El Triasico Superior del borde NW de la Cordillera Ibérica (Prov. de Segovia, Soria y Guadalajara)

The study present results on the preliminary stage of unit definition and mappable divisions in the area of Upper Triassic (Karnian-Rhaetian), NW Iberian Range, province of Segovia, Soria and Guadalajara, Central Spain. The physiographic position of the study area, which is located at a basin edge, allows for the observation of the alternancy of fluvially originated sand bodies characteristic of the sediment source area and mud and evaporates characteristic of central regions of the basin. A total of eleven sections have been described based on particular characteristics, lateral changes thicknesses and have been grouped within four sequences.