La Gran Barranca: un registro único de la evolución de los mamíferos sudamericanos durante el Cenozoico medio

VUCETICH,M. G., CARLINI, A.A.

Sitios de especial Interés Paleontológico y Geológico, SEGEMAR

SEGEMAR

Lugar: BUENOS AIRES; Año: 2008; p. 747 - 757

The southern cliff of the lake Colhué Huapi (south central Chubut), worldwide known as “Gran Barranca”, is one of the most important localities of the South American middle Cenozoic. The best exposures of the Sarmiento Formation, currently divided into five members, are found in this area. This formation bears the most complete sequence of Paleogene and early Neogene faunas of South America. The richness, quality and diversity of its record are excellent. These deposits encompass about 25 million years, from the middle Eocene up to the early Miocene. The 49 mammal associations found can be grouped in seven different faunas, corresponding to seven of the Land-Mammal Ages in which the South American Cenozoic is divided. This sequence yielded the single continental evidence for the Southern Hemisphere of the first global Cenozoic climatic cooling, corresponding to the first Antarctic glaciation, occurred during the Eocene-Oligocene transition. One of the most outstanding points of this sequence is the association of climatic events and faunistic change, detected through the improvement of the temporal calibration. In sum, this faunistic sequence in a restricted area allows the reconstruction of the main steps of mammal and environment evolution for the middle Cenozoic of Southern South America.