period, the northern part of India was affected by a late phase of the Pan-African orogeny which is marked by an unconformity between Ordovician continental conglomerates and the underlying Cambrian marine sediments. Numerous granitic intrusions dated at around 500 Ma are also attributed to this event. In the Early Carboniferous, an early stage of rifting developed between the Indian subcontinent and the Cimmerian Superterranes. During the Early Permian, this rift developed into the Neotethys ocean (Fig. 2). From that time on, the Cimmerian Superterranes drifted away from Gondwana towards the north. Nowadays, Iran, Afghanistan and Tibet are partly made up of these terranes. In the Norian (210 Ma), a major rifting episode split Gondwana in two parts. The Indian continent became part of East Gondwana, together with Australia and Antarctica. However, the separation of East and West Gondwana, together with the formation of oceanic crust, occurred later, in the Callovian (160-155 Ma). The Indian plate then broke off from Australia and Antarctica in the Early Cretaceous (130-125 Ma) with the opening of the "South Indian Ocean" (Fig. 3). In the Late Cretaceous (84 Ma), the Indian plate began its very rapid northward drift covering a distance of about 6000 km, with the oceanic-oceanic subduction continuing until the final closure of the oceanic basin and the obduction of oceanic ophiolite onto India and the beginning of continent-continent tectonic interaction starting at about 65 Ma in the Central Himalaya. The change of the relative speed between the Indian and Asian plates from very fast (18-19.5 cm/yr) to fast (4.5 cm/yr) at about 55 Ma is circumstantial support for collision then. Since then there has been about 2500 km of crustal shortening and rotating of India by 45° counterclockwise in the Northwestern Himalaya to 10°-15° counterclockwise in North Central Nepal relative to Asia (Fig. 4). While most of the oceanic crust was "simply" subducted below the Tibetan block during the northward motion of India, at least three major mechanisms have been put forward, either separately or jointly, to explain what happened, since collision, to the 2500 km of "missing continental crust". The first mechanism also calls upon the subduction of the Indian continental crust below Tibet. Second is the extrusion or escape tectonics mechanism which sees the Indian plate as an indenter that squeezed the Indochina block out of its way. The third proposed mechanism is that a large part (~1000 km ()