GEOMORPHOLOGICAL EVOLUTION OF A COASTAL D RAINAGE - THE EXAMPLE OF THE TOUQUES (BASSE-NORMANDIE)

In the Touques drainage basin, Jive alluvial terraces have been distin guished. A multiscale approach in a continental basin was undertaken, combining different stratigraphic and geomorphic analyses. Stratigraph ic and sedimentologic analyses play an essential role, because of the interaction between climate and sea-level variations and tectonics. In the Touques valley, the alluvial sheets cover the Middle and Upper Qu aternary. Each fluvial sequence is correlated with a glacial-interglac ial climatic cycle. The numerous episodes of channel entrenchment and terrace formation arise from a Quaternary regional uplift. Valuable in formation is obtained through detailed analysis of the morphology (mor phometric and drainage pattern analyses). The longitudinal profiles of the rivers and the hypsometric integrals are related to the immaturit y of the drainage basins subjected to recurrent sea-level changes. (C) Academie des sciences/Elsevier, Paris.