Cretaceous southward growth and topographic shaping of the proto-Tibetan Plateau: Insights from low-temperature thermochronology and adakitic rocks

The Tibetan Plateau was formed by long-term terrane accretion and block collision, controlled by complicated Mesozoic-Cenozoic geodynamic mechanisms. However, its detail Cretaceous evolution history remains controversial. This study compiles available low-temperature thermochronology results and adakitic rocks data from the Qiangtang and Lhasa terranes to investigate its evolution. Two collected datasets synthetically demonstrate a deep-surface coupling relationship with rapid exhumation and crustal thickening during -120-80 Ma over the Qiangtang and Lhasa terranes. These terranes amalgamated before 120 Ma, resulting in rapid uplift and crustal thickening of southern Qiangtang during 120-80 Ma. Meanwhile, other sub-terranes outside of the southern Qiangtang terrane, including northern Qiangtang, northern Lhasa, and central Lhasa, also underwent stepwise surface uplift due to intense folding and thrusting. Instead of continuous crustal thickening, the northern and central Lhasa sub-terranes experienced intense erosion and delamination of early thickened crust during -90-80 Ma. Furthermore, the southern Lhasa sub-terrane rapidly uplifted during 70-60 Ma due to the Neo-Tethyan subduction. Eventually, the Cretaceous high geomorphic configuration across the Qiangtang and Lhasa terranes was shaped by terrane collision, lower crustal delamination, and Neo-Tethyan subduction prior to the India-Asia continental collision.