Petrographic and geochemical characteristics of the lacustrine black shales from the Upper Triassic Yanchang Formation of the Ordos Basin, China: Implications for the organic matter accumulation
文献类型：期刊论文
| 作者 | Wang, Cheng1,4; Wang, Qinxian1; Chen, Guojun2; He, Long1,4; Xu, Yong2,4; Chen, Linying3; Chen, Duofu1,3 |
| 刊名 | MARINE AND PETROLEUM GEOLOGY
 |
| 出版日期 | 2017-09-01 |
| 卷号 | 86页码:52-65 |
| 关键词 | Black shale Organic matter accumulation Primary productivity Redox conditions Sedimentation rate Volcanic ash Upper Triassic Ordos basin |
| ISSN号 | 0264-8172 |
| DOI | 10.1016/j.marpetgeo.2017.05.016 |
| 文献子类 | Article |
| 英文摘要 | The lacustrine black shales in the Chang7 Member from the Upper Triassic Yanchang Formation of the Ordos Basin in Central China are considered one of the most important hydrocarbon source rocks. However, the mechanism of organic accumulation in the black shales remains controversial. To resolve the controversy, with the former paleontological data of Yanchang Formation and sedimentation rate data of the Chang7 black shales, we investigated the typical intervals of the Chang7 black shales (TICBS) which were obtained by drilling in Yaowan at the southern margin of the Ordos Basin and performed various sedimentary, isotopic and geochemical analysis, including the sedimentary petrography, pyrite morphology, total organic carbon (TOC) and total sulfur (TS), the ratio of pyritic Fe to total Fe (DOPT), major and trace elements, together with pyritic sulfur isotopes (delta S-34(py)). The high sulfur content, enrichment of redox-sensitive trace metals, and the lower sedimentation rate of the TICBS in addition to the presence of marine spined acritarchs and coelacanth fossils indicate that the TICBS were deposited in a lacustrine environment possibly influenced by seawater. The petrographic observations show a thick layer of black shale with interlayers of thin layered siltstone (silty mudstone) and laminated tuff, which were related to the turbidity currents and volcanism, respectively. The U/Th, C-S, and Mo-U covariations, pyrite morphology, DOPT, combined with the delta S-34(py), suggest that the deposition occurred beneath the anoxic-sulfidic bottom waters, which was intermittently influenced by the oxygen-containing turbidity. The Ni/Al and Cu/Al possibly show extremely high to high primary productivity in the water column, which might be connected with the substantial nutrients input from seawater or frequently erupted volcanic ash entering the lake. In addition, the coincidence of an increased abundance of TOC with increased P/Al, Ni/Al, Cu/Al and U/Th, as well as relatively consistent Ti/Al suggest that the accumulation of the organic matter might be irrelevant to the clastic influx, and was mainly controlled by the high primary productivity and anoxic-sulfidic conditions. Further, the covariations of TOC vs. P/Al and TOC vs. Ba/Al indicate that the high primary productivity led to the elevated accumulation and burial of organic matter, while the anoxic to sulfidic conditions were likely resulted from an intense degradation of the organic matter during the early diagenesis. In summary, the organic matter accumulation is ultimately attributed to the high primary productivity possibly resulted from seawater or volcanic ash entering the lake. (C) 2017 Elsevier Ltd. All rights reserved. |
| WOS关键词 | SULFUR ISOTOPE FRACTIONATION ; RARE-EARTH-ELEMENTS ; APPALACHIAN BASIN ; SEDIMENTARY-ROCKS ; MARINE-SEDIMENTS ; PYRITE FORMATION ; RICH SEDIMENTS ; BIOLOGICAL PRODUCTIVITY ; CONTINENTAL-MARGIN ; SULFATE REDUCTION |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000411296600004 |
| 出版者 | ELSEVIER SCI LTD |
| 资助机构 | National Natural Science Foundation of China(41321002 ; scientific and technological project B of the strategic precursor ; Chinese Academy of Sciences(XDB10000000) ; 41272144) ; National Natural Science Foundation of China(41321002 ; scientific and technological project B of the strategic precursor ; Chinese Academy of Sciences(XDB10000000) ; 41272144) ; National Natural Science Foundation of China(41321002 ; scientific and technological project B of the strategic precursor ; Chinese Academy of Sciences(XDB10000000) ; 41272144) ; National Natural Science Foundation of China(41321002 ; scientific and technological project B of the strategic precursor ; Chinese Academy of Sciences(XDB10000000) ; 41272144) |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/61944]  |
| 专题 | 地质与地球物理研究所_兰州油气中心 |
| 通讯作者 | Wang, Qinxian; Chen, Duofu |
| 作者单位 | 1.Chinese Acad Sci, Guangzhou Inst Geochem, CAS Key Lab Ocean & Marginal Sea Geol, Guangzhou 510640, Guangdong, Peoples R China 2.Chinese Acad Sci, Key Lab Petr Resources Res, Lanzhou 730000, Gansu, Peoples R China 3.Shanghai Ocean Univ, Coll Marine Sci, Shanghai Engn Res Ctr Hadal Sci & Technol, Shanghai 207306, Peoples R China 4.Univ Chinese Acad Sci, Beijing 100049, Peoples R China |
| 推荐引用方式 GB/T 7714 | Wang, Cheng,Wang, Qinxian,Chen, Guojun,et al. Petrographic and geochemical characteristics of the lacustrine black shales from the Upper Triassic Yanchang Formation of the Ordos Basin, China: Implications for the organic matter accumulation[J]. MARINE AND PETROLEUM GEOLOGY,2017,86:52-65. |
| APA | Wang, Cheng.,Wang, Qinxian.,Chen, Guojun.,He, Long.,Xu, Yong.,...&Chen, Duofu.(2017).Petrographic and geochemical characteristics of the lacustrine black shales from the Upper Triassic Yanchang Formation of the Ordos Basin, China: Implications for the organic matter accumulation.MARINE AND PETROLEUM GEOLOGY,86,52-65. |
| MLA | Wang, Cheng,et al."Petrographic and geochemical characteristics of the lacustrine black shales from the Upper Triassic Yanchang Formation of the Ordos Basin, China: Implications for the organic matter accumulation".MARINE AND PETROLEUM GEOLOGY 86(2017):52-65. |
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来源：地质与地球物理研究所
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