中国南海不同板块边缘沉积盆地构造特征

Tectonic Characteristics on the Sedimentary Basins with Different Plate Margins in the South China Sea

基于科学考察区域联测剖面资料,结合南海大地构造背景研究,对南海主要的新生代沉积盆地的构造特征进行了对比分析。研究表明,区域联测剖面穿越的沉积盆地的构造特征具有显著的差异,具体表现在大地构造背景、重磁场特征、盆地基底、断裂性质、构造线方向以及火成岩发育等方面。南海断裂的发育与盆地形成具有密切的关系,南海北部主要表现为NE向张性断裂控制的沉积盆地;西部主要表现为NW向和近SN向走滑断裂控制的沉积盆地;南部比较复杂,张性、压性、剪性断裂都有发育,但以NE向的南沙海槽逆冲断裂及其控制的南沙海槽盆地最具代表性;东部主要指南海中央海盆,断裂和海底火山共同控制了该区上新世—第四纪沉积。

This paper makes a comparative analysis on the structural characteristics of the main Cenozoic sedimentary basins of the South China Sea, based on the regional jointed survey data and combined with geotectonic setting research. The study shows the structural features of the sedimentary basins crossed by the regional tieline are very different, and the disparities are concretely displayed in such aspects as geotectonic setting, gravity and magnetic field, basin basement, fault property, tectonic line trend and igneous rock, etc.. There are close relations between fault development and basin formation of the South China Sea. The northern South China Sea mainly displays N-E direction tension fractures and sedimentary basins under the control of the fractures; the western South China Sea mainly develops N-W direction and near S-N direction strike-slip faults and sedimentary basins under the control of the faults; the southern South China Sea is rather complicated, where tension, compression and shear faults exist but the N-E direction Nansha trough thrust fault and the Nansha Trough basin under the control of the thrust are the most representative; the eastern South China Sea refers to the central sea basin of the South China Sea here, in which fractures and submarine volcanoes control the Pliocene-Quaternary deposit.