Constraining the terminal Ediacaran seawater chemistry by Mg isotopes in dolostones from the Yangtze Platform, South China

doi:10.1016/j.precamres.2022.106700

	Constraining the terminal Ediacaran seawater chemistry by Mg isotopes in dolostones from the Yangtze Platform, South China
	Zhang, Pan 3; Huang, Kang-Jun 3; Luo, Mao 1,2; Cai, Yaoping 3; Bao, Zhian 3
刊名	PRECAMBRIAN RESEARCH
	2022-08-01
卷号	377 页码:18
关键词	Ediacaran Animal biomineralization Dolomite cement Seawater chemistry Mg isotopes
ISSN号	0301-9268
DOI	10.1016/j.precamres.2022.106700
通讯作者	Huang, Kang-Jun(hkj@nwu.edu.cn) ; Luo, Mao(maoluo@nigpas.ac.cn)
英文摘要	The advent of animal biomineralization at the terminal Ediacaran remarkably changed the marine ecological system. Changed seawater Mg/Ca ratio is considered as an important external trigger for this transition, but the intrinsic relationship between seawater Mg/Ca variation and animal biomineralization is not well constrained due to the lack of reliable archives. To constrain the coeval seawater chemistry and explore its role in the origin of metazoan biomineralization, we systematically conducted petrographical and geochemical investigations on dolostones from the terminal Ediacaran (similar to 551 Ma) Dengying Formation of the Yangtze Block in South China. The well-preserved sedimentary fabrics, growth zones as well as cathodoluminescent bands in microbialites and fibrous dolomite cements in the Algal Dolomite Member of the Dengying Formation indicate these dolomites were formed during syn-sedimentary diagenesis. The distribution patterns of rare earth elements in these dolomite components documented relatively anoxic shallow water conditions. Furthermore, negative correlations between O and Mg isotope compositions in well-preserved dolomite components indicate the variable mixture of freshwater with seawater in the shallow platform environment. The pervasive influence of freshwater on seawater indicates an enhanced riverine input, and it should be dominated by silicate weathering flux due to the heavier Mg isotopic compositions in freshwater endmember. Enhanced silicate weathering flux at the basal Dengying Formation may be related to the abundant erosions and exposures caused by the significant changes in Earth's surface tectonic and climatic conditions at the late Ediacaran. Consequently, the increased silicate weathering flux would deliver more Mg cations and net alkalinity to the oceans than the mixed weathering flux, which probably facilitated the subsequent skeletonization of early animals.
资助项目	National Natural Science Foundation of China[41973008] ; National Natural Science Foundation of China[41890845] ; National Natural Science Foundation of China[42072004] ; National Natural Science Foundation of China[42130206] ; Strategic Priority Research Program of Chinese Academy of Sciences[XDB26000000] ; Chinese Academy of Sciences Talents Program[2018-039]
WOS关键词	RARE-EARTH-ELEMENT ; MAGNESIUM-ISOTOPE ; DOLOMITE ; CARBONATES ; DIAGENESIS ; BIOMINERALIZATION ; EVOLUTION ; CERIUM ; BASIN ; SEAS
WOS研究方向	Geology
语种	英语
出版者	ELSEVIER
WOS记录号	WOS:000832987800005
资助机构	National Natural Science Foundation of China ; Strategic Priority Research Program of Chinese Academy of Sciences ; Chinese Academy of Sciences Talents Program
内容类型	期刊论文
源URL	[http://ir.nigpas.ac.cn/handle/332004/41120]
专题	中国科学院南京地质古生物研究所
通讯作者	Huang, Kang-Jun; Luo, Mao
作者单位	1.Chinese Acad Sci, Ctr Excellence Life & Palaeoenvironm, 39 East Beijing Rd, Nanjing 210008, Peoples R China 2.Chinese Acad Sci, State Key Lab Palaeobiol & Stratig, Nanjing Inst Geol & Palaeontol, 39 East Beijing Rd, Nanjing 210008, Peoples R China 3.Northwest Univ, Dept Geol, State Key Lab Continental Dynam, Shaanxi Key Lab Early Life & Environm, Xian 710069, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Pan,Huang, Kang-Jun,Luo, Mao,et al. Constraining the terminal Ediacaran seawater chemistry by Mg isotopes in dolostones from the Yangtze Platform, South China[J]. PRECAMBRIAN RESEARCH,2022,377:18.
APA	Zhang, Pan,Huang, Kang-Jun,Luo, Mao,Cai, Yaoping,&Bao, Zhian.(2022).Constraining the terminal Ediacaran seawater chemistry by Mg isotopes in dolostones from the Yangtze Platform, South China.PRECAMBRIAN RESEARCH,377,18.
MLA	Zhang, Pan,et al."Constraining the terminal Ediacaran seawater chemistry by Mg isotopes in dolostones from the Yangtze Platform, South China".PRECAMBRIAN RESEARCH 377(2022):18.