Non-mantle-plume process caused the initial spreading of the South China Sea
Non-mantle-plume process caused the initial spreading of the South China Sea
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非地幔柱过程导致南海的初步扩张
DOI：
10.1038/s41598-020-65174-y
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发表时间：
2020-05
影响因子：
4.6
通讯作者：
Zhifei Liu
中科院分区：
文献类型：
--
作者：
Xun Yu;Zhifei Liu
地幔柱过程被认为是南中国海打开的主要动力学机制，但由于缺乏岩浆在初始海底扩张中的关键证据，争议仍然存在。国际海洋发现计划（IODP）第367次考察在U1500地点成功地发现了大洋中脊玄武岩（MORB），它代表了渐新世早期南海初始扩张的岩浆活动。本文通过玄武岩全岩和橄榄石斑晶的地球化学研究，探讨海南地幔柱对南海演化的潜在影响。主量和微量元素分析表明，玄武岩主要受橄榄石分离结晶作用的影响，是由尖晶石橄榄岩源熔融而成，不含幔源辉石岩。计算的最原始玄武岩的地幔位温远低于冰岛的地幔柱相关MORB，但与其他地方的正常MORB相似。岩石成分和地幔位温与地幔柱模型明显矛盾，表明渐新世早期不存在地幔柱。因此，南海的初始扩张应该是由非地幔柱过程引起的，最有可能是由太平洋板块向西俯冲引起的。
The mantle plume process is thought to be the prevailing dynamic mechanism for the South China Sea opening, but controversy persists due to the lack of critical evidence of magma in the initial seafloor spreading. International Ocean Discovery Program (IODP) Expedition 367 successfully recovered at Site U1500 the mid-ocean ridge basalt (MORB) representing the magma activity of the initial spreading of the South China Sea during the earliest Oligocene. Here we present the whole-rock and olivine phenocryst geochemistry of the basalts to constrain the potential influence of the Hainan mantle plume on the evolution of the South China Sea. Major and trace elemental compositions indicate that the basalts were mainly influenced by fractional crystallization of olivine and formed by melting of a spinel peridotite source without any pyroxenite in mantle source. The calculated mantle potential temperature of those most primitive basalts is much lower than plume-related MORB of Iceland, but similar to normal MORB elsewhere. Both lithological composition and mantle potential temperature clearly contradict with the mantle plume model, signifying that the mantle plume didn’t exist at the earliest Oligocene. Therefore, the initial spreading of the South China Sea should be caused by non-plume processes, most likely by the westward subduction of the Pacific Plate.
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影响因子：
3.5
作者：
Herzberg, C.;Asimow, P. D.
通讯作者：
Asimow, P. D.
影响因子：
0.8
作者：
S. Verma
通讯作者：
S. Verma
影响因子：
5.3
作者：
Guoliang Zhang;Qing Luo;Jian Zhao;M. Jackson;Lishuang Guo;Li-feng Zhong
通讯作者：
Guoliang Zhang;Qing Luo;Jian Zhao;M. Jackson;Lishuang Guo;Li-feng Zhong
影响因子：
3.5
作者：
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通讯作者：
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影响因子：
5.3
作者：
Li, Xian-Hua;Li, Jie;Xu, Yi-Gang;Li, Xiang-Hui
通讯作者：
Li, Xiang-Hui