The study of the quaternary deposits at the Sado Basin (south sector) allowed to establish geomorphological and sedimentological relationships between "Raña" deposits and river terraces. The identification of the "Raña" surfaces and their tectonic dislocations, as well as of the terrace levels, shows a well-defined altimetric relationship between those two deposits, only for each undisturbed block. Morphometric, granulometric and morphoscopic analysis clearly indicate the "Raña" deposits as the main source to the fluvial terrace deposits.
