Sedimentary record of Mesozoic deformation and inception of ...carroll/publications/pdf/Greene...

317

Geological Society of AmericaMemoir 194

2001

Sedimentary record of Mesozoic deformation and inception of the Turpan-Hami basin, northwest China

Todd J. Greene*Department of Geological and Environmental Sciences, Stanford University, Stanford, California, 94305-2115, USA

Alan R. Carroll*Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA

Marc S. Hendrix*Department of Geology, University of Montana, Missoula, Montana 59812, USA

Stephan A. Graham*Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305-2115, USA

Marwan A. Wartes*Department of Geology and Geophysics, University of Wisconsin, 1215 West Dayton Street, Madison, Wisconsin 53706, USA

Oscar A. Abbink*Laboratory of Palaeobotany and Palynology, Utrecht University, Utrecht, The Netherlands

ABSTRACT

The Turpan-Hami basin is a major physiographic and geologic feature of north-west China, yet considerable uncertainty exists as to the timing of its inception, its latePaleozoic and Mesozoic tectonic history, and the relationship of its petroleum systemsto those of the nearby Junggar basin. To address these issues, we examined the late Paleozoic and Mesozoic sedimentary record in the Turpan-Hami basin through a series of outcrop and subsurface studies. Mesozoic sedimentary facies, regional un-conformities, sediment dispersal patterns, and sediment compositions within the Turpan-Hami and southern Junggar basins suggest that these basins were initiallyseparated between Early Triassic and Early Jurassic time.

Prior to separation, Upper Permian profundal lacustrine and fan-delta facies andTriassic coarse-grained braided-fluvial–alluvial facies were deposited across a contigu-ous Junggar-Turpan-Hami basin. Permian through Triassic facies were derived mainlyfrom the Tian Shan to the south, as indicated by northward-directed paleocurrent di-rections. This is consistent with the sedimentary provenance of Triassic sandstone (meanQm29F29Lt42, Qp23Lvm49Lsm28, and Qm51P25K24) and conglomerate (&32% graniticclasts) in the northern Turpan-Hami basin. We interpret a relative increase in quartz andfeldspar concentration and a relative decrease in volcanic lithic grains in the northernTurpan-Hami basin to reflect unroofing in the Tian Shan and exposure of late Paleozoicgranitoid rocks. In addition, two basinwide unconformities of Late Permian–EarlyTriassic and Early Triassic–middle-Late Triassic age attest to deformation within theTurpan-Hami basin and associated continued uplift and erosion of the Tian Shan.

*E-mails: Greene, [email protected]; Carroll, [email protected]; Hendrix, [email protected]; Graham, [email protected]; Wartes, [email protected]; Abbink, [email protected].

Greene, T.J., et al., 2001, Sedimentary record of Mesozoic deformation and inception of the Turpan-Hami basin, northwest China, in Hendrix, M.S., and Davis,G.A., eds., Paleozoic and Mesozoic tectonic evolution of central Asia: From continental assembly to intracontinental deformation: Boulder, Colorado, Geologi-cal Society of America Memoir 194, p. 317–340.

318 T.J. Greene et al.

INTRODUCTION

The present-day Turpan-Hami basin is a major physio-graphic feature of central Asia. It contains the second lowest el-evation on earth (-154 m), yet is bounded on its northern flank

by the Bogda Shan, a major mountain range containing peaks ashigh as 5570 m (Fig. 1A). Few published data bear directly onthe initiation of the Turpan-Hami basin or its premodern physio-graphic and depositional history. Post-Carboniferous sedimen-tary facies, paleocurrent dispersal patterns, and sandstone

By Early Jurassic time, the Turpan-Hami basin and the southern Junggar basinbecame partitioned by uplift of the Bogda Shan, a major spur of the Tian Shan. In contrastto the thoroughgoing northward-directed Permian-Triassic depositional systems, Lowerthrough Middle Jurassic strata begin to reflect ponded coal-forming, lake-plain environ-ments within the Turpan-Hami basin. These strata contain paleocurrent indicators re-flecting flow off the intervening Bogda Shan. Abasinwide LowerJurassic– Middle Jurassicunconformity in the Turpan-Hami basin suggests continued uplift and erosion of the BogdaShan, consistent with a return to more lithic-rich sandstone and volcanic-rich conglomer-ate compositions. These sedimentary facies, paleocurrent, and provenance data sets pro-vide the best available constraints on the initial uplift of the Bogda Shan and the firstdocumentary evidence of intra-Mesozoic shortening within the basin.

T88-625

T89

-465

UrumqiJimsar

Baiyanghe Turpan

BOGDA SHAN

Hami

CHOL TAGH

Flaming Mtn.

T88-635

Taican-2

Ancan-1

Paleozoic gabbroic rocks

Pre-Mesozoic igneous andmetamorphic rocks

Taibei Sag

N44°

N42°

N44°

N42°

E92°E86° E90°E88° E94°

E92°

E86°

E90°E88°

E94°

T84

-200

TokesunSag

Ha-3

Aiweiergou

TaoshuyuanZaobishan

Kekeya

Taoshuyuan

southern Junggar Basin

Cenozoic

Cretaceous (K1 + K2)

Upper Jurassic (J3)

Lower-Middle Jurassic (J1 + J2)

Middle-Upper Triassic (T2 + T3)

Permian-Triassic (P2 - T1)

Permian (P1 + P2)

Carboniferous volcanic rocks

seismic lineT88-635

Legend50 kmN

well

Late Paleozoic granitoid rocks

sedimentary depression

fault

study locality

*

*

TURPAN-HAMIBASIN

Shisanjianfang Sandaoling

C

P2

J1-T

T2-3

P-T1

C

T2-3J1-T3

J2

K

KJ2-3

J2-3T-P

T-PC

C

(Mu, 1994)

K

T-P

CT-P

J

C

(Li and Jiang, 1987)

P1C

P2-T1

T2-3

J2

P2

T2-3T1

T

P1-2

C

A.

B.

*

*

JUNGGAR BASIN

TARIM BASIN

CHINA

SOUTH SHAN

TURPAN-HAMIBASIN

SHANBOGDA SHAN

KUQA

DUSHANZI

KORLA

0 100 km

TRIASSIC JURASSIC CRETACEOUS CENOZOIC

TIAN

TIAN SHAN

URUMQI

KURUKTAGH

+

+ + + + + +

+ + + +

+

+ +

TURPAN HAMI

N44°

E92°

N42°

N

BARKOL TAGH

CHINA

CENTRAL

SHANTIAN

NORTHTIAN

+

+

E86°

E92°E86°

N44°

N42°

PRE-MESOZOIC

Figure 1. A: Location map of study area within Xinjiang Uygur Autonomous Region, northwestern China. Boxed area is shown in detail in B. B: Geologic map of Turpan-Hami basin, showing various study locations in basin, location of seismic lines and wells referred to in text, and twomain western sedimentary depressions, Tokesun Sag and Tabei Sag (adapted from Chen et al., 1985). Solid black circles show general strati-graphic relationships and unconformities of Carboniferous through Cretaceous strata at various locations; data for each black circle are from thisstudy unless otherwise noted. Fault locations are adapted from Chen et al. (1985) and Allen et al. (1993).

Sedimentary record of Mesozoic deformation and inception of the Turpan-Hami basin 319

compositions from the southern Junggar and northern Tarimbasins (Hendrix et al., 1992; Carroll et al., 1995) suggest that theJunggar and Tarim basins have existed as discrete physiographicfeatures, separated by the intervening Tian Shan, since late Paleozoic time. However, previous interpretations of the time ofinception and early structural style of the Turpan-Hami basinvary widely. Hendrix et al. (1992) suggested, on the basis of paleocurrents, sedimentary facies, and isopach data, that theTurpan-Hami basin was established as a discrete physiographicfeature by Early Jurassic time, in response to compressional up-lift of the Bogda Shan. Allen et al. (1995) proposed that the Tur-pan basin was one of several major depocenters created bytranstensional rotation within a Late Permian–Triassic sinistralshear system. In determining the sedimentary provenance ofnorthern Turpan-Hami deposits, Greene et al. (1997) andGreene and Graham (1999) suggested that granitic cobbles con-tained within Lower Triassic deposits were derived solely fromthe Central and South Tian Shan blocks, south of the Turpan-Hami basin, and inferred that the ancestral Bogda Shan had notbeen uplifted by that time.

Better timing constraints for the initiation of the Turpan-Hami basin are especially important because they bear directlyon the lateral extent of thick, organic-rich Upper Permian la-custrine shale in the southern Junggar basin. Carroll et al. (1992)and Clayton et al. (1997) demonstrated that these and equivalentstrata are the source of oils produced at the Karamay oil fieldand other fields along the northwestern Junggar basin margin,which collectively are thought to contain reserves of 2–3 billionbarrel oil fields (Taner et al., 1988). If the initial separation ofthese two basins by the Bogda Shan occurred during post-LatePermian time, then it is possible that the rich lacustrine sourcerocks in the southern Junggar basin may extend into the Turpan-Hami basin (Fig. 1B).

At a more regional level, structural, geochronologic, andsedimentologic evidence suggests that, during Mesozoic time,the Turpan-Hami and Bogda Shan area existed within a broaderzone of contractile deformation that underwent several episodesof shortening. Mesozoic contractile structures have been docu-mented in the subsurface of the Junggar and Tarim basins (Liuet al., 1979; Liu, 1986; Wu, 1986; Li and Jiang, 1987; Peng et al., 1990; Zhao et al., 1991a, 1991b; Li, 1995; Hendrix et al.,1996; Wu et al., 1996), and Mesozoic fission-track ages fromthe core of the Tian Shan (Dumitru et al., this volume) suggestsignificant Mesozoic unroofing. Hendrix et al. (1992) docu-mented several successions of coarse, alluvial conglomerate ineach basin and inferred that they represent episodic reneweddowncutting of the ancestral Tian Shan. Hendrix (2000) inter-preted variations in the composition of Mesozoic sandstonefrom the southern Junggar and northern Tarim basins to reflectpolyphase deformation of the ancestral range. Vincent and Allen(this volume) documented several Mesozoic angular unconfor-mities and coarse conglomerate successions in the northeasternJunggar basin and interpreted them to reflect far-field deforma-tion originating at the southern continental margin of Asia. Allen

et al. (1993) also identified two Mesozoic compressionalepisodes in the Turpan-Hami basin and suggested that LowerPermian marine facies in the northern Turpan basin were de-posited as a foreland basin fill related to north-vergent thrustfaults in the Tian Shan region.

Key to understanding the tectonic and sedimentary historyof the Turpan-Hami basin is better documentation of the recordof sedimentary fill within the basin, combined with informationregarding the history of uplift and unroofing of the Bogda Shan.Unfortunately, very little information has been published aboutthe structure of the interior of the Bogda Shan; access to key ex-posures is difficult, and there are no seismic lines that transectthe range. Tectonic interpretations from the Turpan-Hami basinare largely limited either to specific reports on a focused petroleum-related topic (Huang et al., 1991; Wang et al., 1993,1998; K. Cheng et al., 1996; L. Liu et al., 1998), or regional interpretive syntheses that lack detailed data sets and hence areimpossible to evaluate critically (Fang, 1990, 1994; Li andShen, 1990; Shen, 1990; Chen, 1993; Tao, 1994; Allen et al.,1995; Shao et al., 1999b). Shao et al. (1999b), for example, usedbasin subsidence curves to infer a period of Late Permian ther-mal subsidence that was followed by a Middle-Triassic to earlyTertiary period of flexural subsidence for the Turpan-Hamibasin. However, error bars for age control are absent, and paleo-elevation level is set at sea level for the past 250 m.y. in theiranalysis. Likewise, numerous Chinese authors have publishedreports on Early-Middle Jurassic depositional history and se-quence stratigraphy, mainly due to its importance in petroleumtrapping for Turpan-Hami oil production (Wu and Zhao, 1997;Li, 1997; Qiu et al., 1997; and many others). These reports,however, are difficult to assess because stratigraphic and sedi-mentologic data are not presented. Marine sequence strati-graphic nomenclature is often used to describe high-resolutionlacustrine base-level changes during Early-Middle Jurassictime, without presenting accurately located seismic lines, well-log cross sections with appropriate well logs used for correlat-ing flooding surfaces or sequence boundaries (e.g., gamma-raylog), or fossil assemblages to justify age control.

In order to better define the timing of initial formation of theTurpan-Hami basin and, by extension, the initial uplift of theBogda Shan, we examined key outcrops of Mesozoic strata, oilwell cores and electrical logs, and seismic lines during the sum-mers of 1996, 1997, and 1998. We collected Permian throughJurassic stratigraphic and sedimentologic data at four differentlocalities along the northern basin margin of Turpan-Hami (Fig. 1B): Aiweiergou (westernmost corner), Taoshuyuan(west), Zaobishan (north-central), north of the town of Shisan-jianfang (east), and Sandaoling (east). We measured and de-scribed &20 stratigraphic sections from exposed Mesozoicstrata, and we used those data as the basis for interpreting the en-vironment of deposition for each section. We also examined ninepreviously unpublished reflection seismic profiles from the in-terior of the basin, along with data from oil well boreholes, andwe used those to compliment our surface data set. In addition to


providing data on the timing of initiation of the Turpan-Hamibasin as a depositional entity, we sought to examine the structureof the basin and its record of fill for evidence of Mesozoic short-ening, as has been suggested from other basins of western China.In this chapter, we summarize our data pertaining to Mesozoicsedimentary facies relations and sediment dispersal systemswithin the Turpan-Hami basin. We integrate those data withsandstone composition and conglomerate clast count data. Col-lectively, these data provide the best available constraints onMesozoic shortening within the Turpan-Hami basin, and, indi-rectly, on the initial uplift of the Bogda Shan.

STRATIGRAPHY AND SEDIMENTOLOGY

Our sedimentary data set, described in detail in the follow-ing, indicates that several fundamental changes in depositionalstyle occurred in the Turpan-Hami basin in Permian throughMiddle Jurassic time. This depositional history can be summa-rized as follows: Upper Permian strata are marked by fine-grained, mostly profundal lacustrine, fan-delta, and fluvialfacies (Carroll et al., 1992; Wu and Zhao, 1997; Carroll, 1998;Wartes et al., 1998, 1999, 2000), whereas Triassic deposits con-tain coarse-grained braided-fluvial–alluvial facies. In sharpcontrast are Lower through Middle Jurassic strata that reflect theponding of water in coal-forming, lake-plain environments.Concomitant with this major change in Jurassic environmentswas a shift during Early and Middle Jurassic time in the mainsedimentary depocenter, from the western Tokesun Sag to thenorth-central Tabei Sag (Fig. 1B: Huang et al., 1991; Wang et al., 1996; Qiu et al., 1997; Wu and Zhao, 1997).

Age control

Due to the lack of interbedded datable volcanic units and apaucity of paleomagnetic studies, age assignments in the Turpan-Hami basin are based solely on plant microfossil(spores, pollen), plant macrofossil, and vertebrate fossil assem-blages. This study relies heavily on new palynological results(Abbink, 1999) derived from selected mudrocks within bore-hole core and outcrop samples (Fig. 2). Age interpretations arebased on the first occurrence datum and/or last occurrence da-tum of spores and pollen (sporomorphs). Most of the strati-graphic ranges of the encountered sporomorphs are notcalibrated against marine faunas from northwest China (e.g.,Huang, 1993; Ouyang, 1996). We therefore conducted a datasearch to determine the range of the stratigraphic marker taxafor northwest China based on selected literature references fromother regions. Furthermore, on the basis of the overall contentof the sporomorph assemblages, the palynoflora of our samplesare not considered to be endemic; rather, the floral associationsclosely resemble those of Europe and of the former USSR. Onthe basis of our palynological studies, along with independentage assignments published by Chinese paleontologists (Liao

et al., 1987; Z. Cheng et al., 1996; Wang et al., 1996), most for-mations are dated to the epoch level, sufficient for the tectonicinterpretations in this paper (Fig. 2).

Triassic

Taodongou (east Taoshuyuan). At Taodongou (Figs. 1and 3A), 144 m of Lower Triassic strata (T1s; see Fig. 2 for for-mation abbreviations herein) are truncated by an erosional un-conformity and overlain by at least 70 m of Middle to UpperTriassic (T2-3k) conglomerate (Figs. 3B and 4A). The lower 80 m of T1s are mostly red to pink mudstone locally interbed-ded by 4–8 m sandy conglomerate interbeds that sharply fine tosiltstone. The upper 64 m of the T1s section represent a series ofstacked upward-fining sandy conglomeratic intervals &8–16mthick that fine to siltstone; little to no mudstone is exposed. Ero-sional contacts are common at the base of each package. Towardthe top of the T1s, the upward-fining sand packages pinch outlaterally over 20–30 m. An erosional contact with &25 m of re-lief separates the T1s deposits from the overlying higher energyT2-3k conglomerate (Fig. 3B). The latter consists of clast-supported conglomerate containing abundant tabular and troughcross stratification with 71 m relief. Cross-bedded sandy lenses,& 1 m thick, are common; little mudstone is present.

We interpret these deposits to represent two different de-positional environments. The lower 144 m of T1s depositsrecord relatively low energy flow associated with a braidedriver flood plain (Nanson and Croke, 1992). The upper 64 mrecord increasing depositional energy and erosive power thatproduced minor channels over a braid plain. Following an&25-m-deep incision, a gravel bed braided-fluvial systemdominated, incising large channels and depositing a seriesof gravel bars (Miall and Gibling, 1978). Hendrix et al. (1992)described similar deposits from Upper Canfanggou Group(lowermost Triassic) strata at Taodongou (Fig. 3A). They de-scribed a detailed 50 m section of coarse conglomerate andlenticular sandstone and siltstone red beds deposited in abraided-fluvial–alluvial environment.

Zaobishan. Three measured sections were described on ameter scale at the Zaobishan locality (Fig. 4, B, C, and D). Sec-tions 4B and 4C both record Lower Triassic and Middle-UpperTriassic deposits on the north and south flanks of a large east-west–trending Carboniferous-cored anticline (Figs. 5A and 6),and are chronostratigraphically similar to the measured sectionat Taodongou (Fig. 4A).

Both measured sections 4B and 4C can be divided into alower fine-grained section and an upper coarse-grained section,presumably separated by an erosional unconformity at the 25 mmark (although we observed an erosional contact in section 4B,this contact is covered at section 4C). The lower finer grainedportion consists of fine- to medium-grained sandstone beds withtrough cross-beds and planar bed stratification. The lower halfof section 4B is relatively lower energy than 4C, the former con-


Shaofangou (T1s)

Sangonghe (J1s)

Sanjianfang (J2s)

Carboniferous

Mid

dle/

Upp

er (

T2-

3)Lo

wer

(P

1)U

pper

(P

2)

Daheyan (P2d)

Taierlong (P2t)

Quanzijie (P2q)

Wutonggou (P2w)

Guodikeng (P2g)

Badaowan (J1b)

Taoxigou (P1t)

Jiucaiyuan (T1j)

Haojagou (T3h)

Huangshanjia (T3hs)

Karamay (T2-3k)

Tria

ssic

Per

mia

nJu

rass

ic

Age Formation

Xishanyao (J2x)

0

1

2

3

Schematicstratigraphy

?

mudstone

sandstone

conglomerate

volcanic

coal

unconformity

1

2

(km)

2

1

3

2

SP Resistivity

4

5

6

3

Ha-3 well (Figure 10C)

Ancan-1 well (Figure 10B)

1) Jurassic undifferentiated: Alete Bisaccate pollen undifferentiated, Perinopollenites elatoides, Punctatisporites spp.

2) Lower Jurassic (Hettangian-Aalenian): Chasmatosporites minor, Apiculatisporis globosus, common Striatella spp.

6) Upper Permian (Wordian): Hamiapollenites bullaeformis, Lunatisporites noviaulensis, Vittatina spp., Klausipollenites schaubergeri, Weylandites striata, Cordaitina, Gardenasporites, Protohaploxipinus, Straitoabieites, Gordonisporites

5) Upper Permian*: Limatulasporites, Lundbladispora, Taeniaesporites, Bisulcocypris sp.

3) Upper Triassic (Late Norian): Lordonispora fossulata, Vallasporites spp., Araucaricites australis, Patinasporites denus, Stereisporites puncta4) Middle-Upper Triassic*: Alisporites, Cyclogranisporites, Duplexisporites

Palynological assemblagesLo

wer

(J1

)M

iddl

e (J

2)

Qiketai (J2q)

* from the Tu-Ha Petroleum Bureau,Ancan-1 well

sampled for palynology

Key100 mvertical scale:

(km)

Well logs on seismic lines

6

Lower(T1)

Figure 2. Generalized strati-graphic and lithologic chart ofTurpan-Hami stratigraphy fromCarboniferous through MiddleJurassic strata with reportedfauna and flora assemblages andstratigraphic positions of majorunconformities discussed in text.Palynological assemblages fromHa-3 and Ancan-1 wells serve asage control for seismic line draw-ings. Unless otherwise noted, allpalynology-based age interpreta-tions are from Abbink (1999). ForUpper Permian age assignment ofsample 6, note that associationwith Limatulasporites (=Gor-donisporites) and Taeniasporites(=Lunatisporites) is not typicalLate Permian. Although latestPermian samples from Salt Range(Pakistan) contain the taxa, thesetaxa are also typical for Early Tri-assic, in particular in north China(Ouyang and Norris, 1988).

taining paleosol horizons and the latter having more stackedtrough cross-bedded sandstone beds. Paleocurrent indicatorspoint north-northeast for section 4C. At the 25 m mark in bothsections, a sharp increase in grain size occurs, above which are at least 30 m of polymictic conglomerate containing large(71 m relief) trough cross-beds mantled by pebbles and smallcobbles. The upper half of section 4B consists of sandy con-glomerate with 1–2-m-thick medium- to coarse-grained troughcross-bedded sandstone lenses distributed throughout the sec-tion. The conglomerate consists of 2–10-m-thick shingled,

lenticular packages that grade from clast supported at theirscoured bases to matrix supported.

We interpret sections 4B and 4C to be similar in deposi-tional style to section 4A. The Lower Triassic (T1s) sectionsrecord lower energy deposition in a braided river flood plain or distal sheetflood environment (Nanson and Croke, 1992).Middle-Upper Triassic (T2–3k) strata recorded a major changein depositional energy represented by gravelly braided-fluvialsystems (Miall and Gibling, 1978) with associated sandy over-bank sheet flows. Hendrix et al.’s (1992) description of Triassic


2 km

N43o15'

E89o00'E88o55'

section 4A

section 7B

N43o14'

N

C. Section 7B, Lower Jurassic deposits

B. Section 4A, Triassic depositsMiddle-Upper Triassic

Karamay Formation (T2-3k)

Lower TriassicShaofangou Fm. (T1s)

erosional surface

section 4A

~10 m

A. Taodongou locality, east Taoshuyuan

section 7B

~20 m

*from Hendrix et al. (1992)

T1 section*J1 section*

Figure 3. A: Corona Satellite image of Taodongou locality in eastTaoshuyuan. Black lines show locations of sections 4A and 7B fromthis study, as well as Lower Triassic (T1) and Lower Jurassic (J1) mea-sured sections from Hendrix et al. (1992). B: Intra-Triassic erosionalsurface at Taodongou, where braided-fluvial deposits of Karamay For-mation (T2-3K) overlie Shaofangou Formation (T1s); stratigraphic“up” is to upper right of photo. White bar shows location of portion ofmeasured section 4A. C: Entire 66 m measured section 7B (shown aswhite line) representing Lower Jurassic flood-plain deposits; strati-graphic “up” is to upper left of photo.

deposits at Qijiagou (southern Junggar basin) was similar to thatfor Triassic strata at Zaobishan and Taodongou. Namely, fine-grained red beds of lowermost Triassic deposits sharply grade tocoarse braided fluvial conglomerate of the Middle-Upper Trias-sic Karamay Formation.

Section 4D was measured in a valley of Lower Triassic de-posits (T1s) and is presented as a photomosaic in Figure 5B.Generally, section 4D consists of 2–10-m-thick lenses of troughcross-bedded conglomerate packages interbedded with 1–2-m-thick medium- to coarse-grained, trough cross-bedded sand-stone. Cobbles commonly mantle the troughs within theconglomerate, and scoured basal contacts are ubiquitous. Mea-sured paleocurrent indicators for trough cross-beds point northand northeast (Fig. 5C).

The excellent two-dimensional valley-wall exposureshown in Figure 5B contains all the major elements of a classicgravel-bed braided-fluvial system (Miall, 1996), i.e., abundantgravel bars, sandy bedforms, and stacked, channelized sandyconglomerate packages with numerous internal erosion sur-faces, lack of fines, and few observed downstream accretionsurfaces. Zhao et al. (1991) documented similar T1s deposits inthe Dalongou area (southern Junggar basin) on the north side ofthe Bogda Shan, and also interpreted them to reflect a braided-fluvial environment. A modern analog for the coarse-grainedTriassic deposits throughout Turpan-Hami occurs in the westernTian Shan in the Lake Issyk-kul area of Kyrgyzstan, where intermontane basins commonly contain gravel-dominated braidedriver environments with associated transverse bars (Sgibnev andTalipov, 1990; Rasmussen and Romanovsky, 1995).

Shisanjianfang. Section 4E depicts Middle-Upper Trias-sic conglomerate just north of the town of Shisanjianfang (Figs. 1 and 4E). Several 4–18-m-thick beds of clast- and matrix-supported conglomerate interfinger with medium- tocoarse-grained trough cross-bedded sandstone. The mean paleo-current indicator direction points north-northeast. We also in-terpret section 4E to represent deposition in a braided-fluvialsystem with occasional lower energy sand-rich, matrix-supportdeposition similar to those described herein.

Lower and Middle Jurassic

We studied exposures of Lower and Middle Jurassic de-posits in the western part of the basin at Aiweiergou, in thenorth-central part of the basin at Kekeya, at Taodongou (eastTaoshuyuan), and in the eastern Hami basin at Sandaoling (Figs. 1 and 7). We also studied Middle Jurassic strata in the cen-tral part of the basin at Flaming Mountain where thick sandstonepackages of the Xishanyao and Sanjianfang Formations (J2xand J2s) and lacustrine deposits of the Qiketai Formation (J2q)are exposed (Huang et al., 1991; Schneider et al., 1992; C. Wanget al., 1996; Liu and Di, 1997; H. Wang et al., 1997; Wu andZhao, 1997; L. Liu et al., 1998; Greene et al., 2000).

Aiweiergou. Near the Aiweiergou coal mine, we measureda 240 m section of Lower Jurassic Badaowan Formation (J1b)

70

60

50

40

(m)

conglomerate

sandstone

siltstone

mudstone

conglomerate lag

trough cross-bedsmantled with cobbles

upward finingupward coarsening

mud parting

low-anglecross-bedding

trough cross-bedding

large-scale troughcross-bedding (>1 m)

plane-bed stratification

Ca-rich stringers

organic material

concretions

mudmvccob

grain size

partially covered interval

20

30

10

0

T1s

0

T2-3k/T1s(north section)

covered hillslope

10

20

70

80

0

10

20

30

40

50

T2-3k/T1s(south section)

(m)

0

16

32

48

64

80

96

112

128

144

0

16

32

48

64

48

40

32

24

16

8

0 (n = 51)trough limbs

N

(n = 48)trough limbs

N


N


N

Taodongou locality:east Taoshuyuan

Zaobishan locality Shisanjianfanglocality

mudmvccob

grain size

LEGEND

erosional unconformity

(~25 m scour)

4B

4C

4D

T2-3k/T1s T2-3k4A

4E

Triassic outcrops of the Turpan-Hami basin

mudmvccob

grain size

mudmvccob

grain size

mudmvccobgrain size

~200

m s

ectio

n

Zaobishan locality

(m)

(m)

(m)

Middle/UpperTriassic (T2-3k)

Lower Triassic(T1s)

grav

el-b

ed b

raid

ed fl

uvia

lgr

avel

-bed

bra

ided

fluv

ial

grav

el-b

ed b

raid

ed fl

uvia

l

grav

el-b

ed b

raid

ed fl

uvia

l

grav

el-b

ed b

raid

ed fl

uvia

l

brai

ded

river

floo

d pl

ain

min

or c

hann

els

on b

raid

pla

in

brai

ded

river

floo

dpla

in

shee

tfloo

d di

stal

bra

ided

Figure 4. Summary of Triassic measured sections in Turpan-Hami basin. Note erosional unconformity betweenundifferentiated Middle-Upper Triassic conglomerate scouring into fine sandstone of Lower Triassic depositsin sections 4A, 4B, and 4C. This erosional surface (photo in Fig. 3B) is present at both Zaobishan and Taodon-gou (east Taoshuyuan) as well as in seismic line T88-635. Note that paleocurrent indicators are directed northto northeast in sections 4C, 4D, and 4E.


5km

N

A. Zaobishan localityE90o20' E90o25' E90o30' E90o35'

N43o20'

N43o16'

N43o12'

d

B. Lower Triassic braided fluvial deposits, section 4DW

E

~10 m

C. Paleocurrent indicators


N

section 4C

section 4D

section 4B

section 4D

Figure 5. A: Corona Satellite image of Zaobishan locality showing location of sections 4B, 4C, and 4D. White box shows location of photo-mosaic pictured in part B. B: Photomosaic of Lower Triassic braided-fluvial deposits at Zaobishan. Black lines highlight interpreted depositionalsurfaces. White line represents 76-m-long measured section 4D. Stratigraphic “up” is to top of photo. Note numerous large-scale cross-beds in-dicating flow to right (northeast). C: Photo of ubiquitous trough cross-sets (pencil for scale) measured at locality pictured in B, along with cor-responding stereoplot of measured paleocurrent indicators. Mean vector indicates northeast sediment-dispersal direction.

deposits (Fig. 7A). The lower 96 m consist mainly of 8–16-m-thick, clast-supported, polymictic cobble conglomerate withseveral associated 1–2-m-thick medium- to coarse-grained,trough cross-bedded and plane-bed laminated sandstone lenses.Conglomerate intervals commonly contain scoured basal con-tacts and are laterally continuous over several meters. Con-glomerate clasts are 2–8 cm and are well rounded. Woodfragments are common, as are interbeds of 0.5–1-m-thick, rippled, fine-grained sandstone and siltstone.

We interpret this portion of the Badaowan Formation tohave been deposited in a gravel-sand meandering fluvial envi-ronment (cf. Nijman and Puigdefábregas, 1978; Campbell and

Hendry, 1987). Conglomerate beds have crude horizontal strati-fication, and they commonly interfinger with large-amplitudecross-bedded sandy facies. The rippled siltstone beds are mostlikely interchannel overbank deposits or abandoned channelsand meander scars on the flood plain that are preserved as siltplugs. Campbell and Hendry (1987) described modern gravelmeander lobes on the Saskatchewan River that contain many ofthe same elements as this portion of the Badaowan Formation:horizontal gravel sheets, interfingering cross-bedded pebblysands, and clay-silt plugs.

The remainder of the section (above the 96 m mark) is rela-tively finer grained and more organic rich than the underlying

0

500

1000

1500

2000

2500

TR

IAS

SIC

T2-

3kT

1sh

T1j

P2-

T1

P2w

P2q

P2t

P2d

P1y

CARBON-IFEROUS.

PE

RM

IAN

(m)

mudstone conglomerate

ANDESITIC FLOWS

MIXED MARINE CARBONATE AND SILICICLASTICS:Thinly bedded micritic limestone, red mudstone, and chert.

VESICULAR BASALTIC AND ANDESITIC FLOWS

ALLUVIAL FAN AND LACUSTRINE: Interbedded limestone andconglomerate with well preserved tufa, overlain by variablylaminated, profundal lacustrine mudstone and fine sandstone.

BRAIDED FLUVIAL: Dominantly well-organized conglomerateof mostly andesitic clast composition. Abundant trough cross-bedding and occasional large silicified trees are present;interbedded sandstone beds display well-developed cross-bedding.

MEANDERING FLUVIAL-LACUSTRINE: Upward-fining sequencesof trough cross-bedded sandstone; sequences are typically scouredat their base and capped by a rippled surface. The fine-grainedsection is dominated by calcareous siltstone and mudstoneinterbedded with thin, laterally continuous limestone.

LAKE PLAIN-MEANDERING FLUVIAL: Dominantly redmudstone and siltstone interbedded with sandy micriteand occasional plane-laminated sheet sandstone and minortrough cross-bedded sandstone.

BRAIDED FLUVIAL: Well-organized conglomerate withcobble-mantled (>1 m) trough sets. Cross-bedded sand lenses arecommon. Sandy conglomerate beds are rich in alkalic plutonicclasts.

FLOOD PLAIN, DISTAL SHEETFLOOD: Upward-fining sandpackages with abundant well-developed trough cross-bedded,regularly interbedded mudstone and siltstone, occasional paleosols,and rare conglomerate.

ALLUVIAL-BRAIDED FLUVIAL: Dominated by cobble conglomerate,with abundant scour features. Individual conglomerate packagesupwardly fine to medium-coarse sandstone. The sequence isbounded by a basal erosional unconformity at its base.

FLOOD PLAIN-ANASTOMOSING FLUVIAL: T2-3 braided fluvialsequence gradually fines upward to interbedded mud and/orsiltstone with fine to medium sandstone containing troughcross-bedding. Two coal seams (<1 m thick) are interbedded withsiltstone.

N

sections4B, 4C

section 4Dn = 23, trough limbs

N

P2dtrough limbs

n = 94

Palynology andPaleocurrentIndicators

Lithofacies/Depositional Environment

n = 48, trough limbs

N

n = 46, trough limbs

N

1 1) Middle - early late Permian:Vittatina spp., Klausipollenites schaubergeri, Hamiapollenites bullaeformis, Cordaitina spp., Gardenasporites, Protohaploxipinus, Straitoabieites

Summary stratigraphic column for Zaobishan locality

Figure 6. Measured stratigraphic section of Permian through Triassic deposits at Zaobishan with descriptions of lithostratigraphy anddepositional environment (see Figs. 1 and 5 for locations). This generalized section at Zaobishan is typical along north rim of Turpan-Hami basin. Note that paleocurrent indicators for Upper Permian and Lower Triassic deposits are pointed northwest to north-east. Arrow (labeled 1) points to location of P2t mudstone from which we recovered mid-early Late Permian palynomorphs.

deformedmud interbeds

mud rip-ups

0.5 m mudrip-up

logs and casts(0.5 m)

amalgamated

amalgamated

(m)

40

30

20

10

0

60

50

40

30

20

10

0

200

150

100

50

240

sequencerepeats

mudmvccob

conglomerate

sandstone

siltstone

mudstone

conglomerate lag

clast-supportedconglomerate

trough cross-bedsmantled with cobbles

upward-coarsening

mud parting

trough cross-bedding

plane-bed stratificationcoal fragments

concretions


coal

rippleswoody material

mud rip-up clast

plant material

grain size

Taodongou locality:east Taoshuyuan

Aiweiergou locality

Kekeya locality

(m)

LEGEND

Lower-Middle Jurassic outcrops ofthe Turpan-Hami basin7A

7B

7C

(m)

mudmvccob

grain sizemudmcob

grain size

N

upward-finingsequence

mud/coalfinemed

anos

tom

osed

riv

er o

n de

ltaic

floo

d pl

ain

grain size

Sandaoling locality

7D

40

30

20

10

0

(m)

climbing ripples

root casts

covered interval

J1b

J1b

J1b

J2x

3

sampled for palynology

0

low-angle cross-bedding

photo in Figure 8B

photo inFigure 9B

grav

el-s

and

mea

nder

ing

river

sand

y m

eand

erin

g riv

er

flood

pla

in a

djac

ent t

o m

eand

er-b

elt s

yste

m

sand

y br

aide

d-flu

vial

-dis

tal s

heet

flood

1

1) Lower Jurassic (Toarcian): abundant Striatella cf. balmei,Quadraeculina anellaeformis

2) Jurassic undifferentiated:Alete bisaccate pollen undiff., Deltoidospora spp.,Perinopollenites elatoides, Punctatisporites spp.

3) Middle Jurassic (Bajocian-Bathonian): Neoraistrickia bacclifera, N. truncata, Quadraeculina anellaeformis

Palynological assemblages

2

2

Figure 7. Summary of Lower and Middle Jurassic outcrops throughout Turpan-Hami basin (see Fig. 1B for localities). Measured sec-tion 7A, at Aiweiergou, represents only portion of thick Lower Jurassic strata in western depression of Turpan-Hami (Tokesun Sag).Section 7B (photo in Fig. 3C) represents contemporaneous deposits in north-central depression (Tabei Sag). Generally, Lower Juras-sic deposits in Tabei Sag are not as thick and coarse as Lower Jurassic deposits in Tokesun Sag. Section 7C is from Kekeya locality.Paleocurrent indicators in measured section 7C are directed south to southeast, signifying reversal from previously north- to northeast-directed paleocurrent indicators in Permian and Triassic deposits. Middle Jurassic deposits from Sandaoling coal mine are described in section 7D. Numbered arrows signify positions of samples studied for palynology; interpreted ages and palynologi-cal assemblages for each sample are listed in legend (Abbink, 1999).


2 km

E90o05'

section 7C

E90o07'

N43o13'

N43o11'N

A. Kekeya locality

B. Trough cross-bedding in J1b deposits, section 7C


NC. Paleocurrent indicators

Figure 8. A: Corona Satellite photo of Kekeya locality showing loca-tion of section 7C. B: Trough cross-bedding associated with sand-richbraided-fluvial facies of Lower Jurassic Badaowan Formation (J1b)described in section 7C (photo is from 40 m mark of section 7C). Strati-graphic “up” is to upper right of photo. C: Stereoplot of measured paleocurrent indicators from section 7C. Mean vector indicates south-southwest sediment-dispersal direction.

section (Fig. 7A). We interpret this section to represent a sandymeandering depositional environment with associated crevassesplays, flood-plain, and overbank deposits. This interval con-sists of three main upward-fining successions (30–60-m thick),each consisting of basal scouring cross-bedded conglomerateand sandstone capped by siltstone, carbonaceous mudstone, andcoal with high mud content. In the lower portion (96–134 m),mudstone is interbedded with tabular fine-grained, trough cross-bedded sandstone beds (61 m thick) and a couple of 3–5-m-thick high-mud humic coal seams, abundant wood fragments,and plant material. The tabular sandstone layers most likelyrecord periodic flooding events or small chute channels de-posited on a meander flood plain. The next overlying section(134–196 m) upwardly fines from medium-grained, troughcross-bedded sandstone with rare 61 m conglomerate lenses tocoal and carbonaceous mudstone containing plant debris andnumerous concretions. This section could either represent pro-grading sandy bars or a meandering fluvial channel. The finalportion (205–236 m) consists of an upward-fining package witha scoured base and a basal conglomerate lag that abruptly finesto a medium- to coarse-grained, trough cross-bedded sandstonewith dispersed cobbles. We interpret these repeating upward-fining cycles to reflect small meander channels.

Taodongou (east Taoshuyuan). Excellent lateral exposureof J1b deposits can be observed near the Taodongou coal minein north-central Turpan-Hami (Fig. 3, A and C). Measured sec-tion 7B encompasses 65 m (represented by a white line in Fig. 3C) of mostly green-gray mudstone capped by a 4–5-m-thick coal seam. An 8-m-thick succession of amalgamated, fining-upward sandstone beds occurs midway through the sec-tion. These beds contain trough cross-beds mantled by pebbles,plane-bed stratification, and scoured basal contacts. Overall, theTaodongou J1b section records deposition on a flood plain,overbank environment with associated crevasse splays that areprobably part of larger meander-belt system. Hendrix et al.(1992) also examined lowermost Jurassic deposits at Taodon-gou that they interpreted to be from a braided-fluvial floodplain; however, no attempt is made to correlate the two sections.

Kekeya. Near the Kekeya coal mine (Figs. 1B and 8) wemeasured a detailed 44-m-thick section of J1b deposits (sec-tion 7C). The lowermost 4 m consist of coal interbedded withdark gray, carbonaceous shale containing abundant coaly woodfragments. These units are overlain by 40 m of amalgamated2–8-m-thick intervals of medium- to coarse-grained, troughcross-bedded sandstone. Silicified logs and casts to 0.5 m long,mud rip-up clasts, and basal conglomerate lags are all commonthroughout the section. Trough cross-bed orientations generallyindicate paleoflow to the south-southwest (Fig. 8, B and C). Onthe basis of the lack of lateral accretion surfaces and abundanterosional features with ubiquitous mud rip-up clasts and woodydebris, we interpret this succession to reflect sandy braided-fluvial or distal sheetflood sedimentation along a flood plain(Olsen, 1989; Miall, 1996).

Sandaoling. In the eastern Turpan-Hami basin, 50 kmnorthwest of Hami, we measured Middle Jurassic coaly strata

in the Sandaoling coal mine (Figs. 1B and 9). The base of sec-tion 7D contains a 12-m-thick coal seam, overlain by organic-rich interbedded coal and laminated mudstone with small (1 mthick) channelized sand bodies containing cross-bedding, coalfragments, and root casts (Fig. 9B). The channels appear to beisolated, with minimal evidence for lateral migration, and arebounded by flood-plain deposits. We interpret the depositionalenvironment as an anastomosed river deposited on a subaque-ous, deltaic flood plain, as Smith (1986) described for the Mag-dalena River in northwestern Columbia.

REGIONAL UNCONFORMITIES

Pre-Tertiary uplift of the Bogda Shan undoubtedly wouldhave affected the Mesozoic sedimentary fill of the Turpan-Hamibasin on a regional scale, and therefore might be expressed asregional unconformities. To test this hypothesis, we examinedsurface exposures, as well as nine different regional seismic re-flection lines throughout the Turpan-Hami basin (made avail-able by the Chinese National Petroleum Corporation). Theseismic lines were shot either parallel (east-west) or perpendicu-lar (north-south) to the basin axis, and were recorded down to&3.0 s (two-way traveltime). Two sets of two crossing seismic


A. Sandaoling locality

section 7D

B. Root casts in J2x deposits, section 7D

1 m

Figure 9. A: Outcrop of anastomosed river deposits described in sec-tion 7D (black line) from Middle Jurassic Xishanyao Formation (J2x)at Sandaoling coal mine (Figs. 1B and 7D). Note person for scale at bot-tom of photo. B: Photo of root casts (indicated by arrows) from 16 meter mark of section 7D. Stratigraphic “up” is to top for both photos.

line drawings are presented (see Fig. 1B for locations): T84–200and T88-635 in the west part of Turpan-Hami (Fig. 10, A and B),and T89-465 and T88-625 in the east (Fig. 10, C and D). Paly-nology from this study, as well as from the Turpan-Hami Petro-leum Bureau, provide age control for Permian through Jurassicreflectors intersecting the Ancan-1 and Ha-3 wells (Figs. 1B, 2,and 10, B and C).

On the basis of seismic line interpretations and outcrop observations, at least four different regional unconformities canbe identified (Fig. 1B): (1) Upper Permian–Lower Triassic (P2-T1); (2) Lower–Middle-Upper Triassic (T1-T2-3); (3) Lower-Middle Jurassic (J1-J2); and (4) Jurassic-Cretaceous (J-K).Because of the thick Jurassic through Tertiary section in thenorthern half of the basin (75 km in the Tabei Sag; Wu andZhao, 1997), no pre-Jurassic reflectors were imaged close to theBogda Shan.

An Upper Permian–Lower Triassic (P2-T1) angular uncon-formity occurs at the Aiweiergou locality (Fig. 11) and on seis-mic line T88-635 (Fig. 10B). It is important to note that althoughan Upper Permian–Lower Triassic angular unconformity is pre-sent in the southern and western portions of the basin, localitiesto the north in the southern Junggar basin (e.g., Jimsar; Fig. 1B)show conformable P2-T1 stratigraphy (Yang et al., 1986; Liao et al., 1987; Hendrix et al., 1992; Carroll et al., 1995; Tanget al., 1997).

At both Taodongou (east Taoshuyuan) and Zaobishan, anerosional unconformity marks a major sedimentologic breakfrom Lower Triassic sandstone and paleosols (T1) to deeplyscoured Middle-Upper Triassic (T2-3) conglomeratic deposits(Fig. 4, A and B). The T1-T2-3 unconformity is also expressedin the eastern side of seismic line T88-635 (Fig. 10B). A slightlyyounger intra-Upper Triassic unconformity appears in seismicline T88-625 (Fig. 10D).

Although we observed no exposures of the Lower-MiddleJurassic (J1-J2) contact, the J1-J2 unconformity is a convincingerosional surface on all of the seismic lines (Fig. 10, A, B, C,and D). In map view, the discordance persists for as much as 50 km on both strike and dip seismic lines (Figs. 1B and 10). It is especially important to understand this feature because Turpan-Hami basin petroleum source-rock intervals and reser-voirs are within Lower and Middle Jurassic strata (Huang et al.,1991; Wang et al., 1996; Wu and Zhao, 1997). Hence, this un-conformity has direct ramifications for the lateral preservationof source rocks and the geometry of petroleum traps.

A prominent Jurassic-Cretaceous (J-K) angular unconfor-mity appears in seismic line T89-465 in the eastern Hami area(Fig. 10C). Although we did not observe a J-K unconformity atFlaming Mountain, it is recognized by many Chinese publica-tions in the western Turpan-Hami area (Li and Shen, 1990; Zhaoet al., 1991a, 1991b; Mu, 1994; Wang et al., 1994).

PALEOCURRENT DATA

Paleocurrent indicator data from this study were collectedfrom limbs of trough cross-beds and from imbricated clasts influvial deposits. After correcting for structural dip, the three-dimensional planes of trough cross-beds were plotted as poleson a stereographic plot (lower hemisphere projection). The poleto a statistical best-fit great circle through all of the trough poledata describes the average paleocurrent direction for the de-posits (cf., DeCelles et al., 1983). For clast imbrication data,the pole of each restored imbrication plane was plotted on a rosediagram along with the mean vector (bin = 1°). Although thesmall number of paleocurrent indicators is not statistically sig-nificant, it is sufficient to define broad temporal and regionaltrends.

Figure 12 summarizes paleocurrent data from this study aswell as five other reports for Permian through Jurassic depositsof the Turpan-Hami and southern Junggar basins (Carroll, 1991;Zhao et al., 1991; Hendrix et al., 1992; Schneider et al., 1992;

0.0s

1.0s

2.0s

T87-450 T87-620D T88-456 T89-459 T88-462 T93-663

T89-465

K

T3hs

T2-3k

T1

T87-467 T89-470 T88-473 T89-476 T89-478 T89-481 T89-482

poor data

T89-484 T96-486 T89-489 T88-4930.0s

1.0s

WT88-62510 km

E

ST93-613

T1

T2-3k

K

T89-615E T88-620

T88-625

T87-630 T88-635 T91-640 T87-665 T89-667

(poor data)

?

T91-673 T88-677 T91-683 T89-687T89-681 T89-689

Ha-3 well

T90-692N

J2

J1

T3

2.0s

3.0s

T89-46510 km

1.0s

2.0s

3.0s

T3h

T3hs

J2x

J2x

J1b

T3h

1

2

3

SP Resistivity

(km)

1.0s

1

2

4SP Resistivity

(km)

N

1.0 s

2.0 s

unresolvedstructurearea

unresolved

1.0 s

2.0 s

S

?

Naiqian-4 wellNaiqian-5 well

T88-635

T86-642 T86-646 T87-199 T84-650 T86-654 T86-658

surface control at Flaming MountainJ2 J3

T84-20010 km

Legendbase Tertiary unconformity (T)

base Cretaceous unconformity (K)

base Middle Jurassic unconformity (J1-J2)

intra-Triassic unconformity (T1-T2-3 or T3-T3)

fault

truncated reflector

name of seismic crossline T86-658

685 m

J2

J1

1.0 s

2.0 s

3.0 s

1.0 s

2.0 s

3.0 s

ET84-200

T88-175T86-165 T84-165T87-156T85-637T86-150T84-145

T86-140T86-638W

T1

Ancan-1 well

T194-82

10 km T88-635

J2

P2

T1

T2-3

T2-3

P23

T2

J2

T84-625

B

C

D

A

Figure 10. Line drawings of four reflection seismic time profiles (seconds are in two-way traveltime) across Turpan-Hami basin(see Fig. 1B for locations). Lines T84-200 (north-south trending) and T88-635 (east-west) are from western portion of basin, nearTabei Sag, and lines T89-465 (north-south) and T88-625 (east-west) are from eastern portion of basin, near Hami. Ancan-1 (totaldepth 4222 m) and Ha-3 (total depth 3001 m) wells provide stratigraphic control for lines T88-635 and T89-465, respectively. For-mation abbreviations (see Fig. 2 for key) for specific reflectors are indicated where age control is sufficient. Boxed intervals withineach well are expanded in Figure 2 with their corresponding palynological age interpretations. Tu-Ha Petroleum Bureau providedseismic ties to wells, based on extensive previous experience with seismic interpretations basinwide. Cross-lines are labeled at topof each seismic line drawing. Note Lower Jurassic–Middle Jurassic (J1-J2) unconformity that appears on all lines (parts A, B, C,D). Also note intra-Triassic deformation on lines T88-635 (part B) and T88-625 (part D), as well as Permian-Triassic (P2-T1) un-conformity near Ancan-1 well (part B).


~40 m

~40 m

Lower Jurassic

Lower Triassic

Upper Permian

truck

road

x

x

A.

B.

Figure 11. A: Angular unconformity at Aiweiergou (westernmost Turpan-Hami) between Upper Permian rocks(P2t) and Lower Triassic red beds (T1j).See Figure 1B for location. B: Line trac-ing interpretation of photo in part A.Squiggle lines denote approximate lo-cation of P2-T1 unconformity; truck(highlighted with box) hauling coal provides scale. X indicates sampled forpalynology. Middle-Late Permian age is based on presence of Klausipollenitesschaubergeri and of Alisporites/Falcis-porites cpx. (Abbink, 1999). See Fig-ure 7A (legend) for Lower Jurassic palynological assemblage (section 7Awas measured along strike from this exposure).

Carroll et al., 1995; Yu et al., 1996). At the Taoshuyuan localityin northern Turpan-Hami, previous workers noted a reversalfrom northward-directed paleocurrent indicators in Permianstrata (Carroll et al., 1995) to southward-directed paleocurrentsin Lower Jurassic strata (Hendrix et al., 1992), suggesting aninitial uplift of the Bogda Shan between Permian and EarlyJurassic time. Yu et al. (1996) reported divergent paleocurrentsin Lower Jurassic deposits on either side of the Bogda Shan, im-plying that the Turpan-Hami and Junggar basins were separatedby Early Jurassic time or earlier. However, Shao et al. (1999b)presented paleocurrent data from Lin (1993) for both sides ofthe Bogda Shan that suggested convergent Lower Jurassic de-positional systems that drained into a Bogda Shan depocenter.

This study presents paleocurrent indicator data from four lo-calities in the Turpan-Hami basin. Upper Permian cobble clast im-brication at Aiweiergou suggests east-directed sediment transport(Fig. 12A). At Zaobishan, trough cross-bedding in Lower Triassicbraided-fluvial deposits (Fig. 6) indicates a general northeastwardpaleocurrent direction, consistent with paleoflow off the ancestralTian Shan, south of the Turpan-Hami basin. The Shisanjianfanglocality also contains Lower to Middle Triassic braided-fluvial de-posits with northeastward-directed paleocurrent indicators (Figs.4E and 12A). These data differ markedly from measurements oftrough cross-bedding from Lower Jurassic fluvial deposits atKekeya that indicate transport to the south (Figs. 8C and 12B).Collectively, we interpret these paleocurrent data and data from

BOGDA SHAN

CHOLTAGH

southern Junggar basin

Turpan-Hami basin

Manastotal Mesozoic(n = 241)

BOGDA SHAN

CHOLTAGH

Taoshuyuan

southern Junggar basin

Legend50 kmN

Turpan-Hami basin

Late Paleozoicgranitoid rocks

1 Hendrix et al., 19922 Carroll et al., 1995 and Carroll, 19913 Yu et al., 19964 Schneider et al., 19925 X. Zhao et al., 19916 this study

Mesozoic rocks

Paleozoic rocks

Cenozoic rocks

paleocurrent references

A. Permian-Triassic

B. Jurassic

AiweiergouP2d, pebble imbrication

(n = 48)

TianchiJ2x, J2t

XishanyouJ3q

(n = 12)

Manas total Mesozoic(n = 241)

Taoshuyuan

J1b(n = 11)

(n = 40)

KekeyaJ1b, trough limbs

(n = 34)

Zaobishan

(n = 94)(n = 143)

Shisanjianfang

(n = 17)(n = 51)

trough limbs

trough trough limbspebble imbrication

ToutunheJ1

(n = 46)

Baiyang River

J1b, pebbleimbrication

Meiyaogou

J1b, foresets

Baiyanghe

J1b, pebble imbrication

(n = 12)pebble imbrication

pebble imbrication

pebble imbrication

Jimsar

(n = 17)

Qijiagou

T2-3(n = 43)

T1-2

Dalongou

T1

trough axes

(n = 66) (n = 79)P2w

PermianundividedUrumqi

P2

(n = 10)

(n = 48)

Permianundivided Pd2

T1P2

T2-3

11

1

1

3

63

3

4

11

2

5

2

1

2 6

6

1,2

J1b, pebbleimbrication

Subashigou3

6 limbs

E90E88E86 E92

N44

N42

E90E88E86

E92

N44

N42

Figure 12. Summary of all paleocurrent indicator data from this study as well as from five other studies (see legend for list of references). Notereversal from north-directed paleocurrents in Permian-Triassic time (A) to south-directed paleocurrents during Jurassic time (B). See text for dis-cussion of paleocurrent indicator data format.


previous reports to reflect northward pre-Jurassic transport in theTurpan-Hami basin, off the ancestral Tian Shan located to thesouth, followed by a reversal to south-directed paleoflow duringJurassic time as the ancestral Bogda Shan was uplifted.

SANDSTONE AND CONGLOMERATE PROVENANCE

Provenance studies of Mesozoic sedimentary strata withinthe Turpan-Hami basin are an especially powerful tool for pale-ogeographic reconstruction, because the Paleozoic rocks ex-posed in the ranges surrounding the Turpan-Hami basin arecompositionally different from each other (Wen, 1991; Hopsonet al., 1998). The Bogda Shan, located north of the Turpan-Hamibasin, consists almost entirely of intermediate to mafic vol-canics and related plutonic rocks (Chen et al., 1985). Felsic plu-tonic rocks are very minor in modern exposures of the BogdaShan (Fig. 1B). In contrast, the central and south Tian Shanblocks to the south and west of Turpan-Hami (Fig. 1A) containnumerous exposures of late Paleozoic granitoids (Wen, 1991;Hopson et al., 1998), emplaced during the final phase of tectonicamalgamation of the Tian Shan (Tilton et al., 1986; Coleman,1989; Feng et al., 1989; Kwon et al., 1989). In order to use thecomposition of Mesozoic sedimentary strata to constrain the ini-tial timing of uplift of the Bogda Shan, we focused our effortson the northern flanks of the Turpan-Hami basin, located clos-est to present-day exposures of the Bogda Shan and currently re-ceiving erosional detritus from that mountain range (Graham et al., 1993). Our rationale was that these localities should havebeen the first to receive sediment unequivocally derived fromthe Bogda Shan. In our provenance studies, outlined in the fol-lowing, we use sandstone petrography and conglomerate clastcounts to infer that Lower Triassic deposits were derived solelyfrom the central and south Tian Shan blocks, south of the Turpan-Hami basin, and that the ancestral Bogda Shan had not beenuplifted by that time.

Sandstone framework grains

Sandstone point-count data from this study are comparedwith similar data from upper Paleozoic and Mesozoic sandstonefrom the Turpan-Hami basin (Carroll et al., 1995; Shao et al.,

1999a; Hendrix, 2000; Fig. 13). We point-counted a small set ofTriassic sandstone samples (n = 7) from the Turpan-Hami basin,using a modified Gazzi-Dickinson method (see Graham et al.,1993, for detailed techniques; Dickinson and Suczek, 1979;Dickinson, 1985). The raw point-count data (Table 1) were nor-malized into detrital modes following the methods of Ingersollet al. (1984) and plotted on standard ternary diagrams (Fig. 13)in order to provide direct comparison with previous provenancestudies in the area (e.g., Carroll, 1991; Hendrix, 2000).

Despite the relatively small number of samples counted forthis study (Table 1), when integrated with data from previousworkers, several important trends appear to characterize Per-mian through Lower Jurassic sandstone samples from the Turpan-Hami basin. Carboniferous and Permian sandstone con-tains abundant volcanic lithic grains and plagioclase feldspar(Fig. 13; mean Qm4F41Lt55, Qp1Lvm95Lsm4, and Qm10P84K6).We interpret the lithic-rich Carboniferous and Permian samplesto reflect erosional unroofing of volcanic cover strata from thesouthern Tian Shan, a conclusion supported by north-trendingpaleocurrent indicators from these strata (Fig. 12A; Carroll et al., 1990; Shao et al., 1999b). Jurassic sandstone is also richin lithic-volcanic grains (mean Qm23F21Lt56, Qp12Lvm56Lsm32,and Qm53P27K20), but Hendrix (2000) interpreted these compo-sitions to reflect erosional unroofing of volcanic strata in theBogda Shan, consistent with south-directed paleocurrent mea-surements in the northern Turpan-Hami basin (Fig. 12B). Incontrast to lithic volcanic-dominated Carboniferous, Permian,and Jurassic sandstone samples from the Turpan-Hami basin areTriassic sandstone compositions containing lower modal per-centages of total lithic grains (Lt) and higher percentages ofpotassium feldspar (mean Qm29F29Lt42, Qp23Lvm49Lsm28, andQm51P25K24). Greene et al. (1997) interpreted these composi-tional characteristics to reflect Triassic erosional unroofing oflate Paleozoic granites in the central and south Tian Shan, con-sistent with northeastward-directed Triassic paleocurrent indi-cators (Fig. 12A). Shao et al. (1999a) described a simpleunroofing history based on point counts of Turpan-Hami sand-stones that showed mean values in QFLt%Lt decreasing andQFLt%Q increasing from Permian through Tertiary time; no-tably, they showed no increase in quartz or feldspar content forTriassic samples.


Qm

F Lt

Qm

KP

Jurassic(n = 6)Triassic

(n = 7)

Carboniferous-Permian(n = 4)

MagmaticArc

ContinentalBlock

RecycledOrogen

Circum-PacificVolcanoplutonic

Carboniferous-Permian(n = 4)

Triassic(n = 7)

Jurassic(n = 6)

Qp

LsmLvm

Carboniferous-Permian(n = 4) Jurassic

(n = 6)

Triassic(n = 7)

Arc Orogen

Collision suture,fold-thrustbelt

subduction complex

Figure 13. Summary of sandstoneprovenance point-count data ofTurpan-Hami basin. Means (closedsquares) and standard deviationfields (polygons; 1s) are shown foreach time slice. Global provenancesuites proposed by Dickinson andSuczek (1979) are provided forcomparison. Qm, monocrystallinequartz; F, total feldspars; Lt, to-tal lithic grains; K, potassiumfeldspar; P, plagioclase; Qp, poly-crystalline quartz + chert; Lvm,volcanic and metavolcanic lithics;Lsm, sedimentary + metamorphiclithics. All Mesozoic data, exceptTriassic data from Turpan-Hamibasin (this study), are from Hendrix(2000); all Paleozoic data are fromCarroll (1991). Although data aretoo few to be statistically signifi-cant, they are sufficient to definebroad temporal and regionalchanges in sandstone composition.Note relative enrichment in QmFLt%Qm and QmPK%K forTriassic sandstone as well as over-all enrichment in Qm for Mesozoicsandstone relative to Paleozoicsandstone.

Conglomerate data

We conducted conglomerate clast lithology counts at fourlocalities along the northern basin rim: Taoxigou (westTaoshuyuan), Aiweiergou, Zaobishan, just north of the town ofShisanjianfang, and Kekeya (Figs. 1B and 14). Permian con-glomerate at Taoxigou consists mainly of limestone clasts mostlikely derived from the underlying marine Upper Carboniferousdeposits (Carroll et al., 1995). At Aiweiergou, Upper Permianconglomerate (P2d) consists mainly of intermediate and maficvolcanic clasts. At Zaobishan, conglomerate clasts in Lower Tri-assic fluvial deposits contain anomalously high percentages of pink granitic and aplitic dike rock cobbles (32%), whereasMiddle-Upper Triassic conglomerate is dominated by veinquartz and mafic and intermediate volcanic compositions (Fig. 14). At Shisanjianfang, Middle-Upper Triassic clast lithol-ogy is dominantly intermediate and mafic and felsic volcanicsas well as granitic clasts. Lower Jurassic conglomerate atKekeya has a well-mixed population of clast lithologies, al-though granitic clasts are notably absent. Yu et al. (1996) alsoreported conglomerate clast percentages for Lower Jurassicstrata at Baiyang River and Taoshuyuan: high proportions ofvolcanic clasts (80% and 95%, respectively) and low percent-ages of granitic clasts (0% and 15%, respectively).

High percentages of felsic plutonic clasts in Lower Triassicdeposits at Zaobishan contrast sharply with Permian and Juras-sic conglomerate containing few or no felsic plutonic clasts(Fig. 14). We interpret this to reflect deeper erosion and unroof-ing of exposed Paleozoic granites in the central and south TianShan, consistent with sandstone compositions and northward-directed paleocurrents. Granitic clasts are also very rare in Upper Permian strata at Aiweiergou and Zaobishan, where con-glomerate is dominated by intermediate volcanic clasts mostlikely derived from erosion of Carboniferous andesitic coverstrata (Carroll et al., 1995).

DISCUSSION

Tectonic setting of the North Tian Shan–Bogda Shan block

Details regarding the Paleozoic tectonic setting of the NorthTian Shan–Bogda Shan (NTS/BS) block are uncertain, yet haveobvious implications for the subsequent fill of the Turpan-Hamibasin. For example, if the Bogda Shan existed as an active islandarc until the Early Permian, as has been proposed by various au-thors (Hsü, 1988; Coleman, 1989; Wang et al., 1990;Allen et al.,1991, 1992; Fang, 1994; Mu, 1994), then it is unlikely that theTurpan and Junggar basins were depositionally linked during


0% 50% 100%

Conglomerate clast counts

felsic volcanicvein quartz

chert unknownfelsic plutonic

sedimentary

intermediate/mafic volcanic

intermediate-mafic plutonic

LEGEND: CLAST TYPES

Carbon-iferous

Low

erM

iddl

e/U

pper

Low

erU

pper

Daheyan (P2d)Taierlong (P2t)Quanzijie (P2q)Wutonggou (P2w)Guodikeng (P2g)

Badaowan (J1b)

Taoxigou (P1t)

basement

Shaofangou (T1s)

Jiucaiyuan (T1j)

Haojagou (T3h)

Huangshanja (T3hs)

Karamay (T2-3k)

Tria

ssic

Per

mia

nJu

rass

ic

Low

er/M

iddl

e

Age Formation

Songonhe (J1s)

Xishanyao (J2x)

Kekeya(J1b; section 7C)

n = 119

Zaobishan(T2-3k; section 4C)

n = 125

Shisanjianfang(T2-3k; section 4E)

n = 104

Zaobishan(T1s; section 4D)

n = 202

Aiweiergou (P2d)n = 113

Taoxigou:west Taoshuyuan (P1t)

n = 115

Location (Formation)number of counts

Figure 14. Composite stratigraphic chart with summary of conglomerate clast count data collected in Turpan-Hami basin. Although mostlymafic to intermediate clast compositions are dominant, felsic plutonic clasts in Lower Triassic conglomerate (T1s) at Zaobishan (measuredsection 4D) are higher than in underlying or overlying units.

Late Permian time. However, this scenario is in direct conflictwith concordant, north-directed paleocurrent indicators in theTurpan-Hami and Junggar basins (Fig. 12A) and isotopic prove-nance data that support post-Permian uplift of the Bogda Shan(Greene et al., 1997; Greene and Graham, 1999). Moreover, onthe basis of facies relations and organic geochemical attributes,many authors have reported contemporaneous Upper Permianorganic-rich lacustrine deposits on both sides of the Bogda Shanin the southern Junggar and Turpan-Hami basins, implying a

unified Junggar-Turpan-Hami lake system (Liu et al., 1979;Taner et al., 1988; Nishaidai and Berry, 1991; Carroll et al.,1992; Ren et al., 1994; Brand et al., 1993; Wang et al., 1996;Greene, 1997; Wartes et al., 1998, 1999, 2000).

Many Chinese authors refer to the Bogda Shan as either alate Paleozoic intracontinental rift belt disrupting a Devonian–Middle Carboniferous passive margin (Huang et al., 1991;Fang, 1990; Chen, 1993; Lin, 1993; Wang et al., 1996; Wu et al.,1996; Wu and Xue, 1997; Wu and Zhao, 1997; Y. Liu et al.,


1998), or as a focal point of extension due to mantle diapirismbeneath the Bogda Shan (Zhu and Zhao, 1992; Tao, 1994).These works, however, are largely conceptual in nature and pre-sent no outcrop, subsurface, or geochemical data that support alate Paleozoic Bogda rift.

Others agree that oceanic crust of unknown width and anassociated island arc complex, termed the North TianShan–Bogda Shan block, was being subducted under the north-ern margin of the Central Tian Shan block (also referred to asthe Yili microcontinent) during Carboniferous time; arc-relatedmagmatism ceased during the Late Carboniferous (Z. Wang etal., 1986; C. Wang et al., 1990; Zhou, 1987; Coleman, 1989;Hopson et al., 1989; Carroll et al., 1990, 1995; Windley et al.,1990; Allen et al., 1991, 1992; Wen, 1991; Sengör et al., 1993;Z. Cheng et al., 1996; Wu et al., 1996; Wu and Zhao, 1997).The precise temporal and spatial distribution and the polarityof subduction represented by the North Tian Shan–BogdaShan volcanic rocks, however, are uncertain (see Carroll et al.,1990, 1995; Windley et al., 1990; Allen et al., 1991, for discus-sion of possible paleogeographic scenarios). Carroll et al.(1995) interpreted 1 km of shallow-marine deposits andandesitic and dacitic volcanic flow rocks in the south andsouthwest Bogda Shan as representing an emergent Late Car-boniferous Bogda Shan island arc. If arc-related magmatismshut off soon after, this allows a time span of 20–30 m.y. forany topographic highs to be eroded before Late Permian depo-sition. We infer that such an episode of erosion is manifested inthe basinwide Carboniferous–Lower Permian angular uncon-formity observed throughout the Turpan-Hami basin (Fig. 1B;Liao et al., 1987; Carroll et al., 1999). This interpretation per-mits the Bogda Shan to be a part of a Late Carboniferous islandarc chain without being a physiographic barrier between theTurpan and southern Junggar basin during Late Permian andEarly Triassic time.

Allen et al. (1995) proposed that Permian–Triassic mag-matism in the Turpan-Hami basin was the result of transten-sional rotation within a Late Permian–Triassic sinistral shearsystem. In the Turpan-Hami basin, they based this on mapped(but undated) Lower Permian mafic volcanic rocks andtholeitiic dike rocks intruding late Paleozoic turbidites. Gab-broic bodies in the western Bogda Shan were interpreted as evi-dence of Permian magmatism by Windley et al. (1990) andAllen et al. (1991, 1995). However, an alternative interpretationis that the mapped gabbroic bodies of Chen et al. (1985) are hy-pabyssal intrusives from diorite-trondhjemite magmas that aretypical of arc magmatism (Clifford Hopson, 1999, personalcommun.). These rocks were analyzed by Hopson et al. (1989)and yielded a U-Pb radiometric age of 328 ; 10 Ma (Carbonif-erous); confirming the pre-Permian arc-related history of thewestern Bogda Shan (Carroll et al., 1995).

Carroll et al. (1999) reported several north-south–trendingmafic dike rocks in the Lower Permian Taoxigou Group at theTaoshuyuan locality (Fig. 1B). Their inferred Early Permian agederives from crosscutting relationships with shallow-marine

Upper Carboniferous rocks, which are in turn overlapped byUpper Permian lacustrine rocks. In addition, on the basis ofstratigraphic and sedimentologic relationships, Carroll et al.(1999) reported a large north-south–trending Lower Permiannormal fault with as much as 3 km of displacement. Both fea-tures are interpreted as indicators of Early Permian extension ina direction normal to earlier Devonian-Carboniferous east-west–trending compressional features.

Paleogeographic models

On the basis of the results of our study, along with data andinterpretations by other workers, we offer the following sce-nario for the paleogeographic and tectonic evolution of the Turpan-Hami basin (Fig. 15).

Late Permian. Shortening and folding of Upper Permianstrata occurred in the western and southern parts of Turpan-Hami (Fig. 15A). Subsequent latest Permian–earliest Triassicuplift of the Central Tian Shan resulted in beveling of UpperPermian strata, and deposition of Lower Triassic strata, asdemonstrated in outcrop at Aiweiergou (Fig. 11) and by seis-mic line T88-635 (Fig. 10B). Zhou (1997) and Dumitru et al.(this volume) inferred a period of rapid Permian-Triassic cool-ing in the Central Tian Shan, farther to the west, based onapatite fission-track data. Notably, the northern part of Turpan-Hami, as well as a southern Junggar locality (Jimsar), containcontinuous Permian through Triassic sections (Fig. 1B; Yang etal., 1986; Liao et al., 1987; X. Zhao et al., 1991; Tang et al.,1997), suggesting that these more distal localities were not af-fected by the deformation.

Several lines of evidence point to continuous Permian de-position across the Turpan-Hami and Junggar basins. Wartes et al. (1998, 1999, 2000) reported the existence of a large LatePermian Junggar-Turpan-Hami lake system represented by acomplex association of lake marginal and basinal facies on bothsides of the Bogda Shan. There are other reports of widespreadUpper Permian lacustrine deposition within at least four maindepocenters in the Turpan-Hami basin; however, no sedimento-logic or stratigraphic data have been presented (Allen et al.,1993, 1995; Mu, 1994; Wang et al., 1996; Wu and Zhao, 1997).Paleocurrent indicators suggest sediment dispersal from southto north, through the present-day Bogda Shan (Fig. 12A; Carroll, 1991; X. Zhao et al., 1991; Hendrix et al., 1992; Carrollet al., 1995). Coeval sandstone and conglomerate is extremelyvolcanic rich, indicating erosion of the extinct Carboniferousarc (Figs. 13 and 14).

Although we infer a proximal foreland setting for the Upper Permian deposits in Figure 15A, isopach trends for Per-mian strata are ambiguous, given the currently available data.Wu and Guo (1991) published north-south seismic lines be-tween Urumqi and Jimsar indicating northward thinning of Upper Permian deposits; in contrast, Carroll et al. (1992, 1995)and Wartes et al. (2000) reported Upper Permian thicknesses insouthern Junggar that greatly exceed those of Turpan-Hami.

NTS island arc

NTS island arc extinct NTS

x

xx x

x ++ +

CTS NTS-BS extinct island arc"suture zone"

Junggar-Turpan-Hami lake

xx

x x x x

xx x

x

xx

Z

Z'Z Z'

xx x

+++

Tian Shanfold-thrust belt

Z Z'xx x

x

xx x

x

Z

Z'

Z

Z'

x xx

x

x

x

x x

x x

xx

x

JUNGGAR-TURPAN-HAMI LAKE

Z Z'xx x

x

proto Bogda Shan

Late Permian

Triassic

Early-Middle Jurassic

coarse clastics

sandy clastics

fine clastics

Central Tian Shan (CTS) arc

North Tian Shan (NTS) andBogda Shan (BS) island arc

xx

+ ++ arc/within plate granites

mafic dikes

paleocurrentdirection

reverse/normalfault

unconformity

100 km N

foredeep

Tian Shan fold-thrust belt

CENTRAL TIAN SHAN

NTS Fault

NTS Fault

CENTRAL TIAN SHAN

CENTRAL TIAN SHAN

NTS Fault

no vertical scale

Bogda Shan ++

C.

B.

A.

Tian Shanfold-thrust belt

fault

granitic clasts

island arc

extinct

extinct

wedge-top

Figure 15. Schematic, nonpalinspastic paleogeographic model of study area from Late Permian to Early-Middle Jurassic time. A: Subsequent toCarboniferous collision between the Central Tian Shan arc and the North Tian Shan–Bogda Shan island arc, north-vergent Tian Shan fold-thrustbelt began shedding debris into contiguous Turpan-Hami-Junggar basin. Large Late Permian lacustrine system spanned most of basin, with sed-iment dispersal generally directed north. During this time, Bogda Shan had not been uplifted (its present-day position is outlined). Greene andGraham (1999) also reported existence of Permian within-plate granites (cf. Pearce et al., 1984) in present-day Bogda Shan. See Wartes et al.(2000) and Carroll et al. (1995) for more detailed descriptions of Permian paleogeography. B: Triassic time was dominated by coarse-clastic de-position as compression in north-vergent Tian Shan fold-thrust belt continued. Several intra-Triassic unconformities in Turpan-Hami basin sug-gest repeated uplift and erosion of Tian Shan, although there is no break in sedimentation between Permian and Triassic time in southern Junggarbasin. Dissection of Tian Shan fold-thrust belt unroofed Central Tian Shan granitoid rocks (e.g., T1s deposits at Zaobishan; Fig. 14) as sedimentdispersal was still directed to north (Greene et al., 1997). C: By Early Jurassic time, shortening of Tian Shan fold-thrust belt continued, and BogdaShan became significant physiographic feature partitioning southern Junggar basin from Turpan-Hami. As thrusting initiated in Bogda Shan area,amalgam of faulted Carboniferous island-arc basement, recycled Permian and Triassic deposits, mafic dike rock, and within-plate granites be-came structurally displaced to create proto-Bogda Shan. Paleocurrents diverged away from Bogda Shan as sediment was ponded within inter-montane Turpan-Hami basin.


However, if we assume that the Turpan-Hami basin was in awedge-top position relative to a northward-vergent Tian Shanfold-thrust belt, then basinward stratal thickening of Upper Per-mian deposits toward the southern Junggar basin would be en-tirely permissible (cf. DeCelles and Giles, 1996). This wouldexplain the abundant regional and local unconformities near theorogenic wedge, the coarseness and extreme immaturity of Up-per Permian deposits, localized lacustrine deposits that possiblyformed in isolated piggy-back basins, and the northward-thick-ening of Upper Permian strata toward the Junggar foredeep(Fig. 15A).

Triassic. An abrupt change to coarser, more fluvial-alluvial–dominated environments characterizes most of the Tri-assic in the Turpan-Hami basin (Figs. 4 and 15B). As the centraland south Tian Shan became more dissected, felsic plutons wereunroofed and contributed erosional detritus to Lower Triassicfluvial deposits across the Turpan-Hami basin. The T1-T2-3 unconformity observed at Zaobishan (Fig. 4B), Taodongou(Figs. 3B and 4A), and in seismic line T88-635 (Fig. 10B) couldreflect deformation due to renewed uplift of the Tian Shan to the south, although this idea remains to be further tested. At amore regional scale, Hendrix et al. (1992) inferred an episode of Late Triassic uplift of the Tian Shan that resulted in largecoarse-clastic deposition in the southern Junggar and northernTarim basin.

Conglomerate and sandstone provenance data also sup-port Triassic unroofing of the Tian Shan via an increase of K-feldspar–rich felsic clasts and decrease in total lithic grains inLower and Middle Triassic braided-fluvial deposits (Figs. 14and 15). Based on isotopically enriched eNd initial values ofthese felsic clasts, Greene and Graham (1999) inferred a Cen-tral Tian Shan provenance. In addition, paleocurrent indicatorsat Zaobishan and Shisanjianfang are directed north to northeastaway from the ancestral Tian Shan (Fig. 12A). The paucity ofgranitic pebbles in modern drainages coming off the BogdaShan at Zaobishan and Taoxigou (west Taoshuyuan) is furthercircumstantial evidence supporting a non-Bogda Shan Triassicprovenance for the northern Turpan basin. All of these data to-gether imply that the Bogda Shan was not a significant positivephysiographic feature during Triassic time.

Early Jurassic through Middle Jurassic. Our analysis ofJurassic strata reveals a distinct change in depositional style inLower Jurassic deposits (Figs. 7 and 15C) represented by an in-crease in swampy, lacustrine, and meander-belt systems. A ma-jor reorganization of basin physiography and possibly the onsetof internal drainage in the basin is implied by the existence of aJ1-J2 unconformity across much of the basin (Fig. 10). Figure10 shows four examples of seismic lines where truncated LowerJurassic reflectors are overlapped by Middle Jurassic reflectors.Our palynological studies provide age control both above andbelow the unconformity in the Ha-3 well (Figs. 2 and 10C);Jurassic age control for seismic lines T84-200 and T88-635(Fig. 10, A and B) was provided by the Tu-Ha Petroleum Bureaufor the Naiqian-4, Naiqian-5, and Ancan-1 wells. In addition,

based on total thickness of Lower and Middle Jurassic strata(provided by the Tu-Ha Petroleum Bureau), we infer a shift inJurassic depocenters from the western Tokesun Sag to the north-central Taibei Sag (Fig. 1B). Notably, many other studies reporta widespread Triassic-Jurassic unconformity throughout theTurpan-Hami basin, although no age control data are presented(Wang et al., 1994; D. Li, 1995; W. Li, 1997; Qiu et al., 1997;Wu and Xue, 1997; Wu and Zhao, 1997).

Southward-directed paleocurrent indicators in the northernTurpan-Hami basin contrast with northward-directed indica-tors in the southern Junggar basin and thus suggest divergentsediment-dispersal patterns on both sides of the Bogda Shan forLower Jurassic strata (Fig. 12B; Hendrix et al., 1992; Schneideret al., 1992; Yu et al., 1996). Jurassic sandstone compositionscontain higher percentages of lithic-volcanic detritus, reflectingJurassic erosion of the Bogda Shan (Fig. 13). Hendrix (2000)noted increased percentages of radiolarian chert from Jurassicsamples on the northern and southern flanks of the Bogda Shanand suggested that the chert may have been derived from theJurassic unroofing of small, intraarc basins within the range. Inaddition, Chinese facies maps show Jurassic internal drainagepatterns confined by the Bogda Shan to the north and the TianShan to the south (Huang et al., 1991; Qiu et al., 1997; Wu andZhao, 1997), suggesting that by this time, the Turpan-Hamibasin had become a single depositional basin, separated fromthe southern part of the Junggar basin.

CONCLUSIONS

1. Uplift of the Bogda Shan occurred later than Early Triassictime. The composition of sandstone and conglomerate inLower Triassic strata on the north flanks of the Turpan-Hamibasin suggests derivation from late Paleozoic granite in theTian Shan to the south. This remains to be tested for south-ern Junggar Lower Triassic deposits. Because volumetricallysignificant granites are absent in the Bogda Shan to the north,we infer that the Bogda Shan was not being erosionally un-roofed during Early Triassic time.

2. Pre-Early Jurassic initial uplift of the Bogda Shan is sup-ported by paleocurrent indicators from Lower Jurassic stratathat are north directed north of the Bogda Shan but south di-rected south of the Bogda Shan. Pre-Jurassic uplift of theBogda Shan is also supported by lithic-volcanic–rich Juras-sic sandstone exposed along the northern and southern flanksof the Bogda Shan, inferred to have been derived from un-roofing of Carboniferous arc-related volcanics in the ances-tral mountain range.

3. Regional seismic reflection lines and outcrop studies indi-cate several intra-Mesozoic shortening events affected theTurpan-Hami basin. We interpreted angular unconformitiesof Upper Permian–Lower Triassic (P2-T1), Lower-Middle-Upper Triassic (T1-T2-3), Lower-Middle Jurassic (J1-J2),and Jurassic-Cretaceous (J-K) age, indicating that the


intra-Mesozoic shortening recorded in other basins of westernChina also affected physiography in the Turpan-Hami basin.

4. Continued uplift of the Bogda Shan during Early Jurassictime caused a major reorganization of depositional systemsin the Turpan-Hami basin and erosional beveling of LowerJurassic and older strata. Jurassic depositional systems in theTurpan-Hami basin were inundated with the supply of sedi-ment derived from erosion of the Bogda Shan, resulting in abasinwide J1-J2 angular unconformity. This feature couldhave been associated with a basinwide shift of Jurassic de-pocenters, from Early Jurassic deposition principally in thewestern depression (Tokesun Sag) to Middle Jurassic depo-sition principally in the north-central depression (Tabei Sag).

5. The post-Early Triassic constraints on initial uplift of theBogda Shan described in this chapter suggest that organic-rich Upper Permian lacustrine deposits in the Turpan-Hamibasin were likely contiguous with voluminous organic-richlacustrine deposits in the southern and central Junggar basin.Because these deposits are the primary petroleum sourcerock in the Junggar basin, the suggestion that their updipequivalents are present in the Turpan-Hami basin increasesthe petroleum source-rock potential of that basin.

ACKNOWLEDGMENTS

The Chinese National Petroleum Corporation and the Tur-pan-Hami Petroleum Bureau arranged invaluable logistical andtechnical support as well as access to outcrop and subsurfacedata. K. Cheng, X. Zeng, W. Wang, T. Hu, A. Su, and X. Zhangassisted greatly in interpreting the stratigraphy of the Turpan-Hami basin as well as providing access to key regional seismiclines and wells. A. Hessler provided outstanding field assistanceduring the 1997 season. Discussions with G. Ernst, A. Hanson,C. Hopson, J. Hourigan, L. Hsiao, C. Johnson, M. McWilliams,B. Ritts, X. Ying, Y. Yue, and D. Zhou improved this manuscript.We are grateful to C. Cooper, M. Allen, S. Vincent, and T. Law-ton for their constructive reviews. Acknowledgment is made tothe donors of The Petroleum Research Fund, administered bythe American Chemical Society, for partial support of this re-search (ACS-PRF32605-AC2). Additional funding came fromthe American Association of Petroleum Geologists and the Stan-ford University McGee Fund. Financial support during the termof this research project was also provided by the GraduateSchool of the University of Wisconsin and the Stanford-ChinaIndustrial Affiliates, an industrial consortium that has includedAgip, Arco, Chevron, Exxon, Japan National Oil Corporation,Mobil, Phillips, Shell, Statoil, Texaco, Triton, and Unocal.

REFERENCES CITED

Abbink, O.A., 1999, Palynology of outcrop and core samples from the Turpan-Hami basin, northwest China: Utrecht, The Netherlands, Laboratory ofPalaeobotany and Palynology Report 9916, 18 p.

Allen, M.B., Windley, B.F., Zhang, C., Zhao, Z.Y., and Wang, G.R., 1991, Basinevolution within and adjacent to the Tien Shan Range, northwest China:Geological Society of London Journal, v. 148, p. 369–379.

Allen, M.B., Windley, B.F., and Zhang, C., 1992, Paleozoic collisional tecton-ics and magmatism of the Chinese Tian Shan, central Asia: Tectono-physics, v. 220, p. 89–115.

Allen, M.B., Windley, B.F., Zhang, C., and Guo, J., 1993, Evolution of the Tur-pan basin, Chinese central Asia: Tectonics, v. 12, p. 889–896.

Allen, M.B., Sengör, A.M.C., and Natal’in, B.A., 1995, Junggar, Turfan, andAlakol basins as Late Permian to ?Early Triassic extensional structuresin a sinistral shear zone in the Altaid orogenic collage, central Asia: Geological Society of London Journal, v. 152, p. 327–338.

Brand, U., Yochelson, E.L., and Eagar, R.M., 1993, Geochemistry of Late Per-mian non-marine bivalves: Implications for the continental paleo-hydrology and paleoclimatology of northwestern China: Carbonates andEvaporites, v. 8, p. 199–212.

Campbell, J.E., and Hendry, H.E., 1987, Anatomy of a gravelly meander lobe inthe Saskatchewan River, near Nipawin, Canada, in Ethridge, F.G., et al.,eds., Recent developments in fluvial sedimentology: Society of Eco-nomic Paleontologists and Mineralogists Publication 39, p. 179–189.

Carroll, A.R., 1991, Late Paleozoic tectonics, sedimentation, and petroleum po-tential of the Junggar and Tarim basins, northwest China [Ph.D. thesis]:Stanford, California, Stanford University, 405 p.

Carroll, A.R., 1998, Upper Permian lacustrine organic facies evolution, southernJunggar Basin, northwest China: Organic Geochemistry, v. 28, p. 649–667.

Carroll, A.R., Graham, S.A., Hendrix, M.S., Chu, J., McKnight, C.L., Xiao, X.,and Liang, Y., 1990, Junggar basin, northwest China: Trapped late Paleo-zoic Ocean: Tectonophysics, v. 181, p. 1–14.

Carroll, A.R., Brassell, S.C., and Graham, S.A., 1992, Upper Permian lacustrineoil shales, southern Junggar basin, northwest China: American Associa-tion of Petroleum Geologists Bulletin, v. 76, p. 1874–1902.

Carroll, A.R., Graham, S.A., and Hendrix, M.S., 1995, Late Paleozoic amalga-mation of northwest China: Sedimentary record of the northern Tarim,northwestern Turpan, and southern Junggar basins: Geological Societyof America Bulletin, v. 107, p. 571–594.

Carroll, A.R., Wartes, M.A., and Greene, T.J., 1999, Sedimentary evidence forEarly Permian normal faulting, southern Bogda Shan, northwest China:Geological Society of America Abstracts with Programs, v. 31, no. 7,p. A369–A370.

Chen, M., 1993, Structural styles of the Turpan-Hami basin: Petroleum Explo-ration and Development, v. 20, no. 5, p. 1–7.

Chen, Z., Wu, N., Zhang, D., Hu, J., Huang, H., Shen, G., Wu, G., Tang, H., andHu, Y., 1985, Geologic map of Xinjiang Uygur Autonomous Region:Beijing, Geologic Publishing House, scale 1:2 000 000.

Cheng, K., Su, A., Zhao, C., and He, Z., 1996, Study of coal-generated oil in theTuha basin: 30th International Geological Congress, Progress in geol-ogy of China: Beijing, Geological Publishing House, p. 796–799.

Cheng, Z., Wu, S., and Fang, X., 1996, The Permian-Triassic sequences in thesouthern margin of the Junggar basin, and the Turpan basin, Xinjiang,China, in International Geologic Congress, 30th, Field Trip GuidebookT394: Beijing, Geological Publishing House, 25 p.

Clayton, J.J., Yang, J., King, J.D., Lillis, P.G., and Warden, A., 1997, Geo-chemistry of oils from the Junggar basin, northwest China: AmericanAssociation of Petroleum Geologists Bulletin, v. 81, p. 1926–1944.

Coleman, R.G., 1989, Continental growth of northwest China: Tectonics, v. 8,p. 621–636.

DeCelles, P.G., and Giles, K.A., 1996, Foreland basin systems: Basin Research,v. 8, p. 105–123.

DeCelles, P.G., Langford, R.P., and Schwartz, R.K., 1983, Two new methods ofpaleocurrent determination from trough cross-stratification: Journal ofSedimentary Petrology, v. 53, p. 629–642.

Dickinson, W.R., 1985, Interpreting provenance relations from detrital modesof sandstone, in Zuffa, G.G., eds., Provenance of arenites: Hingham,Massachusetts, D. Reidel Publishing Company, p. 333–361.


Dickinson, W.R., and Suczek, C.A., 1979, Plate tectonics and sandstone com-positions: American Association of Petroleum Geologists Bulletin, v. 63,p. 2164–2182.

Fang, G., 1990, Initial studies about Bogda Mountains late Palaeozoic aulaco-gen: Xinjiang Geology, v. 8, p. 133–141.

Fang, G., 1994, Paleozoic plate tectonics of eastern Tianshan mountains Xin-jiang, China: Acta Geologica Gansu, v. 3, p. 34–40.

Feng, Y., Coleman, R.G., Tilton, G., and Xiao, X., 1989, Tectonic evolution ofthe west Junggar region, Xinjiang, China: Tectonics, v. 8, p. 729–752.

Graham, S.A., Hendrix, M.S., Wang, L.B., and Carroll, A.R., 1993, Collisionalsuccessor basins of western China: Impact of tectonic inheritance on sandcomposition: Geological Society ofAmerica Bulletin, v. 105, p. 323–344.

Greene, T.J., 1997, Petroleum geochemistry of Upper Permian and Middle Juras-sic source rocks and oils of the Turpan-Hami basin, northwest China:American Association of Petroleum Geologists Bulletin, v. 81, p. 1774.

Greene, T.J., and Graham, S.A., 1999, Isotopic provenance of Devonian-agedgranitic cobbles and geochemistry of Bogda Shan granitoids markingthe inception of the Turpan-Hami basin, northwest China: GeologicalSociety of America Abstracts with Programs, v. 31, no. 7, p. A374.

Greene, T.J., Carroll, A.R., Hendrix, M.S., and Li, J., 1997, Permian-Triassicbasin evolution and petroleum system of the Turpan-Hami Basin, Xin-jiang Province, northwest China: American Association of PetroleumGeologists and Society of Economic Paleontologists and MineralogistsAnnual Meeting Abstracts, v. 6, p. 42.

Greene, T.J., Carroll, A.R., Hendrix, M.S., Cheng, K., and Zeng, X.M., 2000,Sedimentology and paleogeography of the Middle Jurassic Qiketai For-mation, Turpan-Hami basin, northwest China, in Gierlowski-Kordesch,E., and Kelts, K., eds., Lake basins through space and time: AmericanAssociation of Petroleum Geologists Studies in Geology 46, p. 141–152.

Hendrix, M.S., 2000, Evolution of Mesozoic sandstone compositions, south-ern Junggar, northern Tarim, and western Turpan basins, northwestChina: A detrital record of the ancestral Tian Shan: Journal of Sedi-mentary Research, v. 70, p. 520–532.

Hendrix, M.S., Graham, S.A., Carroll, A.R., Sobel, E.R., McKnight, C.L.,Schulein, B.J., and Wang, Z., 1992, Sedimentary record and climatic im-plications of recurrent deformation in the Tian Shan: Evidence fromMesozoic strata of north Tarim, south Junggar, and Turpan basins, north-west China: Geological Society of America Bulletin, v. 105, p. 53–79.

Hendrix, M.S., Graham, S.A., Amory, J.A., and Badarch, G., 1996, Noyon Uulsyncline, southern Mongolia: Lower Mesozoic sedimentary record of the tectonic amalgamation of central Asia: Geological Society ofAmerica Bulletin, v. 108, p. 1256–1274.

Hopson, C., Wen, J., Tilton, G., Tang, Y., Zhu, B., and Zhao, M., 1989, Paleo-zoic plutonism in east Junggar, Bogdashan, and eastern Tianshan,northwest China: Eos (Transactions, American Geophysical Union),v. 70, p. 1403–1404.

Hopson, C.A., Wen, J., and Tilton, G.R., 1998, Isotopic variation of Nd, Sr, andPb in Paleozoic granitoid plutons along an east Junggar-Bogdashan-Tianshan transect, northwest China: Geological Society of America Ab-stracts with Programs, v. 30, no. 5, p. 20.

Hsü, K.J., 1988, Relict back-arc basins: Principles of recognition and pos-sible new examples from China, in Kleinspehn, K.L., and Paola, C.,eds., New perspectives in basin analysis: New York, Springer-Verlag,p. 245–263.

Huang, D., Zhang, D., Li, J., and Huang, X., 1991, Hydrocarbon genesis ofJurassic coal measures in the Turpan Basin, China: Organic Geochem-istry, v. 17, p. 827–837.

Huang, P., 1993, An Early Jurassic sporopollen assemblage from the north-western margin of the Junggar Basin, Xinjiang: Acta Micropalaeonto-logica Sinica, v. 10, p. 77–88.

Ingersoll, R.V., Fullard, T.F., Ford, R.L., Grimm, J.P., Pickle, J.D., and Sares,S.W., 1984, The effect of grain size on detrital modes; a test of the Gazzi-Dickinson point-counting method: Journal of Sedimentary Petrology, v. 54, p. 103–116.

Kwon, S.T., Tilton, G.R., Coleman, R.G., and Feng, Y., 1989, Isotopic studiesbearing on the tectonics of the west Junggar region, Xinjiang, China:Tectonics, v. 8, p. 719–727.

Li, D., 1995, Hydrocarbon occurrences in the petroliferous basins of westernChina: Marine and Petroleum Geology, v. 12, p. 26–34.

Li, G., and Shen, S., 1990, On the formation and evolution of Turpan-Hamibasin and its characteristic of bearing oil and gas, Xinjiang: Bulletin ofXi’an Institute Geological and Mineral Resources no. 28: Beijing, Chi-nese Academy of Geological Sciences, p. 25–36.

Li, J., and Jiang, J., 1987, Survey of petroleum geology and the controlling fac-tors for hydrocarbon distribution in the east part of the Junggar basin:Oil and Gas Geology, v. 8, p. 99–107.

Li, W., 1997, Sequence stratigraphy of Jurassic in Taibei Sag, Turpan-Hamibasin: Oil and Gas Geology, v. 18, p. 210–215.

Liao, Z., Lu, L., Jiang, N., Xia, F., Sung, F., Zhou, Y., Li, S., and Zhang, Z., 1987,Carboniferous and Permian in the western part of the east TianshanMountains: Beijing, Eleventh Congress of Carboniferous Stratigraphyand Geology, Guide Book Excursion 4, 50 p.

Lin, J.Y., 1993, Sedimentary sequence of the Bogda Rift: Discussion about theformation and evolution of the entire intercontinental sedimentarybasin in the northern Xinjiang [Ph.D. thesis]: Xi’an, Northwest Uni-versity, 104 p.

Liu, H., 1986, Geodynamic scenario and structural styles of Mesozoic andCenozoic basins in China: American Association of Petroleum Geolo-gists Bulletin, v. 70, p. 377–395.

Liu, H., Lian, H., Cai, L., Xia, Y., and Liu, L., 1979, Evolution and structuralstyle of Tian Shan and adjacent basins, northwestern China: Earth Sci-ence, v. 19, p. 727–741.

Liu, L., and Di, S., 1997, Characteristics of Middle Jurassic sedimentation andreservoir pore evolution in Turpan Depression: Oil and Gas Geology, v. 18, p. 17–18.

Liu, L., Liu, Y., and Di, S., 1998, Sedimentation and diagenesis of Qiketai Forma-tion, in north Turpan Depression: Oil and Gas Geology, v. 19, p. 238–243.

Liu, Y., Wu, T., Cui, H., and Feng, Q., 1998, Paleogeothermal gradient and geo-logic thermal history of the Turpan-Hami basin, Xinjiang: Science inChina, ser. D, v. 41, p. 62–68.

Miall, A.D., 1996, The geology of fluvial deposits: Sedimentary facies, basinanalysis, and petroleum geology: Berlin, Springer-Verlag, p. 208–211.

Miall, A.D., and Gibling, M.R., 1978, The Siluro-Devonian clastic wedge ofSomerset Island, Arctic Canada, and some regional paleogeographic im-plications: Sedimentary Geology, v. 21, p. 85–127.

Mu, Z., 1994, Permian and Triassic formation distribution and palaeogeo-graphical pattern of Turpan-Hami basin: Xinjiang Petroleum Geology,v. 14, p. 14–20.

Nanson, G.C., and Croke, J.C., 1992, A genetic classification of flood plains:Geomorphology, v. 4, p. 459–486.

Nijman, W., and Puigdefábregas, C., 1978, Coarse-grained point bar structurein a molasse-type fluvial system, Eocene Castisent sandstone formation,south Pyrenean Basin, in Miall, A.D., ed., Fluvial sedimentology: Cana-dian Society of Petroleum Geologists Memoir 5, p. 487–510.

Nishidai, T., and Berry, J.L., 1991, Geological interpretation and hydrocarbonpotential of the Turpan basin (NW China) from satellite imagery: Jour-nal of Petroleum Technology, v. 13, p. 35–58.

Olsen, H., 1989, Sandstone-body structures and ephemeral stream processes inthe Dinosaur Canyon Member, Moenave Formation (Lower Jurassic),Utah, U.S.A.: Sedimentary Geology, v. 61, p. 207–221.

Ouyang, S., 1996, Spore-pollen assemblage from Bquinshan Group, Qinghaiand its geological age: Acta Palaeontologica Sinica, v. 35, p.1–25.

Ouyang, S., and Norris, G., 1988, Spores and pollen from the Lower TriassicHeshanggou Formation, Shaanxi Province, North China: Review ofPalaeobotany and Palynology, v. 54, p. 187–231.

Pearce, J.A., Harris, N.B.W., and Tindle, A.G., 1984, Trace element discrimi-nation diagrams for the tectonic interpretation of granitic rocks: Journalof Petrology, v. 25, p. 956–983.


Peng, X., Hu, B., and Liu, L., 1990, A restudy for pre-Bogda mountain foldedzone: Xinjiang Petroleum Geology, v. 11, p. 276–295.

Qiu, Y., Xue, S., and Ying, F., 1997, Continental hydrocarbon reservoirs ofChina: Beijing, Petroleum Industry Press, p. 87–104.

Rasmussen, K.A., and Romanovsky, V.V., 1995, Late Holocene climate changeand lake-level oscillation; Issyk-kul, Kyrgyzstan, Central Asia: Societyof Economic Paleontologists and Mineralogists Program and Abstracts,v. 1, p. 103.

Ren, Z., Jiang, H., Liu, Y., and Li, W., 1994, Organic geochemical characteriza-tion of the Permian-Jurassic source rocks in Aiweiergou and Taoyuanzisections on the bordering areas of the Tu-Ha basins: Experimental Pe-troleum Geology, v. 16, p. 1–9.

Schneider, W., Zhao, X., Long, N., Zhao, Y., and Falke, M., 1992, Sedimentaryenvironment and tectonic implication of Jurassic in Toutunhe area, Jung-gar basin: Xinjiang Geology, v. 10, p. 192–203.

Sengör, A.M.C., Natal’in, B.A., and Burtman, V.S., 1993, Evolution of the Altaid tectonic collage and Paleozoic crustal growth in Eurasia: Nature,v. 364, p. 299–307.

Sgibnev, V.V., and Talipov, M.A., 1990, Evolution of the Issyk-kul sedimenta-tion basin (Tien-Shan) during Quaternary [abs.]: 13th International Sedi-mentological Congress, v. 13, p. 202.

Shao, L., Li, W., and Yuan, M., 1999a, Characteristic of sandstone and its tec-tonic implications of the Turpan basin: Acta Sedimentologica Sinica, v. 17, p. 95–99.

Shao, L., Stattegger, K., Li, W., and Haupt, B.J., 1999b, Depositional style andsubsidence history of the Turpan Basin (NW China): Sedimentary Ge-ology, v. 128, p. 155–169.

Shen, J., 1990, The characteristics of petroleum geology in Chaiwopu basin:Xinjiang Petroleum Geology, v. 11, p. 297–310.

Smith, D.G., 1986, Anastomosing river deposits, sedimentation rates and basinsubsidence, Magdalena River, northwestern Colombia, South America:Sedimentary Geology, v. 46, p. 177–196.

Taner, I., Kamen-Kaye, M., and Meyerhoff, A.A., 1988, Petroleum in the Jung-gar basin, northwestern China: Journal of Southeast Asian Earth Sci-ences, v. 2, p. 163–174.

Tang, Z., Parnell, J., and Longstaffe, F.J., 1997, Diagenesis and reservoir po-tential of Permian-Triassic fluvial/lacustrine sandstones in the southernJunggar basin, northwestern China: American Association of PetroleumGeologists Bulletin, v. 81, p. 1843–1865.

Tao, M.X., 1994, Tectonic environmental analysis of Turpan-Hami basin: Onthe genetic relationship between basin and orogenic belt of continentalinner plate: Acta Sedimentologica Sinica, v. 12, p. 40–50.

Tilton, G.R., Kwon, S.T., Coleman, R.G., and Xiao, X., 1986, Isotopic studiesfrom the West Junggar Mountains, northwest China: Geological Societyof America Abstracts with Programs, v. 18, p. 773.

Wang, C., Ma, R., and Ye, S., 1990, Allochthonous terranes in eastern Tianshan,northwest China, in Wiley, T.J., et al., eds., Terrane analysis of China andPacific rim: Circum-Pacific Council for Energy and Mineral Resources,Earth Science Series, v. 13, p. 257–260.

Wang, C., Luo, B., and Zheng, G., 1993, Organic geochemical characteristicsand genesis of crude oils from the Terpan basin, China: Acta Sedimen-tologica Sinica, v. 11, p. 72–81.

Wang, C., Cheng, K., Xu, Y., and Zhao, C., 1996, Geochemistry of Jurassic coal-derived hydrocarbon of Turpan-Hami basin: Beijing, Petroleum Indus-try Press, 247 p.

Wang, C., Fu, J., Sheng, G., Zhang, Z., Xia, Y., and Cheng, X., 1998, Labora-tory thermal simulation of liquid hydrocarbon generation and evolutionof Jurassic coals from the Tu-Ha basin: Acta Geologica Sinica, v. 72,p. 276–284.

Wang, H., Liu, W., Chen, Y., Mou, Z., Li, B., and Zhu, H., 1997, Sedimen-tary microfacies and petroleum productivity of Sanjianfang For-mation in Wenxi-I and Wen-V blocks: Oil and Gas Geology, v. 18, p. 252–256.

Wang, S., Zhang, W., Zhang, H., and Tan, S., 1994, Petroleum geology of China:Beijing, Petroleum Industry Press, p. 411–414.

Wang, Z., Wu, J., Lu, X., Zhang, J., and Liu, C., 1986, An outline on the tectonicevolution of the Tian Shan of China: Chinese Academy of GeologicalSciences Institute of Geology Bulletin, v. 15, p. 81–92.

Wartes, M.A., Greene, T.J., and Carroll, A.R., 1998, Permian lacustrine paleo-geography of the Junggar and Turpan-Hami basins, northwest China:American Association of Petroleum Geologists Annual Convention, Ex-tended Abstracts, v. 2, p. A682.

Wartes, M.A., Carroll, A.R., and Greene, T.J., 1999, Permian sedimentary evo-lution of the Junggar and Turpan-Hami basins, northwest China: Geo-logical Society ofAmericaAbstracts with Programs, v. 31, no. 7, p.A291.

Wartes, M.A., Carroll, A.R., Greene, T.J., Cheng, K., and Ting, H., 2000, Per-mian lacustrine deposits of northwest China, in Gierlowski-Kordesch,E., and Kelts, K., eds., Lake basins through space and time: AmericanAssociation of Petroleum Geologists Studies in Geology 46, p. 123–132.

Wen, J., 1991, Geochronological and isotopic tracer studies of some granitoidrocks from Xinjiang, China: Constraints on Paleozoic crustal evolutionand granitoid petrogenesis [Ph.D. thesis]: Santa Barbara, University ofCalifornia, 163 p.

Windley, B.F., Allen, M.B., Zhang, C., Zhao, Z.Y., and Wang, G.R., 1990, Paleozoic accretion and Cenozoic redeformation of the Chinese TienShan range, central Asia: Geology, v. 18, p. 128–131.

Wu, C., and Xue, S., 1997, Sedimentology of petroliferous basins in China: Bei-jing, Petroleum Industry Press, p. 384–400.

Wu, T., and Zhao, W., 1997, Formation and distribution of coal measure oil-gasfields in Turpan-Hami Basin: Beijing, Petroleum Industry Press, 262 p.

Wu, T., Zhang, S., and Wang, W., 1996, The structural characteristics and hydrocarbon accumulation in Turpan-Hami coal-bearing basin: ActaPetrolei Sinica, v. 17, p. 12–18.

Wu, Z., 1986, Characteristics of evolution and division of tectonic structure inJunggar basin and the appraisal of gas and oil: Xinjiang Geology, v. 4,p. 20–34.

Wu, Z., and Guo, F., 1991, Second discussion of Bogda nappe tectonic and itsoil-gas accumulation: Xinjiang Geology, v. 9, p. 40–49.

Yang, J., Qu, J., Zhou, H., Cheng, Z., Zhou, T., Hou, J., Li, P., Sun, S., Li, Y.,Zhang, Y., Wu, X., Zhang, Z., and Wang, Z., 1986, Permian and Triassicstrata and fossil assemblages in the Dalongkou area of Jimsar, Xinjiang:Ministry of Geology and Mineral Resources Geologic Memoir, ser. 2,no. 3: Beijing, Geological Publishing House, 262 p.

Yu, C., Jiang, Y., and Liu, S., 1996, Jurassic sedimentary boundary between theJunggar and Turpan-Hami basins in Xinjiang: Sedimentary Facies andPalaeogeography, v. 16, p. 48–54.

Zhao, W., Li, W., and Yan, L., 1991a, Types, characteristics of oil-gas pools andhydrocarbon distribution regularities in Turpan-Hami basin: Oil and GasGeology, v. 12, p. 351–363.

Zhao, W., Yuan, F., and Zeng, X., 1991b, The structural characteristics of Turpan-Harmy basin: Acta Petrolei Sinica, v. 13, p. 9–18.

Zhao, X., Lou, Z., and Chen, Z., 1991, Response of alluvial-lacustrine depositsof Permian-Triassic Canfanggou Group to climate and tectonic regimein Dalonggou area, Junggar basin, Xinjiang: China Earth Sciences, v. 1,p. 343–354.

Zhou, D., 1997, Studies in the tectonics of China: Extensional tectonics of thenorthern margin of the south China sea; amalgamation and uplift of theTian Shan; and wedge extrusion model for the Altyn Tagh fault [Ph.D.thesis]: Stanford, California, Stanford University, 354 p.

Zhou, R., 1987, The advance on isotope geochronology of Xinjiang: XinjiangGeology, v. 5, p. 15–105.

Zhu, Y., and Zhao, J., 1992, Quaternary paleoglacier and neotectonic movement onthe northern slope of Bogda Mountain: Xinjiang Geology, v. 10, p. 40–50.

Manuscript Accepted by the Society June 5, 2000

Printed in the U.S.A.

Sedimentary record of Mesozoic deformation and inception of ...carroll/publications/pdf/Greene...

Documents

Transcript of Sedimentary record of Mesozoic deformation and inception of ...carroll/publications/pdf/Greene...