RASGOS LITOLÓGICOS Y FOSILÍFEROS DE LA FORMACIÓN PASCUA (PLEISTOCENO TARDÍO) EN SU LOCALIDAD TIPO, PROVINCIA DE BUENOS AIRES

E. FUCKS , M. L. AGUIRRE , E. SCHNACK , G. ERRA , N. RAMOS

Universidad Nacional de Córdoba

Congreso; III Congreso Argentino de Cuaternario y Geomorfología; 2006

ABSTRACT A review from geomorphologic and fossiliferous standpoints at Puente de Pascua, type locality of the Pascua Formation (Late Pleistocene marine transgression, +6-8m s.n.m.; minimum radiocarbon age of 40 ka A.P.; 120 ka?, MIS 5e), allows to recognize lithological and palaeontological features uncommon for the Pampean area. The sediments as a whole are typical of estuarine and littoral environments, and facies of low energy intertidal environment, beaches and dunes culminating in typical loessic deposits are evident. The molluscan fauna and the microfauna (foraminifers, ostracods) correspond to a marginal marine environment and corroborate clear salinity changes in comparison with the modern littoral at Río de La Plata area. The marine sequence indicates the innermost boundary for this ingression in the whole area. The abundance of T. plebeius in living position and well preserved points out the chance at this locality of performing reliable dating on autochthonous or parautochthonous elements with no dissolution, cementation, abrasion or other taphonomic signatures, quite an uncommon situation for the marine Pleistocene along the whole coastal area of Argentina.