PALEOCENE/EOCENE POLLEN ASSEMBLAGES FROM THE LIGORIO MÁRQUEZ FORMATION, CENTRAL PATAGONIA,

Patagonia) is of fluvial to backmarsh origins of the Paleogene/Eocene. This strata is no more than 60 m thick and is composed of coal seams and flood plain deposits with abundant plant fossils, which have been the focus of attention in attempting to understand the floristic and climate history of southern South America during the early Tertiary period. The purpose of this palynological research is to confirm the presence or absence of Nothofagus pollen and to reconstruct the palynoflora of the Ligorio Márquez Formation. The consideration of this matter originated with a preliminary pollen report (Yoshida, 1990) suggesting the presence of temperate taxa such as Nothofagus and Podocarpaceae, which was inconsistent with the known tropical/subtropical megaflora from the same Formation (Suárez et al., 2000). Yoshida’s (1990) hypothesis, if he was right, would reorganise the paleofloral and/or chronological frameworks during the Tertiary period south of Chile Chico, in order to reconcile with regional supertropical climate of the Late-Paleocene/Early-Eocene derived from the so-called Cenozoic Climate Optimum (e.g. Bowen et al., 2004; Svensen et al., 2004). Phytogeographically, central Patagonia (which includes the Mina Ligorio Márquez area) is vital to an understanding of the history of Nothofagus migration through the Gondowana continent. Nothofagus (or Nothofagaceae) first appeared during the late Cretaceous period, and expande