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基于覆盖南海的水深、重力、磁力以及地震资料,结合区域地层特征,通过地质与地球物理综合解释研究,明确了南海区域断裂和前新生代基底构造格局特征.古生代以来,受控于特提斯和太平洋两大构造域影响,导致南海地区板块汇聚与分离,不同时期南海构造应力环境各异,形成了性质不同的四周陆缘,致使北部陆缘主要为拉张型断裂,南部陆缘为挤压型断裂,西部陆缘为走滑型断裂,而东部陆缘则为海沟俯冲型断裂,以NE-NEE向、NW向和近SN向3组走向为主.在此研究基础上,海陆综合考虑,结合地块构造层序列、沉积建造、变质作用以及构造演化历史,以地块拼接带(蛇绿岩带、蛇绿混杂岩带及扩张边缘带)作为二级构造单元的分界线,以主要走滑断裂作为三级构造单元的分界线,将南海及其围区划分为8个二级构造单元以及9个三级构造单元.南海地区基底构造单元具有不同的构造层,沉积建造以及变质作用,显示出不同时期具有不同的构造属性.本文的研究结果将有助于进一步了解南海地区基底构造格局以及揭示前新生代构造演化过程,为该区新生代构造演变提供基底制约.
Based on the data of water depth, gravity, magnetic force and seismic data covering the South China Sea, combined with the regional stratigraphic features, through the comprehensive interpretation of geology and geophysics, the characteristics of the structural and structural features of the South China Sea fault and the Pre-Cenozoic basement are clearly defined. Since Paleozoic, And the two major tectonic domains in the Pacific Ocean, resulting in convergence and separation of plates in the South China Sea. The tectonic stress environment in the South China Sea varies in different periods and forms four surrounding continental margins of different nature, resulting in mainly tensile fractures in the northern continental margin and continental margins in the southern margin Pressure fracture, the western continental margin is a strike-slip fault, while the eastern margin is the trench subduction type, with NE-NEE direction, NW direction and near SN direction as the main group. On the basis of this study, Considering the combination of block sequence, sedimentary formation, metamorphism and tectonic evolution history, we consider the block splicing zone (ophiolite zone, ophiolitic melange zone and expansion margin zone) as the dividing line of secondary structural unit The main strike-slip faults are the dividing line of tertiary structural unit, which divides the South China Sea and its surrounding area into 8 secondary structural units and 9 tertiary structural units. The basement structural units in the South China Sea are different Tectonic layer, sedimentary structure and metamorphism show different tectonic attributes in different periods.The results of this paper will help to further understand the structure of the basement in the South China Sea and reveal the tectonic evolution of the Pre-Cenozoic, Provide base constraints.