Late Triassic successive amalgamation between the South China and North China blocks: Insights from structural analysis and magnetic fabrics study of the Bikou Terrane and its adjacent area, northwestern Yangtze block, central China

ABSTRACT The Bikou Terrane, located at the conjunction of Longmenshan fold-thrust belt and west Qinling orogenic in centeral China, was involved Late Triassic collision between South China North blocks. Terrane has preserved crucial information on structural geometry kinematics tectonics, is therefore great importance for reconstructing Paleo-Tethyan evolutionary history. However, multi-phase tectonic events are unsettled. This work presents detailed analysis based both field laboratory works, which reveals three phases deformation its adjacent areas, including top-to-the-SW shearing related to SW-ward thrusting (DI) mainly north top-to-the-NNW NNW-ward (DII) strike-slip faulting (DIII) locally developed northern Terrane. Anisotropy magnetic susceptibility (AMS) study not only support multiphase but also reveal a gradual transition from DII-related fabrics DIII-related Integrating published geochronological data, it constrained that DI occurred ca. 237–225 Ma, DII 224–219 DIII possibly during Early Cretaceous. Based regional event corresponds block reflects intracontinental amalgamation Yangtze block, indicates successive block. Intracontinental adjustment represented by (DIII event) after final By applying AMS deciphering deformation, our suggests useful tool analysis.