Timing of Cenozoic Intense Deformation and Its Implications for Petroleum Accumulation, Northern Margin of Tianshan Orogenic Belt, Northwest China

As proved by the analysis of growth strata and regional study, the intense tectonism of the Cenozoic in the northern margin of Tianshan Orogenic Belt initiated at about 10–7 Ma BP and associated with intense tectonic deformation, led to the formation of three thrust belts at the northern margin of Tianshan Orogenic Belt. The time of intense deformation is much younger than that of the southern Tianshan, which suggests that the tectonic deformation propagated from the southern Tianshan to the northern Tianshan due to the India-Asia collision. The intense deformation of the Late Cenozoic resulted in relatively gentle deformation in the western Uromuqi-Qigu anticline and widespread tectonic deformation transporting and retrogressing from the south to the north. The differential tectonic deformation indicates that the front of thrust belt is beneficial to hydrocarbon accumulating. Moreover, for the intense denudation and uplifting along the structure belt of foreland, structures with gentle deformation are advantageous to the preservation of oil and gas accumulating during the early phase.