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Title: Upper Permian lacustrine oil shales, southern Junggar basin, northwest China

Abstract

Upper Permian organic-rich lacustrine mudstones (oil shales) that crop out in the southern Junggar basin rank among the richest and thickest petroleum source rock intervals in the world, with maximum TOC values reaching 34% and Rock-Eval pyrolytic yields (S[sub 2]) up to 200 kg HC/t rock. Lacustrine sedimentary facies define an overall transgressive-regressive cycle of approximately 2000 m gross thickness, which includes approximately 800 m of source rocks averaging 4.1% TOC and 26.2 kg HC/t rock. Basinal facies comprise silicic, organic-rich, laminated lacustrine mudstones and interbedded siltstones; organic matter contained in the mudstones ranges in composition from type I to type III. Basinal facies were deposited in a deep, oxygen-deficient, stratified lake. Lake-margin facies consist of nonlaminated siliciclastic mudstones, rippled dolomitic silstones and sandstones, and minor limestones. Maximum TOC values are approximately 6%. Desiccation cracks are common in the marginal facies, but evaporite minerals are rare or absent. Biomarker correlation parameters measured from rock extracts exhibit significant stratigraphic variability, but strongly support the hypothesis that Upper Permian lacustrine oil shales charge the giant Karamay field in the northwestern Junggar basin. Karamay oils are characterized by high relative abundances of [beta]-carotane. This characteristic is restricted to desiccated facies in the outcropmore » sections, however. We therefore propose that an abundance of [beta]-carotane indicates elevated environmental salinities during deposition of the oil shales. 16 figs., 9 tabs.« less

Authors:
; ;  [1]
  1. Stanford Univ., CA (United States)
Publication Date:
OSTI Identifier:
6914242
Resource Type:
Journal Article
Journal Name:
AAPG Bulletin (American Association of Petroleum Geologists); (United States)
Additional Journal Information:
Journal Volume: 76:12; Journal ID: ISSN 0149-1423
Country of Publication:
United States
Language:
English
Subject:
04 OIL SHALES AND TAR SANDS; CHINA; OIL SHALE DEPOSITS; EXPLORATION; OIL SHALES; CHEMICAL COMPOSITION; GEOLOGY; PERMIAN PERIOD; PYROLYSIS; ASIA; BITUMINOUS MATERIALS; CARBONACEOUS MATERIALS; CHEMICAL REACTIONS; DECOMPOSITION; ENERGY SOURCES; FOSSIL FUELS; FUELS; GEOLOGIC AGES; GEOLOGIC DEPOSITS; MATERIALS; MINERAL RESOURCES; PALEOZOIC ERA; RESOURCES; ROCKS; SEDIMENTARY ROCKS; SHALES; THERMOCHEMICAL PROCESSES; 040200* - Oil Shales & Tar Sands- Reserves, Geology, & Exploration

Citation Formats

Carroll, A R, Brassell, S C, and Graham, S A. Upper Permian lacustrine oil shales, southern Junggar basin, northwest China. United States: N. p., 1992. Web.
Carroll, A R, Brassell, S C, & Graham, S A. Upper Permian lacustrine oil shales, southern Junggar basin, northwest China. United States.
Carroll, A R, Brassell, S C, and Graham, S A. 1992. "Upper Permian lacustrine oil shales, southern Junggar basin, northwest China". United States.
@article{osti_6914242,
title = {Upper Permian lacustrine oil shales, southern Junggar basin, northwest China},
author = {Carroll, A R and Brassell, S C and Graham, S A},
abstractNote = {Upper Permian organic-rich lacustrine mudstones (oil shales) that crop out in the southern Junggar basin rank among the richest and thickest petroleum source rock intervals in the world, with maximum TOC values reaching 34% and Rock-Eval pyrolytic yields (S[sub 2]) up to 200 kg HC/t rock. Lacustrine sedimentary facies define an overall transgressive-regressive cycle of approximately 2000 m gross thickness, which includes approximately 800 m of source rocks averaging 4.1% TOC and 26.2 kg HC/t rock. Basinal facies comprise silicic, organic-rich, laminated lacustrine mudstones and interbedded siltstones; organic matter contained in the mudstones ranges in composition from type I to type III. Basinal facies were deposited in a deep, oxygen-deficient, stratified lake. Lake-margin facies consist of nonlaminated siliciclastic mudstones, rippled dolomitic silstones and sandstones, and minor limestones. Maximum TOC values are approximately 6%. Desiccation cracks are common in the marginal facies, but evaporite minerals are rare or absent. Biomarker correlation parameters measured from rock extracts exhibit significant stratigraphic variability, but strongly support the hypothesis that Upper Permian lacustrine oil shales charge the giant Karamay field in the northwestern Junggar basin. Karamay oils are characterized by high relative abundances of [beta]-carotane. This characteristic is restricted to desiccated facies in the outcrop sections, however. We therefore propose that an abundance of [beta]-carotane indicates elevated environmental salinities during deposition of the oil shales. 16 figs., 9 tabs.},
doi = {},
url = {https://www.osti.gov/biblio/6914242}, journal = {AAPG Bulletin (American Association of Petroleum Geologists); (United States)},
issn = {0149-1423},
number = ,
volume = 76:12,
place = {United States},
year = {Tue Dec 01 00:00:00 EST 1992},
month = {Tue Dec 01 00:00:00 EST 1992}
}