Eogene to Neogene north‐eastward expansion of the arcuate tectonic belt in north‐east Tibetan Plateau: Constraints from detrital zircon geochronology and heavy minerals

Abstract

The north‐eastward extrusion of the Tibetan Plateau has always been under debate. The arcuate tectonic belt is located at the north‐east margin of the Tibetan Plateau and bears crucial information about the tectonic and geomorphic evolution of north‐east Tibetan Plateau. Combined with sedimentary sequence, detrital zircon U–Pb geochronology, and heavy mineral combinations, significant provenance transformation can be determined both in the south‐west and north‐east of the arcuate tectonic belt during the Eocene to Miocene. The far‐field effect of north‐eastward extrusion of the Tibetan Plateau first arrived at the south‐west of the arcuate tectonic belt during the Miocene and resulted in the angular unconformity between the Eocene Qingshuiying period and Miocene Zhangenbao Formation. Then the regional exhumation spread from south‐west to north‐east across the arcuate tectonic belt, and sedimentary hiatus developed between the Miocene Zhangenbao period and Pliocene Ganhegou period. Therefore, tectonic uplift and mountain building of the arcuate tectonic belt expanded north‐eastward during the Eogene to Neogene. This research shed new insights on the north‐eastward extrusion of the Tibetan Plateau from the coupling relationship between basin and range.