Geomorphology of the Aran Valley (Upper Garonne Basin, Central Pyrenees)

Abstract

Geomorphological mapping in mountain regions is key for a better understanding of past and present environmental dynamics. Here, we present a 1:25000 scale geomorphological map covering 553 km2 of the Aran Valley, Upper Garonne Basin (Central Pyrenees). The map identifies 44 different geomorphological units classified under glacial, periglacial, nival, karst, slope, alluvial, and fluvial categories. The area includes geomorphic evidence of past Quaternary glaciations reconstructed based on the distribution of moraines from the valley floor to the highest cirques. Following deglaciation of the valley, the landscape was mainly reshaped by periglacial, slope, alluvial and fluvial processes. In addition to paleoenvironmental reconstruction, the map can also be used to promote geoheritage and geoconservation, as well as for planning. As such, it is of relevance for areas exposed to natural hazards, since present-day slope failures and debris flows frequently impact the villages and infrastructures across the valley floor.