CONSIDERACIONES SOBRE LOS CAMBIOS CLIMATICOS DURANTE EL PLEISTOCENO TARDIO-RECIENTE EN LA PROVINCIA DE BUENOS AIRES. ASPECTOS ECOLOGICOS y ZOOGEOGRAFICOS RELACIONADOS

Abstract

The climatic and environmental conditions during Late- Recent Pleistocene in the Buenos Aires Province are discussed. The discussion is based on geological units and studies of Local Faunas. Several lithostratigraphic units were distinguished and correated with a Glacial Cycle and its minor phases (sensu Fairbridge, 1972). These units, in decreasing order of age, are: Pascua Fm.: marine coastal deposits assignable tentatively to the Last Interglacial. Overlay sandy-silt and silty-sand of the Pampiano Fm. (upper part), with an intercalate pedalferric buried soil. Contemporaneously begun -in the valleys- the depositation of sands, silts and clays of the Guerrero Member of the Luján Fm. Over these sediments was developed the Puesto Callejón Viejo Soil, buried -in the in1and zone- by fluvial sediments of the Río Salado Member of the Luján Fm., and -in thc coastal zone- by marine sediments of Las Escobas Fm. The Destacamento Río Salado Fm. (deposited in marsh and coastal lagoons) and the eolic sediments of the lower part of La Postrera Fm., are considered, tentatively, contemporaneous with the sediments of the Guerrero Member of Luján Fm. The Puesto Berrondo Soil developed on the units that bury the Puesto Callejón Viejo Soil. In the Present they are overlain by the- Alluvium. The Luján (Guerrero Member), La Postrera (lower part) and Destacamento Río Salado Formations, are assignable to the Pleniglacial phase. In the first and second units there are mammals that in the Present integrate the Patagonica and Central biocenosis (Paleoclimatology - Late-Recent Pleistocene – Local Faunas - Buenos Aires Province).