Evolution of subducting mantle lithosphere at a continental plate boundary

Abstract

Although it is apparent that at continental convergence mantle lithosphere can be accommodated by a subduction-like style of deformation, it is not clear how this process evolves and how it is different from "classical" plate subduction. Using numerical models of the crust-mantle system these issues are considered for the case of a simplified continent-continent plate collision. The results suggest that subducting mantle lithosphere is prone to detach, resulting in a reversal of subduction polarity; alternatively it may undergo symmetric plate consumption with steepening and possible roll-over/polarity reversal. The style of post collisional subduction is largely controlled by the strength (e.g., dependent on temperature, assumed rheology) of the mantle lithosphere.