期刊
GEOLOGICAL MAGAZINE
卷 156, 期 11, 页码 1924-1948出版社
CAMBRIDGE UNIV PRESS
DOI: 10.1017/S0016756819000293
关键词
geobiology; animal biomineralization; authigenesis; aragonite; karstification; alkalinity; Cloudina
资金
- UMD Geology Department
- NASA Astrobiology Institute at UW-Madison
- ET-HOME (Evolution and Tracers of the Habitability of Mars and Earth) Astrobiology Research Consortium in Belgium
- Analytical, Environmental and Geo-Chemistry research group at VUB
- American Association of Petroleum Geologists (AAPG) Grants-In-Aid Program Marilyn Atwater Memorial Grant
- Explorers Club Washington Group
- open research grant of the State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences [193107]
- NASA Exobiology grant [NNX12AR91G, 80NSSC18K1086]
- NSF Sedimentary Geology and Palaeontology grant [EAR0844270, EAR1528553]
- Young Scientists Fund of Shaanxi Province [2015KJXX-26]
The terminal Ediacaran Dengying Formation (c. 551.1-538.8 Ma) in South China is one of two successions where Ediacara-type macrofossils are preserved in carbonate facies along with skeletal fossils and bilaterian animal traces. Given the remarkable thickness of carbonate-bearing strata deposited in less than 12.3 million years, the Dengying Formation holds the potential for construction of a relatively continuous chemostratigraphic profile for the terminal Ediacaran Period. In this study, a detailed sedimentological and chemostratigraphic (delta 13C(carb), delta O-18(carb), delta C-13(org), delta S-34(pyrite), and Sr-87/Sr-86) investigation was conducted on the Dengying Formation at the Gaojiashan section, Ningqiang County of southern Shaanxi Province, South China. Sedimentological results reveal an overall shallow-marine depositional environment. Carbonate breccia, void-filling botryoidal precipitates and aragonite crystal fans are common in the Algal Dolomite Member of the Dengying Formation, suggesting that peritidal facies were repeatedly karstified. The timing of karstification was likely early, probably soon after the deposition of the dolomite sediments. The presence of authigenic aragonite cements suggests high alkalinity in the terminal Ediacaran ocean. Geochemical analysis of micro-drilled samples shows that distinct compositions are registered in different carbonate phases, which should be considered when constructing chemostratigraphic profiles representative of true temporal variations in seawater chemistry. Integrated chemostratigraphic data suggest enhanced burial of organic carbon and pyrite, and the occurrence of extensive marine anoxia (at least in the Gaojiashan Member). Rapid basinal subsidence and carbonate accumulation during a time of elevated seawater alkalinity and increased rates of pyrite burial may have facilitated the evolutionary innovation of early biomineralizing metazoans.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据