鄂尔多斯盆地中部气田剥蚀脊与沟槽

鄂尔多斯盆地中部气田位于稳定克拉通中央古隆起东部，是与奥陶系海相碳酸盐岩有关的风化壳型气田。由于古岩溶作用明显，风化壳顶面具有显著的岩溶地貌特征，形成了独特的沟台并存格局。前人对这一地区地貌研究中，在气田东部和西部划分出多条树枝状沟槽，并认为它们成因相同。通过最新资料研究，认为二者特征差异明显：西部为剥蚀脊，是古中央隆起带向古海盆由面状剥蚀到脊状延伸部分，其奥陶系上部地层缺失是风力作用和化学溶蚀、淋滤作用造成的；东部为沟槽，奥陶系上部地层因线状流水侵蚀和溶蚀作用缺失。图2表1参6

Denudation ridges and erosion flutes in the central gas field, Ordos Basin

The gas field in the center of Ordos Basin is formed in the eastern central paleo-uplift of the stable craton. They are of weathering crust and related to Ordovician marine carbonate. Due to obvious paleo-karsi, erosion flutes and platform co-exit at the top of the weathering crust. According to the previous studies, the erosion flutes on the eastern and western borders are of the same origin, the latest data show that there are clear differences between them. The western ones are denudation ridges, which are the extension of the planar denudation during the change from central paleo-uplift to paleo-marine basin. Stratum lacuna of the Ordovician top in the western ones are caused by wind action, chemical corrosion, and leach; whereas that in the eastern ones by linear erosion and chemical erosion.