南海珠江21Ma深水扇特征及控制因素

Characteristics and controlling factors of Zhujiang deep-water fans developed in 21 Ma,South China Sea

通过对珠江口盆地白云凹陷三维地震资料解释、钻井、测井及岩心资料的观察和描述,对21 Ma发育的深水扇特征、沉积模式及控制因素进行研究。结果表明:岩心上发育正递变层理、鲍马序列和滑塌变形等多种典型重力流构造,指示了沉积物为半深海环境下的重力流沉积;地震资料上可识别出水道、水道堤岸复合体、朵体等典型深水扇构型;21 Ma深水扇沉积模式为陆架边缘三角洲-峡谷-深水扇的沉积模式,是在珠江口盆地的构造格局、相对海平面变化、坡折带演化、断裂系统的形成及古珠江三角洲的物源供给能力等多种因素的控制和有效配置下形成的。

By interpretation of the 3D seismic data, observation and analysis of the drilling, well logging and core data from Baiyun sag in Pearl River Mouth Basin, the characteristics, sedimentary model and controlling factors of deep-water fans in 21Ma were researched. The resuhs indicate that several kinds of gravity-flow structures are discovered in the core such as normally graded bedding, Bouma sequence and slump deformation bedding, all of which indicate a kind of gravity flow deposits in bathyal environment. In seismic profile, typical sedimentary architectures of the fans are recognized, which include channels, channel-levee complex and lobes. In 21Ma, the Baiyun sag developed the kind of shelf-margin delta-valley-submarine fan sedimentary model is mainly controlled by tectonic framework, relative sea-level changes, slope break belt evolution, formation of faults as well as the material supply of the Pearl River delta.