Bioestratigrafía basada en quistes de dinoflagelados del Eoceno tardío - Mioceno del pozo Ombucta x-1, Cuenca del Colorado, Argentina

Abstract

Dinoflagellate cysts are present in varying amounts allowing age interpretation for the section. Selected dinoflagellate cysts events, mainly last occurrences, suggest five age intervals: late Miocene to early Pliocene, late Miocene, mid Miocene, Oligocene to early Miocene and Eocene to Oligocene. The comparison of the selected dinoflagellate events with previous studies carried out by other authors indicates that these events are consistent throughout the basin. The composition of the dinoflagellate assemblages, with dominance of gonyaulocoids over peridinioids, reflects poor nutrient oceanic conditions. Low dinocyst/pollen ratios at the end of the Miocene and during the Oligocene suggest relatively nearshore environments confirmed by high dominance of the complex Operculodinium israelianum/centrocarpum. Sediments ranging from mid to early Miocene in age show high dinocyst/pollen radios associated with oceanic species acmes.