Two-dimensional thermal-mechanical models of thick-skinned, salt-based fold- and thrust belts, such as the Zagros,SW Iran, are used to address: 1) the degree of deformation and decoupling between cover and basement rocks dueto the presence of a weak salt detachment; 2) the reactivation potential of pre-existing basement normal faults dueto brittle or ductile behavior of the lower crust (as related to cold or hot geothermal gradients); and 3) variations indeformation style and strain distribution. The geometry and kinematics of the orogenic wedge and the activity ofpre-existing basement faults are strongly influenced by the geothermal gradient (defined by the Moho temperature,MT) and basement rheology. We infer that the MT plays a major role in how the lower and upper crust transferdeformation towards the foreland. In relatively hot geotherm models (MT = 600C at 36 km depth), the lowermostbasement deforms in a ductile fashion while the uppermost basement underlying the sedimentary cover deformsby folding, thrusting, and displacements along pre-existing basement faults. In these models cover units abovethe salt detachment are less deformed in the hinterland. In relatively cold geotherm models (MT = 400C at 36km depth), deformation is mainly restricted to the hinterland of the models where basement imbricates form.Detachment folding, thrusting and gravity gliding occur within cover sediments above uplifted basement blocks.Gravity gliding contributes to a larger amount of shortening in the cover compared to the basement.