Opening and evolution of the South China Sea constrained by studies on volcanic rocks:Preliminary results and a research design

作     者：XU YiGang WEI JingXian QIU HuaNing ZHANG HuiHuang HUANG XiaoLong 

作者机构：State Key Laboratory of lsotope GeochemistryGuangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China Graduate University of Chinese Academy of SciencesBeijing 100049China 

基　　金：supported by the National Natural Science Foundation of China (91128203) the CAS/SAFEA International Partnership Program for Creative Research Teams (KZCX2-YW-Q04-06) the National Basic Research Program of China (2011CB808906) 

出 版 物：《Chinese Science Bulletin》 (Chinese Science Bulletin)

年 卷 期：2012年第57卷第24期

页      码：3150-3164页

摘      要：The South China Sea (SCS) is characterized by abundant seamounts, which provide important information about the evolution of the SCS and related deep processes. Cenozoic volcanism in the SCS and its surroundings comprises three stages relative to the spreading of the SCS:prespreading (>32 Ma), syn-spreading (32-16 Ma), and post-spreading (<16 Ma). The pre-spreading magmatism predominantly occurs on the northern margin of the SCS and in South China coastal areas and shows a bi-modal affinity. The syn-spreading magmatic activity was very limited on the periphery of the SCS, but may be concentrated in the SCS. However, seafloor samples of this stage are not available yet because of overlying thick sedimentary deposits. Post-spreading magmatism is widespread in the central and southwest sub-basins of the SCS, Hainan Island, Leizhou Peninsula, Thailand, and Vietnam. These are mainly alkali basalts with subordinate tholeiites, and display OIB-type geochemical characteristics. The Dupal isotope anomaly and presence of high-magnesian olivine phenocrysts suggests their possible derivation from the Hainan mantle plume. The temporal and spatial distribution of Cenozoic volcanism in the SCS and its surroundings may be accounted for either by plate stress re-organization before and after SCS spreading, or by ridge suction of plume flow during opening of the SCS. If the latter is the case, the volcanic rocks within the SCS basin may not be typical mid-ocean ridge basalts (MORB). It remains puz-zling, however, that the transition between the South China continental margin and the SCS basin does not have features typical of a volcanic rifted margin. Clearly, the relationship between mantle plume and SCS opening needs further evaluation. A better un-derstanding of the link between deep processes and opening of the SCS not only requires enhanced studies on igneous petrogene-sis, but also is heavily dependent on systematic sampling of seafloor rocks.

主 题 词：中国南海 火山岩 DUPAL同位素异常 开幕式 进化 设计 海底山脉 岩浆活动 

学科分类：0709[理学-地质学] 070901[070901] 07[理学] 

核心收录：

D　O　I：10.1007/s11434-011-4921-1

馆 藏 号：203319184...