Advances in the biostratigraphy of the Agrio Formation (Lower Cretaceous) of the Neuquén Basin, Argentina: ammonites, palynomorphs, and calcareous nannofossils

Detailed stratigraphic logging and systematic studies on late Valanginian–early Barremian ammonites from the Agrio Formation of the Neuquén Basin of west-central Argentina, have provided a detailed local ammonite zonation. Here we combine the ammonite data with an initial study of calcareous nannofossils and palynomorphs from two sections to produce a provisional integrated biostratigraphy for the Agrio Formation. While the palynomorphs are essentially of local value only, especially the continental forms, the nannofossils and the ammonites allow some correlations to be made with the European Mediterranean `standardʹ sequences.