Geotectonic background of M Basin and its evolution features

Abstract：The M Basin is located in the northernmost part of Talas-Fergana (Karatau) large strike-slip fault, and its tectonic features show that the basin has experienced complicated formation and evolution process. The authors analyzed the geotectonic background of M Basin based on the growing basin-controlling history of the fault, identified the basin style and studied the evolution features of the basin. The results show that, under the influence of plate motion, the basin-controlling fault experienced left-lateral strike-slip at the early stage and right-lateral strike-slip at the later stage. The M Basin is a strike-slip extensional basin formed in Early-Middle Jurassic, belonging to a strike-slip extensional imbricated fan tectonic system. The evolution of the basin can be divided into five stages: initial tensional fault (in Late Triassic), fault subsidence (in Early-Middle Jurassic), transition from faulted subsidence to depression (in Late Jurassic), depression (in Cretaceous) and dwindling uplift (in Paleogene), in which the Early-Middle Jurassic period is the main stage for basin fracture extension, deposition and subsidence, and the Cretaceous period is the main stage for basin depression.