Exhumation history of the Micangshan-Hannan Dome since Cretaceous and its tectonic significance: Evidences from Apatite Fission Track analysis

Abstract

Apatite Fission Track (AFT) data of the Micangshan-Hannan Dome region is reported in this work. It is shown that AFT ages decrease gradually from the inner part of the Micangshan-Hannan Dome to North Sichuan Basin, which is consistent with the piggyback propagation model of thrusting in the region proposed by previous works based on seismic survey profiles. Thermal history modeling of the AFT data shows that the Micangshan-Hannan Dome experienced two episodes of rapid cooling occurred in Cretaceous (before -90Ma) and Late Cenozoic (since about 15Ma) respectively. The Cretaceous rapid cooling of this region is coeval with the regional cooling event in Qinling-Dabie Orogen, which is possibly r..