MODELLING OF TECTONIC-SURFACE PROCESS FEEDBACK ON STRAIN LOCALISATION DURING OROGENESIS USING A DISCRETE ELEMENT MODEL

There is an intrinsic link between the evolution of faults and localised erosion in mountain belts. For instance the removal and transport of material through an orogen affects the strain distribution and thus localisation of faulting. In turn the faulting feeds back into the evolution of the orogen. Finite element models have demonstrated the significance of preferential denudation in tectonically active settings (Willett, Orogeny and orography), however the model flexibility is limited by the constraint that the matrix must remain intact for efficient processing. This hinders modelling of the transport of mass through a system, such as through faulting or denudation. The application of a Discrete Element Model, DEM, provides an alternative approach. Instead of a grid that distorts under the application of boundary conditions, a DEM consists of an array of spheres connected by springs. Previous applications include rock fracture experiments and extensional tectonics. These springs can be broken and reformed allowing mass to be transported through a system and faults to propagate large displacement along discrete fault planes. We will investigate the feedback between faulting and erosional denudation on a mountain belt scale with a variety of boundary conditions that are comparable to real examples, such as the Southern Alps, New Zealand.