The coupling between erosion and tectonics is most likely to be efficient in regions of ongoing tectonic activity, especially in regions of continental convergence where the collision between two continents leads to crustal thickening and, by isostasy, to surface uplift. This uplift causes relief (i.e. slope) to be created, which triggers erosion by channel incision or, under colder climatic conditions, the formation of glaciers that will rapidly reshape the landform.

In this chapter, we are going to investigate the effect of continental collision on the temperature structure of the crust; we will also present some of the most widely accepted models for crustal deformation and, most importantly, describe the respective consequences they have for the path followed by rock particles as they travel through the orogen, ultimately to be exposed at the surface. The combination of these processes will provide us with appropriate (that is, quantitative) constraints on the predicted temperature history of particles from which we should be able to predict cooling ages.

At the end of this chapter we will demonstrate how these predictions can then be used to constrain the tectonic evolution of an active mountain belt, including the timing of the onset of convergence, the present-day rate of convergence and its variation along the strike of the orogen. To illustrate this approach, we will consider a dataset collected in the Southern Alps of New Zealand that has been interpreted using state-of-the-art quantitative methods (Batt and Braun, 1999; Herman et al., 2006).