Study on the role of weak lower crust in Cenozoic tectonic deformation of Qinghai-Tibet Plateau by an integrated centrifugal analog modeling and numerical simulation approach

The India-Asia collision resulted in the formation of Qinghai-Tibet Plateau. Lower crustal flow model was proposed to explain the mechanism of Cenozoic tectonic deformation of Qinghai-Tibet Plateau. In this study， we propose a new approach by combining centrifugal analog modeling with numerical simulation to simulate the uplift history of the plateau based on the lower crustal flow model， and to investigate the material migration characteristics and the influence of crustal motion velocity and ductile layer viscosity on the plateau topography. The models reproduce steep-sided flat-topped geomorphic features and clockwise rotation at Eastern Himalayan Syntaxis， verifying the rationality of the models. The results show that the greater the crustal motion velocity and the greater the ductile layer viscosity， the steeper the terrain change; and conversely， the smaller the crustal motion velocity and the smaller the ductile layer viscosity， the gentler the terrain change. This study further indicates that the weak lower crust plays an important role in the formation of geomorphic features and material migration characteristics of Qinghai-Tibet Plateau， and provides a new insight for the study of the uplift mechanism of the Tibetan Plateau.