Lower Cretaceous (Berriasian–Aptian) bioestratigraphy of the Neuquén Basin

Abstract: The Berriasian-Aptian succession i the Neuqurn Basin is mainly marine in the lower part and non-marine inthe 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 besuggested with the 'standard ' stages and zones of the Tethyan Mediterranean rea. Several nannofossil bioevents are recognized, and these provide evidence for correlation with Tethyan areas. Correlations suggested by both groups are asonably consistent. Berriasian-Aptian palyno-morphs include both terrestrial and marine forms. Several terrestrial ssemblages can be recognized, but the marine forms are mainly long-ranging taxa, especially in the Agrio Formation. The infill of the Neuqurn Basin comprises more than 6000 m of marine and continental sedimen-tary rocks ranging in age from Late Triassic t