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

As a Jurassic-Cretaceous nonmarine basin under interplate tectonic regime since the Indosinian movement at the end of Triassic in age,the Ordos Basin boundaried by a large active thrust belt onto the west Ordos margin is situated in the west part of the North Chick Craton. Its formative mechanism is commonly influenced by the sinistral sheared stress derived from the relative motion between the Eastern Asia continental and Kula-Pacific ocean plates on the east, and by the dextral sheared stress derived from the tectono-accretion onto the south Asia continental margin of the Tethys terranes, such as the Qiangtang and Lhasa 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, the first generation is so-called Ordos Coal-forming Basin.A blind thrust-ridge depositional model is proposed in this paper to explaine the lack of potential gravel fan deposystem in the west Ordos foredeep, and the occurence of good-quality, thick coal seams origined from the peat-forming swamp on the flood plain between major channelbelts.