GEOLOGIC MAP OF THE CORONA NORTH 7.5 ...Santa Ana Mountains to southwest, marine fossil-bearing...
1
CORRELATION OF MAP UNITS U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 02-22 Prepared in cooperation with the CALIFORNIA DIVISION OF MINES AND GEOLOGY GEOLOGIC MAP OF THE CORONA NORTH 7.5' QUADRANGLE, RIVERSIDE and SAN BERNARDINO COUNTIES, CALIFORNIA Base from U.S. Geological Survey 7.5' Corona North quadrangle, 1967 Polyconic projection Geology mapped by D.M. Morton, 1995; and C.H. Gray, Jr., 1975 1 0 1 MILE 1 2 1 KILOMETER 0 .5 1 CONTOUR INTERVAL 20 FEET SCALE 1:24,000 GN MN 15 DESCRIPTION OF MAP UNITS MODERN SURFICIAL DEPOSITS—Sediment recently transported and deposited in channels and washes, on surfaces of alluvial fans and alluvial plains, and on hillslopes. Soil-profile development is non-existent. Includes: Artificial fill (late Holocene)—Deposits of fill resulting from human construction or mining activities; restricted to three noncontiguous areas (1) south of 91 Freeway, (2) on Norco Navel Reservation, and (3) sand and gravel mining in Santa Ana River channel Very young wash deposits (Holocene)—Deposits of active alluvium; confined to main channel of Santa Ana River. Consists mostly of unconsolidated sand and gravel in river channel. Sediment subject to localized reworking mainly during winter months. YOUNG SURFICIAL DEPOSITS—Sedimentary units that are slightly consolidated to cemented and slightly to moderately dissected. Alluvial fan deposits (Qyf series) typically have high coarse:fine clast ratios. Younger surficial units have upper surfaces that are capped by slight to moderately developed pedogenic-soil profiles (A/C to A/AC/B/C ox profiles). Includes: Young wash deposits (Holocene and late Pleistocene)—Sand, gravel and boulder deposits. Young alluvial fan deposits (Holocene and late Pleistocene)—Gray-hued sand and cobble- and gravel-sand deposits derived from lithic diverse sedimentary units. Deposits north of Santa Ana River (Qyf a ) consist of gray-hued, unconsolidated, arkosic sand derived from varied metamorphic and granitic lithologies in San Gabriel and San Bernardino Mountains north and east of quadrangle. May contain lesser interdigitated sedimentary wedges from Peninsular Ranges sources to south. Unit shows slight coarsening toward mountains to north. South of Temescal Wash, unit is mostly cobble- to granule- sized gravel. Locally, young alluvial fan deposits are divided into subunits based on sequential terrace development and other factors; one such unit is found in quadrangle: Young alluvial fan deposits, Unit 1 (Holocene and late Pleistocene)—Consists of pale-gray, unconsolidated, cobble- to granule- sized gravel. Restricted to single fan flanked by two younger Qyf fans in southern part of quadrangle. Forms older part of Qyf unit Young alluvial channel deposits (Holocene and late Pleistocene)—Gray, unconsolidated alluvium consisting of medium- to fine-grained sand and lesser silt flooring Temescal Wash and several of its tributaries in the southwestern part of quadrangle. North of Santa Ana River, includes sediments in Mill Creek drainage Young eolian deposits (Holocene and late Pleistocene)—Sand dune deposits, inactive except for very minor amount of sediment movement during Santa Ana wind storms. Chiefly unconsolidated, moderately well sorted, fine- to medium-grained sand OLD SURFICIAL DEPOSITS—Sedimentary units that are moderately consolidated and slightly to moderately dissected. Older surficial deposits have upper surfaces that are capped by moderately to well-developed pedogenic soils (A/AB/B/C ox profiles and Bt horizons as much as 1 to 2 m thick and maximum hues in the range of 10YR 5/4 and 6/4 through 7.5YR 6/4 to 4/4 and mature Bt horizons reaching 5YR 5/6). Includes: Old wash deposits (late to middle Pleistocene)—Consists chiefly of sand. Gray to reddish-brown, unconsolidated to slightly indurated. Restricted to single occurrence flanking north side of Santa Ana River southwest of Mira Loma Old alluvial fan deposits (late to middle Pleistocene)—Indurated, sandy alluvial fan deposits, except south of 91 Freeway in south-central part of quadrangle where unit is predominantly gravel. Covers extensive areas south of Santa Ana River, commonly at base of steep bedrock slopes. North of Santa Ana River, found in and east of Mira Loma. Most of unit is slightly to moderately dissected and reddish-brown. Some Qof includes thin, discontinuous surface layer of Holocene alluvial fan material. Includes: Old alluvial fan deposits, Unit 1 (middle Pleistocene)—Indurated, gravely alluvial fan deposits. Most are slightly to moderately dissected; reddish-brown. Some deposits include thin, discontinuous surface layer of Holocene alluvial fan material. In quadrangle, restricted to single 5 km 2 fan west of Corona Old alluvial channel deposits (late to middle Pleistocene)—Alluvial deposits consisting mainly of sand, but containing minor gravel and silt. Gray to reddish-brown, unconsolidated to indurated. Generally slightly dissected. Restricted to two isolated occurrences east and west of Mira Loma on north side of Santa Ana River Old alluvial valley deposits (late to middle Pleistocene)—Fluvial deposits along valley floors. Consists of moderately indurated, commonly slightly dissected sandy alluvium, containing lesser silt, and clay-bearing alluvium. Some deposits include thin alluvial deposits of Holocene age. Restricted to area between La Sierra and Home Gardens in southeastern part of quadrangle VERY OLD SURFICIAL DEPOSITS—Sediments that are slightly to well consolidated to indurated, and moderately to well dissected. Upper surfaces are capped by moderate to well developed pedogenic soils (A/AB/B/C ox profiles having Bt horizons as much as 2 to 3 m thick and maximum hues in the range 7.5YR 6/4 and 4/4 to 2.5YR 5/6) Very old alluvial fan deposits (early Pleistocene)—Mostly well-dissected, well-indurated, reddish-brown sand deposits. Commonly contains duripans and locally silcretes. Forms large area east of Norco generally flanking steep bedrock slopes. North of Santa Ana River, forms broad area that is part of fans emanating from Puente Hills west of quadrangle Very old alluvial channel deposits (early Pleistocene)—Gravel, sand, and silt; reddish-brown, well-indurated, surfaces well-dissected. Underlies large area between Santa Ana River and Temescal Wash Late Cenozoic sedimentary rocks in Norco area (early Pleistocene to late Pliocene?)—Moderately indurated sandstone, conglomeratic sandstone, and conglomerate. In Norco area, unit includes locally derived clasts as well as clasts derived from San Bernardino Mountains. Found in and west of Norco, on both sides of Santa Ana River Sandstone of Norco area (Pliocene)—Poorly exposed, unnamed, marine sandstone. Forms isolated areas of outcrop south of Norco and north of Temescal Wash. Unconsolidated, greenish-yellow sandstone having sparse conglomerate lenses. Locally contains abundant, poorly preserved shallow marine fossils including Anadara cf. A. trilineata (Conrad), Chione sp., Lucinoma cf. L. annulata (Reeve), and Diodora sp. (J.D. Mount, per. commun., 1973). Unit may represent shallow- water eastward extension of Fernando Formation. Sparse conglomerate lenses include clasts of exotic silicic volcanic rocks. In places, ash of Taylor Canyon (per. commun., A.M. Sarna-Wojcicki, 1990) at base of formation is nonconformably buttressed against granitic rock. Ash deposited on granite are interpreted be tide pool deposits. Age of ash is 2.6 Ma Contact—Generally located within ±15 meters Fault—High angle. Strike-slip component on all faults is right-lateral; dip-slip component is unknown, but probably reflects valley-highland relations. Dashed where located within ±30 meters; dotted where concealed; queried where existence questionable. 70 Strike and dip of beds Inclined Qw Qyf Qvof Puente Formation (early Pliocene and Miocene)—Marine sandstone, siltstone, and shale. Named by Eldrige and Arnold (1907) for exposures in Puente Hills. English (1926) extended distribution of Puente Formation to area south of Puente Hills, subdividing three units, from youngest to oldest, (1) shale, sandstone, and conglomerate (2) sandstone, and (3) shale. Daviess and Woodford (1949) subdivided Puente Formation in northwestern Puente Hills into four members, from youngest to oldest, (1) Sycamore Canyon Member, (2) upper siltstone ember, (3) sandstone member, and (4) lower siltstone member. Schoellhamer and others (1954) later designated formalized member names that are in current usage. Only Sycamore Canyon Member found in quadrangle; restricted to single locality in southwestern corner: Sycamore Canyon Member (early Pliocene and Miocene)— Predominantly sandstone and pebble conglomerate. Sycamore Canyon Member is laterally variable, composed of varying amounts of pale gray, thick-bedded to massive, medium- to coarse-grained, friable sandstone; pale gray, thin-bedded, siliceous siltstone; pale gray, poorly bedded siltstone, and brownish-gray, massive conglomerate. Elsewhere contains bathyal depth foraminiferal fauna (Yerkes, 1972) Vaqueros and Sespe Formations, undifferentiated (early Miocene, Oligocene, and late Eocene)—Interbedded marine and nonmarine sandstone and conglomerate assigned to the Vaqueros and Sespe Formations. Occurs only in southwestern corner of quadrangle. In Santa Ana Mountains to southwest, marine fossil-bearing strata of Vaqueros Formation are bed-by-bed interlayered with nonmarine rocks of Sespe Formation to degree that formations cannot be mapped as separate units. Undifferentiated unit locally includes boulder conglomerate (Woodford and others, 1973) Micropegmatite granite of Gavilan Ring Complex (Cretaceous)—Fine- grained, pink-tinted, leucocratic granite having distinctive micropegmatitic texture. Restricted almost entirely to Corona North quadrangle. Forms elongate band of outcrops between Corona and Norco. Underlies about 3 km 2 Micropegmatite and granodiorite of Cajalco pluton, undifferentiated (Cretaceous)—Mixed unit of micropegmatite and massive granodiorite to monzogranite. Micropegmatite is fine grained and granodiorite to monzogranite is medium to coarse grained. Found southwest and southeast of Norco. Rocks probably related to, but not mapped as part of Cretaceous Cajalco pluton Granite of the Riverside area (Cretaceous)—Medium- to coarse-grained, massive- to faintly-foliated, leucocratic biotite granite. Contains about 1 to 3 percent biotite. Inclusions are sparse or absent except locally in western part of body where granite contains 2 to 8 percent biotite and sparse to abundant inclusions of quartz diorite, granodiorite, and fine- grained mafic rock. At Mount Rubidoux, east of quadrangle, rocks contain sparse hypersthene and fayalitic olivine and moderately abundant equant inclusions of dark-gray fine-grained rock. Rock at Mount Rubidoux termed "fine leucogranite of Rubidoux Mountain" by Larsen (1948). Restricted to a single outcrop at east edge of quadrangle south of La Sierra Heights Mount Hole Granodiorite (Cretaceous)—Massive, hornblende-biotite granodiorite. Medium- to coarse-grained; structureless. Moderately leucocratic compared to most hornblende-bearing rocks in region. Weathers to form large boulders of disintegration. Named by Larsen (1948) for exposures at Mount Hole, east of Norco. Forms narrow, roughly tabular body several kilometers long between Norco and La Sierra, and a smaller body 0.7 km to the east La Sierra Tonalite (Cretaceous)—Massive biotite tonalite. Fairly dark- colored compared to other units in region containing no hornblende, but alteration found in much of rock tends to darken it. Medium- to coarse- grained; structureless. Much of tonalite is altered to secondary minerals, especially epidote and chlorite, and contains localized zones that are thoroughly altered to epidote, quartz, and chlorite; some highly altered rocks contain tourmaline and sulfide minerals. Large body exposed west of La Sierra and larger mass, partly covered by Quaternary deposits, underlies Norco area. Named by Larsen (1948) for exposures in vicinity of La Sierra. Cajalco pluton (Cretaceous)—Mostly biotite and hornblende-biotite monzogranite and granodiorite. Informally named for exposures in Cajalco area, Lake Mathews 7.5’ quadrangle (Morton, 1999). Rocks of Cajalco pluton were included within Cajalco quartz monzonite by Dudley (1935) and within Woodson Mountain granodiorite by Larsen (1948). Body is composite, shallow-level pluton emplaced by magmatic stoping within largely volcanic and volcanoclastic rocks. It was tilted eastward and eroded to progressively greater depths from west to east. Southeast of quadrangle, upper part of pluton contains very prominent halo of highly tourmalinzed rock. Zircon ages are 109.5 Ma id and 112.6 Ma ip (pers comm Premo, 1998). Within quadrangle includes: Monzogranite—Western part of pluton, including rocks in Corona North quadrangle, typically is medium-grained, equigranular, hypauto- morphic-granular to subporphyritic monzogranite and subordinate granodiorite. Includes irregularly variable amounts of angular inclusions mostly, if not entirely, derived from stoping of Cretaceous Estelle Mountain volcanics. Number, size, and reliability of identity of inclusion parent rock increases from east to west. In western part of pluton, included masses of volcanic rock comprise large volume of pluton. In northern and northeastern part of pluton stoped masses of hornblende gabbro are abundant. Granodiorite and gabbro, undifferentiated—Mixed granodiorite and gabbro. In quadrangle, restricted to single area of exposure near southeastern corner where granitic rock contains high concentrations of stoped hornblende gabbro. In some areas, including Corona North quadrangle, granite and gabbro are intimately intermixed producing very heterogeneous rock Quartz diorite (Cretaceous)—Medium- to coarse-grained biotite- hornblende quartz diorite. Most is slightly to well foliated and contains discoidal to pancake-shaped melanocratic inclusions in foliation plane. Grades into diorite and biotite-hornblende tonalite. Exposed around and north of La Sierra Heights Diorite, undifferentiated (Cretaceous)—Mostly fine-to medium-grained, massive, dark gray to nearly black hornblende diorite. Forms approximately 1 km 2 mass northwest of Home Gardens in southeastern part of quadrangle Gabbro (Cretaceous)—Mainly hornblende gabbro. Includes Virginia quartz-norite and gabbro of Dudley (1935), and San Marcos gabbro of Larsen (1948). Typically brown-weathering, medium-to very coarse- grained hornblende gabbro; very large poikilitic hornblende crystals are common, and locally gabbro is pegmatitic. Much of unit is quite heterogeneous in composition and texture. Includes noritic and dioritic composition rocks. Exposed west of La Sierra Heights On many SCAMP geologic map plots, including the Corona North 7.5' quadrangle, characteristic grain size information is displayed using subscripted alpha characters (e.g. Qyf g , Qov a ), where the characters conform to the following definitions: a - arenaceous (very coarse sand through very fine sand) b - boulder gravel (>25mm) g - gravel (cobble through granule gravel) s - silty c - clayey m- marl p - peat 1 2,3 Version 1.0 By Douglas M. Morton and C.H. Gray, Jr. Digital preparation by Kelly R. Bovard and Michael Dawson 1 1 Qya science for a changing world science for a changing world 117 37' 30" 34 00' 117 30' 34 00' 117 30' 33 52' 30" 117 37' 30" 33 52' 30" QUATERNARY CENOZOIC Holocene Pleistocene TERTIARY Qw Qyf CRETACEOUS Pliocene Qya Qaf Qof Qaf ? Qoa Kgb Kmhg Kqd Krg Qof Qyf 1 Qye Qow Qof 1 Qoa Qvoa Qov SURROUNDING 7.5' QUADRANGLES Corona North 7.5' Riverside West Prado Dam Lake Mathews Black Star Canyon Corona South Ontario Guasti Fontana In the Description of Map Units, the Ma following U/Pb ages has an attached subscript; Ma id for isotope dilution analyses, and Ma ip for ion probe analyses. Qow Qyf 1 Qye Qof 1 Qov QTn Qvoa Tpsc Tvs Tns Kcg Klst Kd Kmhg Kcg QTn Tns Miocene Eocene MESOZOIC Qvof Kmp Tpsc Kmpc Krg Tvs Kmp o o o o o o o o o Classification of plutonic rock types (from IUGA, 1973, and Streckeisen, 1973). A, alkali feldspar; P, plagioclase feldspar; Q, quartz. Quartz Syenite Quartz Monzonite Quartz Monzodiorite Syenite Monzonite Monzodiorite Granite Alkali-feldspar Granite Tonalite Diorite Syenogranite Granodiorite Monzogranite Quartz Diorite 90 65 35 10 5 20 60 Q Q A P 60 20 5 60 Kgb Kqd GEOLOGIC SUMMARY The Corona North quadrangle is located near the northern end of the Peninsular Ranges Province. All but the southwestern tip of the quadrangle is within the Perris block, a relatively stable, rectangular in plan, area located between the Elsinore and San Jacinto fault zones. The southwestern tip of the quadrangle is marginally within the Chino fault zone. Cretaceous plutonic rocks that are part of the composite Peninsular Ranges batholith underlie most of the quadrangle. These rocks are exposed in a roughly triangular-shaped area bounded on the north by the Santa Ana River and on the south by Temescal Wash, a major tributary of the Santa Ana River. A variety of mostly intermediate composition granitic rocks occur in the quadrangle, mainly monzogranite and granodiorite, but ranging from micropegmatitie granite to gabbro. Most rock units are massive and contain varying amounts of meso-and melanocratic, equant-shaped inclusions. The most widespread granitic rock is monzogranite of the Cajalco pluton, a large composite intrusion that extends some distance south and east of the quadrangle. North of Corona is a body of micropegmatite that appears to be unique in the batholith rocks. Diagonally bisecting the quadrangle is the Santa Ana River. North of the Santa Ana River alluvial deposits are dominated by the distal parts of alluvial fans emanating from the San Gabriel Mountains north of the quadrangle. Widespread areas of the fan deposits are covered by a thin layer of wind blown sand. Alluvial deposits in the triangular-shaped area between the Santa Ana River and Temescal Wash are quite varied, but consist principally of locally derived older alluvial fan deposits. These deposits rest on remnants of early Quaternary to late Tertiary age, nonmarine sedimentary deposits that were derived from both local sources and sources as far away as the San Bernardino Mountains. These deposits in part were deposited by an ancestral Santa Ana River. Several non- contiguous remnants of late Tertiary (Pliocene) marine sandstone that include some conglomerate lenses are scattered through the area between Norco and Temescal wash. Clasts in the conglomerate lenses include siliceous volcanic rocks exotic to this part of southern California. This sandstone was deposited as the southeastern-most part of the Los Angeles sedimentary marine basin and were deposited along a rocky shoreline developed in the granitic rocks, much like the present day shoreline at Monterey, California. Most of the sandstone and granitic paleoshoreline features have been removed by quarrying and grading in the area between Porphyry and Highway 91. However, excellent exposures of the paleoshoreline features are in highway road cuts on the north side of Highway 91 just east of the 91-15 interchange and on the east side of U.S. 15 just north of the interchange. South of Temescal Wash, a series of both younger and older alluvial fan deposits emanate from the Santa Ana Mountains southeast of the quadrangle. In the southwesternmost corner of the quadrangle is a small exposure of sandstone and pebble conglomerate of the Sycamore Canyon member of the Puente Formation of early Pliocene and Miocene age and sandstone and conglomerate of undivided Vaqueros and Sespe Formations of early Miocene, Oligocene, and late Eocene age. REFERENCES Daviess, S.N., and Woodford, A.O., 1949, Geology of the northwestern Puente Hills, Los Angeles County, California: U.S. Geological Survey Oil and Gas Investigation, Preliminary Map 83. Dudley, P.H., 1935, Geology of a portion of the Perris block, southern California: California Jour. of Mines and Geology. v. 31, no. 4, p. 487- 506. Eldridge, G. H., and Arnold, R., 1907, The Santa Clara Valley, Puente Hills, and Los Angeles oil districts, southern California: U.S. Geol. Survey Bull. 309, 266 p. English, W.A. 1926, Geology and oil resources of the Puente Hills Region, California: U.S. Geol. Survey Bull. 768. 110 p. Larsen, E.S., 1948, Batholith and associated rocks of Corona, Elsinore, and San Luis Rey quadrangles, southern California: Geol. Soc. of America Mem. 29, 182 p. Morton, D. M., 1999, Preliminary digital geologic map of the Santa Ana 30' X 60' quadrangle, southern California: U.S. Geological Survey Open- File Report 99-172, 61p., scale, 1:100,000 Rogers, T.H., 1965, Santa Ana sheet: California Division of Mines and Geology geologic map of California, scale, 1:250,000. Schoellhamer, J.E., Kinney, D.M., Yerkes, R.F. and Vedder, J.G., 1954, Geologic map of the northern Santa Ana Mountians, Orange and Riverside Counties, California: U.S. Geol. Survey Oil and Gas investigations Map OM 154, scale, 1:24,000. Streckeisen, A.L., 1973, Plutonic rocks—Classification and nomenclature recommended by the IUGA Subcommission on Systematics of Igneous Rocks: Geotimes, v. 18, p. 26-30. Woodford, A.O., McCulloh, T.H., and Schoellhamer, J.E., 1973, Paleographic significance of metatuff boulders in middle Tertiary strata, Santa Ana Mountains, California: Geol. Soc. America Bull. v. 83, no. 11, p. 3433-3436. Yerkes, R.F., 1972, Geology and oil resources of the western Puente Hills area, southern California: U.S. Geol. Survey Prof. Paper 420-C, 63 p. Klst Qyw Kd Kcgb 1 U.S. Geological Survey Department of Earth Sciences University of California Riverside, CA 92521 California Division of Mines and Geology 107 South Broadway Los Angeles, CA 90012 3 Deceased 2 Kcgb Kmpc Qyw 65 104 98 95 11 5 108 103 114 1 01 94 11 6 110 109 109 109 96 102 104 95 90 96 93 9 2 100 102 95 94 10 3 94 108 1 08 82 87 87 86 8 6 81 88 88 8 6 8 6 88 87 86 83 85 85 90 91 91 90 92 88 85 81 84 84 79 73 71 68 71 73 80 61 60 63 66 92 89 90 61 66 60 59 55 5 4 58 56 57 5 3 6 7 68 69 52 51 50 48 49 4 7 44 42 40 41 43 34 46 4 5 1 6 17 33 2 6 27 31 38 3 9 37 30 29 2 8 25 22 2 4 21 23 19 20 1 8 1 3 1 2 11 15 14 7 4 9 6 10 73 10 7 64 106 105 63 62 96 104 108 116 108 102 96 106 104 102 100 102 100 98 106 98 88 100 90 Corona Ri v e r sid e P e rr is La ke Els inor e 86 84 84 78 72 64 S A N J A C I N T O F A U L T Z O N E E L S I N O R E F A U L T Z O N E C H I N O F A U L T Palm Springs Indio 0 5 10 15 20KM 90 6 6a 1 2 4 8 9 7 5 3 32 35 36 67 39a 70 71 72 N Location of Corona North quadrangle relative to major structural blocks of the northern Peninsular Ranges batholith. Conventional potassium-argon biotite ages of Cretaceous granitic rocks are hand contoured, and are considered to reflect the cooling history of the batholith rather than representing ages of emplacement. Contouring of ages in each of the three structural blocks separated by the Elsinore and San Jacinto fault zones, was done independently of ages in adjacent blocks. Red band shows offset of 98 to 108 contours across Elsinore fault zone. Faults as shown are simplified from Rogers, 1965. 63 37 Sample locality, showing sample numbers and potassium-argon ages. W H I T T I E R F A U L T Z O N E Santa Rosa Mts mylonite zone Santa Ana Block Perris Block San Jacinto Block Approximate location of boundary separating plutons having well developed penetrative fabrics on the east, from essentially structureless plutons on the west. 101 1a Corona North 7.5' quadrangle This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, firm, or product names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. This map was printed on an electronic plotter directly from digital files. Dimensional calibration may vary between electronic plotters and between X and Y directions on the same plotter, and paper may change size due to atmospheric conditions; therefore, scale and proportions may not be true on plots of this map. Digital files available on World Wide Web at http://geopubs.wr.usgs.gov LOCATION MAP
Transcript of GEOLOGIC MAP OF THE CORONA NORTH 7.5 ...Santa Ana Mountains to southwest, marine fossil-bearing...
CORRELATION OF MAP UNITS
U.S. DEPARTMENT OF THE INTERIORU.S. GEOLOGICAL SURVEY
OPEN-FILE REPORT 02-22Prepared in cooperation with the
CALIFORNIA DIVISION OF MINES AND GEOLOGY
GEOLOGIC MAP OF THE CORONA NORTH 7.5' QUADRANGLE, RIVERSIDE and SAN BERNARDINO COUNTIES, CALIFORNIA
Base from U.S. Geological Survey7.5' Corona North quadrangle, 1967Polyconic projection
Geology mapped by D.M. Morton, 1995; and C.H. Gray, Jr., 1975
1 0 1 MILE12
1 KILOMETER0.51
CONTOUR INTERVAL 20 FEET
SCALE 1:24,000
GN
MN
15
DESCRIPTION OF MAP UNITS
MODERN SURFICIAL DEPOSITS—Sediment recently transported and deposited in channels and washes, on surfaces of alluvial fans and alluvial plains, and on hillslopes. Soil-profile development is non-existent. Includes:Artificial fill (late Holocene)—Deposits of fill resulting from human
construction or mining activities; restricted to three noncontiguous areas (1) south of 91 Freeway, (2) on Norco Navel Reservation, and (3) sand and gravel mining in Santa Ana River channel
Very young wash deposits (Holocene)—Deposits of active alluvium; confined to main channel of Santa Ana River. Consists mostly of unconsolidated sand and gravel in river channel. Sediment subject to localized reworking mainly during winter months.
YOUNG SURFICIAL DEPOSITS—Sedimentary units that are slightly consolidated to cemented and slightly to moderately dissected. Alluvial fan deposits (Qyf series) typically have high coarse:fine clast ratios. Younger surficial units have upper surfaces that are capped by slight to moderately developed pedogenic-soil profiles (A/C to A/AC/B/Cox profiles). Includes:Young wash deposits (Holocene and late Pleistocene)—Sand, gravel and
boulder deposits.Young alluvial fan deposits (Holocene and late Pleistocene)—Gray-hued
sand and cobble- and gravel-sand deposits derived from lithic diverse sedimentary units. Deposits north of Santa Ana River (Qyfa) consist of gray-hued, unconsolidated, arkosic sand derived from varied metamorphic and granitic lithologies in San Gabriel and San Bernardino Mountains north and east of quadrangle. May contain lesser interdigitated sedimentary wedges from Peninsular Ranges sources to south. Unit shows slight coarsening toward mountains to north. South of Temescal Wash, unit is mostly cobble- to granule- sized gravel. Locally, young alluvial fan deposits are divided into subunits based on sequential terrace development and other factors; one such unit is found in quadrangle:
Young alluvial fan deposits, Unit 1 (Holocene and late Pleistocene)—Consists of pale-gray, unconsolidated, cobble- to granule- sized gravel. Restricted to single fan flanked by two younger Qyf fans in southern part of quadrangle. Forms older part of Qyf unit
Young alluvial channel deposits (Holocene and late Pleistocene)—Gray, unconsolidated alluvium consisting of medium- to fine-grained sand and lesser silt flooring Temescal Wash and several of its tributaries in the southwestern part of quadrangle. North of Santa Ana River, includes sediments in Mill Creek drainage
Young eolian deposits (Holocene and late Pleistocene)—Sand dune deposits, inactive except for very minor amount of sediment movement during Santa Ana wind storms. Chiefly unconsolidated, moderately well sorted, fine- to medium-grained sand
OLD SURFICIAL DEPOSITS—Sedimentary units that are moderately consolidated and slightly to moderately dissected. Older surficial deposits have upper surfaces that are capped by moderately to well-developed pedogenic soils (A/AB/B/Cox profiles and Bt horizons as much as 1 to 2 m thick and maximum hues in the range of 10YR 5/4 and 6/4 through 7.5YR 6/4 to 4/4 and mature Bt horizons reaching 5YR 5/6). Includes:Old wash deposits (late to middle Pleistocene)—Consists chiefly of sand.
Gray to reddish-brown, unconsolidated to slightly indurated. Restricted to single occurrence flanking north side of Santa Ana River southwest of Mira Loma
Old alluvial fan deposits (late to middle Pleistocene)—Indurated, sandy alluvial fan deposits, except south of 91 Freeway in south-central part of quadrangle where unit is predominantly gravel. Covers extensive areas south of Santa Ana River, commonly at base of steep bedrock slopes. North of Santa Ana River, found in and east of Mira Loma. Most of unit is slightly to moderately dissected and reddish-brown. Some Qof includes thin, discontinuous surface layer of Holocene alluvial fan material. Includes:
Old alluvial fan deposits, Unit 1 (middle Pleistocene)—Indurated, gravely alluvial fan deposits. Most are slightly to moderately dissected; reddish-brown. Some deposits include thin, discontinuous surface layer of Holocene alluvial fan material. In quadrangle, restricted to single 5 km2 fan west of Corona
Old alluvial channel deposits (late to middle Pleistocene)—Alluvial deposits consisting mainly of sand, but containing minor gravel and silt. Gray to reddish-brown, unconsolidated to indurated. Generally slightly dissected. Restricted to two isolated occurrences east and west of Mira Loma on north side of Santa Ana River
Old alluvial valley deposits (late to middle Pleistocene)—Fluvial deposits along valley floors. Consists of moderately indurated, commonly slightly dissected sandy alluvium, containing lesser silt, and clay-bearing alluvium. Some deposits include thin alluvial deposits of Holocene age. Restricted to area between La Sierra and Home Gardens in southeastern part of quadrangle
VERY OLD SURFICIAL DEPOSITS—Sediments that are slightly to well consolidated to indurated, and moderately to well dissected. Upper surfaces are capped by moderate to well developed pedogenic soils (A/AB/B/Cox profiles having Bt horizons as much as 2 to 3 m thick and maximum hues in the range 7.5YR 6/4 and 4/4 to 2.5YR 5/6)Very old alluvial fan deposits (early Pleistocene)—Mostly well-dissected,
well-indurated, reddish-brown sand deposits. Commonly contains duripans and locally silcretes. Forms large area east of Norco generally flanking steep bedrock slopes. North of Santa Ana River, forms broad area that is part of fans emanating from Puente Hills west of quadrangle
Very old alluvial channel deposits (early Pleistocene)—Gravel, sand, and silt; reddish-brown, well-indurated, surfaces well-dissected. Underlies large area between Santa Ana River and Temescal Wash
Late Cenozoic sedimentary rocks in Norco area (early Pleistocene to late Pliocene?)—Moderately indurated sandstone, conglomeratic sandstone, and conglomerate. In Norco area, unit includes locally derived clasts as well as clasts derived from San Bernardino Mountains. Found in and west of Norco, on both sides of Santa Ana River
Sandstone of Norco area (Pliocene)—Poorly exposed, unnamed, marine sandstone. Forms isolated areas of outcrop south of Norco and north of Temescal Wash. Unconsolidated, greenish-yellow sandstone having sparse conglomerate lenses. Locally contains abundant, poorly preserved shallow marine fossils including Anadara cf. A. trilineata (Conrad), Chione sp., Lucinoma cf. L. annulata (Reeve), and Diodora sp. (J.D. Mount, per. commun., 1973). Unit may represent shallow-water eastward extension of Fernando Formation. Sparse conglomerate lenses include clasts of exotic silicic volcanic rocks. In places, ash of Taylor Canyon (per. commun., A.M. Sarna-Wojcicki, 1990) at base of formation is nonconformably buttressed against granitic rock. Ash deposited on granite are interpreted be tide pool deposits. Age of ash is 2.6 Ma
Contact—Generally located within ±15 meters
Fault—High angle. Strike-slip component on all faults is right-lateral; dip-slip component is unknown, but probably reflects valley-highland relations. Dashed where located within ±30 meters; dotted where concealed; queried where existence questionable.
70
Strike and dip of beds
Inclined
Qw
Qyf
Qvof
Puente Formation (early Pliocene and Miocene)—Marine sandstone, siltstone, and shale. Named by Eldrige and Arnold (1907) for exposures in Puente Hills. English (1926) extended distribution of Puente Formation to area south of Puente Hills, subdividing three units, from youngest to oldest, (1) shale, sandstone, and conglomerate (2) sandstone, and (3) shale. Daviess and Woodford (1949) subdivided Puente Formation in northwestern Puente Hills into four members, from youngest to oldest, (1) Sycamore Canyon Member, (2) upper siltstone ember, (3) sandstone member, and (4) lower siltstone member. Schoellhamer and others (1954) later designated formalized member names that are in current usage. Only Sycamore Canyon Member found in quadrangle; restricted to single locality in southwestern corner:
Sycamore Canyon Member (early Pliocene and Miocene)— Predominantly sandstone and pebble conglomerate. Sycamore Canyon Member is laterally variable, composed of varying amounts of pale gray, thick-bedded to massive, medium- to coarse-grained, friable sandstone; pale gray, thin-bedded, siliceous siltstone; pale gray, poorly bedded siltstone, and brownish-gray, massive conglomerate. Elsewhere contains bathyal depth foraminiferal fauna (Yerkes, 1972)
Vaqueros and Sespe Formations, undifferentiated (early Miocene, Oligocene, and late Eocene)—Interbedded marine and nonmarine sandstone and conglomerate assigned to the Vaqueros and Sespe Formations. Occurs only in southwestern corner of quadrangle. In Santa Ana Mountains to southwest, marine fossil-bearing strata of Vaqueros Formation are bed-by-bed interlayered with nonmarine rocks of Sespe Formation to degree that formations cannot be mapped as separate units. Undifferentiated unit locally includes boulder conglomerate (Woodford and others, 1973)
Micropegmatite granite of Gavilan Ring Complex (Cretaceous)—Fine-grained, pink-tinted, leucocratic granite having distinctive micropegmatitic texture. Restricted almost entirely to Corona North quadrangle. Forms elongate band of outcrops between Corona and Norco. Underlies about 3 km2
Micropegmatite and granodiorite of Cajalco pluton, undifferentiated (Cretaceous)—Mixed unit of micropegmatite and massive granodiorite to monzogranite. Micropegmatite is fine grained and granodiorite to monzogranite is medium to coarse grained. Found southwest and southeast of Norco. Rocks probably related to, but not mapped as part of Cretaceous Cajalco pluton
Granite of the Riverside area (Cretaceous)—Medium- to coarse-grained, massive- to faintly-foliated, leucocratic biotite granite. Contains about 1 to 3 percent biotite. Inclusions are sparse or absent except locally in western part of body where granite contains 2 to 8 percent biotite and sparse to abundant inclusions of quartz diorite, granodiorite, and fine-grained mafic rock. At Mount Rubidoux, east of quadrangle, rocks contain sparse hypersthene and fayalitic olivine and moderately abundant equant inclusions of dark-gray fine-grained rock. Rock at Mount Rubidoux termed "fine leucogranite of Rubidoux Mountain" by Larsen (1948). Restricted to a single outcrop at east edge of quadrangle south of La Sierra Heights
Mount Hole Granodiorite (Cretaceous)—Massive, hornblende-biotite granodiorite. Medium- to coarse-grained; structureless. Moderately leucocratic compared to most hornblende-bearing rocks in region. Weathers to form large boulders of disintegration. Named by Larsen (1948) for exposures at Mount Hole, east of Norco. Forms narrow, roughly tabular body several kilometers long between Norco and La Sierra, and a smaller body 0.7 km to the east
La Sierra Tonalite (Cretaceous)—Massive biotite tonalite. Fairly dark-colored compared to other units in region containing no hornblende, but alteration found in much of rock tends to darken it. Medium- to coarse-grained; structureless. Much of tonalite is altered to secondary minerals, especially epidote and chlorite, and contains localized zones that are thoroughly altered to epidote, quartz, and chlorite; some highly altered rocks contain tourmaline and sulfide minerals. Large body exposed west of La Sierra and larger mass, partly covered by Quaternary deposits, underlies Norco area. Named by Larsen (1948) for exposures in vicinity of La Sierra.
Cajalco pluton (Cretaceous)—Mostly biotite and hornblende-biotite monzogranite and granodiorite. Informally named for exposures in Cajalco area, Lake Mathews 7.5’ quadrangle (Morton, 1999). Rocks of Cajalco pluton were included within Cajalco quartz monzonite by Dudley (1935) and within Woodson Mountain granodiorite by Larsen (1948). Body is composite, shallow-level pluton emplaced by magmatic stoping within largely volcanic and volcanoclastic rocks. It was tilted eastward and eroded to progressively greater depths from west to east. Southeast of quadrangle, upper part of pluton contains very prominent halo of highly tourmalinzed rock. Zircon ages are 109.5 Maid and 112.6 Maip (pers comm Premo, 1998). Within quadrangle includes:
Monzogranite—Western part of pluton, including rocks in Corona North quadrangle, typically is medium-grained, equigranular, hypauto-morphic-granular to subporphyritic monzogranite and subordinate granodiorite. Includes irregularly variable amounts of angular inclusions mostly, if not entirely, derived from stoping of Cretaceous Estelle Mountain volcanics. Number, size, and reliability of identity of inclusion parent rock increases from east to west. In western part of pluton, included masses of volcanic rock comprise large volume of pluton. In northern and northeastern part of pluton stoped masses of hornblende gabbro are abundant.
Granodiorite and gabbro, undifferentiated—Mixed granodiorite and gabbro. In quadrangle, restricted to single area of exposure near southeastern corner where granitic rock contains high concentrations of stoped hornblende gabbro. In some areas, including Corona North quadrangle, granite and gabbro are intimately intermixed producing very heterogeneous rock
Quartz diorite (Cretaceous)—Medium- to coarse-grained biotite-hornblende quartz diorite. Most is slightly to well foliated and contains discoidal to pancake-shaped melanocratic inclusions in foliation plane. Grades into diorite and biotite-hornblende tonalite. Exposed around and north of La Sierra Heights
Diorite, undifferentiated (Cretaceous)—Mostly fine-to medium-grained, massive, dark gray to nearly black hornblende diorite. Forms approximately 1 km2 mass northwest of Home Gardens in southeastern part of quadrangle
Gabbro (Cretaceous)—Mainly hornblende gabbro. Includes Virginia quartz-norite and gabbro of Dudley (1935), and San Marcos gabbro of Larsen (1948). Typically brown-weathering, medium-to very coarse-grained hornblende gabbro; very large poikilitic hornblende crystals are common, and locally gabbro is pegmatitic. Much of unit is quite heterogeneous in composition and texture. Includes noritic and dioritic composition rocks. Exposed west of La Sierra Heights
On many SCAMP geologic map plots, including the Corona North 7.5' quadrangle, characteristic grain size information is displayed using subscripted alpha characters (e.g. Qyfg, Qova), where the characters conform to the following definitions:
a - arenaceous (very coarse sand through very fine sand)b - boulder gravel (>25mm)g - gravel (cobble through granule gravel)s - siltyc - clayeym- marlp - peat
1 2,3
Version 1.0
By
Douglas M. Morton and C.H. Gray, Jr.
Digital preparation by
Kelly R. Bovard and Michael Dawson 1 1
Qya
science for a changing worldscience for a changing world117 37' 30"
34 00'117 30'
34 00'
117 30'33 52' 30"
117 37' 30"33 52' 30"
QUATERNARY
CENOZOIC
Holocene
Pleistocene
TERTIARY
Qw
Qyf
CRETACEOUS
Pliocene
Qya
Qaf
Qof
Qaf
?
Qoa
Kgb
Kmhg
Kqd
Krg
Qof
Qyf1
Qye
Qow
Qof1
Qoa
Qvoa
Qov
SURROUNDING 7.5' QUADRANGLES
CoronaNorth7.5' Rive
rside
Wes
t
Prado D
am
Lake M
athew
s
Black S
tar
Canyo
n
Coron
a Sou
th
Ontario
Guasti
Fontan
a
In the Description of Map Units, the Ma following U/Pb ages has an attached subscript; Maid for isotope dilution analyses, and Maip for ion probe analyses.
Qow
Qyf1
Qye
Qof1
Qov
QTn
Qvoa
Tpsc
Tvs
Tns
Kcg
Klst
Kd
Kmhg
Kcg
QTn
Tns
Miocene
Eocene
MESOZOIC
Qvof
Kmp
Tpsc
Kmpc
Krg
Tvs
Kmp
o
o
o
o
o
o
o
o
o
Classification of plutonic rock types (from IUGA, 1973, and Streckeisen, 1973).A, alkali feldspar; P, plagioclase feldspar; Q, quartz.
QuartzSyenite
QuartzMonzonite
QuartzMonzodiorite
Syenite Monzonite Monzodiorite
Granite
Alk
ali-f
elds
par G
rani
teTonalite
Diorite
Syen
ogra
nite
Granodiorite
Mon
zogr
anite
Quartz
Diorite
90 65 35 10
5
20
60Q Q
A P
60
20
5
60
Kgb
Kqd
GEOLOGIC SUMMARY
The Corona North quadrangle is located near the northern end of the Peninsular Ranges Province. All but the southwestern tip of the quadrangle is within the Perris block, a relatively stable, rectangular in plan, area located between the Elsinore and San Jacinto fault zones. The southwestern tip of the quadrangle is marginally within the Chino fault zone.
Cretaceous plutonic rocks that are part of the composite Peninsular Ranges batholith underlie most of the quadrangle. These rocks are exposed in a roughly triangular-shaped area bounded on the north by the Santa Ana River and on the south by Temescal Wash, a major tributary of the Santa Ana River. A variety of mostly intermediate composition granitic rocks occur in the quadrangle, mainly monzogranite and granodiorite, but ranging from micropegmatitie granite to gabbro. Most rock units are massive and contain varying amounts of meso-and melanocratic, equant-shaped inclusions. The most widespread granitic rock is monzogranite of the Cajalco pluton, a large composite intrusion that extends some distance south and east of the quadrangle. North of Corona is a body of micropegmatite that appears to be unique in the batholith rocks.
Diagonally bisecting the quadrangle is the Santa Ana River. North of the Santa Ana River alluvial deposits are dominated by the distal parts of alluvial fans emanating from the San Gabriel Mountains north of the quadrangle. Widespread areas of the fan deposits are covered by a thin layer of wind blown sand.
Alluvial deposits in the triangular-shaped area between the Santa Ana River and Temescal Wash are quite varied, but consist principally of locally derived older alluvial fan deposits. These deposits rest on remnants of early Quaternary to late Tertiary age, nonmarine sedimentary deposits that were derived from both local sources and sources as far away as the San Bernardino Mountains. These deposits in part were deposited by an ancestral Santa Ana River. Several non-contiguous remnants of late Tertiary (Pliocene) marine sandstone that include some conglomerate lenses are scattered through the area between Norco and Temescal wash. Clasts in the conglomerate lenses include siliceous volcanic rocks exotic to this part of southern California. This sandstone was deposited as the southeastern-most part of the Los Angeles sedimentary marine basin and were deposited along a rocky shoreline developed in the granitic rocks, much like the present day shoreline at Monterey, California. Most of the sandstone and granitic paleoshoreline features have been removed by quarrying and grading in the area between Porphyry and Highway 91. However, excellent exposures of the paleoshoreline features are in highway road cuts on the north side of Highway 91 just east of the 91-15 interchange and on the east side of U.S. 15 just north of the interchange.
South of Temescal Wash, a series of both younger and older alluvial fan deposits emanate from the Santa Ana Mountains southeast of the quadrangle. In the southwesternmost corner of the quadrangle is a small exposure of sandstone and pebble conglomerate of the Sycamore Canyon member of the Puente Formation of early Pliocene and Miocene age and sandstone and conglomerate of undivided Vaqueros and Sespe Formations of early Miocene, Oligocene, and late Eocene age.
REFERENCES
Daviess, S.N., and Woodford, A.O., 1949, Geology of the northwestern Puente Hills, Los Angeles County, California: U.S. Geological Survey Oil and Gas Investigation, Preliminary Map 83.
Dudley, P.H., 1935, Geology of a portion of the Perris block, southern California: California Jour. of Mines and Geology. v. 31, no. 4, p. 487-506.
Eldridge, G. H., and Arnold, R., 1907, The Santa Clara Valley, Puente Hills, and Los Angeles oil districts, southern California: U.S. Geol. Survey Bull. 309, 266 p.
English, W.A. 1926, Geology and oil resources of the Puente Hills Region, California: U.S. Geol. Survey Bull. 768. 110 p.
Larsen, E.S., 1948, Batholith and associated rocks of Corona, Elsinore, and San Luis Rey quadrangles, southern California: Geol. Soc. of America Mem. 29, 182 p.
Morton, D. M., 1999, Preliminary digital geologic map of the Santa Ana 30' X 60' quadrangle, southern California: U.S. Geological Survey Open-File Report 99-172, 61p., scale, 1:100,000
Rogers, T.H., 1965, Santa Ana sheet: California Division of Mines and Geology geologic map of California, scale, 1:250,000.
Schoellhamer, J.E., Kinney, D.M., Yerkes, R.F. and Vedder, J.G., 1954, Geologic map of the northern Santa Ana Mountians, Orange and Riverside Counties, California: U.S. Geol. Survey Oil and Gas investigations Map OM 154, scale, 1:24,000.
Streckeisen, A.L., 1973, Plutonic rocks—Classification and nomenclature recommended by the IUGA Subcommission on Systematics of Igneous Rocks: Geotimes, v. 18, p. 26-30.
Woodford, A.O., McCulloh, T.H., and Schoellhamer, J.E., 1973, Paleographic significance of metatuff boulders in middle Tertiary strata, Santa Ana Mountains, California: Geol. Soc. America Bull. v. 83, no. 11, p. 3433-3436.
Yerkes, R.F., 1972, Geology and oil resources of the western Puente Hills area, southern California: U.S. Geol. Survey Prof. Paper 420-C, 63 p.
Klst
Qyw
Kd
Kcgb
1 U.S. Geological SurveyDepartment of Earth SciencesUniversity of CaliforniaRiverside, CA 92521
California Division of Mines and Geology107 South BroadwayLos Angeles, CA 90012
3Deceased2
Kcgb
Kmpc
Qyw
65104
98
95
115 108
103
114
101
94
116
110
109
109
10996
102
104
95
90
96
93
92100
102 95
94
103
94
108
108
82
87
8786 86
81
8888 86
86
88
87
86
83
85
85
90
91
91
90
92
88
85
81
84
84
79
73
71
6871
73
80
61
60
63
66
92
89
90
61
66
60
59
55
54
58
56
57
53
67
68
69
52
51
50
48
49
47
44
42
40
41
43
34
46
45
16
17
33
26 2731
38
39
37
30
29
2825
22
24
21
23
19
2018
13
12
11
15
14
74
96
10
73
10764
106
105
63
62
96
104
108116
108
102
96
106
104102
100102
100
98
106
98
88
100
90
Corona
Riverside
Perris
LakeElsinore
86
84
84
78
72
64
S AN
J AC
I NT
O
F A U L T
Z O N E
E L S I N O R E
FA
UL
T
ZO
NE
CH
IN
OF
AU
LT
Palm Springs
Indio
0 5 10 15 20KM
90
6
6a
1
2
4
8
9
75
3
32
35 36
6739a
7071
72
N
Location of Corona North quadrangle relative to major structural blocks of the northern Peninsular Ranges batholith. Conventional potassium-argon biotite ages of Cretaceous granitic rocks are hand contoured, and are considered to reflect the cooling history of the batholith rather than representing ages of emplacement. Contouring of ages in each of the three structural blocks separated by the Elsinore and San Jacinto fault zones, was done independently of ages in adjacent blocks. Red band shows offset of 98 to 108 contours across Elsinore fault zone. Faults as shown are simplified from Rogers, 1965.
6337
Sample locality, showing sample numbers and potassium-argon ages.
W H I T T I E RF A U L T
Z O N E
Santa Rosa Mtsmylonite zone
Santa Ana
Block
Perris
Block
San Jacinto
Block
Approximate location of boundary separating plutons having well developed penetrative fabrics on the east, from essentially structureless plutons on the west.
101 1a
Corona North 7.5'quadrangle
This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, firm, or product names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government.
This map was printed on an electronic plotter directly from digital files. Dimensional calibration may vary between electronic plotters and between X and Y directions on the same plotter, and paper may change size due to atmospheric conditions; therefore, scale and proportions may not be true on plots of this map.
Digital files available on World Wide Web at http://geopubs.wr.usgs.govLOCATION MAP
