Opening of the South China Sea and Upwelling of the Hainan Plume
Opening of the South China Sea and Upwelling of the Hainan Plume
复制标题
南海开放与海南羽流上涌
DOI：
10.1002/2017gl076872
复制
发表时间：
2018-03-28
影响因子：
5.2
通讯作者：
Santosh, M.
中科院分区：
文献类型：
--
作者：
Yu, Mengming;Yan, Yi;Santosh, M.
南海的开放和海南羽流的上涌是东亚构造演化中最具挑战性的问题之一。然而，海南羽流何时以及如何影响南中国海的开放仍不清楚。本文研究了台湾垦丁平原~25 Ma洋中脊玄武岩、IODP 349科考队钻探的~16 Ma洋中脊玄武岩和~9 Ma洋岛玄武岩型疏浚海山玄武岩的地球化学和同位素特征。~25 Ma的MORB显示了一个较少交代耗尽的MORB类地幔源。中新世样品记录了地幔的逐渐富集，可能是海南地幔柱的贡献。我们推测，可能记录羽脊源混合的南海morb可能出现在~23.8 Ma。相反，华南大陆边缘古新世—始新世洋岛玄武岩型板内火山作用与大陆裂谷作用导致的被动上升流肥沃软流圈减压融化有关。
Opening of the South China Sea and upwelling of the Hainan Plume are among the most challenging issues related to the tectonic evolution of East Asia. However, when and how the Hainan Plume affected the opening of the South China Sea remains unclear. Here we investigate the geochemical and isotopic features of the ~25 Ma mid‐ocean ridge basalt (MORB) in the Kenting Mélange, southern Taiwan, ~16 Ma MORB drilled by the IODP Expedition 349, and ~9 Ma ocean island basalt‐type dredged seamount basalt. The ~25 Ma MORBs reveal a less metasomatic depleted MORB mantle‐like source. In contrast, the Miocene samples record progressive mantle enrichment and possibly signal the contribution of the Hainan Plume. We speculate that MORBs of the South China Sea which could have recorded plume‐ridge source mixing perhaps appear since ~23.8 Ma. On the contrary, the Paleocene‐Eocene ocean island basalt‐type intraplate volcanism of the South China continental margin is correlated to decompression melting of a passively upwelling fertile asthenosphere due to continental rifting.