南沙海槽—西北巴拉望构造特征及其意义  

Tectonic Characteristics of Nansha Trough-Northwest Palawan and Its Significance

作　　者：李学杰 汪俊 王哲 姚永坚 祝嵩 Li Xuejie;Wang Jun;Wang Zhe;Yao Yongjian;Zhu Song(Guangzhou Marine Geological Survey/Key Laboratory of Marine Mineral Resources,MNR,Guangzhou 511400,China)

机构地区：[1]中国地质调查局广州海洋地质调查局/自然资源部海底矿产资源重点实验室,广州511400

出　　处：《吉林大学学报（地球科学版）》2024年第4期1081-1094,共14页Journal of Jilin University：Earth Science Edition

基　　金：中国地质调查局项目(DD20160138,GZH201300502,DD20190378);南方海洋科学与工程广东省实验室(广州)人才团队引进重大专项(GML2019ZD0207)。

摘　　要：南沙海槽-西北巴拉望构造对认识南海成因与演化至关重要。综合南海南缘地质地球物理资料分析认为:南沙海槽极薄地壳可能不是古南海的残余,是夭折的扩张中心;南沙海槽存在挤压逆冲作用,形成时间很晚,与南海扩张无关,是南海形成后挤压的结果。南沙海槽挤压作用与西北巴拉望Pagasa楔变形对比表明,南海南缘的挤压作用停止时间东部早于西部;中、南巴拉望蛇绿岩来自其南部往北逆冲的产物,可能表明古南海由南往北俯冲。综上认为南巴拉望蛇绿岩可能来自新特提斯洋壳,中巴拉望蛇绿岩来自古南海洋壳;不同时期洋壳俯冲残余最终被逆冲至岛弧系之上;巴拉望蛇绿岩是长期由南往北逆冲的结果,最后就位时间可能是中晚中新世。The tectonics of the Nansha trough-Northwest Palawan is important for understanding the origin and evolution of the South China Sea(SCS).Based on the analysis of geological and geophysical data in the southern margin of SCS,we suggest that the very thin crust of the Nansha trough may not be the remnant of the Proto South China Sea(PSCS),but may be an abandoned spreading center.As a result of a compressional event after the formation of the SCS,the thrusting structures developed very late on the Nansha trough and were not related to the opening of the SCS.The comparison between the extrusion of the Nansha trough and the Pagasa wedge in Northwest Palawan shows that the time of compressional termination in the east is earlier than in the west in the southern margin of the SCS.The ophiolite in South and Central Palawan was the product of its southern northward thrusting,indicating that the PSCS may subduct from south to north.It is suggested that the Southern Palawan ophiolite may derive from the oceanic crust of Neo-Tethys and the Central Palawan ophiolite may come from the PSCS.The subducted remnants of oceanic crust in different periods were finally overthrusted onto the island arc system.The Palawan ophiolite is the result of a long-term thrusting from south to north,and the time of the final emplacement may be the Middle-Late Miocene.

关 键 词：南海南缘 南沙海槽逆冲构造 古南海 巴拉望蛇绿岩 

分 类 号：P548[天文地球—构造地质学]