南海北部海域中东部陆架坡折带类型与迁移演化及成因

Types and migration of shelf-breaks in the central and eastern parts of the Northern South China Sea and their origin

摘要: 为了研究南海北部海域中、东部陆架坡折带在不同年代的迁移特征，分析了高精度单道地震剖面与地质浅钻等资料。在南海北部海域珠江口外区、东沙区和台湾浅滩区的陆架及陆坡带附近第四纪地层中，共识别出6个三级层序界面以及相应的沉积层序，同时识别了6个区域下切侵蚀面，并以此为依据认识了本区第四纪河道的演化特征，建立了层序地层格架。在此基础上，将该区第四纪陆架坡折带由西至东划分为建设型、侵蚀型和转换型三种类型，讨论了各段陆架坡折带的演化规律，提出构造地貌成因、水下河道发育与沉积物供给等作用均为控制陆架坡折带发育和迁移的主要因素。

Abstract: This paper focuses on the types and characteristics of shelf-break migration in the Central and Eastern parts of the Northern South China Sea in the period of Quaternary. Based on the data of high-resolution seismic profiles and geological cores, six 3^rd order sequences and their boundaries have been identified. Upon the basis, three types of shelf-breaks are recognized as well. They are the shelf-breaks on depositional continental margin, erosional continental margin and tectonic-controlled continental margin from west to east, formed by the joint action of tectonism, underwater channeling, sedimentary supply and other factors.