南海中西部地貌单元划分及其特征和成因分析

南海中西部处于南海北部和南部的过渡带,夹持于印支地块和南海海底扩张中心之间,其特殊的地貌对于研究整个南海地质地貌有重要意义。本文基于广州海洋地质调查局在南海中西部海洋地质调查项目获取的水深、底质调查及地震剖面数据,结合该海域以往研究成果,提取了有关地貌的信息,编制了南海中西部地貌图。把研究区划分出陆架、陆坡和深海盆地三个二级地貌单元,以及水下岸坡、水下浅滩、海岭、峡谷、麻坑、阶地、盆地、海台、海山、深海扇、深海平原等众多次级地貌单元。文章详细描述了该海域各地貌单元的特征,提出了断层、火山、构造隆起和浊流等地质作用是本区地貌形成的主要因素。

Geomorphologic Unit Partition, Characteristics and Genesis of Central and Western South China Sea

The middle and western part of the South China Sea is the transitional zone between the northern and southern parts of the South China Sea. It is located between the Indo-China block and the seafloor spreading center of the South China Sea, and its special geomorphology has important significance for the study of the geomorphology and geological features of the South China Sea. Based on the data of water depth, sediment survey and seismic profile obtained by the Guangzhou Marine Geological Survey Bureau as well as the results of previous studies, the authors extracted the information of geomorphology and compiled the geomorphologic map of the central and western parts of the South China Sea. The study area was divided into three secondary landform units, i.e., continental shelf, continental slope and deep sea basin, and many subordinate landform units such as submarine bank, submarine beach, marine ridge, canyon, pockmark, terrace, basin, marine platform, marine mountain, marine fan, and marine plain. This paper describes the characteristics of the landform units in this area, and puts forward geological factors such as faults, volcanoes, tectonic uplift and turbidity, which are the main factors of geomorphologic formation in this area.