北部湾盆地福山凹陷深湖重力流成因分类、发育机制及沉积模式

福山凹陷为北部湾盆地南缘海南隆起斜坡上的一个新生代断陷湖盆。本文充分利用岩心、测井以及覆盖整个研究区的高分辨率三维地震资料，以层序地层学、沉积学等多种理论为指导，结合沉积岩石学、地震沉积学等相关技术，于古近系流沙港组SQEls₂EST+LST时期，在福山凹陷识别出4种深湖重力流沉积岩相类型；通过岩相组合及其转换特征、砂分散体系、地震相分析，对该时期沉积体系展布特征进行细致剖析，进而建立福山凹陷深湖重力流发育机制和沉积模式：西部地区发育以浊流为主、具有典型浊积水道的湖底扇沉积；而东部地区则以砂质碎屑流沉积形成的远端孤立朵体为主。

Genesis Classification,Development Mechanism and Sedimentary Model of Deep-Lacustrine Gravity Flow in Fushan Sag of Beibuwan Basin

Fushan sag is a Cenozoic faulted lake basin on the slope of Hainan uplift in the southern margin of Beibuwan basin. This paper makes full use of the high-resolution three-dimensional seismic data covering the whole study area. Guided by various theories such as sequence stratigraphy and sedimentology, combined with relevant technologies such as sedimentary petrology and seismic sedimentology,a comprehensive study of the whole study area is carried out. In the period of SQEls₂EST+LST of Liushagang Formation in Paleogene, four types of deep-lacustrine gravity flow sedimentary lithofacies were identified in Fushan sag. Through lithofacies assemblage and its transformation characteristics, sand dispersion system and seismic facies analysis, the distribution characteristics of sedimentary system were carefully analyzed, and then the sedimentary model of deep-lacustrine gravity flow in Fushan sag was established. The lake floor fan deposits with typical turbidite channel developed mainly in the western eastern regions. In this area, the distal solitary bodies formed by sandy clastic deposits are dominant. This study not only has direct significance for the study of sedimentary system in Fushan sag, but also provides theoretical support for many continental fault basins with the same background in Southern China.