Resumen

LESCANO, Marina  y  CONCHEYRO, Andrea. Calcareous Nannofossils From The Agrio Formation (Lower Cretaceous) Southwestern Area Of The Neuquén Basin, Argentina. Ameghiniana [online]. 2009, vol.46, n.1, pp. 73-94. ISSN 0002-7014.

Calcareous nannofossil assemblages recorded in marine rocks of the Lower Cretaceous Agrio Formation in the southern Neuquén Basin are presented here. The Cerro Birrete (39º 16.456´S and 70º 5.94´O), Barda Cerro Marucho (39º 26.685´S and 70º 13.015´O) and Cerro Marucho section (39º 26.443´S and 70º 13.21´O) are analized, being recognized 33 taxa, between them, the reliable markers are: Clepsilithus maculosus Rutledge and Bown, Eiffellithus striatus (Black) Applegate and Bergen, Eiffellithus windii Applegate and Bergen, Nannoconus bucheri Brönnimann, Nannoconus circularis Déres and Achéritéguy. The nannofossil association, of Late Valanginian-Hauterivian age, allow to date of the Agrio Formation in the area and correlate it with others situated in different localities of the basin.

Palabras llave : Biostratigraphy; Calcareous nannofossils; Lower Cretaceous; Neuquén Basin; Argentina.