Late Mesozoic-Cenozoic intracontinental growth and deformation history of the northern Tibetan Plateau and western North China craton

The growth history and formation mechanism(s) of the Cenozoic Tibetan plateau are the subjects of an intense debate with important implications for understanding the kinematics and dynamics of large-scale intracontinental deformation. Because the far-field response of the India-Asia collision has led to the Cenozoic uplift and deformation along the northern margin of the plateau, determining the tectonic evolution of this region is crucial in understanding how the Tibetan plateau was constructed. We present updated field observations coupled with low-temperature thermochronology across this region, from Qaidam basin in the south to the Qilian Shan foreland, to document the deformation and exhumation history. Our thermochronological results suggest that the entire region, including the neighboring North China crater, experienced significant regional late Mesozoic exhumation. The Qilian Shan thrust belt initiated shortly after the India-Asia collision in the Eocene, before the initiation of major thrust belts to the south (e.g., the Eastern Kunlun Shan), which argues for out-of-sequence thrusting rather than a progressive northward migrating deformation pattern in the northern plateau. This early Cenozoic deformation exploited the south-dipping early Paleozoic Qilian suture zone, as interpreted from field mapping and geophysical dada. In the Miocene, strike-slip faulting started to develop along the older Qilian suture zones, which is expressed by the development of the Kunlun and Haiyuan left-slip transpressional systems. Late Miocene deformation and uplift of the Hexi corridor and Longshou Shan directly north of the Qilian Shan represents the most recent phase of outward plateau growth.