Glacial erosion during orogenesis: A study of the intraplate Eurekan Orogeny of Ellesmere Island.

Abstract:

The Eurekan Orogeny of northeastern Ellesmere Island in the Canadian arctic was formed as a result of mountain-building processes in the Paleogene. The orogen developed relatively distant from any active convergent plate boundaries making it a representation of a class of intraplate mountain-building. In this work we investigate the geodynamics of the Eurekan and in particular focus on the potential role of glacial erosion in modifying the orogenesis. The study is motivated by important recent research that has demonstrated a significant interaction between (climate-controlled) surface processes and solid Earth tectonics at collision. Glacial erosion is thought to have the capability of eroding at a rate which matches with that of rock uplift in active orogens, referred to as the “buzz saw” effect of glaciers. Using the geodynamic modelling code of SOPALE we developed forward 2D models of the idealized Ellesmerian lithospheric structure and imposed shortening to explore Eurekan-style orogenic deformation. In the numerical experiments, we modified the erosional algorithm in the model such to investigate various implementations of the glacial buzz saw. The model results show how the surface topography and internal lithospheric structure of the orogeny are modified by variable glacial erosion. In addition to illustrating how the Eurekan orogeny may have evolved, the results provide insight into how the generic orogenic zones may develop in a glacial environment.