PALYNOLOGICAL STUDY OF SPORES FROM SALTO DEL MACHO FORMATION, PALEOGENE OF THE NIRIHUAU BASIN, ARGENTINA

PALYNOLOGICAL STUDY OF SPORES FROM SALTO DEL MACHO FORMATION, PALEOGENE OF THE NIRIHUAU BASIN, ARGENTINA. The first palynological data from the type locality of the Salto del Macho Formation, at the Rio Foyel section, Nirihuau Basin, Argentina, is here presented. Nineteen taxa of trilete and monolete spores of Bryophyta and Tracheophyta (Lycopsida and Polypodiopsida) belonging to the following genera were recorded: Anthocerisporis, Azolla, Baculatisporites, Biretisporites, Cingutriletes, Cyatheacidites, Cyathidites, Ischyosporites, Laevigatosporites, Matonisporites, Muricingulisporis, Peromonolites, Polypodiisporites, Reboulisporites, Retitriletes, Trilites and Tuberculatosporites. The palynoflora is dominated by representatives of the Class Polypodiopsida, with predominant Cyatheaceae and Dicksoniaceae, in asociation whith Osmundaceae and Blechnaceae. The comparison of the record of spores with that of other Paleogene/early Neogene basins from Argentinian Patagonia, Chile and Antartica, made through the PAST program, shows remarkable palynofloristic similarities between Salto del Macho Formation with the spore associations recorded in the Rio Foyel, Chenque and San Julian formations. The accompanying palynoflora (Nothofagaceae, Podocarpaceae, Araucariaceae, Myrtaceae, Botryococcus braunii and low diversity of dinocysts) suggests a marginal-marine enviroment, in conditions of sub-normal salinity and temperate-warm water temperature.