Palinología estadística en el Cretácico de la Cuenca Austral, Plataforma Continental Argentina. II. Seis perforaciones del área Gallegos. III. Discusión y conclusiones

Abstract

Cretaceous statistical palynology of the Austral Basin, Continental Platform, Argentina.  II. Six wells of the Gallegos Area. III. Discussion and conclusions. A statistical study of palynomorph  groups found in six offshore wells of the Gallegos Area in the Austral Basin is here presented. All  samples are sidewall cores. The same groups analyzed in the first part were considered, including the  ratio marine/continental palynomorphs and pteridophytes/gymnosperms/ angiosperms. Percentages of all  groups are presented for the six wells and their significance is analyzed. Pollen assemblages of these  wells are uniform in their taxonomic composition. The main parameters of the most relevant sections  from all studied wells, including one onshore well of the same area that provided useful information in  the past, were selected. Ages based on similarity with known pollen assemblages from the same basin, as  well as recent data provided by microplankton and radiometric studies are given. It is concluded that  during the time span recorded - basal Cretaceous to early-Aptian- two transgressive episodes occurred. A  sequence of plant assemblages is characterized and the main compositional changes of vegetation are  discussed. Finally, correlations with known palynological assemblages from other areas of the Austral  Basin are made.  Key words: Stat i st ical palynology, Cretaceous, s t rat igr aphy, Aus t ral Basin, of f shore,  Argent ina.