Las terrazas del río Miño en el tramo Chantada-As Neves (límite de Galicia-Portugal)

Abstract

Geomorphologic mapping is specially difficult in areas with scarce deposits of uncertain chronology and with multiage and multiorigin forms. This is the case of Galicia. This paper is an attempt to reconstruct the geomorphologic history of Galicia during the Cenozoic in an area especially relevant because of its geodynamic situation. It has been made an exhaustive inventory of the erosive and accumulation terrace levels in a specific section of the Miño, the main river course of the region. Here it is presented the terrace levels list between Chantada and As Neves, their relation to the three etched surfaces R800, R600 and R400, wich are the most relevant because of their areal extent. It is also analyzed their relationship with the longitudinal profile of the river. Using the only existing criteria, i.e., topographic continuity and altitude, it is proposed an evolutionary model substantially determined by the river incision associated with the Paleogene collision among the Euro-Asian and the Iberian Plates. This process geomorphologically begun after the generation of R600 surface which is equivalent in Galicia to the Peninsular Fundamental Surface.