Activities and evolution of thrust faults in Hami depression, Tu-Ha Basin

Key words:  Hami depression  thrust fault  geological model  fault activity  fault evolution

Abstract:

Based on the interpretation of seismic profiles and analysis of fault pattern, three different geological models named single-force thrusting, double-force slipping and basement uplifting were proposed by analyzing the relationship between denudation and sedimentation at the two sides of the fault in Hami depression. Three test fault activity formulas for those different models were given to calculate vertical displacements of the major faults during the Indosinian, the Yanshanian and the Himalayan periods. The results show that the thrusting in Huoshizhen sag is intensive during the Indosinian period, but became weaker and weaker during the Yanshanian period, the activity of fault enhanced only in the south boundary during the Himalayan period. While the thrusting in Sanbao sag initiated during the Indosinian period, and became more intensive during the Yanshanian period, then terminated during the Himalayan period. Differentiation of the fault activity in different sags directly control the formation and evolution of the structural patterns in these sags. The tectonic framework of Huoshizhen sag basically developed during the Indo-china movement, while that of Sanbao sag finally developed after the Yanshanian movement.