Abstract

The presence of microfossils of vegetal origin preserved in sediment from Cerro Guido-Las Chinas complex in Última Esperanza Province, Magallanes Region in Chile, allow us to recognize a vegetation assemblage deposited in a continental environment, where the predominant climatic conditions could be evaluated in a place which was connected by a terrestrial bridge with the Antarctic Peninsula during the Maastrichtian. The Maastrichtian is a geological stage that shows considerable climatic fluctuations of warming and cooling phases during the Upper Cretaceous, an epoch where the planet experimented principally greenhouse climatic conditions. These climatic fluctuations have been mainly studied in marine environment on both hemispheres. Though the identification of the taxa members from this fossil assemblage by palynological studies, the recognition of the “nearest living relative” (NLR) of each identified taxon and the application of the coexistence approach method, the climatic requirement of the modern taxa can be superimposed on those of fossils; resulting in the first paleobotanic and palaeoclimatic reconstruction in this locality from the Austral Patagonia. Preliminary result allow us to mention the presence of spores that dominate the assemblage, followed by conifers like Podocarpus, Dacrydium and Araucaria, while angiosperms are represented by primitive monosulcate pollen grain.