江陵浅水-半深水坳陷湖盆层序地层学特征

以层序地层学理论为指导,系统研究了江陵浅水-半深水坳陷湖盆的层序地层学特征。研究表明:区域不整合界面和沉积转换界面是级层序的主要界面;层序内虽均发育低位、湖侵和高位体系域,但各体系域发育程度是不同的,致使层序的旋回性以非对称为主;层序内各体系域的沉积相构成均以河流三角洲和浅水湖泊为主,而冲积扇、扇三角洲不发育,湖泊水体基本没有发生过明显的扩张、收缩,湖平面的波动没有造成沉积相带的区域性变化,在此基础上,建立了江陵浅水-半深水坳陷湖盆特有的两种层序地层充填模式。

Characteristics of Sequence Stratigraphy of Jiangling Shallow to Semi-deep Water Depressional Lake Basin

Guided with the theory of sequence stratigraphy, the characteristics of sequence stratigraphy of Jiangling shallow to semi-deep water depressional lake basin has been studied systematically. The study indicates that the regional unconformable and sedimentary transformation interfaces are the main interfaces of Ⅲ-order sequence. Though lowstand, highstand and lake transgressive system tracts developed in the studied sequence, the development degrees of different system tracts are quite different, which result in the asymmetric distribution of sequential cycles. The sedimentary facies in different system tracts consist of mainly fluvial delta and shallow lake facies, with alluvial fan and fan delta underdeveloped. The lake water body has experienced no obvious expansion and shrinkage. The fluctuation of water level of the lake has caused no regional changes of sedimentary facies belts. Two particular filling model of sequence stratigraphy have been constructed on the basis of the study results.