Indicios de antecedencia en la red fluvial del sureste de Galicia

Abstract

The present work offers a preliminary analysis of the river network with tertiary antecedents of the Galician SE. The geomorphological observations of the area are centred on the cartography of erosive terraces, scrolled canals, hanging meanders, elbows of capture, and anomalous networks. For its interpretation we interface them with the thalwegs of the principal courses and the Alpine fractures charted by other authors. We propose a chronology for the identified fluvial processes, a chronology which points to a greater river network than has been estimated so far. Of these seven identified tendencies three presented a regional entity (ENE-WSW, NE-SW, N-S) and four local (NW-SE, SW-NE, SE-NW, S-N). The principal character of the paleo-network ENE-WSW (river Sil) is confirmed. And as a hypothesis we propose, for the Sierra de Queixa-San Mamede, the character of positive paleo-relief of Mesozoic inheritance. This relief has undergone severa1 processes of isostatic raising and also tectonic during the Alpine Mountain-building. These raisings have caused the superimposition of captures in the SE spurs of the Sierra de Queixa-San Mamede.