Tectonic Evolution of the Ailao Shan–Red River Fault since the Middle Miocene from Apatite Fission Track Thermochronology and its Implications for Tibetan Plateau Growth

Abstract

The temporal and spatial evolution of the Ailao Shan–Red River (ASRR) fault zone, which serves as an important accommodation zone for the extrusion and escape of the Southeastern Tibetan Plateau, is crucial for analyzing the uplift and growth of the plateau. Based on the petrology and apatite fission track analysis, the tectonic history and active pattern of the ASRR fault zone since the middle Miocene are determined in this study. The ASRR fault zone exhibits 12–8 Ma and 8–4 Ma rapid cooling phases since the middle Miocene. The 12–8 Ma and 8–4 Ma cooling may imply that the dextral movement of the ASRR fault zone presents a migration trend from northwest to southeast, accompanied by the weakening of the activity intensity, which is directly related to deformation processes, including extrusion boundary migration and active tectonic movements of the southeastern Tibetan Plateau, since the middle–late Miocene.