Continental collision and slab break-off: numerical models and surface observables

Abstract

Collision zones worldwide show a vast array of complexity that is difficult to relate to simple collision dynamics. Here we address the problem of linking surface observables to collision dynamics through the use of two and three-dimensional numerical models. We will focus on two specific observables, topography and the presence of ultra-high pressure metamorphic terranes. Our model topography predictions are used to explain the uplift and subsidence history for the Arabia-Eurasia collision. This allows us to relate the post-collisional marine deposits, found on the overriding plate, to a steepening of the subduction interface.
Our three-dimensional model is used to explore possible exhumation mechanisms for the Western Gneiss Complex in Norway. From these models we show how an asymmetric collision can help drive exhumation of material that has experienced comparable conditions to the Western Gneiss Complex. The linking of upper mantle and lithosphere dynamics to both topography observation and exhumation patterns allow better understanding of the subduction and collision process.