Cenozoic pulsed deformation history of northeastern Tibetan Plateau reconstructed from fission-track thermochronology

Abstract

The synorogenic basin deposits and bedrocks of their source terranes within and along the Tibetan Plateau contain fundamental information regarding the spatiotemporal evolution of the largest orogenic plateau on Earth. The Guide–Xining region is located on the northeastern portion of the Tibet and its Eocene–early Pleistocene basin succession is well preserved. By integrating apatite fission-track thermochronology from sedimentary and basement samples, with heavy minerals and paleocurrent data, we decipher an almost complete sequence of exhumation and depositional events during the Cenozoic. Our data indicates that the initial deformation along the Guide–Xining region occurred since the Eocene, with the reorganization of the regional tectonomorphology and the formation of a broad basin. Thereafter, this single large basin was disrupted by multiple episodes of exhumation and deformation. Our study illuminate that the multiple-stage active processes (occurred at 49–42, 36–32, 23–19, 16–13 and 8–4Ma) work together to produce the current NE Tibetan Plateau.