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Upper Permian Oil Shale Deposits of Northwest China: World’s Largest? Alan R. Carroll Department of Geology and Geophysics University of Wisconsin-Madison Largest Oil Shale Deposits Deposit Period Oil In Place (106 tons) United States (Green River Fm.) Tertiary 213,000 United States (Phosphoria) Devonian 35,775 United States (Eastern) Devonian 27,000 United States (Heath Fm.) Teriary 25,778 Russia (Olenyok basin) Cambrian 24,000 Republic of Congo ? 14,310 Brazil (Irati Fm.) Permian 11,448 (Dyni, J. R., 2006, Geology and Resources of Some World Oil-Shale Deposits: USGS Scientific Investigations Report 2005–5294, 42 p.) China Lake Basins Late Permian Early Jurassic Early Cretaceous Oligocene Late Permian Junggar-Turpan-Hami Lake (Carroll, and Wartes, 2003) • Permian Lake approximately equal in area to modern Caspian Sea Tectonic Setting • Junggar-Turpan-Hami basins part of Altaid orogenic collage, lie at center of Asia • Substrate has oceanic affinities; trapped or accreted ocean crust • Continuous non-marine sedimentation from Permian onward • Deformation focused on basin margins Map: Exxon Tectonic Basin Model • Compressional uplift of basin-bounding “walls” • Turpan-Hami basin in wedge-top position? Comparison to Green River Fm. • Similar or greater in area • Greater thickness • Silicic vs. carbonate-rich • Similar richness? Late Permian Lacustrine Deposits (Carroll, and Wartes, 2003) • Distributed in several basins • Post-Permian deformation • Outcrops in foothills of Bogda Shan (Jurassic and later uplift) Junggar South-North Cross Section Hongyanchi Fm. Lucaogou Fm. Jingjingzigou Fm (Carroll, and Wartes, 2003) • Regionally correlative interval up up to 2000+ m thick Tianchi Section (N. Bogda Shan) • Jingjingzigou, Lucaogou Fms. • Dominantly silicic mudstone, siltstone • Average 4% TOC over 800 m interval • Total outcrop thickness ≥1300 m (Carroll et al., 1992) Underfilled (Jingjingzigou Fm.) m-scale cycles shrinkage cracks dolomicrite (Carroll, 1998) Balanced-fill (Lucaogou, Taerlong Fms.) oil shale turbidites (Carroll, 1998) Overfilled (Hongyanchi Fm.) Silicic mudstone, freshwater limestone (Carroll, 1998) Organic Enrichment (Jingjingzigou, Lucaogou, Honyanchi Fms) Mean = 34.9 mg/g (samples ≥ 0.5% TOC) Mean = 64.4 mg/g Mean = 4% (all samples) (samples ≥ 5% TOC) Max. 225.7 mg/g Mean = 5.7% (samples ≥ 5% TOC) Max. 34.3% • Sample Interval ~ 10 m • ~1500 m total section (N = 153) Junggar Permian-Sourced Oils • Permian oils in northwestern, central, and eastern Junggar basin • Southern Junggar basin over-mature due to deep Mz-Cz. burial Conclusions • NW China Permian lacustrine deposits cover an area approximately equal to Caspian sea, and locally exceed 2 km in thickness • Based on LECO and Rock Eval measurements, maximum richness appears to be comparable to Green River Formation • Much of the original oil potential has already been expended by thermal maturation, due to deep post-Permian burial • Remaining resource likely very large, but detailed mapping and bulk assay data have not been published • Structural complexity will influence exploitation • These deposits are absent from previous global oil shale assessments, and surprisingly poorly known even within China • More work needed! Acknowledgements Collaborators Funding • Y. Liang • Stanford-China Industrial Affiliates • S. A. Graham • Donors of the Petroleum Research Fund, American Chemical Society • M. S. Hendrix • T. J. Greene • M. A. Wartes • Graduate School, University of Wisconsin For More Information Carroll, A. R., 1998, Upper Permian Lacustrine Organic Facies Evolution, Southern Junggar Basin, NW China: Organic Geochemistry, v. 28, p. 649-667. Carroll, A. R., and Bohacs, K. M., 2001, Lake Type Control on Hydrocarbon Source Potential in Nonmarine Basins: American Association of Petroleum Geologists Bulletin: American Association of Petroleum Geologists Bulletin, v. 85, p. 1033-1053. Carroll, A. R., and Wartes, M. A., 2003, Organic Carbon Burial by Large Permian Lakes, Northwest China, in Chan, M. A., and Archer, A. W., eds., Extreme depositional environments: mega end members in geologic time: Geological Society of America Special Paper 370, p. 91-104. Carroll, A. R., Brassell, S.C., and Graham, S.A., 1992, Upper Permian lacustrine oil shales of the southern Junggar basin, northwest China: American Association of Petroleum Geologists Bulletin, v. 76, p. 1874-1902. Carroll, A. R., Graham, S.A., and Hendrix, M.S., 1995, Late Paleozoic tectonic amalgamation of northwestern China: sedimentary record of the northern Tarim, northwestern Turpan, and southern Junggar basins: Geological Society of America Bulletin, v. 107, p. 571-594. 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 Paleozoic Ocean: Tectonophysics, v. 181, p. 1-14. Graham, S.A., Brassell, S., Carroll, A. R., Xiao, X., Demaison, G., McKnight, C.L., Liang, Y., Chu, J., and Hendrix, M.S., 1990, Characteristics of selected petroleum source rocks, Xinjiang Uygur Autonomous Region, China: American Association of Petroleum Geologists Bulletin, v. 74, p. 493-512. Wartes, M. A., Carroll, A. R., and Greene, T. J., 2002, Permian Stratigraphic Evolution of the Turpan-Hami Basin and Adjacent Regions, Northwest China: Constraints on Post-amalgamation Tectonic Evolution: Geological Society of America Bulletin, v. 114, p. 131-152. Wartes, M. A., Carroll, A. R., Greene, T. J., Cheng, K., and Hu, T., 2000, Permian lacustrine deposits of northwest China, in Gierlowski-Kordesch, E. H., and Kelts, K., eds., Lake Basins Through Space and Time: American Association of Petroleum Geologists Studies in Geology #46, p. 123-132.