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Bioestratigrafía del Oligoceno-Plioceno temprano de la Cuenca del Colorado (Argentina) basada en quistes de dinoflagelados

2002; Volume: 34; Issue: 3 Linguagem: Inglês

0556-655X

M. Verónica Guler, G. Raquel Guerstein,

Environmental and Cultural Studies in Latin America and Beyond

espanolSe realizo el analisis bioestratigrafico de las perforaciones Dx-1 y Fx-1 y se reconocieron cinco intervalos estratigraficos: Mioceno superior a Plioceno inferior, Mioceno superior, Mioceno medio, Mioceno inferior a Oligoceno superior y Oligoceno inferior. Las determinaciones de edades se basaron en los datos de ultimas presencias de especies de quistes de dinoflagelados seleccionados. La correlacion propuesta entre los pozos Fx-1, Dx-1 y Cx-1 esta basada principalmente en biohorizontes de ultimas presencias de cinco taxones seleccionados: Labyrinthodinium truncatum truncatum, en depositos de edad minima Tortoniense; Cleistosphaeridium ancyreum, indicando una edad no mas joven que Mioceno medio; Cannosphaeropsis quattrocchiae, cuyo registro no se conoce con posterioridad al Mioceno temprano, y Spinidinium cf. macmurdoense y Enneadocysta? dictyostila, que indican una edad rupeliense o mas antigua. English[Oligocene-Early Pliocene biostratigraphy of the Colorado Basin, Argentina, based on dinoflagellate cysts] The biostratigraphic analysis of ditch cutting samples from the Dx-1 and Fx-1 wells in the Colorado Basin, Argentina, yielded five stratigraphic intervals: upper Miocene to Pliocene, upper Miocene, mid Miocene, lower Miocene to upper Oligocene and lower Oligocene. Age assignments are based on the last appearance datums (LADs) of selected dinoflagellate species, among assemblages consisting of a total of 47 dinoflagellate cyst taxa. Correlation between wells Fx-1, Dx-1 and Cx-1 is mainly based on highest occurrences biohorizons of five selected taxa: Labyrinthodinium truncatum truncatum Piasecki emend. de Verteuil and Norris, in deposits no younger than Tortonian; Cleistosphaeridium ancyreum (Cookson and Eisenack) Eaton et al., in middle Miocene sediments; Cannosphaeropsis quattrocchiae Guerstein et al., species not known from sediments younger than early Miocene in age and, Spinidinium sp. cf. S. macmurdoense (Wilson) Lentin and Williams and Enneadocysta? dictyostila (Menendez) Stover and Williams, species with non confirmed records in sediments younger than Rupelian.