La formación Capas Rojas: caracterización y génesis

Abstract

The characteristics (lithofacies, biofacies, age, thickness, vertical and lateral relations, etc.,) and significance of the Capas Rojas Formation (Upper Cretaceous-Eocene) are analysed. This formation crops out widely in the Subbetic (External Zones of the Betic Cordillera). The Capas Rojas Formation presents a great uniformity in the wide sectors of this cordillera and has its equivalent in facies and age, in the Scaglia Rossa Formation of the Apennines and southern Alps and also in equally analogous formations in other Alpine Mediterranean domains. From the available sedimentological and paleoecological data, mainly from the macrofossils (isolated rudists and echinoids) content and from the ichnofacies analysis, it is concluded that its deposition took place in a hemipelagic marine environment with a moderate depth (a few hundreds of metres) during a long interval of time (40-50 Ma) with a very low sedimentation rate (a few millimetres per thousand years). From the analysis of the evolution of the continental margin in which was deposited, and of their equivalents in other Alpine domains, is deduced that the beginning of its deposition recorded the end of the differentiation in troughs and swells of these passive margins in the advanced stages of the rifting, so that this unit, in wide sector of the basin covered areas with an irregular topography in the bottom, mainly controlled by faults and slowly leveled them.