Morphotectonic map in the Viana and Valdeorras regions (northwest Iberian Peninsula)

Abstract

The scarcity of Cenozoic sediments and the dense vegetation cover in the northwest of the Iberian Peninsula make difficult to study the alpine and recent tectonics. In this context, geomorphological mapping is a useful tool to detect tectonic structures with influence on the relief. This paper presents the morphotectonic mapping of the central southern sector of the Sil river basin. This mapping focuses on a family of NNE-SSW oriented strike-slip faults, which include the Conso fault and the Viana fault (included in the Penacova-Régua-Verín fault system). These faults have been previously mapped and interpreted, as late variscan faults and, later, as reactivated faults during the Alpine Orogeny. The morphotectonic mapping depicts fluvial landforms as anomalous drainage networks, river bends or oversized saddles, which have been interpreted as features of tectonic activity.