Carbonate-hosted manganese deposits and ocean anoxia
文献类型：期刊论文
| 作者 | Chen, Fangge1,7; Wang, Qingfei1,2,4; Pufahl, Peir K.7; Matheson, Edward J.6; Xian, Haiyang5; Nan, Jingbo3; Ma, Huan1; Deng, Jun1 |
| 刊名 | EARTH AND PLANETARY SCIENCE LETTERS
 |
| 出版日期 | 2023-11-15 |
| 卷号 | 622页码:13 |
| 关键词 | authigenic precipitation biotic crises carbonate -hosted manganese deposits oceanic anoxia Late Paleozoic and Early Triassic upwelling environments |
| ISSN号 | 0012-821X |
| DOI | 10.1016/j.epsl.2023.118385 |
| 英文摘要 | Late Devonian (ca. 360 Ma), Early Carboniferous (ca. 330 Ma), and Early Triassic (ca. 250 Ma) manganese deposits in the South China Block support an emerging view that some Mn carbonates form through direct synsedimentary (authigenic) precipitation. These Mn carbonates accumulated on distal shelves and are interbedded with lime mudstone and heterozoan carbonates that accumulated in coastal upwelling environments. Lithofacies, Ce anomalies combined with vanadium, uranium, and molybdenum enrichments indicate that the Mn carbonates were primarily precipitated under anoxic conditions. We provide a robust dataset to clarify the precipitation pathway of these Mn carbonates and explore the implications of using them as proxies of regional shallow water and deep-ocean anoxia. In the studied deposits, Mn calcite encases dolomite rhombs (<10 mu m) or aggregates, indicating heterogenous nucleation, which is supported by similar lattice parameters of both minerals with a small lattice mismatch (<2.1%). The presence of micro-sized euhedral rhombs and subhedral aggregates of rhombs, the non-stoichiometric compositions, and characteristic organic matter Raman spectroscopy peaks near the D and G bands in the dolomite nuclei suggest an organogenic origin. Authigenic organogenic dolomite precipitation is interpreted to have preconditioned the sediment with nucleation sites for the subsequent precipitation of Mn carbonates in the shallow seafloor. This is consistent with delta C-13 values (-2.61 parts per thousand) of Mn carbonate bulk samples that are slightly lower than coeval seawater (0.31 parts per thousand, from host rocks), suggesting incorporation of C-12 during microbial respiration of sedimentary organic matter during the precipitation of organogenic dolomite and hydrothermal sourced inorganic carbon. The absence of Mn in shallow facies suggests terrestrial input of Mn was minimal. Geochemical and sedimentologic evidence suggests that coastal upwelling delivered manganous anoxic deep waters to the shelves. Eu/Eu* ratios (<1.5) and decoupling of Fe and Mn imply long-range transport of hydrothermal Mn, during which hydrothermal fingerprints were muted through mixing with ambient seawater. The transport of hydrothermal Mn to shelves indicates that the regional deep oceans at the time must have been anoxic, as Mn2+ would be easily oxidized and become insoluble under oxygen-rich conditions, preventing its long-distance transport. This precipitation pathway and depositional model implies that Mn carbonates are a largely unrecognized proxy for tracking ancient oceanic redox fluctuations, particularly during times of well-oxygenated global oceans. Hence, these Mn deposits record at least transient regional deep-ocean oxygen depletion in the generally well-oxygenated Late Paleozoic and Early Triassic oceans. The recognition that this periodic anoxia was broadly coeval with the anoxia-related Hangenberg, Serpukhovian, and Permian-Triassic biotic crises suggests a potential relationship between Mn carbonate accumulation and extinction events. (c) 2023 Elsevier B.V. All rights reserved. |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:001100855500001 |
| 源URL | [http://ir.gig.ac.cn/handle/344008/78952]  |
| 专题 | 中国科学院矿物学与成矿学重点实验室 |
| 通讯作者 | Wang, Qingfei |
| 作者单位 | 1.China Univ Geosci, State Key Lab Geol Proc & Mineral Resources, Beijing 100083, Peoples R China 2.East China Univ Technol, State Key Lab Nucl Resources & Environm, Nanchang 330013, Peoples R China 3.Southern Univ Sci & Technol, Dept Ocean Sci & Engn, Shenzhen 518055, Peoples R China 4.29 Xueyuan Rd, Beijing 100083, Peoples R China 5.Chinese Acad Sci, Guangzhou Inst Geochem, CAS Key Lab Mineral & Metallogeny, Guangdong Prov Key Lab Mineral Phys & Mat, Guangzhou 510640, Peoples R China 6.Cape Breton Univ, Dept Math Phys & Geol, Sydney, NS B1P 6L2, Canada 7.Queens Univ, Dept Geol Sci & Geol Engn, Kingston, ON K7L 3N6, Canada |
| 推荐引用方式 GB/T 7714 | Chen, Fangge,Wang, Qingfei,Pufahl, Peir K.,et al. Carbonate-hosted manganese deposits and ocean anoxia[J]. EARTH AND PLANETARY SCIENCE LETTERS,2023,622:13. |
| APA | Chen, Fangge.,Wang, Qingfei.,Pufahl, Peir K..,Matheson, Edward J..,Xian, Haiyang.,...&Deng, Jun.(2023).Carbonate-hosted manganese deposits and ocean anoxia.EARTH AND PLANETARY SCIENCE LETTERS,622,13. |
| MLA | Chen, Fangge,et al."Carbonate-hosted manganese deposits and ocean anoxia".EARTH AND PLANETARY SCIENCE LETTERS 622(2023):13. |
入库方式： OAI收割
来源：广州地球化学研究所
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