气候变化领域集成服务门户(CCPortal): Reconstruction of paleoceanic redox conditions of the lower Cambrian Niutitang shales in northern Guizhou; Upper Yangtze region

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DOI	10.1016/j.palaeo.2019.109457
	Reconstruction of paleoceanic redox conditions of the lower Cambrian Niutitang shales in northern Guizhou; Upper Yangtze region
	Wu C.; Zhang L.; Zhang T.; Tuo J.; Song D.; Liu Y.; Zhang M.; Xing L.
发表日期	2020
ISSN	0031-0182
卷号	538
英文摘要	The paleoceanic redox conditions and the vertical and spatial distribution of organic-matter-rich lower Cambrian Niutitang shales are varied in the Upper Yangtze region, China. An integrated approach, including organic geochemistry, major and trace elemental geochemistry, and X-ray diffraction (XRD) mineralogy, was used to characterize changes in redox conditions and to determine key controls on organic-matter accumulation during deposition of the lower Cambrian Niutitang shales. A 202-m-long cored well located in Kaiyang County in northern Guizhou, China, was thoroughly characterized by the integrated approach in this study. Vertically, total organic carbon (TOC-) rich siliceous and argillaceous black shales were developed in the Lower and Middle Niutitang Formation, and TOC-lean silty shales were found in the Upper Niutitang Formation. The TOC content in the Lower and Middle Niutitang shales ranges from 0.27% to 6.7%, with an average value of 2.1%, and it decreases from 0.30% to 0.11% in the Upper Niutitang Formation shales. The TOC-rich siliceous shales in the Lower Niutitang Formation were characterized by high total sulfur content, enrichment in redox-sensitive trace elements, high Corg:P ratios, and high authigenic Mo[sbnd]U covariation, indicating they were deposited under persistent anoxic conditions. Most organic-rich shales from the Middle Niutitang Formation were deposited under anoxic conditions, whereas a few intervals having low TOC contents were deposited in a predominantly oxic depositional environment. In contrast, the Upper Niutitang Formation were deposited under fully oxic conditions. A combination of high primary productivity and enhanced organic preservation under euxinic water column conditions is the key control on organic-matter accumulation in the Lower Niutitang Formation shales. However, a coupling of redox depositional environment and terrestrial mineral dilution plays an important role in organic-matter accumulation and preservation in the Middle Niutitang Formation. Similar organic-matter abundance distribution and carbon isotope excursion of organic matter in the sediments deposited at different depositional facies on the Yangtze Platform suggest regional isotopically homogenous organic carbon input due to the widespread transgressive event with deep basinal waters being transported into the shallow shelf environments at the base of the lower Cambrian. As a result, δ13Corg distribution patterns can be used as a stratigraphic correlation marker in the Upper Yangtze region. © 2019 Elsevier B.V.
英文关键词	Niutitang Formation; Organic-matter richness; Organic-rich shales; Paleoredox conditions; Stratigraphic correlation
语种	英语
scopus关键词	Cambrian; carbon isotope; depositional environment; organic matter; paleoceanography; reconstruction; redox conditions; shale; spatial distribution; stratigraphic correlation; sulfur; total organic carbon; trace element; X-ray diffraction; China; Guizhou; Kaiyang; Yangtze Platform
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/150683
作者单位	Key Laboratory of Petroleum Resources, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu Province 730000, China; Bureau of Economic Geology, The University of Texas at Austin, Austin, TX 78713, United States; PetroChina Research Institute of Petroleum Exploration and Development, Beijing, 100083, China
推荐引用方式 GB/T 7714	Wu C.,Zhang L.,Zhang T.,et al. Reconstruction of paleoceanic redox conditions of the lower Cambrian Niutitang shales in northern Guizhou; Upper Yangtze region[J],2020,538.
APA	Wu C..,Zhang L..,Zhang T..,Tuo J..,Song D..,...&Xing L..(2020).Reconstruction of paleoceanic redox conditions of the lower Cambrian Niutitang shales in northern Guizhou; Upper Yangtze region.Palaeogeography, Palaeoclimatology, Palaeoecology,538.
MLA	Wu C.,et al."Reconstruction of paleoceanic redox conditions of the lower Cambrian Niutitang shales in northern Guizhou; Upper Yangtze region".Palaeogeography, Palaeoclimatology, Palaeoecology 538(2020).