Abstract:

Along the west edge of Ordos fault block,there is a bunch of zigzag faults which,in fact.comprises part of the great N-S treading tectonic belt running through central China.This belt is inherited from the basement,which control-ling the formation and deformation of its sedimentary covers.During the period when tension stress prevailed,the fault belt took the form of normal fault with its west side seriously subsiding in the Paleozoic stage,but its east side subsided in the Mesozoic.In the period of compression,i.e.at the late stage of its tectonic cycle,it took the from of eastwards thrust-ing with some folds accompanied.The deformation caused by the Caledonian Orogeny was not quite violent,while intensive imbricate thrust faults were formed by the Yanshanian Orogeny during Late Jurassic.Compressed by the Siberian and Indian plates unequally both from the north and south during the Yanshanian Orogeny,Ordos area was subjected to clock-wise rotation enhanced by Alashan fault block squeezing toward it from the west.So this results in the above mentioned tectonic deformation along the west edge of Ordos fault block.It is concluded that this fault belt possesses better prospects for petroleum exploration due to the existence of source rocks on its both sides and good preservation condition along the fault belt and its eastern area.