Reconciling Punctuated Thrust Deformation in the Context of Orogenesis: Implications for the Localization of Uplift and Exhumation

Understanding the controls on uplift, exhumation and topography in orogenesis requires integrating the effects of both climatic and tectonic forcing. The potential for climatic forcing of individual structural units within thrust wedges has recently been hotly debated and tested. Here we use a recently developed discrete element model (Naylor et al., 2005) to analyse the behavior of individual thrust units in the context of doubly-vergent thrust wedges. The results demonstrate a naturally punctuated signal of thrust activity that has been widely recognised from field studies. The model predicts that rates of surface uplift, frontal accretion and exhumation should be punctuated on a timescale linked to thrust sheet geometry and convergence rates. This timescale ranges from 0.1 to 4 Myr for various settings, and hence should be calculated before external forcings such as climate are invoked. REF: Naylor, M., Sinclair, H. D., Willett, S. & Cowie, P., (2005) A discrete element model for orogenesis and accretionary wedge growth. Jour. Geophys. Res. V. 110