| 东南印度洋中脊澳大利亚-南极洲不整合带地区岩浆供应与构造作用沿洋脊的变化 |
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| 引用本文： | 刘守金,林间,周志远,张帆.东南印度洋中脊澳大利亚-南极洲不整合带地区岩浆供应与构造作用沿洋脊的变化[J].海洋学报(英文版),2020,39(1):118-129. |
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| 作者姓名： | 刘守金 林间 周志远 张帆 |
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| 作者单位： | 边缘海大洋与大洋地质重点实验室, 中国科学院南海海洋研究所, 广州, 510301;中国科学院大学, 北京, 100049,边缘海大洋与大洋地质重点实验室, 中国科学院南海海洋研究所, 广州, 510301;美国伍兹霍尔海洋研究所, 伍兹霍尔, 02543,边缘海大洋与大洋地质重点实验室, 中国科学院南海海洋研究所, 广州, 510301;海洋科学与工程系, 南方科技大学, 深圳, 518055,边缘海大洋与大洋地质重点实验室, 中国科学院南海海洋研究所, 广州, 510301;海洋科学与工程系, 南方科技大学, 深圳, 518055 |
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| 基金项目： | The National Key R&D Program of China under contract Nos 2018YFC0310105 and 2018YFC0309800; the China Ocean Mineral Resources R&D Association under contract No. DY135-S2-1-04; the National Natural Science Foundation of China under contract Nos 41890813, 91628301, 41976066, 41706056, 41976064, 91858207 and U1606401; the Chinese Academy of Sciences under contract Nos Y4SL021001, QYZDY-SSW-DQC005 and 133244KYSB20180029; the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) under contract No. GML2019ZD0205. |
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| 摘 要： | We analyzed seafloor morphology and geophysical anomalies of the Southeast Indian Ridge(SEIR) to reveal the remarkable changes in magma supply along this intermediate fast-spreading ridge. We found systematic differences of the Australian-Antarctic Discordance(AAD) from adjacent ridge segments with the residual mantle Bouguer gravity anomaly(RMBA) being more positive, seafloor being deeper, morphology being more chaotic, M factors being smaller at the AAD. These systematic anomalies, as well as the observed Na_(8.0) being greater and Fe_(8.0) being smaller at AAD, suggest relatively starved magma supply and relatively thin crust within the AAD.Comparing to the adjacent ridges segments, the calculated average map-view M factors are relatively small for the AAD, where several Oceanic Core Complexes(OCCs) develop. Close to 30 OCCs were found to be distributed asymmetrically along the SEIR with 60% of OCCs at the northern flank. The OCCs are concentrated mainly in Segments B3 and B4 within the AAD at ～124°–126°E, as well as at the eastern end of Zone C at ～115°E. The relatively small map-view M factors within the AAD indicate stronger tectonism than the adjacent SEIR segments.The interaction between the westward migrating Pacific mantle and the relatively cold mantle beneath the AAD may have caused a reduction in magma supply, leading to the development of abundant OCCs.
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| 关 键 词： | 海洋核杂岩 岩浆供应 东南印度洋脊 岩石圈变形 澳大利亚-南极洲不整合带 |
| 收稿时间： | 2018/10/8 0:00:00 |
Large along-axis variations in magma supply and tectonism of the Southeast Indian Ridge near the Australian-Antarctic Discordance |
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| Liu Shoujin,Lin Jian,Zhou Zhiyuan and Zhang Fan.Large along-axis variations in magma supply and tectonism of the Southeast Indian Ridge near the Australian-Antarctic Discordance[J].Acta Oceanologica Sinica,2020,39(1):118-129. |
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| Authors: | Liu Shoujin Lin Jian Zhou Zhiyuan and Zhang Fan |
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| Institution: | 1.Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China2.University of Chinese Academy of Sciences, Beijing 100049, China3.Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA4.Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou 523936, China |
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| Abstract: | We analyzed seafloor morphology and geophysical anomalies of the Southeast Indian Ridge (SEIR) to reveal the remarkable changes in magma supply along this intermediate fast-spreading ridge. We found systematic differences of the Australian-Antarctic Discordance (AAD) from adjacent ridge segments with the residual mantle Bouguer gravity anomaly (RMBA) being more positive, seafloor being deeper, morphology being more chaotic, M factors being smaller at the AAD. These systematic anomalies, as well as the observed Na8.0 being greater and Fe8.0 being smaller at AAD, suggest relatively starved magma supply and relatively thin crust within the AAD. Comparing to the adjacent ridges segments, the calculated average map-view M factors are relatively small for the AAD, where several Oceanic Core Complexes (OCCs) develop. Close to 30 OCCs were found to be distributed asymmetrically along the SEIR with 60% of OCCs at the northern flank. The OCCs are concentrated mainly in Segments B3 and B4 within the AAD at~124°-126°E, as well as at the eastern end of Zone C at~115°E. The relatively small map-view M factors within the AAD indicate stronger tectonism than the adjacent SEIR segments. The interaction between the westward migrating Pacific mantle and the relatively cold mantle beneath the AAD may have caused a reduction in magma supply, leading to the development of abundant OCCs. |
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| Keywords: | Oceanic Core Complexes magma supply Southeast Indian Ridge lithospheric deformation Australian-Antarctic Discordance |
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