鄂尔多斯聚煤盆地的形成及构造环境

鄂尔多斯盆地是印支运动使中国大陆处于板内构造体制之后，座落于华北克拉通西部的侏罗－白垩纪盆地，并存在４个阶段的世代演替，其中第一世代是聚煤盆地。这是在中国东部左旋剪切与西部右旋剪切派生的挤压构造应力作用下形成的，但在西侧构造活动带的前渊位置缺乏大型砾质扇，这种情况显著是由于鄂尔多斯西缘掩冲带前缘存在的隐伏冲断脊，阻碍了粗粒碎屑流向盆地注入，因而在广阔的泛滥平原上形成了优质厚煤层。

FORMATION OF THE ORDOS BASIN AND ITS COAL-FORMING TECTONIC ENVIRONMENT

s a Jurassic-Cretaceous nonmarine basin under interplate tectonic regime since the Indosinianmovement at the end of Triassic in age,the Ordos Basin boundaried by a large active thrust belt onto thewest Ordos margin is situated in the west part of the North Chick Craton. Its formative mechanism iscommonly influenced by the sinistral sheared stress derived from the relative motion between the EasternAsia continental and Kula-Pacific ocean plates on the east, and by the dextral sheared stress derived from thetectono-accretion onto the south Asia continental margin of the Tethys terranes, such as the Qiangtang andLhasa Blocks, and Songpan-garze Complex, on the west as well.The evidence firnished by detailed stratigraphic, sedimentologic and subsidence analyses shows'with fully satisfactory that 4 generations have existed as a successive evolution of the Ordos Basin. Of which, thefirst generation is so-called Ordos Coal-forming Basin.A blind thrust-ridge depositional model is proposed inthis paper to explaine the lack of potential gravel fan deposystem in the west Ordos foredeep, and theoccurence of good-quality, thick coal seams origined from the peat-forming swamp on the flood plain betweenmajor channelbelts.