Biotic and environmental changes across the Cretaceous/Paleogene boundary in Patagonia

CASADIO, SILVIO; GRIFFIN, MIGUEL; PARRAS, ANA; CONCHEYRO, ANDREA; FELDMANN, RODNEY; GASPARINI, ZULMA; PARMA, GRACIELA

San Luis

Otro; 10 Reunión Argentina de Sedimentología; 2004

Universidad Nacional de Cuyo

The late Maastrichtian molluscan fauna of the Neuquén Basin includes species of characteristically austral genera (e.g. Neilo, Australoneilo, Lahillia, Austrotrigonia and Pacitrigonia), supporting the northward extension – into Northern Patagonia – of the range of some elements of the Weddellian Province during the late Maastrichtian (Zone CC26; Perch-Nielsen, 1985). Concheyro and Villa (1996) recorded the presence of calcareous nannofossil  taxa typical of high latitudes and suggested that this could be related to a northward expansion of the Falkland Plateau Bioprovince – as defined by Wind (1979) – which would have reached north to 36ºS during Chron 30N. Similarly, Gasparini et al. (2003) pointed out that the northern Patagonian Maastrichtian elasmosaurids are closely related to those of the same age from the Antarctic Peninsula and New Zealand, they supporting the hypothesis of a southern Gondwana distribution for some pelagic reptiles (Novas et al., 2002). This contradicts Olivero et al. (1990), who believed that the Northern Patagonian Masssif acted as a paleogeographic barrier restricting the connection between the Chubut River area and the area north of the Colorado River. Displacement of high latitude species towards mid latitudes is probably...