The interplay of lithology, tectonics and climate in the morphology of Corsica

Abstract

The morphology of the landscape on the island of Corsica in the western Mediterranean is transient with clear topographic asymmetry. The geology of the island can be divided into two units – Hercynian Corsica and Alpine Corsica, with contrasting lithology, climate and structural controls between them. Here, topographic analysis is used to assess the influence of each of these factors on landscape form. Disequilibrium in the landscape is illustrated by analysing chi and Gilbert metrics which indicate active drainage divide migration, along with a new metric that quantifies tributary heights above the main stem channel. Climate in the region has fluctuated dramatically from the Messinian salinity crisis through to Quaternary glaciation. However, analysis of the size and distribution of knickpoints across the island does not reflect specific base-level changes. Instead, basement structures control valley orientation and conditioning of the landscape by glaciation exerts strong controls on drainage evolution.