南海北部新生代构造迁移特征

选择南海北部比较有代表性的珠江口、琼东南和中建南3个盆地作为研究区,对所获取的剖面进行了地震解释工作,运用地震地层学和构造地质学等方法对我国南海北部新生代演化史开展研究,探讨了南海北部陆缘各区域构造演化差异及规律。结果表明,南海北部陆缘构造活动在时序上存在着迁移的特征,体现出自北向南"珠江口盆地→琼东南盆地"、"珠江口盆地→中建南盆地"构造事件逐渐变晚的趋势。因此,南海北部陆缘破裂从北部开始,以"撕裂"的方式逐渐向南推进,同时排除了红河断裂的叠加影响,南海北部自北向南断陷活动强度逐渐减弱。在其后的演化中,构造沉降与物质充填中心的迁移以一种更加复杂的方式进行。

CENOZOIC TECTONIC MIGRATION IN THE NORTHERN SOURTH CHINA SEA

We selected the Pearl River Mouth Basin, the Qiongdongnan Basin and the Zhongjiannan Basin as the three targets for study of the Cenozoic tectonic migration in the Northern South China Sea. Interpretation was carried out for the seismic profiles across the above basins. Integrated methods, such as seismostratigraphy, structural geology and others, were adopted to reveal the Cenozoic tectonic evolution of the northern South China Sea and the tectonic evolutionary pattern of each basin in order to find out the history of tectonic migration and regional differences on the northern margin of the South China Sea. The results proved that Cenozoic tectonic migration did happen in this region following N-S direction. Tectonic events became gradually younger from the Pearl River Mouth Basin to the Qiongdongnan Basin and from the Pearl River Mouth Basin to the Zhongjiannan Basin. The rifting apart of the South China Sea started from the north, and gradually moved southward. In spite of the influence of the Red River fault zone, the intensity of the rifting process became weaker from north to south as well. The tectonic migration would certainly make the tectonic pattern of subsidence as well as depositional centers more complicated.