Application of Geomorphic indices to the study of the basin of the river Adra (Almería)

Abstract

The application of geomorphic indices indicators of active tectonics (Mountain-front Sinousity index, Stream-length gradient index, Ratio of Valley floor widht / Valley height, Ratio of basin wide) in the Adra Drainage basin shows the occurrence, from the tectonic point of view, of several especially active sectors. Particularly stand out two mountainous fronts, in the south of Sierra Nevada and in the western border of Sierra de Gádor. That of the south of Sierra Nevada presents high gradients in the longitudinal profiles of the rivers crossing it, moreover high values in the ratios of valley-floor width to valley height and very elongated basins. These results indicate the progressive uplift of both sierras. Also stand out the existence of a fault zone situated in the south border of the Alpujarran Corridor, well marked by several indices and a process of antecedence in an anticlinal structure situated to the south of the Benínar damp, cut by the river Adra, showing very high values in the stream length-gradient index of the tributaries there flowing.