Evidence for constriction and Pliocene acceleration of east-west extension in the North Lunggar rift region of west central Tibet

摘要: [1] The active north trending North Lunggar rift in west central southern Tibet exposes an extensional metamorphic core complex bounded by east dipping low-angle normal fault. Apatite and zircon (U-Th)/He thermochronology thermal modeling of the document a minimum timing for inception at >10 Ma rapid footwall exhumation between 5 2 Ma. Miocene cooling rates were initially slow to moderate 400°C Ma−1 4–10 mm a−1. Footwall isotherms significantly compressed during resulting elevated transient geothermal gradient 50 90°C km−1. The magnitude horizontal extension is 8.1–12.8 km; maximum 15–20 km, less south ~10 km. Mean Pliocene rate 1.2–2.4 mm a−1 ~120° direction. Results are similar magnitude, rate, orientation slip kinematically linked Lamu Co dextral strike-slip fault north. This suggests state constrictional strain time along this stretch Bangong-Nujiang suture from which emanates. onset region may be explained crustal thickening gravitational orogenic collapse, followed accelerated rifting localized stretching increased magmatic activity, potentially driven position northward extent underthrusting Indian lithosphere.