Project Title: Quantifying the control of rock mass properties on the surface topography and erosion of subduction systems.

Supervisor: Niels Hovius, Jens Turowski

Objectives: To determine how rock mass properties control the topographic evolution of tectonic deformation zones and the quality and quantity of erosional fluxes from these areas, and to develop and calibrate expressions allowing explicit inclusion of these properties in landscape evolution models. This will be achieved by topographic analysis of emergent subduction systems with a range of exhumed geologies; detailed analysis of geomorphic process styles and rates across lithological gradients; and laboratory experiments simulating geomorphic work on substrates with specific mechanical properties. Regional topographic analysis and fieldwork will be located, as much as possible, within the subduction systems studied in other projects of the ETN.

Expected Results: The project will work towards calibrated, quantitative expressions of rock mass and geo-mechanical controls over bulk landscape erosion and geomorphic process rates for use in process models and landscape evolution models. Further products will include quantitative case studies of the effects of outcrop geology on geophysical and geomorphological scales and tribological rules for erodibility of geological materials. The results will serve as input for coupled surface-geodynamic models of evolving subduction systems, investigating, explicitly, the effects of developing topographic loads on the tectonic evolution of the system.

Academic secondment: ETH, T. Gerya, 3 months in year 3, to implement surface geomechanical effects in geodynamic modelling. Industry secondment: Schulze Powder Technology, 3 months in year 2, to work on quantification of geomechanical properties.

Links to other projects: Coordinated fieldwork and topographic analysis of natural laboratories of projects ESR8,10,12,13,14; Imple-mentation of surface geomechanical effects in models used to evaluate evolution of study areas of subduction systems in projects ESR2,4.