The faults in the west of Tangguzibasi sag can be divided into Madong cover detachment faulting system and Tangnan basement involved faulting system, depending on the characteristics of the seismic profiles. Faults of Madong system are all detached in the Middle Cambrian salt layer, the faults of Tangnan system are short, and most of them cut deeply into the basement. Faults in Madong and Tangnan system were products of the collision between Tarim Plant and Altyu Massif, during Middle Caledonian. From Middle Ordovician to Silurian, the intense activity of the Altyu fault passed the stress from south to north. In late Ordovician, stress passed to Mazhatage-Yecheng area, resisted by the rigid basement there, the counteracting force firstly formed the thrust belt in the weak basement of Madong area. The basement of Tangnan area was also rigid, and so there were few faults formed during that period. At the end of Ordovician, the stress became stronger, and basement involved and piedmont thrust faults were formed in Tangnan area, from north tosouth. The reactivation of the Madong thrust belt was the manifestation of the collision between Kunkun block and Paleotethys in Late Hercynian. The fault style of Madong and Tangnan were controlled by the distance from orogenic belt, the thickness of Middle Cambrian salt, and the type of basement.
Journal of Central South University：Science and Technology