SANDSTONE PETROGRAPHY OF CONTINENTAL DEPOSITIONAL SEQUENCES OF AN INTRAPLATE RIFT BASIN: WESTERN CAMEROS BASIN (NORTH SPAIN) JOSE ARRIBAS,l ANGELA ALONSO,2 RAMON MAS,3 AMPARO TORTOSA,l MAGDALENA RODAS,4 JOSE F. BARRENECHEA,4 4 JACINTO ALONSO-AZCAAATE,5 AND ROSANA ARTIGAS 1 Departamento de Petrologiay Ge(Xjuimica, Facultad de Ciencias Geol6gicas, Universidad Complutense de Madrid, 28040-Madrid, Spain e-mail:
[email protected] 2 Laboratorio de Geologia, Universidad de A Coruiia, Spain 3 Departamento de Estratigrafia, Facultadde Ciencias Geol6gicas, UniversidadComplutens e de Madrid, 28040-Madrid, Spain 4 Departamento de Cristalografiay Mineralogl'a, Facultad de Ciencias Geo16gicas, Universidad Complutense de Madrid, 28040-Madrid, Spain 5 Departamento de Fisica-Quimica, Facultadde Ciencias del MEdioAmhiente, Universidad de Castilla-La Mancha, 45004-Toledo, Spain ABSTRACT: The Cameros Basin in Central Spain is an intraplate rift INTRODUCIION basin that developed from Late Jurassic to lVIiddle Albian time along The Cameros Basin, located in the northern part of the Iberian Range, NW-SE trending troughs. The sedimentary basin fill was deposited is one of the basins forming part of the Mesozoic Iberian RiftSystem (Mas predominantly in continental environments and comprises several de et al. 1993; Guimera et al. 1995; Salas et al. 2001). The IberianRift System positional sequences. These sequences consist of fluvial sandstones that was inverted during the Paleogene and today corresponds to the Iberian commonly pass upward into lacustrine deposits at the top, producing Range (Fig. 1). The Cameros Basin was formed duimg intraplale rifling considerable repetition of facies. This study focused on the western which took place from Late Jurassic to the Early Albian time, when Iberia sector of the basin, where a total of seven depositional sequences (DS- 1 was separated fromEurope, in conjunction -withthe opening of the oceanic to DS-7) have been identified.