Record of Crustal Thickening and Synconvergent Extension from the Dajiamang Tso Rift, Southern Tibet

North-trending rifts throughout south-central Tibet provide an opportunity to study the dynamics of synconvergent extension in contractional orogenic belts. In this study, we present new data from Dajiamang Tso rift, including quantitative crustal thickness estimates calculated trace/rare earth element zircon data, U-Pb geochronology, and zircon-He thermochronology. These constrain timing rates exhumation rift a basis for evaluating dynamic models extension. Our results also semi-continuous record Mid-Cretaceous Miocene evolution Himalayan-Tibetan belt along India-Asia suture zone. We report igneous ages ~103 Ma 70–42 samples collected Xigaze forearc basin Gangdese Batholith/Linzizong Formation, respectively. Zircon-He cooling rocks hanging wall Great Counter thrust are ~28 Ma, while arc footwalls 16–8 Ma. reveal approximate switch contraction zone (minimum 16 Ma). Crustal-thickness trends geochemistry possible thinning (to ~40 km) immediately prior India-Eurasia collision onset (58 Following initial collision, increases 50 km by 40 with continued thickening until early supported regional Tibetan Magmatism Database. Current based on geophysical observations show no evidence following E–W (~16 Ma), suggesting that modern is likely facilitated underthrusting Indian lithosphere balanced upper plate