Evolution of experimental thrust wedges accreted from along-strike tapered, silicone-floored multilayers

The possible effect of pre-deformational, along-strike sedimentary tapers on the structural architecture of thrust wedges accreted above viscous materials has been commonly underestimated or neglected. We illustrate results of an experimental programme specifically designed to study the impact of this parameter on thrust wedge evolution using sandbox analogue modelling. Two series of experiments were performed: the first series was designed to investigate the sensitivity of wedge growth to the along-strike sedimentary taper variability; the second was designed to investigate the sensitivity of a growing along-strike tapered wedge to the convergence rate. Our experimental results indicate that even gentle pre-deformational along-strike thickness variations in foredeep clastic sequences overlying viscous materials, such as evaporites or overpressured shales, can produce dramatic changes in the first-order structural architecture and kinematic evolution of accreting thrust wedges.