KMS Nanjing Institute of Geology and Palaeonotology,CAS
Germanium/silica ratio and rare earth element composition of silica-filling in sheet cracks of the Doushantuo cap carbonates, South China: Constraining hydrothermal activity during the Marinoan snowball Earth glaciation | |
Cui, Yixin1,2; Lang, Xianguo3,4; Li, Fangbing1,2; Huang, Kangjun5; Ma, Haoran1,2; Li, Chenqing1,2; Pei, Haoxiang6; Li, Chao6; Zhou, Chuanming (周传明)3,4; Shen, Bing1,2 | |
2019-09-15 | |
发表期刊 | PRECAMBRIAN RESEARCH |
ISSN | 0301-9268 |
卷号 | 332页码:17 |
摘要 | The rapid diversification of eukaryotes within 3 million years after the Marinoan global glaciation suggests the potential linkage between the snowball Earth event and biological evolution. To understand how the global glaciation and the biological evolution were linked, it is necessary to reconstruct the sequence of events with high temporal resolution that occurred during the deglaciation. In this study, we focus on silica-filling within sheet cracks. Sheet cracks abundantly occur in the basal part of the Marinoan cap carbonate (635 Ma), and are characterized by the interconnected horizontal and vertical cracks that are sequentially cemented by dolospars, silica and calcite. As the second stage of crack filling, the origin of silica-filling remains controversial. If the seawater origin is confirmed, the silica-filling might archive the signal of ocean chemistry in the aftermath of snowball Earth event. In this study, we measured the Germanium/Silica ratios (Ge/Si) and Rare Earth Elements (REE) compositions of silica-filling from the Doushantuo cap carbonate in the Yangtze Platform, South China. The silica-filling has low Ge/Si ratios (similar to 1 mu mol/mol), and displays a light REE (LREE) depleted REE pattern (normalized to PAAS) with positive Eu anomalies (Eu/Eu*). These results indicate the predominant seawater origin of silica with some contribution from hydrothermal fluid, suggesting the penecontemporaneous precipitation of silica-filling with respect to sheet crack formation. In order to quantify the contribution from hydrothermal fluid, we developed a binary mixing model by using Ge/Si ratio and Eu/Eu* as two independent proxies. The modeling results indicate mixing of similar to 5 vol.% hydrothermal fluid with contemporaneous seawater, or similar to 20 wt.% of Si in silica-filling from hydrothermal fluid. The modeling results also show that the synglacial hydrothermal flux might be one order of magnitude lower than the modem level, suggesting extremely weak hydrothermal activities during the Marinoan snowball glaciation. |
关键词 | Ge/Si ratio Hydrothermal fluid Doushantuo cap carbonate Snowball Earth event Sheet crack |
DOI | 10.1016/j.precamres.2019.105407 |
语种 | 英语 |
关键词[WOS] | PB ZIRCON AGE ; NANTUO GLACIATION ; YANGTZE PLATFORM ; TRACE-ELEMENTS ; METHANE SEEPS ; OCEAN ; CHERT ; SEA ; GE ; FRACTIONATION |
资助项目 | Natural Science Foundation of China[41772359] ; Natural Science Foundation of China[41322021] ; Natural Science Foundation of China[41802024] ; Strategic Priority Research Program (B) of Chinese Academy of Sciences[XDB18000000] |
WOS研究方向 | Geology |
WOS类目 | Geosciences, Multidisciplinary |
WOS记录号 | WOS:000487566500021 |
项目资助者 | Natural Science Foundation of China ; Strategic Priority Research Program (B) of Chinese Academy of Sciences |
出版者 | ELSEVIER |
文献类型 | 期刊论文 |
条目标识符 | http://ir.nigpas.ac.cn/handle/332004/27872 |
专题 | 中国科学院南京地质古生物研究所 |
通讯作者 | Shen, Bing |
作者单位 | 1.Peking Univ, MOE, Key Lab Orogen Belts & Crustal Evolut, Beijing 100871, Peoples R China 2.Peking Univ, Sch Earth & Space Sci, Beijing 100871, Peoples R China 3.Chinese Acad Sci, Nanjing Inst Geol & Palaeontol, CAS Key Lab Econ Stratig & Palaeogeog, Nanjing 210008, Jiangsu, Peoples R China 4.Chinese Acad Sci, Ctr Excellence Life & Paleoenvironm, Nanjing 210008, Jiangsu, Peoples R China 5.Northwest Univ, Dept Geol, Shaanxi Key Lab Early Life & Environm, Xian 710069, Shaanxi, Peoples R China 6.Chinese Acad Geol Sci, Inst Mineral Resources, Beijing 100037, Peoples R China |
推荐引用方式 GB/T 7714 | Cui, Yixin,Lang, Xianguo,Li, Fangbing,et al. Germanium/silica ratio and rare earth element composition of silica-filling in sheet cracks of the Doushantuo cap carbonates, South China: Constraining hydrothermal activity during the Marinoan snowball Earth glaciation[J]. PRECAMBRIAN RESEARCH,2019,332:17. |
APA | Cui, Yixin.,Lang, Xianguo.,Li, Fangbing.,Huang, Kangjun.,Ma, Haoran.,...&Shen, Bing.(2019).Germanium/silica ratio and rare earth element composition of silica-filling in sheet cracks of the Doushantuo cap carbonates, South China: Constraining hydrothermal activity during the Marinoan snowball Earth glaciation.PRECAMBRIAN RESEARCH,332,17. |
MLA | Cui, Yixin,et al."Germanium/silica ratio and rare earth element composition of silica-filling in sheet cracks of the Doushantuo cap carbonates, South China: Constraining hydrothermal activity during the Marinoan snowball Earth glaciation".PRECAMBRIAN RESEARCH 332(2019):17. |
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