Neogene extension and volcanism in the Kunlun Fault Zone, northern Tibet: New constraints on the age of the Kunlun Fault

The geology of the Jingyu basin (north Tibet) provides constraints on the relationship between localized E‐W extension in the Qiangtang block and strike‐slip motion along the Kunlun fault. Eocene to Oligocene SW‐NE compression formed topographic relief in the present western Kunlun Shan. Pull‐apart basins started forming in the western Kunlun ranges around 15 Ma, possibly coincident with the initiation of subduction of the Tarim‐Qaidam lithosphere under the Kunlun Shan. Extensional tectonism is still active, and the Jingyu basin is extending, as a normal fault connected with the Kunlun fault was recently active. Localized extension allows Tertiary and Quaternary shoshonitic magmas to reach the surface from crustal depths of 50 to 60 km. Miocene strike‐slip faulting indicates that the initiation of the Kunlun strike‐slip fault is early Neogene in age and that the total amount of horizontal movement that occurred along the fault has to be reconsidered.