Lower Cretaceous (Berriasian-Aptian) biostratigraphy of the Neuquén Basin

Abstract

The Berriasian-Aptian succession in the Neuquén Basin is mainly marine in the lower part and non-marine in the upper portion. A detailed ammonite zonation is presented for the Berriasian-?Early Barremian interval. While some ammonite taxa are endemic, others are widely distributed and there are several levels where correlation can be suggested with the 'standard' stages and zones of the Tethyan Mediterranean area. Several nannofossil bioevents are recognized, and these provide evidence for correlation with Tethyan areas. Correlations suggested by both groups are reasonably consistent. Berriasian-Aptian palynomorphs include both terrestrial and marine forms. Several terrestrial assemblages can be recognized, but the marine forms are mainly long-ranging taxa, especially in the Agrio Formation.