鄂尔多斯盆地侏罗纪早中期甘陕古河的演化变迁

鄂尔多斯盆地侏罗纪早中期沉积前经过印支运动强烈的构造抬升,使上三叠统延长组遭受不同程度的剥蚀及河谷下切作用,形成了起伏不平的古地形。在侏罗纪早期发育了甘陕古河、庆西等5大古河,其中甘陕古河为主河道。在甘陕古河流域,从富县组到延安组各个时期具有不同的沉积与古地理特点,并一起反映了盆地的构造沉积演化历程。

Evolution of Gan-Shaan paleochannel during Early and Middle Jurassic in Ordos basin

The Upper Triassic Yanchang Fm underwent denudation and incision of river valley to different degrees before the deposition of Lower and Middle Jurassic in Ordos basin due to the strong tectonic uplifting du-(ring) Indosinian movement,resulting in rolling paleotopography.Five major paleo-streams,including Gan-Shaan and Qingxi,were developed in early Jurassic' of which Gan-Shaan paeo-stream was the main stream channel.In the Gan-Shaan paleo-stream drainage area, the strata from Fuxian Fm to Yan'an Fm have different sedimentary and palaeogeographic characteristics,and they altogether reflect the structural and sedimentary evolution history of the basin.