Intra-continental deformation and tectonic evolution of the West Junggar Orogenic Belt, Central Asia: Evidence from remote sensing and structural geological analyses

Abstract

The West Junggar Orogenic Belt (WJOB) in northwestern Xinjiang, China, is located in the core of the western part of the Central Asian Orogenic Belt (CAOB). It has suffered two stage tectonic evolutions in Phanerozoic, before and after the ocean–continental conversion in Late Paleozoic. The later on intracontinental deformation, characterized by the development of the NE-trending West Junggar sinistral strike-slip fault system (WJFS) since Late Carboniferous and Early Permian, and the NW-trending Chingiz-Junggar dextral strike-slip fault (CJF) in Mesozoic and Cenozoic, has an important significance for the tectonic evolution of the WJOB and the CAOB. In this paper, we conduct geometric and kinematic analyses of the WJOB, based on field geological survey and structural interpretation of remote sensing image data. Using some piercing points such as truncated plutons and anticlines, an average magnitude of ~73 ​km for the left-lateral strike-slip is calculated for the Darabut Fault, a major fault of the WJFS. Some partial of the displacement should be accommodated by strike-slip fault-related folds developed during the strike-slip faulting. Circular and curved faults, asymmetrical folds, and irregular contribution of ultramafic bodies, implies potential opposite vertical rotation of the Miao’ergou and the Akebasitao batholiths, resulted from the sinistral strike-slipping along the Darabut Fault. Due to conjugate shearing set of the sinistral WJFS and the dextral CJF since Early Mesozoic, superimposed folds formed with N–S convergence in southwestern part of the WJOB.