The Indus-Yarlung suture zone or the Indus-Yarlung Tsangpo suture is a tectonic suture in southern Tibet and across the north margin of the Himalayas which resulted from the collision between the Indian plate and the Eurasian plate starting about 52 Ma.[1] The north side of the suture zone is the Ladakh Batholith of the Karakoram-Lhasa Block. The rocks of the suture zone consist of an ophiolite mélanges composed of Neotethys oceanic crustal flyschs and ophiolites; the Dras Volcanics: which are basalts, dacites and minor radiolarian cherts – the remains of a mid- to late Mesozoic volcanic island arc; and the Indus Molasse which are an Eocene or later continental clastic sediments.[2]
Some think that the many ophiolites that define the suture are not remnants of a very big ocean, but of a small back-arc basin structure.[3] More recently it has been suggested that these ophiolites formed during EarlyCretaceous subduction initiation (Hu and Stern, 2020). You can watch a video about this at https://www.youtube.com/watch?v=02Xojnf9sYA
Hu, H., and Stern, R. J., 2020. Early Cretaceous Subduction Initiation in Southern Tibet Caused the Northward Flight of India. Geoscience Frontiers 11, 1123-1131.