| Paleoceanographic Indicators for Early Cambrian Black Shales from the Yangtze Platform, South China: Evidence from Biomarkers and Carbon Isotopes | |
CHEN Lan; ZHONG Hong ; HU Ruizhong; XIAO Jiafei; TSAI Louis Loung-Yie; LIN Andrew Tien-Shun; ZOU Yanrong
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| 2011 | |
| Source Publication | Acta Geologica Sinica (English Edition)
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| Volume | 86Issue:5Pages:1143-1153 |
| Abstract | The lower Cambrian Niutitang Formation, a widespread black shale deposition, is of geological interest because of its polymetallic beds, Cambrian explosion, depositional ages, dramatic environmental changes and so on. Previous study focused mainly on inorganic geochemistry and few studies have investigated the organic fractions of upper Neoproterozoic-lower Cambrian strata in South China. Here we report a study of biomarkers plus organic carbon isotopes for black shales from Ganziping, Hunan Province (China). All the saturated hydrocarbon fractions have a unimodal distribution of n-alkanes, a high content of short-chain alkanes and maximize at C19 or C20 (C23 for sample Gzh001). The C27/C29 sterane ratio ranges from 0.77 to 1.20 and 4-methylsteranes are in low abundance. These parameters indicate that algae and bacteria are the important primary producers. Furthermore, biomarker maturity proxies show the samples to be higher maturity. The low Pr/Ph values (<0.7) suggest that the samples were deposited under anoxic conditions and, likely, under stratified water columns. In addition, 25-norhopanes and gammacerane are present as diagnostic indicators of normal marine salinity and dysoxic to anoxic conditions. During the Early Tommotian, known to coincide with a transgression event, small shelly fossils increased in abundance and diversity. Moreover, positive delta 13Corg excursions close to 1.4 parts per thousand occur at the base of the Tommotian stage. In summary, the Early Cambrian black shales were deposited under dramatic paleoenvironmental changes, including oceanic anoxia, higher primary productivity and sea-level rise. |
| Subject Area | 矿床地球化学 |
| Indexed By | 其他 |
| Language | 英语 |
| Document Type | 期刊论文 |
| Identifier | http://ir.gyig.ac.cn/handle/352002/7092 |
| Collection | 矿床地球化学国家重点实验室_矿床地球化学国家重点实验室_期刊论文 矿床地球化学国家重点实验室 |
| Corresponding Author | ZHONG Hong |
| Recommended Citation GB/T 7714 | CHEN Lan,ZHONG Hong,HU Ruizhong,et al. Paleoceanographic Indicators for Early Cambrian Black Shales from the Yangtze Platform, South China: Evidence from Biomarkers and Carbon Isotopes[J]. Acta Geologica Sinica (English Edition),2011,86(5):1143-1153. |
| APA | CHEN Lan.,ZHONG Hong.,HU Ruizhong.,XIAO Jiafei.,TSAI Louis Loung-Yie.,...&ZOU Yanrong.(2011).Paleoceanographic Indicators for Early Cambrian Black Shales from the Yangtze Platform, South China: Evidence from Biomarkers and Carbon Isotopes.Acta Geologica Sinica (English Edition),86(5),1143-1153. |
| MLA | CHEN Lan,et al."Paleoceanographic Indicators for Early Cambrian Black Shales from the Yangtze Platform, South China: Evidence from Biomarkers and Carbon Isotopes".Acta Geologica Sinica (English Edition) 86.5(2011):1143-1153. |
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