CONICET | Buscador de Institutos y Recursos Humanos

The paleovegetation, paleoclimates and paleooceanography of the Paleogene of the Río Foyel section (El Foyel Group), Ñirihuau Basin is considered. This study comprises Troncoso, Salto del Macho and Río Foyel formations. The sporomorphs analysis reflects a regional forest dominated by Nothofagaceae, Myrtaceae, Podocarpaceae and Palmae, deveioped under a temperate to warm-temperate and humid climate. In the studied section the relation between terrestriaVmarine palynomorphs is considered. Ln Troncoso Formation terrigenous palynomorphs dominate over marine eleinents. The frequent presence of gymnosperm pollen with Araucariaceae indicates temperate to humid condition. Salto del Macho Formation shows a retraction of the gymnosperm forest associated with the dominance of the forest of Nothofaps indicating a temperatehumid condition. In the Río Foyel Formation the sporomorphs indicate the presence of a temperate to warm - humid forest with subordinate open areas and a remarkable input from the coastal environment. In the Río Foyel Formation, parasequences are identifiable on the basis of the palynological characteristics which indicate upward shallowing. The bounding surfaces of parasequences are defined as surfaces of flooding which represent a relative sea leve1 rise (marine flooding surfaces). The Río Foyel Formation shows an upward shallowing sequence indicated by the decrease of dinocysts. Different niarineflooding surfaces were detected associated with the diversity and abundance of dinocyst. A comparison of these spore pollen assemblages with others íi-om Patagonia using multivariate statistic techniques shows strong similarities between Troncoso Formation (?Late Eocene) and Slogett Formation (Late Eocene-?Early Oligocene), and between Salto del Macho and Río Foyel formations with Oligoceiie assemblages íi-om Patagonia.