West versus Central Tibet exhumation difference influenced by Indian slab underthrusting

The Tibetan Plateau has an important role in controlling the Asian monsoon, river drainage and biodiversity patterns across Asia. The history of plateau development and its mechanistic links to underthrusting of the Indian plate beneath the Asian plate remain controversial. Here, using mid- to low-temperature thermochronological data and exhumation history modelling, we show differences in the exhumation history of Central and Western Tibet during the middle Cenozoic. Central Tibet has experienced slow exhumation from ~45 million years ago (Ma) to the present while Western Tibet underwent moderate-to-rapid exhumation between 45 and 20 Ma at a rate that exceeds the modern value by an order of magnitude. Movement on large strike-slip faults and climatic forcing can be excluded as the primary reason for the regional exhumation difference. Using bedrock cooling ages and the eruption age of (ultra)potassic lavas as proxies for early exhumation and continental underthrusting, respectively, and combining these with geophysical imaging data, we propose that the spatial differences in exhumation rates at 45–20 Ma are largely attributed to the extent of Indian continental underthrusting, with Western Tibet lying within the underthrust domain and Central Tibet lying outside it. These findings highlight continental underthrusting as a first-order control on collisional plateau development. The extent of Indian continental underthrusting beneath Western Tibet influences its moderate-to-rapid exhumation, relative to slow exhumation in Central Tibet, according to thermochronological data and exhumation history modelling.