La difficile cohabitation de la géologie "profonde" et de la géomorphologie au pied des Monts Ibériques occidentaux/The hard coexistence of "deep" geology and geomorphology at the foot of Western Iberian Ranges

Abstract

Abstract On the northern piedmont of the Western Iberian Ranges, geophysical, geological and geomorphological studies have been under way for several years. The researchers involved have rarely or never met. It is a regrettable situation, insofar as it fails to confront the data used to elaborate tectonic models on the one hand with the geomorphological field evidence and related long-term landscape development models on the other. Thus, the problem of geoscientific consistency and coherence in the Iberian Ranges is not yet solved and has admittedly not even started to be addressed in a comprehensive manner. A two-way approach is advocated and, while geomorphologists must take account of past and present tectonic stress fields, the geophysical models, although intrinsically valid, must be cross-correlated with the sedimentological and geomorphological realities of this particularly complex terrain. Contrary to the large Alpine orogens, where powerful tectonic forces have led to the destruction of most pre-Pliocene landforms, the Western Iberian Ranges preserve relics of quite ancient geomorphic events. These are put forward in this study and must be given credit in a multidisciplinary debate which has hardly begun.