Impacto en la red fluvial del levantamiento costero asociado a la subducción de la dorsal asísmica de Nazca (margen continental de Perú)

Abstract

In the western margin of Peru the subduction of the Nazca Ridge along the Peruvian margin occurs together with the southward lateral motion of the ridge. During this process deformation of the upper part of the coastal region occurs, producing the inversion of the continental shelf and uplift of the coastal area, in the shape of an asymmetrical dome structure, simultaneously to the southward migration. The morphometric analysis of the drainage network provides quantitative data for the identification of anomalies in the fluvial system associated to this process, such as knickpoints in the lower reaches or convexities in the long profiles, and allow the interpretation of its impact and the length of the signals in the fluvial system. Uplift along the coast pre- cedes the ridge arrival. Results illustrate a symmetrical distribution of fluvial morphologies on-shore, in both sides of the ridge subduction zone, and point to a fast regularization or deletion of the anomalies once the active uplift have moved southward.