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DOI	10.1016/j.epsl.2023.118164
	The large decline in carbonate 8238U from a PETM section at Tingri (South Tibet) was driven by local sea-level changes, not global oceanic anoxia
	Zhang, Qinghai; Ding, Lin; Chen, Xinming; Brennecka, Gregory A.; Sun, Yali; Ma, Xuesong; Gao, Bintao; Zhang, Qian; Willems, Helmut
发表日期	2023
ISSN	0012-821X
EISSN	1385-013X
卷号	612
英文摘要	Uranium isotope compositions (8238U) and Th/U in carbonates are being explored as paleoredox proxies to study global oceanic anoxia. However, the impact of changes to local depositional environments that might cause a decline in 8238U and an increase in Th/U has not been thoroughly investigated. Here we report a decline in 8238U (from +0.1 to -0.3%0) and an increase in Th/U from shallow-marine carbonates during the Paleocene-Eocene thermal maximum at Tingri (south Tibet). Changes of 8238U and Th/U are not fully coupled. The decline in 8238U coincided with a local sea-level fall, whereas the increase in Th/U occurred mainly during a sea-level rise. The decline in 8238U likely results from changes in redox conditions of pore waters and in primary carbonate mineralogy. The increase in Th/U is ascribed to reduced authigenic U(IV) accumulation. Our results suggest that changes in local depositional environments can cause behavior of 8238U and Th/U resembling that induced by expanded global oceanic anoxia. This finding calls for caution to consider local factors before applying 8238U and Th/U as global paleoredox proxies. (c) 2023 Elsevier B.V. All rights reserved.
关键词	uranium isotope paleoredox proxy oceanic anoxia Paleocene-Eocene thermal maximum sea-level changes south Tibet
英文关键词	RARE-EARTH-ELEMENTS; URANIUM ISOTOPE FRACTIONATION; EOCENE THERMAL MAXIMUM; MARINE ANOXIA; PORE WATERS; DEEP-SEA; SEAWATER; U-238/U-235; TEMPERATURE; SEDIMENTS
WOS研究方向	Geochemistry & Geophysics
WOS记录号	WOS:000984547400001
来源期刊	EARTH AND PLANETARY SCIENCE LETTERS
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/282970
作者单位	Chinese Academy of Sciences; Institute of Tibetan Plateau Research, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS; Shanghai Jiao Tong University; United States Department of Energy (DOE); Lawrence Livermore National Laboratory; University of Bremen
推荐引用方式 GB/T 7714	Zhang, Qinghai,Ding, Lin,Chen, Xinming,et al. The large decline in carbonate 8238U from a PETM section at Tingri (South Tibet) was driven by local sea-level changes, not global oceanic anoxia[J]. 中国科学院青藏高原研究所,2023,612.
APA	Zhang, Qinghai.,Ding, Lin.,Chen, Xinming.,Brennecka, Gregory A..,Sun, Yali.,...&Willems, Helmut.(2023).The large decline in carbonate 8238U from a PETM section at Tingri (South Tibet) was driven by local sea-level changes, not global oceanic anoxia.EARTH AND PLANETARY SCIENCE LETTERS,612.
MLA	Zhang, Qinghai,et al."The large decline in carbonate 8238U from a PETM section at Tingri (South Tibet) was driven by local sea-level changes, not global oceanic anoxia".EARTH AND PLANETARY SCIENCE LETTERS 612(2023).