干旱区生态环境知识资源中心(Arid): Geochemical constraints on the origin of Neoproterozoic cap carbonate in the Helan Mountains, North China: Implications for mid-late Ediacaran glaciation?

Arid

DOI	10.1016/j.precamres.2019.105361
	Geochemical constraints on the origin of Neoproterozoic cap carbonate in the Helan Mountains, North China: Implications for mid-late Ediacaran glaciation?
	Yang, Jie 1,2; Lyons, Timothy W.2; Zeng, Zuoxun 1; Odigie, Kingsley O.2; Bates, Steve 2; Hu, Lisha 1
通讯作者	Lyons, Timothy W.
来源期刊	PRECAMBRIAN RESEARCH
ISSN	0301-9268
EISSN	1872-7433
出版年	2019
卷号	331
英文摘要	The late Neoproterozoic Era was characterized by dramatic transitions in climate, including Snowball Earth glaciation, and in the increasing oxygenation state of the atmosphere and oceans. However, late Neoproterozoic glacial deposits are poorly documented in North China. To better understand the Neoproterozoic glacial events in North China, we investigated five sections along a north-south transect across the Helan Mountains capturing a transition from shelf margin to intrashelf basin. This effort revealed an excellent exposure of Neoproterozoic diamictite and associated carbonate succession (Zhengmuguan Formation) on the western shelf margin of North China. Sedimentary features in the diamictite indicate that it might be a glacial sequence partially influenced by sediment gravity flows, with values for the Chemical Index of Alternation (CIA) consistent with cold, arid depositional environment. The overlying carbonate succession is sporadic, with exposures confined mostly to southern areas that disappear to the north. Identification of the Zhengmuguan sequence as a cap carbonate is based on the occurrence of distinctive attributes that are widely found in typical Neoproterozoic cap carbonates around the world. The similar to 1.6-m-thick cap carbonate consists of a lower thinly laminated dolomite and an upper thick-bedded dolomite, directly overlying the top of the Zhengmuguan glacial diamictite. Based on field and petrographic observations and high-resolution geochemical analyses of major, trace, and rare earth elements; organic carbon isotopes (delta C-13(org)); and total organic carbon (TOC), we are able to interpret the depositional environments and the possible origin of the cap carbonate. The occurrence of late Ediacaran fossils in the overlying Tuerkeng Formation imply that the Zhengmuguan Formation is mid-late Ediacaran and thus may represent a mid-late Ediacaran glaciation. Our petrographic and geochemical results suggest the Zhengmuguan cap carbonate was initially deposited via glacial meltwater with significant inputs from continental weathering subsequently overprinted by upwelling anoxic deep seawaters along a continental margin. In summary, our data from a poorly known mid-late Ediacaran cap carbonate capture a high-resolution record of shifting climatic and oceanographic conditions of at least regional importance. The uncertainties of these interpretations are high, but the potential importance of these findings justifies the need to publish the data and our conclusions-along with the unavoidable caveats that come with any poorly dated frontier section.
英文关键词	Zhengmuguan cap carbonate Rare earth elements Major and trace elements Organic carbon isotopes Ediacaran glaciation
类型	Article
语种	英语
国家	Peoples R China ; USA
收录类别	SCI-E
WOS记录号	WOS:000486103400011
WOS关键词	RARE-EARTH-ELEMENTS ; UPPER CONTINENTAL-CRUST ; YANGTZE GORGES AREA ; ORGANIC-CARBON ; TRACE-ELEMENT ; SEDIMENTARY ENVIRONMENT ; ISOTOPIC FRACTIONATION ; DOUSHANTUO FORMATION ; PILBARA CRATON ; SOUTH CHINA
WOS类目	Geosciences, Multidisciplinary
WOS研究方向	Geology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/218162
作者单位	1.China Univ Geosci, Sch Earth Sci, Wuhan 430074, Hubei, Peoples R China; 2.Univ Calif Riverside, Dept Earth Sci, Riverside, CA 92521 USA
推荐引用方式 GB/T 7714	Yang, Jie,Lyons, Timothy W.,Zeng, Zuoxun,et al. Geochemical constraints on the origin of Neoproterozoic cap carbonate in the Helan Mountains, North China: Implications for mid-late Ediacaran glaciation?[J],2019,331.
APA	Yang, Jie,Lyons, Timothy W.,Zeng, Zuoxun,Odigie, Kingsley O.,Bates, Steve,&Hu, Lisha.(2019).Geochemical constraints on the origin of Neoproterozoic cap carbonate in the Helan Mountains, North China: Implications for mid-late Ediacaran glaciation?.PRECAMBRIAN RESEARCH,331.
MLA	Yang, Jie,et al."Geochemical constraints on the origin of Neoproterozoic cap carbonate in the Helan Mountains, North China: Implications for mid-late Ediacaran glaciation?".PRECAMBRIAN RESEARCH 331(2019).