PALINOESTRATIGRAFÍA DE LA FORMACIÓN SAN JULIÁN EN EL ÁREA DE PLAYA LA MINA (PROVINCIA DE SANTA CRUZ), OLIGOCENO DE LA CUENCA AUSTRAL

Viviana D. Barreda

Abstract


"Samples containing fossil pollen, spores and a few dinoflagellate cysts were collected from Playa La Mina section, San Julián Formation, Patagonia. The recovered assemblages show important percent and minor composition changes through this section. Major variations take place between the coal assemblage and those of the detrital seams. A community dominated by Myrtaceae, Palmae and Araucariaceae trees, woody vines, scandent shrubs, lianas, aquatic herbs and epiphytic ferns would have been developed in the peat forming marsh. Conversely, communities dominated by Podocarpaceae and Fagaceae trees which may ha ve formed dense forests would have been common in the coastal detrital sediments. However, the presence in these samples of small amounts of Anacardiaceae, Malvaceae, Symplocaceae, Ephedraceae, Gramineae, Compositae and Chenopodiaceae, suggests the beginning of developing of a local open vegetation. The spore-pollen assemblages suggest warm and humid climate conditions, although some areas, probably the inland regions, could have had lower effectíve moisture than others. These spore pollen assemblages also suggest an Oligocene age for Playa La Mina section. "

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