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Cui H, Xiao S, Cai Y, Peek S, Plummer RE, Kaufman AJ. Sedimentology and chemostratigraphy of the terminal Ediacaran Dengying Formation at the Gaojiashan section, South China. GEOLOGICAL MAGAZINE 2019; n/a:10.1017/S0016756819000293. [PMID: 31631899 PMCID: PMC6800678 DOI: 10.1017/s0016756819000293] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The late Ediacaran Dengying Formation (ca. 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 a relatively continuous chemostratigraphic profile for the terminal Ediacaran stage. In this study, a detailed sedimentological and chemostratigraphic (δ13Ccarb, δ18Ocarb, δ13Corg, δ34Spyrite, and 87Sr/86Sr) investigation was conducted on the Dengying Formation at the Gaojiashan section, Ningqiang County of the 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.
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Affiliation(s)
- Huan Cui
- Research Group of Analytical, Environmental and Geo- Chemistry (AMGC), Division of Earth System Science, Vrije Universiteit Brussel (VUB), Brussels 1050, Belgium
- ET-HOME (Evolution and Tracers of the Habitability of Mars and Earth) Astrobiology Research Consortium, Belgium
- NASA Astrobiology Institute, Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
- Department of Geology, University of Maryland, College Park, MD 20742, USA
- Author for correspondence: (H. Cui) or (H. Cui), Present address: Research Group of AMGC, Free University of Brussels (VUB), Brussels 1050, Belgium
| | - Shuhai Xiao
- Department of Geosciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Yaoping Cai
- State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environment, Department of Geology, Northwest University, Xi’an 710069, China
| | - Sara Peek
- Department of Geology, University of Maryland, College Park, MD 20742, USA
- United States Geological Survey, Menlo Park, CA 94025, USA
| | - Rebecca E. Plummer
- Department of Geology, University of Maryland, College Park, MD 20742, USA
- Hydrology and Remote Sensing Laboratory, Beltsville Agricultural Research Center, US Department of Agriculture, Beltsville, MD 20705 USA
| | - Alan J. Kaufman
- Department of Geology, University of Maryland, College Park, MD 20742, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20742, USA
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The origin of bedding-parallel fibrous calcite veins in the Lower Permian Chihsia Formation in western Hubei Province, South China. Sci Bull (Beijing) 2015. [DOI: 10.1007/s11434-015-0903-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Bjerrum CJ, Canfield DE. Towards a quantitative understanding of the late Neoproterozoic carbon cycle. Proc Natl Acad Sci U S A 2011; 108:5542-7. [PMID: 21422280 PMCID: PMC3078370 DOI: 10.1073/pnas.1101755108] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The cycles of carbon and oxygen at the Earth surface are intimately linked, where the burial of organic carbon into sediments represents a source of oxygen to the surface environment. This coupling is typically quantified through the isotope records of organic and inorganic carbon. Yet, the late Neoproterozoic Eon, the time when animals first evolved, experienced wild isotope fluctuations which do not conform to our normal understanding of the carbon cycle and carbon-oxygen coupling. We interpret these fluctuations with a new carbon cycle model and demonstrate that all of the main features of the carbonate and organic carbon isotope record can be explained by the release of methane hydrates from an anoxic dissolved organic carbon-rich ocean into an atmosphere containing oxygen levels considerably less than today.
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Affiliation(s)
- Christian J. Bjerrum
- Nordic Center for Earth Evolution (NordCEE) and Department of Geography and Geology, University of Copenhagen, Øster Voldgade, 10, DK-1350 København K., Denmark; and
| | - Donald E. Canfield
- Nordic Center for Earth Evolution (NordCEE) and Institute of Biology, University of Southern Denmark, Campusvej, 55, DK-5230 Odense M, Denmark
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Jiang G, Zhang S, Shi X, Wang X. Chemocline instability and isotope variations of the Ediacaran Doushantuo basin in South China. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/s11430-008-0116-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Dong J, Zhang S, Jiang G, Zhao Q, Li H, Shi X, Liu J. Early diagenetic growth of carbonate concretions in the upper Doushantuo Formation in South China and their significance for the assessment of hydrocarbon source rock. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/s11430-008-0107-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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