Intracontinental orogenic transition: Insights from structures of the eastern Junggar Basin between the Altay and Tianshan orogens

Detailed subsurface structure of the eastern Junggar Basin is investigated using a large number of high-resolution two-dimensional reflection seismic profiles and well data. Our results reveal thrust faults, some of which are with strike-slip component, and fault-related folds dominating the subsurface structure of the study area. The thrust faults mainly show a divergent pattern towards the west and convergence towards the east. We divide these thrust faults and folds into three structural systems. The north thrust system, located in the north of the study area, is characterized by top-to-the southwest imbricate thrusts initiated from late Paleozoic. The central transpression system, dominating the central study area, mainly consists of thrust faults with visible strike-slip component, active from early Mesozoic until Cretaceous. The South thrust system includes top-to-the southeast thrusts in the southern part of the study area. The existence of these structural systems indicates that the eastern Junggar Basin underwent obvious intracontinental deformation in Mesozoic, probably due to the continuous convergence between the Altay and the Tianshan orogens after the main collision-accretion processes of the Central Asian Orogenic Belt. (C) 2014 Elsevier Ltd. All rights reserved.