MODELLING THE INFLUENCE OF HORIZONTAL ADVECTION, DEFORMATION AND LATE UPLIFT ON DRAINAGE DEVELOPMENT IN THE INDIA-ASIA COLLISION ZONE

We present results of a new model in which we couple a mechanical model to describe continental indentation in plan view, with a landscape evolution model to describe drainage development. The model is used to investigate the competition between collision driven thickening and erosion driven thinning, as well as the lateral displacement and capture of rivers due to horizontal strain and advection. We apply the model to investigate aspects of the drainage system development in the India - Asia collision zone. It is shown that the curvilinear pattern of drainages around the eastern syntaxis is initiated very early on in the orogenic evolution. We also show that capture of the Tsangpo by the Brahmaputra and capture of the Upper Yangtze by the lower Yangtze (thereby deserting the Red River) can be well reproduced by invoking a late uplift event independent of the collision and that affected the entire orogen, except the region of the Sichuan basin. Our results are largely independent of precipitation contrasts.