Castelo Velho de Freixo de Numão: enquadramento geomorfológico

Abstract

The Castelo Velho area stays at very special position because it correspondsto a kind of a crossroad where the large flat surface of the Meseta begins tobe moved by the passage of a major tectonic accident (Vilariça fault) andsimultaneously, carved by the down wearing erosion of the Douro and itstributaries. The major tectonic accident, active during the Quaternary, is underlinedby the rigidity of the Vale da Vila and goes on towards the Vilariçagraben, to the north, and towards Longroiva tectonic basin to the south. Thesite of Castelo Velho, dominating the Vale da Vila and the surface of FozCôa, allows the observation of large areas, in particular a significant part ofthe Meseta, until Marofa mountain. In the pivotal position between the WesternHighlands and the Meseta surface, this area also reflects a sharp changein climate due to the deep groove produced by the river system. This steepvalley creates a special climatic area, the "Alto Douro" region, with a climatethat contrasts with the surrounding plateau areas.