Nuevas aportaciones sobre la influencia marina y la edad de los carbonatos de la Fm Leza en el sector de Préjano (SE de LaRioja). Cretácico Inferior, Cuenca de Cameros

Abstract

The Cameros Basin is a rift basin whose sedimentary infill is essentially continental with some episodes of marine influence. The Leza Fm carbonates (Enciso Gr, Barremian-Aptian) correspond to one of these episodes and their depositional environment has been described as lacustrine with occasional marine incursions. A detailed facies analysis of these carbonates in the Préjano area has led to the conclusion that the depositional environment of the Leza Fm in this area is in fact a system of coastal-lakes filled with brackish water as shown by the abundance of marine microfossils (Dasycladales algae and foraminifera) coexisting with continental microfossils (charophytes). The age of the Dasycladales found in the studied area is Barremian-Albian and thus it confirms the Barremian-Aptian age proposed for the Leza Fm and the Enciso Gr