cultural affiliation will occur only upon these surfaces, except where either younger colluvial and alluvial

138

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~ 0

170

160

150

140

130

Meander Belt

20

15

10

" ........... Erosional 5 Boundaries

~----------------~----------------~----------------~-LO o LEGEND

1 Distance (Kilometers) 2

,.',., .... "-' = Facies boundary = Bounding disconformity

T7T = Paleosol or soil (depth of strips indicates development)

AI = Undifferentiated alluvium Ba = Backswamp facies c = Channel fill facies Ob = Overbank facies Pb = Point bar facies

3

Figure 1. Hypothetical fluvial alloformations within an incised valley. Heinrich (1992).

Modified from

Bedrock

0 Relative Distance (km)

LEGEND

= Bounding disconformity ····· ...... , ... , ..... l'= Minor channel m " r Soil or paleosol associated W = Medina River III i III r = 'h j R II' Wit terrace surface = ecent co uVlum Somerset - - - - - - = Intra-alloformational paleosol Sp = Paleosol

Qa, Qb, Qc, Qd, Qe, and Qf = Unnamed alloformation from oldest to youngest

170

160

150

140

130

Figure 2, Allostratigraphic interpretation of an actual incised valley, the valley of the Medina River at the Richard Beene Site (41 BX831), Bexar County, Texas. Modified from Mandel and Caran (1992),

139

-E '-" c 0

'.p (\S

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20 20

10

0 0

-10 -10

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-30

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10

-20

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Usg = Undifferentiated sands and grav~ ~~:~~~fill -- Facies boundary

Figure 3. Cross-section across a hypothetical alloformtion associated with a me, belt. Constructed using data from Saucier (1969) and other studies.

Bs

Undifferentiated Tertairy Strata

o 5. (k)1 0 Distance m LEG EN D Facies boundary Igmmgl Braide.d stream~ Colluvium -- Erosional boundary :::::::::: deposits ~ Inferred erosional

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10

o

-10

-20

Figure 4. Hypothetical assemblage of fluvial allostratigraphic units associated witt braided stream terraces. Constructed using data from Smith and Saucier (1971).

140

deposits have buried them. Similarly, some early PaleoIndian archaeological deposits might be shallowly buried by the possible continuing accumulation of Peoria Loess into middle Paleo-Indian times along the easternmost edge of Macon Ridge Hillman (1985). Because, these archaeolOgical materials occur only as surficial deposits, they will be mixed and degraded by pedogenic, biologic, and agricultural processes with time. Thus, typical archaeological deposits occurring on the braided fluvial and lacustrine terraces could be expected to have a poor preservation potential and integrity, except where protected by unusual circumstances.

In case of meander belts, evaluations can be made of the occurrence, visibility, preservation, and cultural affiliation of the archaeological deposits for individual meander belts. For example, the stage of development of a specific meander belt will affect the preservation and visibility of archaeological deposits within it. During the avulsion and early meander belt stages of meander belt development, vertical aggradation of natural levees predominates over lateral migration (Farrell 1989). During these stages, any archaeological deposits which form upon these levees will be quickly buried and preserved within the aggrading natural levees. Within a poorly developed meander belt, site preservation will be high, although site visibility might be low.

In addition, if not abandoned early in its evolutjon, a meander belt will eventually enter the fully developed meander belt stage which is characterized by the rapid lateral migration of its channel (Farrell 1989). During the fully developed meander belt stage, the rapid back-andforth migration of an active channel across the meander belt will continually destroy archaeological deposits on the natural levees of its cutbanks and bury archaeological deposits on its point bars. As a result, both preservation potential and visibility of archaeological deposits within a fully developed meander belt will be low until after the time of its abandonment (Munson 1974; Heinrich 1991). Thus, within the area occupied by a fully developed meander belt, archaeological deposits older than it will have been destroyed; archaeological deposits contemporaneous with will have been either buried or destroyed; and archaeological deposits postdating it will occur as surface or shallowly buried deposits with a few exceptions resulting from unique circumstances. The timing of meander belt activity will distinctly influence the age of the archaeological deposits destroyed or occurring as buried and surface deposits.

Summary The alluvial plain of the MissiSSippi Alluvial Valley and the sediments that underlie it can be subdivided into discontinuity-bounded stratigraphic units using the principle of allostratigraphy. Typically, each of these allostratigraphic units will consist of a body of sediments formed by specific set of deposi tional processes during a discrete period of time. As a result, each allostratigraphiC unit should possess archaeological deposits characterized by a specific range of age, cultural affiliation, and occurrence as buried, surface or both types of deposits.

References Autin, W.J., 1989, Geomorphic and Stratigraphic Evolution

of the Middle Amite River Valley, Southeastern Louisiana: [unpublished Ph.D. dissertation]: Louisiana State University, 177p ..

Autin, W. J., 1992, Use of Alloformations for Definition of Holocene Meander Belts in the Middle Amite River, Southern Louisiana. Geological SOciety of America Bulletin, vol. 104, p. 233-241.

Autin, W. J., Burns, S. F., Miller, B. J., Saucier, R. T., and Snead, J. I., 1991, Quaternary Geology of the Lower MissiSSippi River Valley, in Morrison, R.B., ed., Quaternary Nonglacial Geology, Conterminous U. S., The Geology of North America, vol. K-2, Geological Society of America, Boulder, p. 547-582.

Blum, M. D., 1992, Modern Depositional Environments and Recent Alluvial History of the Lower Colorado River, Gulf Coastal Plain of Texas: {unpublished Ph.D. dissertation]: University of Texas at Austin, 286 p.

Farrell, K. M., 1989, Stratigraphy and Sedimentology of Holocene Overbank Deposits of the Mississippi River, False River Region, Louisiana: [unpublished Ph.D. dissertation, Louisiana State University.

Fisk, H. N, 1944, Geological Investigation of the Alluvial Valley of the Lower Mississippi River: Mississippi River Commission, U.S. Army Corps of Engineers, Vicksburg, MissiSSippi.

Fisk, H. N, 1947, Fine-Grained Alluvial Deposits and their Effects on Mississippi River Activity: Mississippi River Commission, U. S. Army Corps of Engineers, Vicksburg, 1vfississi ppi.

Heinrich, P. V., 1982, Geomorphology and Sedimentology of Pleistocene Lake Saline, Southern Illinois: [unpublished M.S. thesis]: University of Illinois, 145 p.

Heinrich, P. V., 1991, A sedimentological explanation for the distribution of archaeological sites in a meander belt as stated by the "relict channel rule": Transactions ofthe Gulf Coast Association of Geological Societies vol. 41, p. 320.

Heinrich, P. V., 1992, The geoarchaeology, geomorphology, and Quaternary geology of Galveston Bay and adjacent Texas Coastal Plain, in, Pearson, Charles, ed., Historic Preservation Plan for Galveston District, Galveston Bay, Texas: Report submitted by Coastal Environments, Inc. to U.S. Army Corps of Engineers, Galveston District, Galveston, Texas.

Mandel, R. D., and Caran, S. C., 1992, Guidebook 10th Annual Meeting South-Central Friends of the Pleistocene - Late Cenozoic alluvial stratigraphy and prehiStory of the inner Gulf Coastal Plain, south-central Texas: Lubbock Lake Landmark Quaternary Research

747

Center Series, no. 4.

Morse, D. F., and Morse, P. A., 1983, Archaeology of the Central Mississippi Valley: Academic Press, New York.

Munson, P.]., 1974, Terraces, meander loops, and archaeology in the American Bottoms, Illinois: Transactions of the Illinois State Academy of Science vol. 67, p.384-392.

Saucier, R. T., 1969, Geological Investigations of the Mississippi River Area, Artonish to Donaldsonville, Louisiana: U.S. Army Engineers Waterways Experimental Station Technical Report, S-69-4 Vicksburg, Mississippi.

Saucier, RT., 1974, Quaternary Geology of the Lower Mississippi Valley: Arkansas Archaeological Survey Research Series No.6, Fayetteville.

Saucier, R T., 1987, Geomorphic interpretations of Late Quaternary terraces in western Tennessee and their regional tectonic implications: U.S. GeolOgical Survey Professional Paper, no. 1336-A.

Shaw, E. W., 1915, Newly discovered beds oflakes in southern and western Illinois and adjacent states: Illinois State Geological Survey Circular, no. 20, p. 139-157.

Smith, F. L., and Saucier, R. T., 1971, Geological investigations of the Western Lowlands areas, Lower Mississippi Valley: U.S. Army Engineers Waterways Experimental Station Technical Report, S-74-5 Vicksburg, Mississippi.

vValker, R. G., and Cant, D. ]., 1984, Sandy fluvial systems, in Walker, G. R, ed., Facies Models, Geoscience Canada Reprint Series No.1, Geological Association of Canada, Toronto, Ontario, p. 71-90.

142

Extractions of Engineering Geology on the Lower Red River

Paul E. Albertson

The purpose of this article is to highlight examples of the engineering geology of the Red River Waterway (RRWW). These are based experiences, such as the site investigations of Lock and Dam # 4, and 5, and geoarchaeological studies, along the RRWW since 1984. For the readers unfamiliar with the practice of engineering geology, its purpose is the application of the science of geology to engineering problems.

Overview The RRWW is a river engineering project designed to assure 9 foot of navigation from its confluence with the Atchafalaya near Simmsport to Shreveport, Louisiana. The engineering works consist of 5 locks and dams, and miles of revetments. Figure 1 shows the location of the locks and dams.

Each lock and dam site reqUired an intensive geotechnical study. The resulting geotechnical portfolios contain closely spaced boring logs of the Quaternary and Tertiary aged sediments. Future opportunities remain in this gray"· ture for Quaternary researchers.

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Table 1 represents some simple relationships between the geologic setting of the locks and dams (LD#) and the resulting engineering response. By coincidence and because the present course of the Red flows on the valley'S east side or against the left valley wall, the left bank locks (LD#2 & 4) are located on Pleistocene sediments. The LD# with odd numbers are located in Holocene alluvium. The Holocene sites required less excavation than the Pleistocene sites but required coffer dams for construction flood control and more extensive dewatering solutions. Therefore, engineering geology is the balancing of geologic site conditions and engineering practices.

Lock and Dam #5 The following is derived from the Design Investigation. LD # 5 is located on the right descending bank in Holocene pOint bar and natural levee deposits (Smith and Russ, 1974). Subcropping beneath the alluvium are Tertiary deposits of

I 10

I I I ~ I I 10 20 )0 ~o Kll~T£~

Figure 1- Location Map of the Red River Waterway

143

TABLE 1

LD # GEOLOGIC SmlNG FOUNDATION EXCAVATION COFFER DAM DEWATERING

HOLOCENE SUBSTRATUM LOWER

2 PLEISTOCENE FLEMING HIGHER

3 HOLOCENE CATAHOULA LOWER

4 PLEISTOCENE WILCOX HIGHER

5 HOLOCENE SUBSTRATUM LOWER

the Wilcox Group. An ancestral Red River drained into the Pendelton Lagoon (Galloway, 1968) during the Paleocene. The fluvio-deltaic processes produced a sequence of laminated clay and silt, massive sand and localized marsh peat. Postdepositional compaction has resultedinfirm claystones, a dense sand body and lignite beds (Albertson, 1987).

Pleistocene streams incised the Tertiary and formed flood plain deposits. These deposits were also eroded and reworked during the Holocene. W#5 site is located in meander belt 5 of Russ (1975) estimated to be 600 years BP. The Holocene sediments can be further divided by geomorphic methods into those reworked in Historic Time. Detailed

NE 66 112 67

MIDWAY

I 50'

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Figure 2 - Lock and Dam #5 Site

III

YES HIGHER

NO LOWER

YES HIGHER

NO LOWER

YES HIGHER

mapping (Smith, 1982) delineated a lower flood plain of historic accretion deposits. By differentiating the site into Holocene and Historic deposits it is possible to account for the topographically higher (elevation 146 feet) Holocene "microterrace" described by Abington (1973). The 13 foot lower historic flood plain (elevation 133 feet) reflects the 15 foot degradation of the Red River following the removal of the Raft by Shreve in 1832 and by Wood ruffin 1873, and the removal of the Rapides in 1892. Historic maps indicate lateral migration and reworking by point bar processes. A litter zone (Figure 2) of clay clasts, gravel and wood was encountered by borings at approximately elevation 80 feet. This high energy debris deposit was used to map the mark left as the historic thalweg crossed the site (Albertson, 1986).

sw 68 69 ELEV. (F .)

150

tOO

50

o

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I·~·.;~I ALLUV IAL AQUIFER

1:-:1 CLAYSTONE

.. LIGNITE

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144

USS EASTPORT

Figure 3 - Site of USS Eastport

Recently, during the construction of LD#5 a human jaw bone was found in the historic substratum 40 feet below the ground surface. The previous understanding that the LD#5 site was formed by migrating historic channels helped District Archaeologist Tommy Birchett determine that the bone was out of cultural context and part of the gravel lag deposit of a 1930 channel. The bone was determined to be over 50 years old but no additional analysis was preformed other than physical examination. According the Native American Grave and Repatriation Act of 1992 the bone was reburied where it was found.

lock and Dam # 4 LD#4 investigation offered an opportunity to study the Pleistocene terraces of the Red River. The terrace at LD#4 had been mapped as Montgomery (Qtm) by Smith and Russ (1974). Harrelson and Smith (1988) redefined the site as Prairie based on thermoluminesence dates of 117,000, 122,000, and 131,000 years B.P. Following the delineation of Russ (1975) the Prairie was thought to represent two episodes of terrace formation, with the upper terrace at elevation 163 as QtPl and the lower terrace at elevation 138 as Qtpz. Later Harrelson (1990) reported radiocarbon dates of 22,350 and 36,550 B.P. obtain from the LD#4 samples. I agree with Harrelson and Smith (1988) that, II These dates represent the first absolute chronometric controls for the late Pleistocene Red River terraces, and will hopefully form the basis for an accurate reconstruction of the Pleistocene history of the Red River Valley". The next step is to place these dates in a stratigraphic context to truly reconstruct the geomorphic framework of the Pleistocene Prairie in the Red River Valley. The presence of a greenish paleosol within the terrace sequence mapped by Richard Hunt in the 1987 Preliminary Design Memorandum remains another strati-

graphic question to be answered. Hopefully, the information discovered at LD#4 can be synthesized by future reevaluation of Fisk's Pleistocene framework.

The excavation of the upstream channel crossed an abandoned channel known as Nicholas Bayou. The bayou is believed to be an anabranch during the Great Raft. The Raft was a series of log jams found on the Red River during historic times. Excavation through the channel exposed an organic rich deposit. Thus, the organic deposit is interpreted a rare remnant of the Red River Raft's deposition.

Pool 3 and the USS Eastport Presently, the U. S. Army Corps of Engineers, Vicksburg District (CELMK) is involved in attempts to recover the remains of the USS Eastport, a civil war ironclad gunboat, as part of the cultural resource investigation associated with the Red River Waterway. One of the purposes of this study is to eval uate the feasibility of engineering methods to safely allow archaeologists to study and recover historic artifacts from the USS Eastport (Albertson and Birchett, 1990). The project area is located along the Red River near the town of Montgomery, Louisiana. Locating the gunboat began by reviewing historic documents concerning the USS Eastport, and conducting an aerial magnetic survey. A distinctive high gamma reading was recorded in the area. Next, a ground magnetic survey was conducted and later plotted to pinpoint and map the anomalies. CELMKdrilled soil borings to explore the anomalies and determine the exact location and depth of burial of the USS Eastport. Boring data characterizing the soil and ground water conditions, were used for the engineering analysiS of the excavation. The artifacts recovered from the boring consisted of wood and coal fragments. All the boring data were examined in crosssection and contour maps. Using these procedures we as-

145

sembled the following artist conception (Figure 3) of the remains of the Eastport resting on top of Tertiary surface and overlain by approximately 50 ft of historic sediments.

The USS Eastport site is located in a former channel of the Red River. Examination of historic channels in the Montgomeryreach shows the Red River locked against the eastern valley wall. The Tertiary sediments provided resistant bank and bed control preventing the river from incising deeper. Therefore, this bend of the river was shallower and formed a geologically controlled obstacle. This obstacle supports historic accounts of grounding by the USS Eastport. By 1892 the historic channel had filled with approximately 20 to 30 ft of sand. Subsequent overbank deposition covered the USS Eastport with 15 to 25 ft of silt, clay and silty sands. Based on the previous information, excavation plans and specs are being developed to conduct an archaeological testing of the wreck this coming summer (1993).

Acknowledgements As the last word for this article of my experiences on the Red River. I wish to thank Garland Watts (former Chief Geologist CELMK) for assigning me to the Red River Waterway (RRWW). I am grateful to George 1. Hunt]r ( Present Chief Geologist CELMK) for entrusting me as project geologist of RRWW Lock and Dam # 5 and coordinator of the Red River Ground Water Study. I am thankful for the many hours discussing the Red River as a laboratory of fluvial engineering geomorphology with Dr. Lawson M. Smith (WES).

References Abington, O.D., 1973, Changing meander morphology and

hydraulics, Red River Arkansas and Louisiana [Ph.d. dissertation]: Baton Rouge, Louisiana, Louisiana State University.

Albertson, P.E., 1987, Engineering, economic, and environmental assessment of the Lower Wilcox Lignite: Gulf Coast Association of Geological Societies Transactions, v. 37, p. 303-312.

Albertson,P.E., 1987, Engineering geomorphic evaluation of Red River Waterway Lock and Dam #5 [abs]: Association of Engineering Geologists Lower Mississippi Valley Section Abstracts, p.4. .

Albertson, P.E. and Birchett, T.C., 1990, Applied geotechniques to the archeological exploration for the U.S.S. Eastport on the Lower Red River, Louisiana [abs]: Geological Society of America Abstracts, v. 23.

Galloway, W.E., 1968, Depositional Systems of the Lower Wilcox Group, North-Central Gulf Coast Basin: Gulf Coast Association of Geological Societies Transactions, v.28.

Harrelson, D.W., 1990, Deposition of a Prairie Terrace Sequence, Red River Parish, Louisiana: Southeastern Geological Society of America, v. 22, p. 17.

Harrelson,D.W.andSmith,L.M.,1988,Thermoluminesence

age dates from a Red River Terrace Sequence, Red River Parish, Louisiana: Southeastern Geological Society of America, v. 20, no. 4, p. 268.

Russ, D.P. 1975, Quaternary geomorphology of the Lower Red River Valley, Louisiana [Ph.D. dissertation]: University Park, Pennsylvania, Pennsylvania State University.

Smith, F.L. and Russ, D.P., 1974, Geological investigation of the Lower Red River-Atchafalaya Basin Area, Louisiana: Geotechnical Laboratory, Waterways Experiment Station, Vicksburg, Mississippi.

Smith, L.M., 1982, Geomorphic investigation of the Bayou Bodcau and Tributaries Project Area, Louisiana:

146

Geotechnical Laboratory, Waterways Experiment Station, Vicksburg, MisSissippi.

Characteristics of Cores fro:m the Upland and Intermediate COlllplex

in the Florida Parishes

Whitney J. Autin, Joann Mossa, and B. J. Miller*

Investigations in the Florida Parishes of southeastern Louisiana have provided revealing insight into the soil stratigraphic properties of the coast-parallel Pleistocene geologic units. Cores have been collected and analyzed from two sites, the first at Jackson, LA representing a stable landscape of the Upland Complex (fables 1 and 2), and the second at Montpelier, LA representing an buried erosion surface of the Intermediate Complex (fables 3 and 4).

Particle Size Data Summary

Jackson site, Upland Complex The sand content is high in the Ap horizon, due to eluviation and plowing. Sand content of 2 to 4.4 per cent in the Bt and Btx is normal for Peoria Loess. The Sicily lsI and Loess ranges from 6.8 to 14.3 per cent sand, which is high for a loess. The Jackson Geosol varies from 23.4 to 57.6 per cent sand, and the trend shows a slight increase with depth. The mixing zones nicely mark the boundaries between units. The silt content of Peoria Loess ranges from 65 to 80 per cent and is typical of a loess. The Sicily Island Loess silt content ranges from 50 to 60 per cent which is less than Peoria Loess. The Jackson Geosol ranges in silt content from 10 to 40 per cent, and its silt content is highest at the top of the unit. This could be an effect of translocation from the Sicily Island Loess into the underlying unit. Clay content illustrates a good argillic horizon pattern for Peoria Loess. The argillic pattern is less pronounces for Sicily Island Loess and the Jackson Geosol. The highest overall clay content is in the Jackson Geosol. This is possibly related to intense weathering during the development of the Jackson Geosol.

The very coarse sand component is mostly associated with the Sicily Island Loess and mixed horizons above and below the unit. The coarse sand content is most common to the Sicil y Island andJ ackson Geosol. The medium sand and fine sand fractions are dominant in the Jackson geosol, occur to a lesser extent in the Sicily Island Loess, and are rarest in the Peoria Loess. The very fine sand content is the largest sand component of the Peoria Loess, increases in the Sicily Island Loess, and is most common in the Jackson Geosol.

The coarse and medium silt are the dominant silt fractions, and coarse silt is generally more abundant. Percentages are highest for the Peoria Loess and lowest for the Jackson Geosol. The fine silt is highest in the Peoria Loess, decreases in the Sicily Island Loess, and is almost insignificant in the

Jackson Geosol. Silt trends are less consistent in Sicily Island Loess than in the Peoria Loess.

Montpelier Site, Intermediate Complex The sand content is high in the Ap, then progressively increases through the Mixed Loess Bt, which is derived from Sicily Island and possibly Peoria Loess. The basal Bt horizon of the Mixed Loess is high like the underlying colluvium. Sand content of the Montpelier Colluvium is too high for loess, approaching 25 per cent. Sand values of 33 to 50 per cent in the Jackson Geosol are typical. The silt content of Mixed Loess is 57 to 66 per cent, and the Montpelier Colluvium is 39 to 46 per cent, which is low for a loess. Silt content of the Jackson Geosol is variable and ranges from 9 to 29 per cent. Clay trends show nice argillic bulges in the Bt2 and Bt3 of the Mixed Loess and the 2Btb2 of the Montpelier Colluvium. A more variable clay content occurs in the Jackson Geosol.

There is more very coarse sand in the Mixed Loess and Montpelier Colluvium than in the Jackson Geosol. The coarse sand trends are erratic, in the Mixed Loess and Montpelier Colluvium, but are consistent in the Jackson Geosol. The medium and fine sand is lowest in the Mixed Loess, has a distinctive increase in the Montpelier Colluvium, and is highest in theJackson Geosol. The medium and

. fine sand show a sharp increase in the basal Mixed Loess, and is erratic in the Montpelier Colluvium. The very fine sand follows medium and fine sand trends, but shows less sharp variations.

Coarse and medium silt are the dominant fractions, with coarse silt slightly more abundant. The percents are slightly higher for Mixed Loess than for Montpelier Colluvium. The Jackson Geosol is low in silt and varies among horizons. The fine silt is low for both Mixed Loess and Montpelier Colluvium. There is almost no fine silt in the Jackson Geosol.

Comparison of Intermediate and High Terraces cores

The Peoria Loess is slightly thicker atJ ackson than the Mixed Loess at Montpelier (195 versus 164 cm). The unit is probably over thickened at Montpelier relative to its distance from the source. Miller et al. (1985) predict 1 to 3 m at Jackson and less than 1 m at Montpelier. Peoria Loess contains more silt and less sand at Jackson than the Mixed

147 * deceased April, 27, 1987

TAOLE 1. TYPICAL PROFILE OF PLIOCENE TO EARLY I'LEISTOCENE UPLAND COMPLEX, JACKSON SITE.

Location: East Feliciana Parish, Louisiana; Lat. 30·46'50" N, Long. 91'10'53" W; in Irreg. Sec. 89, T. 3 S., R. I W., Jackson, LA 7.5-minute topographic quadrangle; is in a plowed field west of an unnamed parish gravel road, 6.3 km south of junction with LA Hwy 10; elevation is 64 m, slope is 0 to I percent.

DEPTH, em HORIZON MATRIX MOTTLE TEX STRUC CONSIST BDY COMMENTS COLOR COLOR

0- IS Ap 10YR 4/3 SiL fr cl Top of Peoria Loess; po; rt frag

15 - 21 Btl 10YR 5/4 SiL fr cJ po

21 - 32 Dt21 7.5YR 5/6 SiCL wk fn sab fr cJ po

32 - 38 Dt22 10YR 5/6 SiCL wk fn sab fr cJ po; rt frag

38 - 52 Dt3 10YR 5/6 SiCL wk vfn sab fr cJ po

52 - 62 Btxl 10YR 5/6 SiL mod fn sab fr gr po; 10YR 2/2 5t and cone; IOYR 7/4 Si f1m

62 - 85 Dtx2 10YR 5/6 10YR 7/2 SiL mod med sab fr cJ po; 10YR 2/2 st and conc; 10YR 7/4 Si f1m

85 - 105 Dtx3 IOYR 5/6 10YR 7/2 SiL mod fn sab fr gr po; 10YR 2/2 5t; 10YR 6/3 Si f1m and tng

105 - 123 Btx4 10YR 5/6 10YR 7/2 SiL wk fn sab fr gr 10YR 2/2 5t; 10YR 6/3 Si f1m and tng

123 - 130 Dtx5 10YR 5/6 10YR 7/2 SiL wk med sab fr cl po; 10YR 2/2 stains; 10YR 6/3 Si f1m and tng

130 - 150 Dtx6 10YR 5/6 10YR 8/2 SiL mod med sab fr gr po; 10YR 2/2 st and conc; 10YR 7/2 Si f1m and tng

150 - 173 BC&2Btl 10YR 7/8 10YR 8/1 SiL wk fn sab fr gr Transition between Peoria Loess and Sicily Island Loess; po; 10YR 2/2; st and conc; 10YR 7/2 Si flm and tng

173 - 195 BC&2Dt2 10YR 6/8 10YR 8/1 SiL wk fn sab fr gr 10YR 2/2 conc; 10YR 7/2 Si f1m and tng

195 - 210 2Dtbl 10YR 6/8 10YR 7/6 SiCL wk vfn sab vhd gr Top of Sicily Island Loess; 2.5YR 4/6 & 5/8 sl and conc

210 - 235 2Dtb2 IOYR 6/8 10YR 7/6 SiCL mod fn sab vhd ab

235 - 250 2Dtvb3 10YR 6/8 10YR 7/6 SiCL mod fn sab vhd cJ lOR 4/6 pIn

250 - 268 2Dtvb4 IOYR6/8 10YR 7/6 SiCL wk vfn sab vhd cl lOR 4/6 pIn; 2.SYR 5/6 Sl

268 - 299 2atb5 10YR 8/1 10YR 8/6 SiCL mod vfn sab vhd gr 2.5YR 5/6 Sl and conc

299 - 316 2Dtb6 10YR 8/1 10YR 8/6 SiCL wk vfn sab vhd gr 7.5YR 4/4 conc

316 - 345 2Btvb7 10YR 6/8 10YR 8/2 SiCL wk vfn sab vhd gr 2.5YR 4/6 & 5/6 st and pIn

345 - 379 2Dtb8 10YR 6/6 10YR 7/4 SiCL mod fn sab vhd gr lOR 5/8 51

379 - 401 2Dtb9 10YR 7/8 10YR 8/1 SiCL mod fn sab vhd gr lOR 5/8 sl

401 - 442 2DC&3Dtl lOR 4/6 10YR 7/6 SiCL wk fn sab vhd ab Transition between Sicily Island Loess and Jackson Geosol; lOR 5/8 st and conc; 10YR 7/2 tng

442 - 458 2DC&3Dt2 lOR 4/6 10YR 8/6 SiCL mod fn sab vhd ab lOYR 7/2 tng

458 - 480 3Dtbl 2.5YR 4/8 10YR 7/6 CL wk fn sab vhd gr Top of Jackson Geosol developed in Citronelle Formation; lOR 5/8 f1m; 10YR 7/2 tng and S-sized C frag

480 - 495 3Dtb2 lOR 5/8 10YR 7/6 CL mod fn sab vhd gr lOR 5/8 f1m and conc; 10YR 7/2 tng and S-sized C frag

495 - 537 3Btb3 2.5YR 5/8 10YR 7/2 CL wk fn sab hd gr lOR 5/8 f1m; 10YR 7/2 tng and S-sized C frag

537 - 566 3Dtb4 2.5YR 5/8 10YR 8/1 CL wk fn sab fr gr lOR 5/8 f1m; 10YR 7/2 tng and S-sized C frag

566 - 588 3Dtb5 2.5YR 5/8 10YR 8/1 C mod fn sab fr gr 10YR 7/6 Sl; lOR 5/8 flm; 10YR 7/2 S-sized C frag

588 - 632 3Dtb6 2.5YR 5/8 10YR 8/1 C wk med sab fr gr lOR 5/8 flm; 10YR 7/2 S-sized C frag

632 - 663 3Dtb7 2.5YR 5/8 C wk med sab fr gr JOYR 7/6 51; lOR 5/8 flm; JOYR 7/2 S-5ized C frag

663 - 710 3Dtb8 2.5YR 5/8 C wk fn sab fr gr 10YR 7/851; lOR 5/8 f1m; 10YR 7/2 S-sized C frag

710 - 757 3Dtb9 2.5YR 5/8 C wk fn sab fr gr 10YR 8/8 stains; lOR 5/8 f1m; 10YR 7/2 S-sized C frag

757 - 770 3Btbl0 2.5YR 5/8 C wk med sab fr gr 10YR 8/4 5t; lOR 5/8 f1m; 10YR 7/2 S-sized C frag

770 - 790 3DCbl lOR 5/8 SCL wk med sab fr gr 10YR 8/6 st; lOR 5/8 f1m; 10YR 8/3 S-sized C frag

790 - 821 3DCb2 lOR 5/8 SCL fr gr lOR 5/8 flm; 10YR 8/3 S-sized C frag

821 - 843 3BCb3 10YR 5/8 SC fr lOR 5/8 f1m; 10YR 8/3 S-sized C frag

148

TABLE 2. PAHTICLE SIZE DATA FROM THE JACKSON SITE.

UNIT HORIZON DEPTH SAND SILT CLAY YCS CS MS FS YFS CSI MSI FSI

PEORIA Ap I 8 10.5 79.8 9.6 0.8 0.7 3.6 2.8 2.7 51.0 25.3 3.6 LOESS

Btl 18 4.4 74.2 21.4 0.0 0.1 0.8 0.8 2.7 38.3 31.6 4.3

Bt21 27 1.9 67.6 30.6 0.0 0.0 0.2 0.4 1.1 35.2 28.3 4.1 I

Bt22 35 2.7 64.9 32.4 0.0 0.0 0.3 0.6 1.7 32.8 27.4 4.7

Bt3 45 3.1 69.4 27.5 0.0 0.1 0.5 0.7 1.8 34.3 29.7 5.4

Btxl 57 3.4 72.1 24.5 0.0 0.4 0.6 0.8 1.6 34.8 31.8 5.5

Btx2 74 3.2 73.6 23.2 0.0 0.4 0.7 0.7 1.3 43.7 25.8 4.1

Btx3 95 3.8 74.0 22.2 0.1 0.2 0.7 0.9 1.8 37.6 32.2 4.3

Btx4 114 3.3 75.1 21.6 0.0 0.3 0.9 0.9 1.3 41.1 30.0 3.9

Btx5 127 3.9 74.8 21.3 0.0 0.3 0.9 1.0 1.7 40.4 31.0 3.3

Btx6 140 4.4 75.9 19.7 0.0 0.2 1.1 1.4 1.8 40.7 31.2 4.0

BCl&2Btl 162 10.5 68.9 20.5 2.1 1.2 2.3 2.5 2.3 46.8 19.6 2.5

BC&2Bt2 184 8.6 67.8 23.6 1.2 0.7 2.0 2.4 2.4 39.8 25.8 2.2

SICILY 2Btbl 203 7.3 61.1 31.6 0.3 0.4 1.7 2.3 2.5 37.3 21.7 2.2 ISLAND LOESS 2Btb2 223 6.0 54.2 39.8 0.4 0.3 1.1 1.8 2.3 34.8 17.6 1.8

2Btvb3 243 7.5 59.1 33.4 0.8 0.3 1.8 2.4 2.2 39.2 17.5 2.5

2Btvb4 259 14.1 53.3 32.6 6.1 2.1 1.8 2.1 2.1 29.4 20.9 3.0

2Btb5 284 6.8 59.0 34.1 0.3 0.7 1.5 2.0 2.3 32.2 24.3 2.5

2Btb6 308 7.6 54.7 37.7 0.0 0.2 2.5 2.7 2.2 29.7 21.7 3.3

2Btvb7 331 10.9 55.5 33.6 0.4 0.6 3.1 3.3 3.5 34.6 18.0 3.0 -_._---_ .. -2Btb8 362 11.8 52.2 36.1 0.2 0.8 3.8 3.8 3.2 34.4 15.0 2.8

2Btb9 390 14.3 49.5 36.1 0.3 0.7 4.9 4.4 4.0 25.9 20.3 3.4

2BC&3BtI 442 15.7 49.2 35.1 0.1 0.5 5.8 5.1 4.3 34.8 11.6 2.7

2B.C&3Bt2 450 19.4 40.9 39.7 0.2 1.2 7.4 6.2 4.3 21.7 16.4 2.8

JACKSON 3Btbl 469 23.4 38.8 37.7 0.0 0.6 9.7 7.6 5.6 20.7 15.4 2.8 GEOSOL

488 31.1 3Btb2 33.1 35.7 0.0 0.9 12.9 10.2 7.2 18.0 12.8 2.3

3Btb3 516 32.1 29.4 38.4 0.0 0.9 13.9 10.2 7.2 15.6 11.8 2.0

3Btb4 552 35.5 25.1 39.5 0.0 0.8 14.8 11.6 8.2 14.5 9.0 1.6

3Btb5 572 35.3 24.2 40.5 0.0 0.8 15.5 11.4 7.7 14.0 8.7 1.5

3Btb6 610 33.9 21.7 44.4 0.0 0.8 15.7 10.5 6.9 12.4 8.2 1.1

3Btb7 648 40.4 10.7 48.8 0.0 0.9 19.2 11.1 9.2 1.4 7.9 1.5

3Dtb8 687 36.0 19.0 45.0 0.0 0.7 17.7 10.0 7.6 10.6 7.3 1.0

3Dtb9 734 37.1 19.2 43.7 0.0 0.8 18.2 9.4 8.7 11.9 5.3 2.0

3Btbl0 764 43.2 16.5 40.4 0.0 0.8 22.2 12.2 8.1 11.8 2.7 1.9

3BCbl 780 57.6 9.6 32.8 0.0 0.9 37.6 13.4 5.6 5.2 2.6 1.8

3BCb2 806 52.3 10.8 37.0 0.0 1.9 35.5 10.5 4.4 6.0 3.2 1.5

3BCtb3 832 48.1 10.9 41.0 0.0 0.7 29.3 13.2 5.0 7.3 2.5 1.0

149

-v.. o

TABLE 3. TYPICAL PROFILE BENEATH MIDDLE PLEISTOCENE INTERMEDIATE COMPLEX, MONTPELIER SITE.

i

i

Location: St. Helena Parish, Louisiana; Lat. 30°40'40" N, Long. 90°39'05" W; in Irreg. Sec. 51, T. 4 S., R. 6 E., Montpelier, LA 7.5-minute topographic quadrangle; site is on a convex ridge in a clear cut forested area east of La. 441, 250 m south of junction with LA Hwy 16; elevation is 41 m, slope is 0 to 1 percent.

DEPTH, em HORIZON STRUC

O- S Ap 10YR 4/4 SiL fr ab Top of Mixed Loess; gr rts

-5 - 14 Btl 10YR 6/6 SiL wk vfn sab fm gr gr rts;' 10YR 2/2 conc

14 - 22 Bt2 IOYR 7/6 SiCL wk fn sab fm cl 2.SYR 5/8 st and conc

22 - 40 Bt3 10YR 7/8 SiCL wk med pty fr gr po; rt tr; IOYR 5/3 hor bands -40 - 56 Bt4 IOYR 7/8 IOYR 6/3 SiL mod med pty fr cl IOYR 2/2 st; IOYR 5/3 hor bands

56 - 100 Bt5 IOYR 7/6 IOYR 5/6 SiL wk med pty fr cl po; IOYR 2/2 cone; IOYR 8/2 Si flm; 2-4 mm chert gvl

100 - 118 Bt&2BtI 10YR 7/8 10YR 7/3 SiL mod med pty fr cl Transition between Mixed Loess and Montpelier Colluvium; po; 10YR 8/2 Si flm

118 - 142 Bt&2Bt2 10YR 7/6 10YR 7/2 SiL mod med pty fr cl 2.5YR 5/8 st and flm

142 - 185 Bt&2Bt3 10YR 8/6 IOYR 7/2 SiL wk fn sab fm cl 2.5YR 5/8 and 5YR 5/6 st

185 - 216 2Btbl 10YR 7/2 10YR 6/6 CL mod med pty fr gr Top of Montpelier Colluvium; lOR 4/8 st

216 - 245 2Btb2 IOYR 7/2 10YR 7/6 SiCL mod tck pty fr gr 7.5YR 6/8 st

245 - 267 2Btb3 5YR 6/8 IOYR 7/6 CL mod tck pty fr gr 2.5YR 5/8 st; IOYR 7/2 tng

267 - 302 2Btb4 5YR 6/8 IOYR 7/6 CL mod tck pty fr gr 2.5YR 5/8 st; 10YR 7/2 tng

302 - 359 2Btb5 2.5YR 5/8 10YR 7/6 CL mod tck pty fr gr IOYR 7/2 tng

359 - 391 2Btb&3Btbl lOR 4/8 10YR 7/6 CL mod med pty fr ab Transition between Montpelier Colluvium and Jackson GeosoI; lOR 4/8 and IOYR 7/6 flm; IOYR 7/2 tng

391 - 418 2Btb&3Btb2 7.5YR 8/0 10YR 7/6 C mod med pty fr ab IOYR 7/6 flm; 10YR 7/1 tng

418 - 495 3Btbl lOR 4/8 C wk vfn sab fr gr Top of Jackson GeosoI; 5YR 7/8 st; lOR 4/8 flm; 10YR 7/1 tng and S-sized C [rag

495 - 553 3Btb2 lOR 4/8 C wk vfn sab fr cl lOR 4/8 flm; 10YR 7/1 tng and S-sized C frag

553 - 576 3BCbl lOR 4/8 CL fm cl lOR 4/8 flm; 10YR 7/8 SiL tng; IOYR 7/1 S-sized C frag

576 - 636 3BCb2 lOR 5/8 SC fr gr IOYR 7/8 st; lOR 5/8 flm; 10YR 8/1 tng; IOYR 7/1 S-sized C frag

636 - 657 3BCb3 lOR 4/8 CL - fr gr IOYR 7/8 st; lOR 4/8 flm; 10YR 8/1 tng; 10YR 7/1 S-sized C frag

657 - 690 3BCb4 2.SYR 4/8 C fr gr IOYR 7/8 st; 2.5YR 4/8 flm; 10YR 8/1 tng; 10YR 7/1 S-sized C frag

690 - 730 3BCb5 2.5YR 4/8 SC fr IOYR 7/8 st; 2.SYR 4/8 flm; IOYR 8/1 tng; 10YR 7/1 S-sized C frag

TADLE 4. PARTICLE SIZE DATA FROM THE MONTPELIER SITE.

UNIT HORIZON DEPTH SAND SILT CLAY YCS CS MS FS YFS CSI MSI FSI

MIXED Ap I 3 12.7 71.7 15.6 0.9 1.4 3.4 4.4 2.5 39.3 28.8 3.6 LOESS

Btl 10 9.0 65.8 25.1 0.6 1.2 2.2 3.1 1.9 35.8 26.9 3.1

Bt2 18 7.3 61.1 31.6 0.2 0.6 1.9 2.7 1.9 29.2 27.8 4.1

Dt3 31 9.5 61.5 28.9 0.5 0.7 2.5 3.7 2.2 31.6 25.9 4.1

Bt4 48 15.2 63.4 21.4 0.4 1.0 4.5 6.5 2.8 37.7 22.3 3.4

Bt5 78 24.3 56.8 18.9 1.0 1.0 6.9 10.6 4.8 27.7 26.0 3.2

1&2Bt6 109 22.7 56.7 20.7 0.3 0.6 6.5 10.8 4.4 33.4 20.1 3.1

1&2Bt7 130 21.0 54.8 24.2 0.3 0.5 6.2 9.7 4.4 25.6 25.6 3.6

1&2Dt8 164 20.9 52.6 26.5 0.3 0.7 6.2 9.4 4.4 30.9 18.6 3.1

MONTPELIER 2Dtbl 196 24.1 45.7 30.2 0.9 1.8 7.5 9.5 4.3 21.0 21.4 3.3 GEOSOL

2Dtb2 231 16.0 44.8 39.2 0.4 0.8 4.6 6.8 3.4 28.9 13.2 2.7

2Btb3 256 25.5 40.7 33.8 0.7 1.4 7.4 10.8 5.2 22.9 '14.7 3.1

---- .-

2Btb4 285 24.5 39.6 35.9 1.0 2.8 7.4 8.6 4.7 18.0 18.5 3.0

2Btb5 331 27.5 38.5 34.0 0.2 0.7 8.9 12.5 5.2 19.6 16.8 2.1

2&3Btb6 375 30.2 31.5 38.3 1.5 2.5 9.9 11.1 5.2 15.6 13.5 2.4

2&3Btb7 405 32.8 23.4 43.8 0.8 1.6 11.4 13.5 5.6 12.6 9.5 1.3

JACKSON 3Btbl 457 42.4 14.1 43.5 0.0 1.0 15.1 19.7 6.6 8.1 5.1 0.9 GEOSOL

3Btb2 514 44.4 10.6 45.0 0.0 1.1 15.4 20.5 7.4 6.3 3.5 0.8

3Btb3 565 40.7 19.5 39.8 0.4 1.2 14.3 18.0 6.9 10.2 7.8 1.5

3Btb4 606 48.4 10.3 41.3 0.1 1.3 18.2 21.0 7.8 6.3 3.3 0.7

3Btb5 647 33.5 28.7 37.8 0.3 1.2 11.9 14.5 5.6 14.6 12.2 1.9

3Btb6 669 44.5 11.7 43.8 0.0 1.1 17.5 19.0 6.9 6.6 3.9 1.2

3Btb7 710 50.4 8.6 41.0 0.0 1.2 23.3 20.4 5.5 4.2 2.9 1.5

151

Loess at Montpelier. The silt components are similar, but Montpelier has slightly more variability in its coarse to medium silt ratio. The mixing zone between Peoria Loess and Sicily Island Loess is distinct and sharply defined. Based on field descriptions, at Jackson it is 45 cm thick and at Montpelier it produces a 164 cm thick unit.

The Sicily Island Loess is 263 cm thick at Jackson and the 1tfontpelier Colluvium is 233 cm thick at Montpelier. Miller etal. (1985) predict 1 to 3 m at Jackson and less than 1 m at Montpelier. The Montpelier Colluvium at Montpelier is significantly over thickened relative to its expected loess accumulation. Sicily Island Loess contains distinctly more silt and less sand at Jackson than the Montpelier Colluvium at Montpelier. The clay distributions are comparable in form. The sand content is dominantly medium to very fine. A near equal mix occurs atJackson, and fine sand dominates at Montpelier. The sand content is more variable with depth at Montpelier. The silt components of the two sites are comparable, both have erratic silt ratios. The mixing zone between Sicily Island Loess and theJ ackson. Geosol is distinctive at Jackson, as is mixing between Montpelier Colluvium and the Jackson Geosol at Montpelier. At Jackson, the 2Btb9 horizon could be included in the mixed zone. This would increase its thickness to 79 cm.

The top oftheJackson Geosol is at 458 cm atJackson and 418 cm at Montpelier. The base of the geosol was not encountered at either site. The Jackson Geosol is slightly sandier at Montpelier than at Jackson. At Jackson, the sandier zones

are deeper in the profile. Montpelier has distinctly less silt than Jackson. The clay content of the both sites are comparable. Sand is dominantly medium to fine. The Montpelier site has more coarse sand and very coarse sand than the Jackson site. Silt content is notable at the top of Jackson Geosol at Jackson, but not at Montpelier. Sand ratios are somewhat consistent for both Montpelier and Jackson sites.

The best loess texture is the Peoria Loess at Jackson. The Sicily Island Loess at Jackson shows signs of reworking and mixing. At Montpelier, both Peoria Loess and Sicily Island Loess have been mixed into the Mixed Loess unit, and Sicily Island Loess is mixed with the upper Jackson Geosol into the Montpelier Colluvium. Mixed zones are sharper and more discrete atJackson. This arises since the whole loess units are mixed at Montpelier. TheJackson Geosol is somewhat finer grained at Jackson, especially in the upper profile. Two possible reasons need to be explored. 1) Weathering produced a clayey soil at both sites and more of this Original profile has been stripped from the Intermediate Complex than the Upland Complex. 2) Facies differences between the Jackson and Montpelier sites produced a finer textured soil at Jackson.

Reference Miller, B.J., Lewis, G. C., Alford,J.J., and Day, W.]., 1985,

Loesses in Louisiana and at Vicksburg, Mississippi:

152

Friends of the Pleistocene, South-Central Cell Field Trip Guidebook, 126 p.

Surface Geologic Mapping in LouisianaIt's Beginnings, Rise, and Recent Decline

Richard P. McCulloh

Preface This paper is abridged and modified from Louisiana Geological Survey (LGS) Open-File Series No. 92-01 (McCulloh 1992). The definition of large-scale used herein (~1:62,500) differs from that currently applied by the U.S. Geological Survey (~1 :25,000) and reflects the once widespread practice of field mapping on IS' topographic quadrangle bases, as well as the mapping historically done in Louisiana parishes. The figures and references omit mention of LGS Open-File Series No. 91-01 byW.J. Autin and R. P. McCulloh, which comprises 1:24,OOO-scale maps of the geology of East Baton Rouge Parish without an accompanying report. Also omitted is mention of 1:62,500-scale geologic mapping of Quaternary deposits along the Red, Ouachita, and Mississippi River bottoms in published technical reports by the U.S. Army Corps of Engineers, Vicksburg District, which are important sources of large-scale Quaternary mapping. The text omits mention of the National Geologic Mapping Act signed into law in 1992. The Act should be a significant improvement over the few million dollars already available to the states annually through the COGEOMAP program, but it is too early to tell what impact the act will have onthe problem outlined herein.

Abstract In recent years a consensus has emerged among geoscientists that geologic mapping in the United States is declining. The U.S. Geological Survey and National Research Council have corroborated this trend and have begun documenting it. Concern stems from increasing needs for geologic maps concurrent with the production decline. The needs partly reflect the demand for derivative maps, based on geology, for environmental work. Louisiana has depended on university professors and students for all of its parish- and largerscale geologic mapping, and has never directly supported geologic mapping except for reconnaissance efforts in the 19th century and small stipends provided to graduate students in the mid-20th century. As a result, the decline in geologic mapping in Louisiana corresponds to a drop-off in mapping done at universities. Only 30 percent of Louisiana parishes were ever mapped in detail, and most of these were done before the 1950s. Geologic mapping, therefore, has been a nonviable research pursuit in Louisiana for decades because the state has failed to find new ways to support it as academic mapping declined. Because fewer investigators are doing field mapping today, a new strategy should first

emphasize compilations at smaller scales, which can lead to subsequent interest in larger-scale investigations-the reverse of the traditional strategy.

The National Decline of Surface Geologic Mapping

Almost all specialized geologic studies except for those in the deep subsurface depend on maps of surface geology for critical basic information. Though mapping may be perceived as routine, good geologic maps are the result of "research of a high order" (Harrison 1963: 225). In recent decades, however, geologic mapping in the U.S. has declined, yet geologic mapping needs increased (Committee on Geologic Mapping 1988; Committee Advisory to the U.S. Geological Survey 1987; U.S. Geological Survey 1987; Figs. 1-2). Mankin (1988) suggested that the need for geolOgiC maps is increasing as a result of the growth of the environmental consulting industry. In the past, the published and unpublished surface geologic maps made by professors and graduate students (usually as thesis or dissertation research) have served as valuable source materials for the compilation of published maps, but academic mapping has declined as well (U.S. Geological Survey 1987).

Declining popularity as a research topic among both researchers and funding agencies could stem from the long

400,000

~ 300,000

!E ~ 200,000

:3 g 100,000

1940's 1950's 1960's 1970's 1980's 1980's projected based

on 1981 -1985

Figure 1. Frequency distribution, by decades, of number of square miles geologically mapped (at scales of 1 inch = 1 mile or larger) in the u.s. (USGS 1987).

153

110 ...-------------.....

100

90

80

70

60

50

40

. 1\ 1\ , \ , \

I \ , \

Last Year of the Kentucky

Project

J

, : \ /'-, I \ ', .... _"

20 \ ... 1 ,.. Number of GO

10

o

Maps Exdusive of Kentucky

1972 74 76 78 80 82 84

Year Of Publication

Figure 2. Frequency distribution of number of quadrangles geologically mapped in the U.S. (USGS 1987). "Kentucky project" refers to the most highly successful state-federal cooperative geologic mapping program to date (Smath 1988; Cressman and Noger 1981; Hagan 1961).

time investment required relative to more specialized studies that permit more rapid publication of research results (Committee Advisory to the U.S. Geological Survey 1987). Additionally, the surface geologic maps and accompanying reports done by university students and professors have traditionally, if published, been issued as county or parish geological bulletins by the appropriate state geological surveys, as in Louisiana. But now the state surveys may be less able to support mapping efforts because their focus is becoming more environmental (U.S. Geological Survey 1987).

One way to pursue geologic mapping in a climate of deemphasis and meager funding is to change mapping strategies by reversing the traditional sequence of moving from larger-scale field mapping to smaller-scale compilations. Geologic maps fulfill the two primary functions of 1) summarizing the existing knowledge of the geology of an area, and 2) stimulating new detailed investigations of the geology of smaller areas. The first of these functions has had the greater influence on the production of small-scale geologic maps in the past. However, smaller-scale compilations can function more to reveal the subareas that need the most work than as apparently fldefinitive" summaries of the geology. States can pursue this strategy with minimal funding. The Texas Bureau of Economic Geology has generated much interest and demonstrated high demand for its series

of 1:2S0,OOO-scale geologic compilations during the last 30 years. Other state surveys can undertake similar intermediate-scale compilations provided production monies are available.

Geologic Mapping in louisiana Early geologic mapping in Louisiana was the product of reconnaissance surveys commissioned by the state legislature and conducted almost exclUSively by geology professors at Louisiana State University (LSU). The first of a total of six geological surveys was begun in 1869 and the modern LGS was created in 1934. In each survey the level of involvement by LSU was high (Howe and Moresi 1933; Pope 1988). With the establishmen t of the modern LGS, the focus shifted from statewide geological reconnaissance to coverage of the state by a series of detailed investigations of the geology of individual parishes.

Although mapping was once pursued actively if only briefly, much of the state remains unmapped, and problems special to coastal-plain areas may have held up surface mapping to some degree in Louisiana. Fluvial and coastal Quaternary deposits cover approximately three-fourths ofthe state, and are unlikely host strata for the resources that attracted traditional surface-geologic investigation elsewhere. In such areas surface-to-subsurface correlation can be critical to the progress of mapping. Even in well drilled areas, however, such correlation may not be straightforward because oil and gas wells are commonly cased to depths of thousands of feet (Fig. 3). Possibly because of such problems, the National Research Council study (Committee on Geologic Mapping 1988) identified the Gulf Coastal Plain as the geological province in the conterminous United States with the highest current need for geologic maps. Mapping controversies in the province are becoming increasingly relevant to many environmental issues.

Louisiana has relied exclusively on mapping by professors and students, and the state has never appropriated sizeable funds to its state geological survey for the direct support of large-scale geologic mapping. The history presented by

N SCHEMATIC DEPTH DISTRIBUTION OF

SUBSURFACE INFORMATION FROM GULF COAST WELL LOGS

OIL AND GAS

WELLS

Figure 3. The problem presented by deeply cased oil and gas wells to the correlation of subsurface stratigraphic units to the surface.

154

s

Published Map and

11: 0 1 Published Map,

Report (LGS) Report Unpublished (LGS)

11:'81 Published Report, No

Map and Report Surface Geologic Map

In Press (LGS) (LGS)

11~41 Unpublished Map,With Or Without Report (LGS and Non-LGS)

Figure 4. Investigations of surface geology of Louisiana parishes ("map" indicates a 1 :62,500- or larger-scale surface geologic map).

Howe and Moresi (1933) indicates that direct legislative support of geologic mapping in Louisiana before the 1930s was limited to support for small-scale reconnaissance mapping of the entire state by LSU professors during the earliest geological surveys in the 1870s and 1880s. After establishmentofthemodern LGSin 1934, the only direct support was the prOVision of small monthly stipends to doctoral students engaged in geologicmappingofparishesfor specificgeological bulletins between the 1930s and the 1970s. In later years this support apparently was not an effective incentive for professors and their students to undertake mapping investigations because until this year LGS published no parishgeology bulletins since 1960.

Geologic mapping normally entails the production of a geologic map and a report describing and interpreting the geology and minerals potential. Figures 4 and 5 show the areal and frequency distributions, respectively, of parish geological investigations, while the cumulative-frequency curve in figure 6 includes only published parish geological bulletins that include both a large-scale (1 :62,500 or larger)

surface geologic map and a report. Figure 6 shows that surface geologic mapping in Louisiana has declined drastically. All of the published reports that include large-scale surface geologic maps of the parishes (Fig. 4, shaded; Fig. 5, shaded) have been issued as geological bulletins by LGS. If we count only these LGS bulletins with both detailed maps and accompanying reports (Fig. 6), barely 30 percent of Louisiana parishes ever had their surface geology mapped, most before 1960 and a majority before 1950.

The decline of surface geologic mapping in Louisiana is a direct result of the deCline of surface-mapping projects among university professors and their masters and doctoral geology students. In Louisiana all published parish geological bulletins (as defined in Fig. 6) to date have been authored solely by graduate students and faculty of the LSU Geology Department. The same person authored the latest (in press; "1991?" in Fig. 4) parish geological bulletin and Louisiana's last published (1960) parish geological bulletin. All unpublished parish geological investigations were authored by faculty and students ofLSU and other Louisiana universities.

155

en w J: C/)

iE « 0.. I.!...

10-

• PlbIished Mcp and Report (lGS)

11l1l~&il1ljl Mcp and Report In Press (lGS)

D PLblished M~, Report UnpLblished (LGS)

PLblished Mcp, No Surface Geologic Mcp (LGS)

k::}H ~~Jis=(E~rt~ Non-LGS)

o 5 0:: W m :E ::::> z 0-

1930 1940 1950 1960 1970 1980 1990 2000 LGS Y

FOUNDED EAR 1934

Figure 5. Frequency distribution of parish-geological investigations in Louisiana.

Because Louisiana has no tradition of state-supported geologic mapping outside of LSU, the conclusion is that the decline in academic mapping projects in Louisiana, predominantly those done under the aegis of LSU, directly caused the decline in surface geologic mapping in the state. The Louisiana example of waning production of surface geologic maps concurrent with declining academic mapping accords with the same trend in the rest of the U.S. but may be more pronounced. However, the history of exclusive reliance on academic mapping in Louisiana is atypical of that in other states (Newell 1989). The cause and effect relationship between the decline in academic mapping projects and in surface geologic mapping in general, here documented for Louisiana and postulated for the U.S. in part, indicates the need for a re-evaluation of the priorities given to surface geologic mapping in university geology departments and among traditional publishers of academic mapping results. The foregoing also makes it clear that, for the decline in geologic map production to be reversed, surface geologic mapping must be recognized as legitimate basic research in geology.

Acknowledgements Figures in this paper were made from slide copy drafted by Robert Paulsell and David McCraw.

References Committee Advisory to the u.s. Geological Survey, National

Research Council 1987. Geologic mapping in the U.S. Geological Survey. Washington, D.C.: National Academy Press. 22 pp.

Committee on Geologic Mapping, National Research Counci11988. Geologic mapping: future needs. Washington, D.C.: National Academy Press. 84 pp.

30

WW >(!) 20 -<!: t-t-<!:z ..J w =>0

~ ffi 10 o a..

__ -------------l1li

O+-~~----~~~~~~~F_~~~~

1930 1940 1950 1960 1970 1980 1990 2000 YEAR

Figure 6. Cumulative percentage (of a total of 64 parishes in Louisiana) of parishes for which geological bulletins, including both a report and 1 :62,500- or larger-scale surface geological map(s), have been published by LGS.

Cressman, E. R. and M. C. Noger 1981. Geologic mapping of Kentucky-a history and evaluation of the Kentucky Geological Survey-U .S. Geological Survey mapping program, 1960-1978. U.S. Geological Survey Circular 801. 22pp.

Hagan, W. W. 1961. Progress report of Kentucky areal geologic mapping program. pp. 11-20 in P. McGrain and T. J. Crawford, eds., Proceedings of the Technical Session Kentucky Oil and Gas Association Twenty-Fifth Annual Meeting. Kentucky Geological Survey, series 10, Special Publication 4.

Harrison, J. M. 1963. Nature and Significance of geological maps in C. C. Albritton, ed., The Fabric of Geology. Stanford, California: Freeman, Cooper & Company. 225-32.

Howe, H. V. and C. K. Moresi 1933. The contribution of Louisiana State University to the development of louisiana geology. Louisiana Conservation Review 3(2):23-33.

Mankin, C. J. 1988. Geologic mapping: will needs be met? Geotimes 33(11):6-7.

McCulloh, R. P. 1992. Surface geologic mapping in louisiana: history, present status, and future prospects. Openfile series no. 92-01. Baton Rouge: Louisiana Geological Survey (in press).

Newell, W. L. 1989. Personal communication. Reston, Virginia: U.S. Geological Survey.

Pope, D. E. 1988. History ofthe Louisiana Geological Survey in A. A. Socolow, ed., The State Geological Surveys: A History. American Association of State Geologists. 177-98.

156

Smath, M. 1. 1988. Kentucky survey's history & challenges. Geotimes 33(10):23-5.

U.S. Geological Survey 1987. National geologic mapping program: goals, objectives, and long-range plans. U.S. Geological Survey Circular 1020. 29 pp.

157

Distinctive Patterns in the Areal Distribution of Stream. Alluvium in North Louisiana

Richard P. McCulloh

Abstract Newly available 7.5' topographic quadrangles for most of north Louisiana illustrate the prevalence of an irregular areal distribution of Holocene stream alluvium characterized by pronounced bottlenecks of alluvial bottom lands in many places. These constrictions of alluvial bottoms are commonly abrupt and affect tributaries and trunk streams of all scales. Recompilation of alluvial mapping on 150+ 7.5' quadrangles at the 1:250,000 scale has indicated that alluvial bottlenecks show variable abundance with no consistent relation to flanking Tertiary or Pleistocene units. However, such bottlenecks appear relatively conspicuous where the gradational sequence between the Eocene Cook Mountain and Cockfield formations crops out over large areas, and where alluvium is flanked by the lower of two principal levels of Prairie terraces. The alluvial bottoms maintain their widths or widen downstream more nearly as expected if this next-higher Prairie surface in some areas is also considered bottomland. These associations indicate that Holocene streams have entrenched the pre-existing late-Pleistocene bottomland and the older units of the upland, but have not completely reworked them through lateral planation. The narrowing and widening of Holocene alluvial bottoms may reflect differential substrate competence of more clayey and sandy facies, respectively, in sub cropping older units. Alluvial mapping also reveals a potentially structural influence on alluvial stream courses in many places. This is reflected by straight reaches and pervasive rectangular (NW- and NEtrending) drainage patterns superposed on even some younger Pleistocene surfaces. The rectangular patterns and, in places, zig-zag courses suggest control by NW- and NEstriking sets of systematic joints and/or faults.

Introduction Two cooperative agreements of the Louisiana Geological Survey (LGS) with the U.S. Geological Survey (USGS) under the USGS COGEOMAP program provided an opportunity to develop mapping and recognition criteria for undi~:rentiated stream alluvium in upland areas of north LOUISIana. The data used were primarily newly available 7.5' topographic maps in the study areas, the Shreveport and Alexandria 1:250,000 quadrangles (Fig. 1). The contour interval of the maps is principally 10 feet, with supplementary 5-foot intervals in places. These photogrammetrically derived topographic maps provide detaile? coverage of the study are~s, over which previously only 15 coverage was largely avaII-

able. The level of detail of alluvial mapping permissible with the new topographic maps in north Louisiana is unprecedented, and indicates the commonness of proportionately tight bottlenecks in alluvial courses, and of rectangular networks of relatively long and straight alluvial courses suggestive of joint and/or fault control of stream courses.

Patterns of Alluvial Distribution in North louisiana

The mapping of Quaternary units in north Louisiana revealed pronounced bottlenecks in many of the Holocene alluvial bottoms (Fig. 1), and showed that such constrictions vary in abundance with no consistent relation to flanking older units. Noteworthy examples specifically occur along Bayou Dorcheat, Black Lake Bayou, Saline Bayou, Dugdemona River, Castor Creek, Bayou D' Arbonne, and Bayou de Loutre and their tributaries. The mapping also showed that the Prairie (Beaumont-equivalent) terraces comprise multiple surfaces, and indicated that two of these constitute the principal, subregion ally extensive levels as recognized by Smith and Russ (1974). Despite the lack of a frequency relationship between alluvial bottlenecks and flanking units, the most conspicuous constrictions of alluvial tracts are those flanked by deposits underlying the lower and younger of these two Prairie surfaces-hereafter referred to as the Prairie lower complex-and those in areas where the gradational sequence between the Eocene Coo~ Mountain (mudstone) and Cockfield (sandstone) formations crops out over large areas.

The close association of the more conspicuous alluvial constrictions with reaches flanked by the Prairie lower complex and the Cook Mountain-Cockfield transition suggests the pOSSibility of substrate control of this type of distribution. Muddy and sandy lithofacies in these older (but still poorly consolidated) deposits may control the areas of narrowing and widening, respectively, in the overlying alluvium. For example, the development may have aspects in common with the fluvial annexation of gravel-mined areas near the channel of the Amite River (in the Florida parishes of Louisiana) during flood stages (Mossa 1985). Sandy facies of the Holocene alluvial fill of the Amite River erode differentially relative to the finer-grained facies (Autin 1989), and mining preferentially exposes coarse-grained material to potential reworking and erosion within the Holocene flood plain. In north Louisiana, streams with Holocene alluvial bottlenecks apparently responded to a

158

~~~~~=~-;~ 2 MILES 2 KILOMETERS

)

Figure 7. Geology of Truxno 7.5' quadrangle, showing characteristic pattern of stream alluvium in north Louisiana. Eocene Cockfield Formation (Ecf) is based on mapping by l.E. Rogers (1987), lower surface of the Prairie terraces (Qpl) mapped by D.l. McCraw, alfuvium (Qal) mapped by the author.

759

50 MILES 50 KILOMETERS

Figure 2. Alluvial-course segments in north Louisiana characterized by relative straightness (discernible at 1 :500,000 scale) suggestive of structural control, and orientation frequency of segments. The outcrop of the Claiborne Group, redrawn and adapted here from Snead and McCulloh (1984), underlies most of these stream segments.

lowering of base level that led to incision of the alluvium into the pre-existing bottomland that now forms the Prairie lower complex. During downcutting and concurrent lateral planation, the coarser-grained lithofacies in this and older units may have been differentially reworked. The possibili ty of differential, substrate-dependent development of alluvial constrictions and widenings was not investigated for this preliminary description because of unavailability of detailed data on lithofacies distribution within areas underlain by the Prairie lower complex and the Cook Mountain-Cockfield transition interval. In such areas, testing for texture-dependent substrate control of alluvial constrictions and widenings will require subsurface data from wells deep enough to penetrate the Holocene alluvial fill. Regardless of possible con troIs on narrowing and widening of Holocene all uvium, the drastically different widths along alluvial tracts may represent a transient condition of incomplete reworking and filling accompanying early entrenchment. This is indicated by the mere 10,000 years since the beginning of the Holocene (Geological Society of America 1983).

The new 7.5' topographic maps of much of north Louisiana indicate another, potentially structural, influence on stream courses. TheCOGEOMAP-supportedinvestigationsentailed 1 :250,OOO-scale recompilation of mapping done on the new quadrangles. The maps show a pervasive rectilinear grain,

superposed on units ranging in age from Tertiary to even some younger Pleistocene surfaces, and indicate that many larger-order streams in north Louisiana have conspicuous straight reaches, straight alluvial bottoms, and rectangular drainage patterns. The most noticeable examples lie within the broad area of outcrop of the Wilcox and Claiborne Groups, and suggest influence by two sets (NW- and NEstriking) of systematic joints or faults. Some of the alluvium in Fig. 1 delineates straight bottoms with northeastward and northwestward trends, entrenched into the underlying Tertiary and Pleistocene units. In places the straight segments in a single course alternate orientations to form a zig-zag pattern; the most striking example of this pattern was observed on the Prairie lower surface west of Lake Bistineau in southern Bossier Parish. The orientation frequencyofthe larger-scale examples of straight stream courses (those discernible at 1:500,000) show two predominant trends, one northwestward and the other northeastward (Fig. 2). These trends are not obviously identical to the predominant northwestward and northeastward strikes of surface and subsurface faults, but the range of trends contains those strikes. However, streams in northeastern Louisiana do include straight segments with northwest trends showing a close correspondence to the northwest strikes of mapped subsurface faults in the same area. Structural control by joints or faults or both is the most plausible explanation of

160

these stream patterns. Streams draining the Wilcox Group outcrop of Sabine Parish appear to be unaffected by NW -and NE-striking surface faults mapped by Andersen (1960). This could reflect more of an influence on drainage by lithologic variability that is greater in the surface Wilcox than in the Claiborne, or by the higher dip on the southeastern flank of the Sabine uplift. Because any structures that may control alluvial bottomlands are obscured by them, and because the structures could have small vertical displacements near the surface, remote-sensing techniq ues may offer the most practicable means of checking for the presence of such structures.

Fisk (1944) discerned a prevalence of northwestward and northeastward trends shown by stream courses in Louisiana, but depicted exclusive control by a roughly orthogonal system of major faults. Saucier (1974) regarded structural controls as having had minimal (if any) influence on the distribution of Quaternary deposits north of the Mississippi deltaic plain, possibly as a cautionary response to Fisk's intrepid fault interpretations. Russ (1975) found limited evidence for fault control, but suggestive indications of regional fracture control, ofthe position and straightness of segments of the Red River valley and some tributaries in north Louisiana. Birdseye et al. (1988) made asimilar case for joint control of drainage patterns in both late-Pleistocene and Holocene sediments in southeastern Louisiana. Zimmerman (1992) adduced multiple lines of evidence in support of major NE- and NW-trending transcurrent fault zones propagated from deepseated basement rocks into younger strata subcropping beneath surficial alluvial deposits. He attributed the course alignments and direction changes of the Mississippi River and other streams in southeastern Arkansas-western Mississippi and eastern north Louisiana to these fault zones. The aerial radiometric map of Duval et al. (1989) shows NW- and NE-trending linear areas of moderate aeroradioactivity (1.5-2.5 ppm eU) in north Louisiana (Gundersen 1993). Documented occurrences of high indoor radon along fault and shear zones (Gundersen et al. 1993) suggest that these intersecting linear belts of moderate radioactivity could be associated with underlying joints and/or faults.

Acknowledgements This paper is abridged from a manuscript submitted to the Louisiana State University Basin Research Institute Bulletin. The work was supported by the U.S. Geological Survey, COGEOMAP program, under cooperative agreement numbers 14-08-0001-A0646 and 14-08-0001-A0878. W.]. Autin, D. J. McCraw, and ]. 1. Snead were co-compilers of the preliminary worksheets of the geology of Shreveport and Alexandria 1:250,OOO-scale quadrangles under these cooperative agreements. Paul Heinrich, Gerald Kuecher, William E. :Marsalis, and Ron Zimmerman reviewed the manuscript.

References Andersen, H. V. 1960. Geology of Sabine Parish. Geological

bulletin no. 34. Baton Rouge: Department of Conservation, Louisiana Geological Survey. 164 pp.

Autin, W.]. 1989. Geomorphic and stratigraphic evolution

of the middle Amite River valley, southeastern Louisiana. Ph.D. dissertation. Baton Rouge: Louisiana State UniverSity. 177 pp. plus appendices.

Birdseye, R. U., G. L. Christians, and ]. L. Olson 1988. Drainage lineaments in late Quaternary sediments Ascension and East Baton Rouge parishes, Louisiana. Abstract. Transactions of the Gulf Coast Association of Geological Societies 38:577.

Duval, ]. S., W. ]. Jones, F. R. Riggle, and]. A. Pitkin 1989. Equivalent uranium map of conterminous United States. Open-file report 89-478. Reston, Virginia: U.S. Geological Survey. 12 pp.

Fisk, H. N. 1944. Geological investigation of the alluvial valley of the lower Mississippi River. Vicksburg, Mississippi: U.S. Army Corps of Engineers. 78 pp.

Geological Society of America 1983. Geologic time scale. Map and chart series MC-50. Boulder, Colorado: Geological Society of America. One sheet.

Gundersen, L. C. S. 1993. Preliminary geologic radon potential assessment of Louisiana. In Schumann, R. R. (ed.), Geologic radon potential of EPA Region 6. Open-File Report 93-_. U.S. Geological Survey. 11 pp. (in press).

Gundersen, L. C. S., R. R. Schumann, and S.]. Wirth 1993. The USGS/EPA radon potential booklets: an introduction. In Schumann, R. R. (ed.), Geologic radon potential of EPA Regions 1-10. Open-File Report 93-_. U.S. Geological Survey. 36 pp. (in press).

Mossa,]. 1985. Management of floodplain sand and gravel mining. Pp. 321-328 in Association of State Floodplain Managers, Flood hazard management in government and the private sector: Proceedings of the ninth annual conference. Special publication no. 12. Boulder: University of Colorado Natural Hazards Research and Applications Information Center.

Rogers,]. E. 1981. Base of Cockfield with alluvium and Cook Mountain in the eastern part of the Shreveport quadrangle, Louisiana. Unpublished map. Scale 1:250,000.

Russ, D. P. 1975. The Quaternary geomorphology of the lower Red River Valley, Louisiana. Ph.D. dissertation. University Park: Pennsylvania State University. 208 pp. plus plates.

Saucier, R. T. 1974. Quaternary geology of the Lower Mississippi Valley. Research series no. 6. Fayetteville: Arkansas Archeological Survey. 26 pp.

Smith, F. L., and D. P. Russ 1974. Geological investigation of the Lower Red River-Atchafalaya Basin area. Technical report S-74-5. Vicksburg, Mississippi: U.S. Army Corps of Engineers Waterways Experiment Station.

Snead,]. I., and R. P. McCulloh (compilers) 1984. Geologic map of Louisiana. Baton Rouge: Louisiana Department of Natural Resources, Louisiana Geological Survey. Scale

161

1:500,000.

Zimmerman, R. K. 1992. Fractured Smackover Limestone in northeast Louisiana; implications for hydrocarbon exploitation. Transactions of the Gulf Coast Association of Geological Societies 42:401-12.

162

1993 FOP Contributors

Paul Albertson Corps of Engineers - Waterways Experiment Station Geotechnical Lab Box 631 Vicksburg, MS 39180-0631

Joe Alford 319 Deer Point Drive Gulf Breeze, FL 32561

Saul Aronow Consulting Geologist 5590 Frost Beaumont, TX 77706

Andres Asian Department of Geological Sciences University of Colorado Boulder, CO 80309-0250

Whitney J. Autin Louisiana Geological Survey Box G, University Station Baton Rouge, LA 70893

William J. Day Department of Agronomy (Formerly) Louisiana State University Baton Rouge, LA 70803

Paul V. Heinrich Dept. of Geology & Geophysics Louisiana State University Baton Rouge, LA 70803

Donald G. Hunter Coastal Environments, Inc. 1260 Main St. Baton Rouge, LA 70802

Joe Holmes Department of Environmental Quality Box 82263 Baton Rouge, LA 70884

David J. McCraw Center for Coastal, Energy, and Envronmental Resources Louisiana State University Baton Rouge, LA 70803

Richard P. McCulloh Louisiana Geological Survey Box G, University Station Baton Rouge, LA 70893

Bobby J. Miller (Deceased) Department of Agronomy Louisiana State University Baton Rouge, LA 70803

Joann Mossa Department of Geography University of Florida Gainesville, FL 32611

Charles E. Pearson Coastal Environments, Inc. , 260 Main St. Baton Rouge, LA 70802

Jim Rogers Consultant Geologist 4008 Innis Drive Alexandria, LA 71303

John Snead Louisiana Geological Survey Box G, University Station Baton Rouge, LA 70893

Arville Touchet Bayou Cajun Environmental Services Rt. 1, Box 1474 Abbeville, LA 70510

Mark Walthall Department of Agronomy Louisiana State University Baton Rouge, LA 70803

163

'::

ROAD lOG The accompanying road log Is designed to provide trip participants with route Information. The log Is also supplemented with scientific and general Information about the areas between trip stops. Each day's log begins In the Alexandria area near the trip headquaters and ends at the final field stop of the day. We will try to mark backwoods Intersections with a FOP arrow sign, look for theml


8:00 0.0 Assemble in Pizza Hut parking lot across MacArthur Drive from the FOP motels. The highway is under construction In this area. Be careful, adhere to all detour Information, and stay with the caravan. Leave the parking lot and head north, following US 71 and US 165.

1.7

2.5

3.7

5.0

9.7

11.0

17.5

18.6

22.5

23.0

28.2

9:00 29.4

11:00 30.5

31.5

32.0

37.1

42.0

48.8

50.0

54.0

Cross Red River bridge. Notice exposure of Miocene strata in the channel banks if the water Is low. This Is a remnant of the historic rapids, from which Rapides Parish obtained its name.

Pass Ft. Buhlow Lake.

junction of US 71 and US 165. Continue to the right on US 165N.

Junction of US 165 and US 167. Turn left onto US 167N.


Enter Grant Parish. From this point to Bentley, we will traverse the typical landscape of Fisk's Bentley Terrace.

Bentley. Continue north on US 167.

site of Bentley Core - RR 11 on left off Brister Loop road. Continue on US 167N.

Town of Dry Prong.

Cross LA 123. Continue north on US 167.

Turn right on Forest Service Road 122 (gravel road). Cross RR tracks and veer right.

STOP 1 at Wlillana Pit, site of Williana core- RR 22. This site Is National Forest property.

Return to US 167 and turn right (north) to Wililana.

Town of Willian a, turn left ~ caution light at abandoned store.

Bear left at liberty Chapel Road. Stay on main road. Look for FOP arrowsl

Turn right (west) onto LA 122 at Faircloth.

Bridges crossing latt Creek.

junction with LA 471. Veer right and stay with LA 122.

Village of New Verda. Stay on LA 122 to Montgomery.

Village of HargiS.

~ -.

'::

55.5

56.5

57.1

58.3

62.1

63.2

66.5

67.4

67.7

73.2

12:00 73.4

Upland Complex contact with Prairie Complex.

Cross Nantachle Bayou.

Ascend Intermediate Complex, Montgomery surface.

Junction with US 71 at Montgomery. Turn right (north) on US 71. Montgomery core site-RR 12 Is on left side of road across RR after making turn.

Enter Winn Parish. This Is the typical Montgomery Terrace landscape of Flsks' type area.

Classic, unleveled pimple mounds can be seen in the pasture on the right side of the road.

St. Maurice, Junction with LA 477. stay on US 71 N to Clarence.

Descend onto Holocene flood plain.

Cross Saline Bayou.

Clarence, Junction with US 84. Stay on US 71 N.

LUNCH STOP AT GRAYSON'S BBQ. Lunch on your own here, there Is a dining room Inside or you can tailgate outside. There Is also a convenience store close by.

1 :00 73.4 After lunch, head south on US 71 back to St. Maurice.

79.9 Turn right on LA 477 to St. Maurice RR cut. Look for FOP arrows on gravel roads.

1:15 80.6 STOP 2 at St. Maurice exposure. This site ison the private right-of-way of the railroad.

3:00 81.3 Return to US 71 and turn right (south).

84.7 Pimple mounds in pasture.

86.0 Grant Parish line.

89.0 Town of Montgomery.

96.5 Pass Wadell.

97.3 Cross Nantachle Bayou spillway.

99.0 Turn right on gravel road and cross RR. Head to Aloha Cemetary.

3:30 99.5 STOP 3 at Aloha Prairie. This site is private property.

5:00 100.0 Return to US 71, turn right (south).

104.0 The Rock at Junction of LA 158 and US 71. Behind Rock Garden Exxon is ~ classic exposure of the Oligocene Catahoula Sandstone. You can return directly to the Alexandria motels by continuing south on US 71. Or you can go directly to the social at Harold Miles Park by following LA 158 to Colfax, Joining with LA 8, and crossing the Red River to Boyce. From Boyce, follow LA 1 south towards Alexandria to the park which is on your right about six miles south of Boyce. Either route is less than 30 miles.

END DAY 1 LOG

DAY 2

TIME MILE FEATURE

8:00 0.0 Assemble in Pizza Hut parking lot across MacArthur Drive from the FOP motels. The highway is under construction In this area. Be careful, adhere to all detour Information, and stay with the caravan. Leave the parking lot and head north, following US 71 and US 165.

0.8 Head north on LA 1.

3.9 Junction with 1-49 and Air Base Road. Stay on LA 1.

4.8 Harold Miles Park on left. Stay on LA 1.

8.4 Stop light at Rapldes. Stay on LA 1.

12.5 Cross over 1-49.

13.6 Town of Boyce. Continue on LA 1 north. ,;-:

14.9 Pass junction with LA 121.

16.8 Turn right to Old Highway 1 at Texaco station. Proceed to stop sign and turn right.

17.7 Gate to Zimmerman Hili.

8:30 18.0 STOP 4 down the road beyond gate. This site is private property.

10:00 18.3 return up Old Highway 1 and turn left to LA 1

18.6 Junction with LA 1, turn left (south) onto LA 1.

20.5 Turn right on LA 121 and follow Bayou Jean de Jean.

25.8 Junction with LA 1200 west at Hot Wells. Stay with LA 121.

27.5 Junction with LA 1200 east to Boyce. Stay with LA 121. Antebellum home at Junction.

30.2 Junction with LA 1202 at McNutt. Take LA 1202 towards England Air Force Base.

32.2 Cross Bayou Rapldes at Lamonthe Bridge. LA 496 joins route.

35.7 Junction of LA 1202 and LA 496 at Well. Stay with LA 496.

37.6 Back gate to England Air Force Base. Enter base and go to STOP 5.

10:30 38.0 STOP 5 England Air Force Base. This site Is now municiapal property.

12:00 39.7 return to La. 496 and head east towards Alexandria.

40.8 Pass Kent House Antebellum Home.

,;-~

12:05 41.0 Junction with US 165 (MacArthur Drive). LUNCH BREAK. Fast Food Is available south on MacArthur Drive from this point. Grab a quick bite or pick up a bag lunch then follow US 71 N towards the Red River bridge. Stop 6 Is ten minutes away and has picnic tables.

1:00

2:00

42.4

43.6

44.6

45.4

46.7

48.8

54.6

57.7

62.5

69.0

Construction area. Veer north on US 71 to Red River Bridge.

Top of bridge. Cross Red River.

Turn left on to Ft. Buhlow Airport Road. Be careful, crossing trafficl

Turn right and cross RR. Enter Fort Buhlow Recreation Area. Picnic facilities are here.

STOP 6. Red River Landlng.Thls site Is public property.

Return to US 71. turn right and follow US 71 S towards Alexandria.

Traffic Circle. Stay on US 71 S (MacArthur Drive) through the city'.'

Cross 1-49. Stay on US 71 S.

Pass LSU at Alexandria campus.

Town of Lecompte (Lea's Diner Is known for It's fine pies (one of two Louisiana restaurants to get the highest rateing from The Underground Gourmet), you can stop here on your return to Alexandria In a couple of hours if you wish and grab a slice of pie and coffee).

72.0 Junction with US 167S at Meeker. Continue on US 71 S.

73.8 Turn right onto Lloyd's Bridge Road (sic). Pass under RR trestle.

2:45 74.5 STOP 7. Loyd's Hall. This site Is private property, tourists are welcome.

4:30 75.00 You can return to Alexandria via US 71 (the route the caravan took) or follow the old road along Bayou Bouef to see flood plain topography and historic plantation agricultural areas. The direct route Is less than 25 miles to the motels. Don't forget the lemon pie at Lea's!

END DAY 2 LOG

I~':


8:00 0.0 . Assemble in Pizza Hut parking lot across MacArthur Drive from the FOP motels. The highway is

0.5

1.9

2.1

2.9

4.1

9.3

15.7

17.8

19.5

23.0

24.4

25.5

9:00 26.0

10:00 26.6

27.4

30.0

35.0

35.5

36.0

37.0

10:30 37.1

12:00 37.5

under construction In this area. Leave the parking lot and head north, onto the construction traffic circie following US 71 and US 165. Watch for a quick right turn.

Turn right (south) on LA 1 S (Bolton Avenue). Follow Bolton Ave.into midtown Alexandria.

Veer left towards Pineville on LA 28 and US 165.

Turn left (south) on LA 28 and LA 1 (Overton St).

Cross Red River, enter Pineville.

Exit LA 107 (to Marksville). Turn right (south) on LA 107 and cross RR.

Junction with LA 3128. This is the highest point on the Day 3 road iog at 160 It elevation. Continue on LA 107 and cross the Intermediate Complex landscape to Kolin.

junction with LA 454 at Ruby. Stay with LA 107. Landscape Is the Holloway Prairie.

Enter Avoyelles Parish.

Town of Center Point.

junction with LA 115. Follow LA 115 towards Marksville.

Turn left on LA 1196 towards us Army Corps of Engineers Lock and Dam.

Turn right and cross levee. Enter Ben Routh Recreation Area. This site is a public park.

STOP 8- Monda Gap.

Return to LA 115. Turn left (south) to Marksville.

Cross Red River bridge.

Pass Monda Community center Road. Stay on LA 115.

Domestic buffalo in pasture on right.

Veer to left of Chevron Station on to S. Washington St.

junction with LA 1. Turn left (south).

Turn left Into the Tunica-Biloxi Indian Reservation. Property of the tribe.

STOP 9 - Avoyelles Prairie. Park at The Marksville Commemorative Area/museum.

This is the end of the 1993 FOP field trip. LA 1 North will return you to Alexandria and 1-49. LAl South will take you to Baton Rouge and 1-10 via New Roads and US 190E. If the weather is nice try taking the St. Francisville Ferry at New Roads across the Mississippi River and south via US 71 to Baton Rouge.

END DAY 3 LOG

Nancy Affeltranger Central Louisiana Archeological Chapter 8425 Fairway Dr Pineville, LA 71360

Saul Aronow Consulting Geologist 5590 Frost Beaumont, TX 77706

Whitney J. Autin Louisiana Geological Survey Box G, University Station Baton Rouge, LA 70893

Mark Bordelon Ringgold Soil Survey Box 528 Ringgold, LA 71068

Charli Braviderer Central Louisiana Archeological Chapter 1020 Oxford St Alexandria, LA 71301-5135

Lee Burras Department of Renewable Resources University of Southwestern Louisiana Lafayette, LA 70504

John Catches Department of Geology Turlington Hall University of Florida Gainesville, FL 32611

Michael C. Cooley USDA - SCS 3636 Government Street Alexandria, LA 71302

Ellis H. Denning Central Louisiana Archeological Chapter 129 Kathy Dr Pineville, LA 71360

Ida A. Dodge Central Louisiana Archeological Chapter 245 Milkyway Dr Pineville, LA 71360

Paul Albertson USCOE- WES Geotechnical Lab Box 631 Vicksburg, MS 39180-0631

Kenneth Ashworth Environmental Analysis Branch USCOE- NOD Box 60267 New Orleans, LA 70160

Andrew Barron Department of Agronomy Louisiana State University Baton Rouge, LA 70803

Bill Boyd Soil Survey 901 Ray St. Rayville, LA 71269

Ken Brown Texas Archeological Research Lab Baleones Research Center #5 10100 Burnett Road Austin, TX 78712-1100

David Carlson Anthropology Department Texas A&M University College Station, TX 77843-4352

John Caughlin 2426 Meadow Brook Drive Valdosta, GA 31602

John Craven Memphis State University JM Smith Building Memphis, TN 38152

D. Bruce Dickson Department of Anthropology Texas A&M University College Station, TX 77843

Jimmy Edwards USDA - SCS 3737 Government Street Alexandria, LA 71302

Thurman Allen SCS 1605 Arizona St. Monroe, LA 71202

Andres AsIan Department of Geological Sciences University of Colorado Boulder, CO 80309-0250

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(

Indiana Geological Survey

.. ~~~0:~~~:.a~~t4~~~~02~;u I/fte

Liz Brady Department of Geography 3141 Turlington Hall University of Florida Gainesville, FL 32611

Scott Burns Department of Geology Portland State University Portland, OR 97207-0751

Brian J. Carter Agronomy Department 160 Ag Hall Oklahoma State University Stillwater, OK 74078

Dominick (Nick) J. Cirincione Texas Archeological Society P.O. Box 363 Hurst, TX 76053

Jerry J. Daigle USDA - SCS 3737 Government Street Alexandria, LA 71302

Jeremy S. Dillon CURA Environmental 10207 N. MacArthur Blvd #319 Irving, TX 75063

Karen Edelvang Institute of Geography University of Copenhagen c\o University of Florida Gainesville, FL 32611 - 2083

~(/AV'lvi+(' V (i, I'c'V~v' ( C I , __ d_~ _________

C. Reid Ferring Box 13078 University of North Texas Denton, TX 76203

Jeffrey Girard Department of Social Sciences Northwestern State University Natchitoches, LA 71497

Peggy Guccione Geology Department OH-118 University of Arkansas Fayetteville, AR 72701

Thomas C. Gustavson Bureau of Economic Geology University of Texas at Austin Austin, TX 78713

Helen Hickman Centenary College 743 Stephenson St. Shreveport, LA 71104

Wayne Hudnall Department of Agronomy Louisiana State University Baton Rouge, LA 70803

Juana L. C. Ibanez Department of Geography University of Texas at Austin Austin, TX 78712-1098

Harold Jeansonne Central Louisiana Archeology Club 1819 Simmons st. Alexandria, LA 71301

Daniel Johnson USDA-SCS Denham Springs, LA

Misehclle Julien 7627 Rambler #151 Dallas, TX 75231

, . Judith Gennett Geology Department Texas A&M University College Station, TX 77843

Charles Ray Givens Department of Earth Science Nicholls State University Thibodaux, LA 70310

Fran P. Guchereau 1913 Military Hwy. Pineville, LA 71360

Stephen A. Hall Department of Geography University of Texas at Austin Austin, TX 78712-1098

Joe Holmes Department of Environmental Quality Box 82263 Baton Rouge, LA 70884

Paul Hudson Department of Geography 3141 Turlington Hall University of Florida Gainesville, FL 32611

Missy Jackson Bureau of Economic Geology University of Texas at Austin Austin, TX 78713

Lillie Jeansonne Central Louisiana Archeology Club 1819 Simmons St. Alexandria, LA 71301

David L. Jones USDA - SCS 100 W Capitol St, Suite 1321 Jackson, MS 39269

Christopher J. Jurgens Texas Water Development Board Box 13231 Austin, TX 78711-3231

Emma Day-Gennett Geology Department Texas A&M University College Station, TX 77843

Paul Gonzales Department of Civil Engineering University of Florida Gainesville, FL 32611

Charles M. Guillory USDA - SCS 3636 Government Street Alexandria, LA 71302

Paul V. Heinrich Dept. of Geology & Geophysics Louisiana State University Baton Rouge, LA 70803

Linda L. Horn Department of Geology University of Florida 1112 Turlington Gainesville, FL 32611

Donald G. Hunter Coastal Environments, Inc. 1260 Main St. Baton Rouge, LA 70802

David Jeane Louisiana Archeological Society 305 Hickory Springhill, LA 71075-2633

Martha E. Jenkins UT Austin 3517 North Hills Dr #C105 Austin, TX 78731

Dennis Jones CCEER Special Programs Louisiana State University Baton Rouge, LA 70803

Salvatore Kaburungu Department of Agronomy Louisiana State University Baton Rouge, LA 70803

Christine Kellam University of Texas at Austin 303 Cedarbrook Court Austin, TX 78753-2107

Richard H. Kesel Dept. of Geography & Anthropology Louisiana State University Baton Rouge, LA 70803

Darwin Knochenmus 4584 Cooper Lane Jackson, LA 70748

Alma Larsen Department of Geological Sciences Memphis State University Memphis, TN 38152

Brad Lee Agronomy Department 162 Ag Hall Oklahoma State University Stillwater, OK 74078-0507

Jocelyn Louissaint Department of Agronomy Louisiana State University Baton Rouge, LA 70803

Richard P. McCulloh Louisiana Geological Survey Box G, University Station Baton Rouge, LA 70893

Toni F. McLaughlin Hawkwind Farms 16591 Old Scenic Hwy Zachary, LA 70791

Joann Mossa Department of Geography 3141 Turlington Hall University of Florida Gainesville, FL 32611

Lee Nordt Department of Soil and Crop Sciences Texas A & M University College Station, TX 77843-2474

Kate Kelly Memphis State University 130 N. McLean, Apt. 2 Memphis, TN 38104

W. Wayne Kilpatrick USDA-SCS 216B Broadway St Minden, LA 71055

Fred K. Kring Louisiana Geological Survey Box G, University Station Baton Rouge, LA 70893

Lisa Laurents Department of Geography 3141 Turlington Hall University of Florida Gainesville, FL 32611

Paul H. Lehman Department of Geography University of Texas at Austin Austin, TX 78712-1098

Jeff Lower Department of Geography 3141 Turlington Hall University of Florida Gainesville, FL 32611

J. B. McHam Department of Geological Sciences Louisiana Tech University Ruston, LA

Chris Meindl Department of Geography 3141 Turlington Hall University of Florida Gainesville, FL 32611

John J. Musser 1863 Tudor Drive Baton Rouge, LA 70815

Larry Oshins Department of Geography 3141 Turlington Hall University of Florida Gainesville, FL 32611

Anne C. Kerr UT-TARL 8524 Burnet Road #621 Austin, TX 78757-7058

James Knight Memphis State University 605 Patterson # 3 Memphis, TN, 38111

Jenny Konwinski Department of Geography 3141 Turlington Hall University of Florida Gainesville, FL 32611

Codi Lazar Department of Geography 3141 Turlington Hall University of Florida Gainesville, FL 32611

Michal E. Lilly USDA - SCS 100 W Capitol St, Suite 1321 Jackson, MS 39269

David J. McCraw CCEER Special Programs Louisiana State University Baton Rouge, LA 70803

Sean C. McLaughlin Rust Environment and Infrastructure 8919 World Ministry Ave Suite 201 Baton Rouge, LA 70810

June Mirecki Department of Geological Sciences Memphis State University Memphis, TN 38134

Rick Naus Department of Geography 3141 Turlington Hall University of Florida Gainesville, FL 3261i

William B. Patterson Department of Agronomy Louisiana State University Baton Rouge, LA 70803

. '

Charles E. Pearson Coastal Environments, Inc. 1260 Main St. Baton Rouge, LA 70802

Donna Porter Agronomy Department Kansas State University Throckmorton Hall Manhattan, KS 66506

Richard S. Rhodes II Department of Geology University of Iowa Iowa City, IA 52242

Francisca Saavedra Department of Geography 3141 Turlington Hall University of Florida Gai/lesville, FL 32611

Joe Saunders Department of Geoscience Northeastern Louisiana University Monroe, LA 71209

Sue K. Smith Department of Geography Louisiana State University 11888 Longridge Dr., Apt. 1011 Baton Rouge, LA 70816

Darwin Spearing Mountain Press 11300 Regency Green #203 Cypress, TX 77429

Donald Charles Stem mans USDA - SCS Box 2062 Tunica, MS 38676

Camille Throckmorton Department of Geography 3141 Turlington Hall University of Florida Gainesville, FL 32611

Dru Trahan Ecotech, Inc. 5420 Corporate Blvd. Suite 201 Baton Rouge, LA 70808

Tim Phillips Kisatchie National Forest 760 Wild Cherry Lane Breaux Bridge, LA 70518

Jennifer Rahn Department of Geography 3141 Turlington Hall University of Florida Gainesville, FL 32611

Jim Rogers Consultant Geologist 4008 Innis Drive Alexandria, LA 71303

Neil Salisbury Geography Department University of .oklahoma Norman, .oK 73019

A. Frank Servello Enviro - Archaeo 234 Rue Beauregard Lafayette, LA 70508

John Snead Louisiana Geological Survey Box G, University Station Baton Rouge, LA 70893

Thomas W. Stafford INSTAAR University of Colorado Boulder, ca 80309-0450

Michael E. Stout Environmental Analysis Branch New .orleans District, CaE Box 60267 ATTN: CELMN-PD-RN New .orleans, LA 70160-0267

Richard S. Toomey III Illinois State Museum 1920 South 10 1/2 St Springfield, IL 62703

Julieann Van Nest Geology Department University of Iowa lo\va City, IA 52242

David E. Pope Louisiana Geological Survey Box G, University Station Baton Rouge, LA 70893

Lori Reed Tarrant County Junior College 828 Jane Lane Weatherford, TX 76086

E. Moye Rutledge Agronomy Department PTSC-115 University of Arkansas Fayetteville, Arkansas 72701

Kelly Salisbury Geography Department University of .oklahoma Norman, .oK 73019

Sara Shake University of Texas at Austin 4707 A Caswell Ave Austin, TX 78751

C. J. Sorenson Department of Geography 213 Lindley Hall University of Kansas Lawrence, KS 66045

Mary Evelyn Starr Garrow and Assoc. 510 S. Main Memphis, TN 38103

Willie J. Terry USDA - SCS Box 817 Tunica, MS 38676-0817

Arville Touchet Bayou Cajun Envionmental Services Rt. 1, Box 1474 Abbeville, LA 70510

Ralph D. Vinson Strecker Museum - Baylor Univ. Rt. 3, Box 680-M Whitney, TX 76692

Mark Walthall Department of Agronomy Louisiana State University Baton Rouge, LA 70803

Nancy Washer School of Music 2567 Rhododendron Ave. Baton Rouge, LA 70808

Don Wyckoff Oklahoma Archeological Survey 130 South Sherry Norman, OK 73069

Matt Zorn Department of Geography 3141 Turlington Hall University of Florida Gaipesville, FL 32611

Larry Ward SCS Room 5404 Federal Bldg. 700 West Capitol Ave. Little Rock, AR 72201-3225

Suzanne Webb Geology Department OH-118 University of Arkansas Fayetteville, AR 72701

Elaine Yodis Nicholls State University Department of Earth Science Box 2189 Thibodaux, LA 70310

Phillip Ward III Agronomy Department 162 Ag Hall Oklahoma State University Stillwater, OK 74078-0507

Beth Wilder Department of Geography 3141 Turlington Hall University of Florida Gainesville, FL 32611

Janet M. Young Department of Geological Sciences Campus Box 521047 Memphis State University Memphis, TN 38134

Geomorphology and Geoarchaeology of the Red River Valley, Louisiana 400DPI

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Transcript of Geomorphology and Geoarchaeology of the Red River Valley, Louisiana 400DPI