Paleosuelos y paleoalteraciones del Weald de la zona oeste de la cuenca de Cameros (borde SW de la Sierra de la Demanda

This paper deals with an approaching to the paleosois and paleoweathering study in a fleld where the contributions are scarce. The study has been realized on the Upper Jurasic-Lower Cretaceous Weald Facies, based on the cartographie 1:50.000 from the I.G.M.E., sheets 277 & 278, "Salas de los Infantes" and "Canales de la Sierra" respectively. The study of the Weald Facies have been considered from three different points of view: Detrital supply. - Changes in the sediment during the "Early Diagenesis". - Changes in te sediment during the "Later Diagenesis". - The sediments were mainly arcosic. The most significant changes happened during the early diagenesis acquiring the sediments their main present features. These features (argillization, reddening and caicretization) have been observed mainly al the top of the secuences, and because that asociated with paleoedaphic activity. About changes during later diagenesis there are mineralogical changes on argillious material in the lutitic facies, and changes asociated with the base of the sequences (silicifications and caolinizations). Key-Words: Paleosols, Paleoweathering, Weald, Cameros Basin.