EOCENE MAMMALS AND CONTINENTAL STRATA FROM PATAGONIA AND ANTARCTIC PENINSULA

GELFO, J.N.; REGUERO, M.A.; LÓPEZ, G.M.; CARLINI, A.A.; CIANCIO, M.; CHORNOGUBSKY, L.; BOND, M.; GOIN, F.J.; TEJEDOR, M.F.

Museum of Northern Arizona Bulletin

Museum of Northern Arizona

Lugar: Flagstaff; Año: 2009 p. 567 - 592

0361-9656

Mammalian faunal succession in South America is well documented through the Eocene from about 47 to 37 Ma.  Patagonian and Antarctic Peninsula basins contain the majority of Eocene land mammal-bearing deposits and these basins have been studied over the last 20 years by many geologists and paleontologists.  The geology of San Jorge (eastern Patagonia), “Volcanic-Pyroclastic Complex” (western Patagonia), and James Ross (Antarctic Peninsula) basins are here reviewed and their faunal content analyzed.  The temporal assignation of Itaboraian and Riochican South American Land Mammals Ages (SALMAs), usually regarded as late Paleocene, is also discussed.  In order to account for the likeness between Eocene faunas, a cluster analysis applying the Simpson coefficient was performed using a data matrix with 216 taxa from 13 faunas.  These faunas represent both classic and new localities from Antarctica, Patagonia, Mendoza, and Tinguiririca, and the taxa include up to three taxonomic categories (genera, family, and order) so that faunas without common genera can be compared.  The analysis supports at least three major clusters.  The first is formed by western Patagonia (Paso del Sapo localities) plus Antarctica, representing faunas that appear to fall biochronologically between the Riochican and Casamayoran SALMAs. The second group is divided between (1) faunas related to the Casamayoran SALMA, and (2) those related to the younger Mustersan SALMA. The latest Eocene – earliest Oligocene faunas are grouped together and represented by three Tinguirirican faunas and a fourth younger fauna which seems to be pre-Deseadan (Oligocene).