珠江口盆地坡折带特征及其对沉积体系的控制

Characteristics of the slope break zones and their controls on the depositional systems in the Pearl River Mouth Basin

本文基于对覆盖全区的二维地震资料研究,在珠江口盆地识别出了大型的陆架坡折及多种小型坡折带,包括侵蚀坡折带、沉积坡折带、断裂坡折带和挠曲坡折带。不同的构造背景发育了不同的坡折带类型。自30Ma年以来,坡折带总体呈向北迁移的趋势。古近纪-早中新世中期以各种小型坡折带为主,主要控制三角洲及扇三角洲等浅水沉积的展布;早中新世中期至今,由于陆架-陆坡体系已形成,坡折带以陆架坡折为主,控制了陆架边缘三角洲及海底扇等较深水沉积的发育。

The Pearl River Mouth Basin is an important petroleum base in the South China Sea. A number of shelf breaks have been distinguished for the depositional systems in the Pearl River Mouth Basin on the basis of 2-D seismic data throughout the whole area, including erosional, sedimentary, fault and flexure slope break zones. These slope break zones have generally migrated northwards since 30 Ma. During the Palaeogene to the middle stage of early Miocene, the small-sized slope break zones predominated, and once had an important effect on the delta and fan delta shallow-water deposits. From the middle stage of early Miocene onwards, the continental shelf break zones have been accentuated, and have exerted the influence on the shelf-margin delta and submarine fan deep-water deposits.