The evolution of high mountain areas
High mountain areas develop as a consequence of the collision of two lithospheric plates. Either an ocean is closed between two plates and there is a collision between two continental plates with the formation of tectonic nappes or a long-lasting subduction with tectonic shortening of the rocks on the upper plate. As a result, in both cases the continental crust is strongly thickened followed by an uplift caused by isostatic adjustment. This uplift is intensified by the interaction of erosional processes and isostatic adjustment and, in case of a continent-continent collision, the slab break-off of the oceanic lithosphere. Finally, this leads to the formation of a strong relief.