Gorge

A narrow, steep-sided valley or ravine with near-vertical walls, cut by a river through resistant bedrock, typically where vertical erosion greatly exceeds lateral erosion. Gorges often form where rivers are superimposed or antecedent relative to uplifted terrain, or where hard rock resists widening. Himalayan gorges include those carved by the Indus, Sutlej and Brahmaputra; the Yarlung Tsangpo (Brahmaputra) Grand Canyon lies in Tibet (China), around the eastern Himalayan syntaxis, and the river enters Arunachal Pradesh afterwards.