Seismic ridge subduction and topography: Foreland deformation in the Patagonian Andes

Present rapid isostatic rebound related to the continental ice cap retreat in the Patagonian Andes is restricted to the region south of Chile triple junction (46°30′S). The uplift rate here is more than two times more rapid than normal isostatic rebounds recorded in the Northern Hemisphere, and requires an abnormally hot mantle with low viscosity. This abnormal mantle may be a consequence of several episodes of ridge collision and development of asthenospheric windows that are inconsistent with periods of cold flat-slab subduction proposed by some authors to explain the arc volcanic gaps.