气候变化领域集成服务门户(CCPortal): Evolution of paleo-weathering during the late Neoproterozoic in South China: Implications for paleoclimatic conditions and organic carbon burial

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DOI	10.1016/j.palaeo.2020.109843
	Evolution of paleo-weathering during the late Neoproterozoic in South China: Implications for paleoclimatic conditions and organic carbon burial
	Ai J.; Zhong N.; George S.C.; Zhang Y.; Yao L.; Wang T.
发表日期	2020
ISSN	0031-0182
卷号	555
英文摘要	The late Neoproterozoic was a key transition time for Earth, involving turbulent fluctuations of the atmosphere-ocean system including Snowball Earth events, supercontinent reorganisation, and revolution of the nutrient cycle, all of which could have potentially triggered the development of increasingly complex life forms. To further investigate the temporal variations of paleoclimatic conditions and to better understand the burial of organic carbon during this interval, comprehensive geochemical and mineralogical analyses were performed on upper Neoproterozoic samples from the Cryogenian Datangpo, the Marinoan-age Nantuo, and the Ediacaran Doushantuo formations in South China. Geochemical compositions indicate that sedimentary rocks from the Doushantuo Formation have a provenance from granodiorite-like rocks, and the Datangpo samples likely have a mixed provenance of basalt and granite. The chemical index of alteration (CIA) values of black shales from the Datangpo and Doushantuo formations are in a similar range (65–85), indicating moderate chemical weathering under a relatively warm and humid climate. However, conspicuous low Rb/Sr ratios and enrichment of chemically immature minerals for the uppermost Doushantuo samples, are indicative of elevated physical erosion during the terminal Ediacaran. Furthermore, a negative correlation between corrected CIA (CIAcorr) and total organic carbon (TOC), and a positive correlation between organic carbon isotopic compositions (δ13Corg) and TOC, imply that supercontinent-related nutrient supply and concomitantly elevated marine primary productivity played an important role in organic carbon burial during the Ediacaran-Cambrian transition. In contrast, elevated chemical weathering under increased temperatures and intensity of the hydrological cycle occurred during the deposition of post-glacial shales from the Datangpo Formation and Member II of the Doushantuo Formation. Enhanced primary productivity fostered by chemical weathering-released nutrients and sequestration of organic carbon by pedogenic clay minerals generated under such climatic conditions, and probably redox condition variations, are inferred to have been the main control on organic carbon burial during this interval. © 2020 Elsevier B.V.
英文关键词	Black shale; Nutrient cycle; Organic carbon isotope; Oxygenation event; Provenance; Weathering
语种	英语
scopus关键词	atmosphere-ocean system; burial (geology); chemical weathering; climate conditions; nutrient cycling; organic carbon; paleoclimate; paleoenvironment; Proterozoic; supercontinent; weathering; China
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/150422
作者单位	State Key Laboratory of Petroleum Resources and Prospecting, College of Geosciences, China University of Petroleum-Beijing, Beijing, 102249, China; Department of Earth and Environmental Sciences, Macquarie University, Sydney, NSW 2109, Australia
推荐引用方式 GB/T 7714	Ai J.,Zhong N.,George S.C.,et al. Evolution of paleo-weathering during the late Neoproterozoic in South China: Implications for paleoclimatic conditions and organic carbon burial[J],2020,555.
APA	Ai J.,Zhong N.,George S.C.,Zhang Y.,Yao L.,&Wang T..(2020).Evolution of paleo-weathering during the late Neoproterozoic in South China: Implications for paleoclimatic conditions and organic carbon burial.Palaeogeography, Palaeoclimatology, Palaeoecology,555.
MLA	Ai J.,et al."Evolution of paleo-weathering during the late Neoproterozoic in South China: Implications for paleoclimatic conditions and organic carbon burial".Palaeogeography, Palaeoclimatology, Palaeoecology 555(2020).