Occurrence of Eocene foraminifera in the Neuquén Basin, Argentina

MALUMIAN, N. ; PARRAS, A.; QUIROGA, A.; NÁÑEZ, CAROLINA; JANNOU, G.

Londres

Conferencia; The Micropalaeontological Society 50th Anniversary Conference 2020 -; 2020

The Jagüel Formation and the overlying Roca Formation, from northern Patagonia, Argentina, represent shelfal deposits that have been assigned a Maastrichtian-Danian age for many years. At the Puesto sin Nombre section, ca. 38° 13´ S lat. and 68° 30´ W long., Neuquén province, they were reported as Danian. The finding of the planktonic foraminifera Guembelitrioides aff. G.nuttalli (Hamilton, 1953), Parasubbotina inaequispira (Subbotina, 1953) and Globorotaloides eovariabilis Huber and Pearson, 2006, in a horizon of the Jagüel Formation in the lower part of this section, suggests an Eocene age. The problematic Dipsidripella liqianyui Huber and Pearson, 2006, is recorded in both the upper part of the Jagüel Formation and the Roca Formation, and it is associated to the benthic foraminifera Boltovskoyella Malumián and Masiuk,1972, Ceratocancris Finlay, 1939, and also to abundant smaller miliolids. Dipsidripella liqianyui is known from the middle Eocene up to the early Oligocene, which is consistent with the stratigraphical range of Boltovskoyella in southern Patagonia. The previously reported occurrence of Globoconusa daubjergensis in the section is probably due to reworking. A revision of the planktonic foraminifera is being conducted to reevaluate the age of the Jagüel and Roca Formations in the Puesto sin Nombre section.