甘肃酒西白垩纪盆地沉积构成及盆地演化动力学分析

甘肃酒西白垩纪盆地是酒西含油气盆地的一个单型盆地,发育了冲积扇、水下重力流扇、扇三角洲、湖泊、河流沉积体系,并在湖盆演化的不同阶段分别形成冲积扇-扇三角洲-滨浅湖-砾质辫状河、近岸水下重力流扇-中深湖-扇三角洲、扇三角洲-中浅湖-河流沉积体系组合型式.依据等时界面,湖盆充填序列可划分为三个构造层序,相对应于初始裂陷、扩张裂陷-热衰减沉降、湖盆萎缩关闭三个演化阶段.研究证明,地幔热柱的形成和衰减、燕山运动等远程应力作用控制盆地的演化。

The Sedimentary Formation and Analyses for Dynamic Evolution of Jiuxi Cretaceous Basin, Gansu Province

In Gansu province,Jiuxi Cretaceous Basin is a monotype basin, in which grows sedimentary system of fan shaped alluvial fan delta, subgravity flow, lacustrine and fluvial facies. It was made up of some patterns combined by sedimentary system of fan shaped alluvium fan delta shallow lakeshore gravelly braided stream, subgravity flow mid deep lacustrine fan delta and fan delta mid shallow fluvial facies. According to isochronic surface, filled sequences in lacustrine basin can be divided into three tectonic sequences corresponding respectively to three evolutionary stages of embryonic rift, spread rift thermal attenuationary subsidence and basin shrinkage closure. On the basis of these evidences, it can be seen that either formation and attenuation of mantle's thermal column or remote stress ,such as Yanshan movement, etc.,controlled the evolution of the Jiuxi Cretaceous Basin.