 It was followed by the subduction of the oceanic Great India Basin, which was located in between the microcontinent and the major Indian craton, under the Asian continent.The second stage of collision occurred after the oceanic crust of the Great India Basin had been consumed, where the major Indian craton finally came into contact and collided with the Asian continental margin (including the previously "merged" microcontinent, which was interpreted to be the modern Tibetan Plateau) at 25–20 Ma.This hypothesis is mainly based on the observation of crustal shortening deficit in the Himalayas.