鄂尔多斯盆地西缘马家滩地区构造沉降特征与三叠纪延长期的盆地属性

Tectonic subsidence characteristics and the basin attribute of Triassic Yanchang Period of Majiatan area in the western margin of Ordos Basin

为了确定鄂尔多斯盆地西缘中段延长期盆地属性,本文以马家滩地区9口探井为基础,通过对构造沉降曲线进行分析,结合盆地沉降曲线正演模拟,将马家滩地区沉降划分为9个阶段,认为延长期盆地西缘马家滩地区应处于弱伸展环境,其中长10段—长8段沉积时期应为岩石圈热冷却作用早期引起的快速沉降阶段,长7段—长1段沉积时期为热冷却作用中后期引起的缓慢沉降,盆地属性应为克拉通内坳陷盆地。

In order to determine the basin attribute of Yanchang Period in the middle of western margin of Ordos Basin, based on 9 exploration wells in Majiatan area, through the analysis of tectonic subsidence curve, combined with forward modeling of basin subsidence curve, the subsidence in Majiatan area was divided into 9 stages, and the Majiatan area in the western margin of the Yanchang Period should be in a weak extensional environment. The sedimentary period of Chang-10 to Chang-8 members should be the rapid subsidence stage caused by early lithospheric thermal cooling, while the sedimentary period of Chang-7 to Chang-1 members should be the slow subsidence caused by middle and late thermal cooling, and the basin attribute should be residual cratonic depression, and the basin attribute should be residual cratonic depression.