The influence of upper mantle on the topographic response of the slab detachment: insights from numerical experiments
Slab detachment is a process that has been invoked to explain rapid uplift, deep seismicity and magmatic activity in several active orogens (e.g., Alps, Himalaya). The negative buoyancy force associated with a slab at depth and its progressive removal during detachment results in a reorganization of forces within the lithosphere and the detaching slab. However, it is not yet clear to which extent slab detachment is the primary cause of the different observations. Deciphering the impact of slab detachment on the observations mentioned above therefore requires a thorough understanding of the physical processes controlling deformation within and around the detaching slab.
Here, we employ numerical models to investigate the nonlinear coupling between mantle flow and slab detachment. As a first step, we develop a simplified 0D necking model that describes the temporal evolution of the thickness of a detaching slab, additionally considering the effects of the nonlinear coupling between upper mantle and detaching slab. This allows us to derive a set of nondimensional numbers which control the slab detachment process. Then we validate 0D numerical experiments using 2D numerical models and connect the topographic evolution with simple parameters.