Exhumation history of the Kampa dome in the southern Tibet: Evidence from low-temperature thermochronology

The orogenic dome structure records the crustal and terrestrial evolution process of the continental-continental collision and its post-collision is an important window for discussing the tectonic evolution of the orogenic belt. The Kampa dome located in the Tethys Himalayas, southern Tibet, is a component of the Northern Himalayan gneiss dome (NHGD), its exhumation process and its dynamic mechanism are still controversial. The zircon U-Pb, zircon fission-track (ZFT) age dating, and three-dimensional numerical simulation of the granite gneiss at the core of the Kampa dome are carried out, the zircon U-Pb age of the Kampa dome is obtained as: 497.89 ±1.2Ma, The FT age of zircon (17-11 Ma) is significantly smaller than the crystallization age of zircon U-Pb, indicating that these ZFT ages are formed by the cooling and uplifting of the dome. The inversion of the ZFT data of the core samples by Pecube shows the Kampa dome has experienced two rapid exhumation events at 15.9-11.4 Ma and~4.2 Ma since the Miocene. Combined with the regional tectonic evolution, we propose that the first rapid exhumation is related to the activity of the South Tibet Detachment System (STDS), and the second rapid exhumation is a response to the climate changing process.