酒西白垩纪盆地沉积构成及盆地演化动力学分析

The depositional architectures and geodynamics of the West Jiuquan basin, Gansu

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。在湖盆演化的不同阶段形成冲积扇 扇三角洲 滨浅湖 砾质辫状河、近岸水下重力流扇 中深湖 扇三角洲和扇三角洲 中浅湖 河流沉积体系组合型式。依据等时界面,将湖盆充填序列划分为3个构造层序,相对应于初始裂陷、扩张裂陷 热衰减沉降和湖盆萎缩关闭3个演化阶段。地幔热柱的形成和衰减、燕山运动等远程应力作用控制着盆地的演化。

The West Jiuquan Cretaceous basin, a monotypic petroliferous basin in Gansu is composed of alluvial fan, subaqueous gravity flow fan, fan delta, lake, fluvial depositional systems. The depositional system associations such as alluvial fanfan deltalittoral to shallowlakegravelly braided river, nearshore subaqueous gravity flow fanmoderate to deep lakefan delta, and fan deltamoderate to shallow lakefluvial associations record the distinctive phases of the basin evolution. The infilling sequences of the basin may be divided, in the light of isochrous surfaces, into three tectonic sequences corresponding to the initial rifting, extension and subsidencethermal subsidence, and basin collapse and closure phases. The evolution of the basin is controlled by the distal stresses such as the waxing and waning of the mantle thermal plumes and Yanshanian movement.