Relief evolution in northern Corsica (western Mediterranean): Constraints on uplift and erosion on long-term and short-term timescales.

The long-term erosional evolution of relief is revealed by low-temperature thermochronometric data, whereas geomorphic features give constraints on the short-term evolution. We discuss the topographic evolution of northeastern Corsica by fission track and (U-Th)/He dating of apatite, the provenance of Neogene alluvial sediments, an analysis of uplifted strath terraces, and the shape of river profiles. Cooling ages indicate high cooling rates of up to 40C/Myr during the early-middle Miocene, when this region was affected by extensional tectonics. Cooling rates are less than 7.5C/Myr from the middle Miocene to the present, when topographic perturbations are detected by variations in the source areas of middle-to-late Miocene alluvial sediments and by the presence of large-scale irregularities along modern river longitudinal profiles. We suggest that the contrast of slow long-term erosion rates and the high local relief in the present Corsican landscape require that the landscape be in a transient state in response to a recent tectonic event.