Extremely 26 Mg-enriched authigenic clays from the Ediacaran Doushantuo Formation (South China) indicating the coupled carbonate-silicate diagenesis
文献类型：期刊论文
| 作者 | Huang, Tianzheng6,7; Shen, Bing6,7; Wang, Xiaoli5; Ma, Haoran3,4; Li, Chao2; Zhou, Chuanming1
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| 刊名 | GLOBAL AND PLANETARY CHANGE
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| 出版日期 | 2024-08-01 |
| 卷号 | 239页码:15 |
| 关键词 | Saponite Clinochlore Mg isotope Reverse weathering Dolomitization |
| ISSN号 | 0921-8181 |
| DOI | 10.1016/j.gloplacha.2024.104500 |
| 通讯作者 | Shen, Bing(bingshen@pku.edu.cn) ; Li, Chao(Re-Os@163.com) |
| 英文摘要 | In the aftermath of Marinoan global glaciation (similar to 650-635 Ma), the deglacial intense continental weathering tended to dramatically lower the atmospheric pCO(2) level, potentially driving the Earth back to the glacial climatic condition. However, the resultant global cooling and glaciation did not occur. The CO2 drawdown by continental weathering might have been compensated by additional CO2 release via reverse weathering in the ocean, as evidenced by abundant precipitations of authigenic clay minerals, for example, Mg-rich saponite and clinochlore in the lower part of Doushantuo Formation (635-551 Ma) in South China. Massive precipitations of Mg-rich authigenic clays imply a distinct marine Mg cycle in the early Ediacaran ocean, but their origins have been debated. Here, we measured the Mg isotopic compositions of authigenic clays from the Doushantuo Formation. Both saponite and clinochlore are extremely Mg-26-enriched, with Mg isotopes of saponite (delta Mg-26(sap)) up to +0.39 parts per thousand and clinochlore up to +1.26 parts per thousand. Considering the Mg isotopic fractionation in saponite precipitation ranging from -0.95 parts per thousand to -1.45 parts per thousand, high delta Mg-26(sap) values requires extremely high seawater Mg isotopic composition (delta Mg-26(sw)), which cannot be resolved by direct precipitation with seawater Mg supply. Instead, it requires other diagenetic processes that elevated the porewater Mg isotopic composition (delta Mg-26(pw)). A numerical model was applied to quantify the Mg isotopic fractionation in diagenesis. The modeling result indicates an earlier dolomitization relative to saponite precipitation might have elevated the porewater Mg isotopes, followed by the precipitation of extremely Mg-26-enriched saponite. The coupled carbonate-silicate diagenesis is a key mechanism sustaining stable seawater Mg concentration and delta Mg-26, highlighting authigenic clay mineral as a buffer for Mg and C cycles counterbalancing massive weathering input after Marinoan glaciation. |
| WOS关键词 | MAGNESIUM ISOTOPE FRACTIONATION ; MINERAL FORMATION ; YANGTZE PLATFORM ; SALINA OMETEPEC ; METHANE SEEPS ; CAP CARBONATE ; SYSTEMATICS ; BEHAVIOR ; MECHANISMS ; SEDIMENTS |
| 资助项目 | National Natural Science Foundation of China[42225304] ; National Natural Science Foundation of China[42293291] ; National Key Research and Development Program of China[2021YFA0718200] |
| WOS研究方向 | Physical Geography ; Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:001262616200001 |
| 出版者 | ELSEVIER |
| 资助机构 | National Natural Science Foundation of China ; National Key Research and Development Program of China |
| 源URL | [http://ir.nigpas.ac.cn/handle/332004/44027]  |
| 专题 | 中国科学院南京地质古生物研究所 |
| 通讯作者 | Shen, Bing; Li, Chao |
| 作者单位 | 1.Chinese Acad Sci, Nanjing Inst Geol & Paleontol, State Key Lab Paleobiol & Stratig, Nanjing 210008, Peoples R China 2.Chinese Acad Geol Sci, Key Lab Rhenium Osmium Isotop Geochem, Beijing 100037, Peoples R China 3.Nanjing Univ, Sch Earth Sci & Engn, Nanjing 210023, Peoples R China 4.Nanjing Univ, Int Ctr Isotope Effect Res, Nanjing 210023, Peoples R China 5.Univ Sci & Technol, Sch Civil & Resource Engn, Beijing 100083, Peoples R China 6.Peking Univ, Sch Earth & Space Sci, Beijing 100871, Peoples R China 7.Peking Univ, Key Lab Orogen Belt & Crustal Evolut, MOE, Beijing 100871, Peoples R China |
| 推荐引用方式 GB/T 7714 | Huang, Tianzheng,Shen, Bing,Wang, Xiaoli,et al. Extremely 26 Mg-enriched authigenic clays from the Ediacaran Doushantuo Formation (South China) indicating the coupled carbonate-silicate diagenesis[J]. GLOBAL AND PLANETARY CHANGE,2024,239:15. |
| APA | Huang, Tianzheng,Shen, Bing,Wang, Xiaoli,Ma, Haoran,Li, Chao,&Zhou, Chuanming.(2024).Extremely 26 Mg-enriched authigenic clays from the Ediacaran Doushantuo Formation (South China) indicating the coupled carbonate-silicate diagenesis.GLOBAL AND PLANETARY CHANGE,239,15. |
| MLA | Huang, Tianzheng,et al."Extremely 26 Mg-enriched authigenic clays from the Ediacaran Doushantuo Formation (South China) indicating the coupled carbonate-silicate diagenesis".GLOBAL AND PLANETARY CHANGE 239(2024):15. |
入库方式： OAI收割
来源：南京地质古生物研究所
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