气候变化领域集成服务门户(CCPortal): Hydrological controls on marine chemistry in the Cryogenian Nanhua Basin (South China)

CCPortal

DOI	10.1016/j.earscirev.2021.103678
	Hydrological controls on marine chemistry in the Cryogenian Nanhua Basin (South China)
	Cheng M.; Zhang Z.; Algeo T.J.; Liu S.; Liu X.; Wang H.; Chang B.; Jin C.; Pan W.; Cao M.; Li C.
发表日期	2021
ISSN	00128252
卷号	218
英文摘要	In order to explore Cryogenian seawater chemistry and its underlying controls, we present an integrated study of iron speciation, major and trace elements, and carbon isotopes of Mn‑carbonates and their host black shales in the Datangpo Formation from three drillcores (Gaodi, Xixibao and Changxingpo) in the Nanhua Basin, South China. A key aspect of this analysis was use of the B/Ga, Sr/Ba, and S/TOC proxies to evaluate paleosalinity variation in this marginal-marine basin. Our results indicate that salinity and redox conditions as well as cycling of Fe-Mn-Mo-C in the basin were hydrologically controlled by the relative fluxes of freshwater from riverine sources and seawater from open-ocean sources. Black shale deposition was associated with low-brackish salinity, probably due to reduced seawater exchange, which contributed to development of stagnant watermass circulation and euxinia in the basin. During such anoxic depositional intervals, Mo show gradient across the basin. In contrast, Mn‑carbonate deposition was associated with relatively higher salinity linked to enhanced exchange of the basinal watermass with the global ocean and to improved deep-water ventilation, which was due to sinking of higher-density ingressing open-ocean waters below lower-density basinal waters (as in the modern Baltic Sea). Enhanced decay of organic matter led to 12C-enriched dissolved inorganic carbon that was precipitated in Mn‑carbonates on the deep basin floor, leading to spatial gradient of inorganic carbon isotope. The shift from euxinic to ferruginous deep-water conditions during such intervals implies that ingressing oceanic waters were sulfate-poor relative to basinal waters. These depositional intervals were also characterized by operation of an active Mn–Fe shuttle that enhanced accumulation of Fe2+, Mn2+, Mo and CO32− in the deep watermass. Our findings demonstrate that the seawater chemistry of the Cryogenian Nanhua Basin was significantly influenced by hydrological factors of both local and global character, and that similarities should be expected for all Cryogenian epicratonic seas, providing new insights into Cryogenian oceanic chemistry evolution and the contemporaneous formation of widespread Mn‑carbonate mines. © 2021 Elsevier B.V.
关键词	Datangpo Formation Iron speciation Mn‑carbonate Redox Salinity Watermass exchange
英文关键词	black shale; carbon isotope; carbonate; iron; redox conditions; salinity; seawater; trace element; water chemistry; water exchange; China
语种	英语
来源期刊	Earth Science Reviews
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203990
作者单位	State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Wuhan), Wuhan, 430074, China; State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences (Wuhan), Wuhan, 430074, China; Department of Geology, University of Cincinnati, Cincinnati, 45221-0013, United States; Yantai Geological Survey Center of Coastal Zone, China Geological Survey, Yantai, 264000, China; School of Earth Sciences, China University of Geosciences (Wuhan), Wuhan, 430074, China; Yunnan Key Laboratory for Palaeobiology, Yunnan University, Kunming, 650091, China; Geological Brigade 103, Guizhou Bureau of Geology and Mineral Exploration and Development, Tongren, 554300, China; School of Geosciences, China University of Petroleum (East China), Qingdao, 266580, China
推荐引用方式 GB/T 7714	Cheng M.,Zhang Z.,Algeo T.J.,et al. Hydrological controls on marine chemistry in the Cryogenian Nanhua Basin (South China)[J],2021,218.
APA	Cheng M..,Zhang Z..,Algeo T.J..,Liu S..,Liu X..,...&Li C..(2021).Hydrological controls on marine chemistry in the Cryogenian Nanhua Basin (South China).Earth Science Reviews,218.
MLA	Cheng M.,et al."Hydrological controls on marine chemistry in the Cryogenian Nanhua Basin (South China)".Earth Science Reviews 218(2021).