Experimental deformation partitioning in obliquely converging orogens with lateral variations of basal décollement rheology: Inferences for NW Zagros, Iran

The rheology of décollement materials fundamentally constrains the kinematic evolution and tectonic architecture of orogenic belts. In this paper, we present the result of an experimental program designed for investigating, by sandbox analog modeling, the impact of the spatial distribution of décollement rheology underneath an inner carbonate platform-basin-outer carbonate platform paleogeographic architecture undergoing traspressional deformations. Our models indicate that viscous décollements at the base of both platforms favor the outward propagation of deformation, duplexing in the Inner Platform (that faces the wedge toe), and deep burial of basinal sediments. On the other hand, frictional rheologies favor internal shortening in the basin, strong uplift and limited burial. Application of experimental results to better constrain the late Cretaceous tectonic evolution of the NW Zagros is discussed.