Structural Styles of the Longmenshan Thrust Belt and Evolution of the Foreland Basin in Western Sichuan Province, China

Abstract

Abstract The Longmenshan thrust system consists of two major groups of structural styles according to the depth of their involvement: basement thrusts ‐ compressional fault blocks; fold ‐ thrust system in the cover. In cross ‐ section, the Longmenshan structural belt is divided into 5 zones. The propagation of the Longmenshan thrust system is piggy ‐ back due to pushing at the early stage and overstep due to gravity sliding at the late stage. Balanced cross ‐ sections and palinspastic reconstruction reveal that the total sliding displacement of the thrust system amounts to 120 km. The tectonic evolution of the Tethys domain in western Sichuan has experienced 5 stages: continental break ‐ up; ocean ‐ continent subduction; continent ‐ arc collision; orogenic thrusting; uplift of western Sichuan.