Project aim: to investigate the drainage evolution of the eastern Himalaya in order to constrain models of crustal deformation and better understand the inter-relationships between tectonics, surface processes, erosion and climate. The Himalaya provides a type example on which a number of models of the causes and consequences of crustal deformation are based. The unusual drainage configuration of the eastern syntaxial region has been used to differentiate between models of crustal deformation: It has been interpreted by some as distorted antecedent drainage and applied as a passive strain marker of lateral extrusion, but interpreted by others as the result of tectonically-induced river capture events. One such capture event, that of the Yarlung Tsangpo by the Brahmaputra, has potentially resulted in sufficient erosion to cause major exhumation of the syntaxial region, thus providing a viable example of erosion-tectonic coupling, possibly triggered by monsoon intensification. Determining if and when river capture of the Yarlung Tsangpo by the Brahmaputra occurred is key to testing these models of crustal deformation and erosion-tectonic coupling, and is the objective of this project.