南海海域地壳结构特征及其构造意义  

Characteristics of the Crustal Structure in the South China Sea and Their Tectonic Significance

作　　者：邱燕[1] 汪俊[1] 阎贫[2] 黄文凯[1] 朱本铎[1] 王彦林[2] Qiu Yan;Wang Jun;Yan Pin;Huang Wenkai;Zhu Benduo;Wang Yanlin(Guangzhou Marine Geological Survey,Guangzhou 510075,China;South China SeaInstitute of Oceanology,CAS,Guangzhou 510301,China)

机构地区：[1]广州海洋地质调查局,广州510075 [2]中国科学院南海海洋研究所,广州510301

出　　处：《南海地质研究》2016年第1期1-39,共39页Gresearch of Eological South China Sea

摘　　要：本文利用近数十年来所获得的深部地壳结构探测资料,结合前人研究成果,对南海地壳结构特征开展了系统分析,并简述了其构造意义。南海海域分布陆壳、减薄型陆壳、洋陆过渡壳和洋壳等地壳类型,壳下高速层分布较广,地壳结构颇为复杂。陆壳分布在海域外缘海岸带和大部分陆架区一带;减薄型陆壳分布在岛礁区、部分陆架区和大部分陆坡区;洋壳主要分布在中央海盆。在中央海盆与周缘减薄陆壳间,由于洋壳莫霍面在短距离内急剧下降深入周缘区域,形成洋陆过渡壳。壳下高速层分布在大部分陆坡和洋壳部分区域。地壳结构特征揭示,在拉张演化之前,本区地壳首先遭受隆升剥蚀,导致上地壳不同程度地减薄,致使上地壳目前的厚度差别巨大。中央海盆的洋壳为新生代海底扩张事件所形成,且扩张过程不甚稳定,扩张前期裂谷较为发育。Using the data of deep comprehensive geophysical reconnaissance during recent decades and integrating previous achievements,the characteristics of the crustal structure in the South China Sea and their tectonic significance have been systematically studied in this paper.The crustal structure of the sea is quite complicated,in which continental crust,thinner-continental crust,continental-oceanic transitive crust and oceanic crust distribute widespread with high velocity layers under crust.Continental crusts distribute at the edge of the sea,coastal zones and portion of shelves,while thinner丒continental crusts distribute in the areas of islands,reefs,fraction of shelves and portion of slopes and oceanic crust mainly develops in the center basin while continental-oceanic transitive crusts develop between the centre basin and the areas around it because of the burial depth of oceanic crust Moho failing rapidly from the basin to its rim in short distance.The high velocity layers distribute under the crusts of slopes and a large part of oceanic crust.The characteristics of crustal construction reveal that before the evolution of crustal extension,this area uplifted firstly and then all crust had been inordinately eroded and attenuated,resulting in the great disparity of the thickness of upper continental crust.The oceanic crust in centre basin was formed by the seafloor spreading event but the spreading process was instability and many rifts generated prior to spreading activity.

关 键 词：南海海域 地壳类型 速度模型 地壳结构特征 构造意义 

分 类 号：P315.2[天文地球—地震学]