鄂尔多斯断块据其北、东、南缘出露状况,不少人曾认为断块内缺失上元古界。近年来据深井和深层地震资料分析,断块中南部大面积分布有上元古界,可能仅相当于长城系和蓟县系。它以石英岩、安山岩、碳酸盐岩为主,与下古生界呈平行不整合,在继承性的断陷中心可与下元古界顶部的与担山石群相当的地层呈微角度不整合,在断块边缘受经、纬向构造格局控制,从断块北、南、西三侧向断块内迅速变薄尖灭;在断块内受北东向断陷控制,断陷内地层可达三千米以上,并向两侧迅速变薄以至尖灭。上元古界发育状况表明存在由地槽区伸向稳定块体内部的裂堑(Aulacogen)型构造。它的发现说明断块内深部有一套新的生储盖组合,且具有较好的含油特别是含气远景。 Ordos block according to its northern, eastern and southern margins, many people thought that the absence of the Proterozoic fault block. In recent years, according to deep and deep seismic data analysis, large-scale distribution of central and southern Palaeogene Proterozoic, may only be equivalent to the Great Wall and Jixian line. It is mainly composed of quartzite, andesite and carbonate rock and is parallel unconformity with the Lower Paleozoic. The inherited fault center can be at a micro-angle with the top of the Lower Proterozoic strata corresponding to the Danfeng Group It is controlled by the pattern of latitudinal and weft tectonics at the margin of the fault block and rapidly thinned and pinched within the fault block from the north, south and west sides of the fault block. Within the fault block, it is controlled by the north-east fault depression and the fault depression in the hinterland Layer up to three kilometers above, and rapidly thinning on both sides to pinch off. The development of the Proterozoic Proterozoic indicates that there is a Aulacogen-type structure extending from the geosyncline to the interior of the stable block. Its discovery shows that there is a new reservoir-cap assemblage in the deep part of the fault block and has better oil bearing, especially gas-bearing visions.