Uranium-thorium isotope systematics of cold-seep carbonate and their constraints on geological methane leakage activities
文献类型：期刊论文
| 作者 | Wang, Maoyu5,9; Chen, Tianyu5,8,9; Feng, Dong7; Zhang, Xin8; Li, Tao5,9; Robinson, Laura F.1; Liang, Qianyong6; Bialik, Or M.4; Liu, Yuanyuan5,9; Makovsky, Yizhaq2,3 |
| 刊名 | GEOCHIMICA ET COSMOCHIMICA ACTA
 |
| 出版日期 | 2022-03-01 |
| 卷号 | 320页码:105-121 |
| ISSN号 | 0016-7037 |
| 关键词 | Cold-seep carbonate Element mapping U-Th dating Methane leakage duration |
| DOI | 10.1016/j.gca.2021.12.016 |
| 通讯作者 | Chen, Tianyu(tianyuchen@nju.edu.cn) |
| 英文摘要 | Marine methane hydrates are a huge and dynamic carbon reservoir found mainly at the continental margins, and their stability might be affected by climate-associated pressure and temperature changes on the seafloor. Reconstructing the growth history of cold-seep carbonates, which formed during seafloor methane leakage, could help to constrain methane hydrate stability in the geological past. However, U-Th isotope systematics of these complex carbonate cements have not yet been system-atically investigated on the micro-scale, leaving uncertainties in the U-series geochronology which is commonly applied to date the seep carbonates. In this study, we have developed multiple in-situ analytical methods, including U-Th isotope analysis by laser ablation MC-ICPMS, elemental concentration mapping by laser ablation ICPMS, as well as organic distribution mapping by Raman Spectroscopy, to provide insights into the U-series geochemistry and geochronology for the different types of cold-seep carbonates. Our result demonstrates that U-238 and Th-232 of these carbonates are dominantly derived from seawater and detrital particles, respectively. As the [Th-230/Th-232] (activity ratio) of micro-domains with high [Th-232/U-238] is negligibly affected by U decay, we have directly determined the initial [Th-230/Th-232] of the cold-seep carbonates which is 0.7 +/- 0.1 (2 SD, n = 12). In general, U-series isotopes show closed-system behavior within our studied analytical precision in the interior of the seep cements, and the initial [Th-230/Th-232] derived from the isochron approach is consistent with the in-situ direct determination. A notable exception is a calcitic pipe sample with highly enriched U in its rim which has also experienced post-depositional mobilization. Our method is then applied to a large set of seep carbonate samples from the upper continental slope of the northern South China Sea (SCS). The obtained U-series ages provide evidence that cold seep was likely continuously active since at least ~72 ka in the northern SCS, but the timing and duration of methane leakage vary between different sites within this region. While the upper continental slope methane hydrates are highly susceptible to destabilization under changing bottom water conditions, our extensive dating on seep carbonates from the SCS further indicates that bottom water P-T conditions could exert contrasting impacts on methane hydrate stability at different depths within the same geological setting. Overall, the in-situ U-series geochronological method developed in our study has the potential to date cold-seep carbonates efficiently and reliably, offering new opportunities to probe into the history of methane leakage in the late Quaternary. (C)& nbsp;2021 Elsevier Ltd. All rights reserved. |
| 资助项目 | National Natural Science Foundation of China[41822603] ; National Natural Science Foundation of China[41991325] ; National Natural Science Foundation of China[42021001] ; Guangdong Basic and Applied Basic Research Foundation[2019B030302004] ; China Geological Survey[DD20190218] ; CAS Interdisciplinary Innovation Team[JCTD-2018-12] |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| 出版者 | PERGAMON-ELSEVIER SCIENCE LTD |
| WOS记录号 | WOS:000786623000004 |
| 源URL | [http://ir.qdio.ac.cn/handle/337002/178861]  |
| 专题 | 海洋研究所_深海极端环境与生命过程研究中心 |
| 通讯作者 | Chen, Tianyu |
| 作者单位 | 1.Univ Bristol, Sch Earth Sci, Bristol BS8 1RJ, Avon, England 2.Univ Haifa, Leon H Charney Sch Marine Sci CSMS, Hatter Dept Marine Technol, IL-31905 Haifa, Israel 3.Univ Haifa, Leon H Charney Sch Marine Sci CSMS, Dr Moses Strauss Dept Marine Geosci, IL-31905 Haifa, Israel 4.Univ Malta, Dept Geosci, Marine Geol & Seafloor Surveying, Msida, MSD, Malta 5.Nanjing Univ, Sch Earth Sci, State Key Lab Mineral Deposits Res, Nanjing 210023, Peoples R China 6.China Geol Survey, Guangzhou Marine Geol Survey, MLR Key Lab Marine Mineral Resources, Guangzhou 510070, Peoples R China 7.Shanghai Ocean Univ, Coll Marine Sci, Shanghai Engn Res Ctr Hadal Sci & Technol, Shanghai 201306, Peoples R China 8.Chinese Acad Sci, Inst Oceanol, Ctr Deep Sea Res, Ctr Ocean Mega Sci, Qingdao 266071, Peoples R China 9.Nanjing Univ, Engn & Frontiers Sci Ctr Crit Earth Mat Cycling, Nanjing 210023, Peoples R China |
| 推荐引用方式 GB/T 7714 |
Wang, Maoyu,Chen, Tianyu,Feng, Dong,et al. Uranium-thorium isotope systematics of cold-seep carbonate and their constraints on geological methane leakage activities [J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2022,320:105-121. |
| APA |
Wang, Maoyu.,Chen, Tianyu.,Feng, Dong.,Zhang, Xin.,Li, Tao.,...&Makovsky, Yizhaq.(2022). Uranium-thorium isotope systematics of cold-seep carbonate and their constraints on geological methane leakage activities .GEOCHIMICA ET COSMOCHIMICA ACTA,320,105-121. |
| MLA |
Wang, Maoyu,et al." Uranium-thorium isotope systematics of cold-seep carbonate and their constraints on geological methane leakage activities ".GEOCHIMICA ET COSMOCHIMICA ACTA 320(2022):105-121. |
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来源：海洋研究所
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