Revisión del conocimiento paleontológico del Paleozoico tardío del Uruguay

Abstract

Palaeontological studies on the strata from the Late Palaeozoic of Uruguay are reviewed, with emphasis on the proposals of biostratigraphic correlation. Although a formal scheme is lacking, several papers have assigned the fossiliferous assemblages especially to zonations of the Chacoparanense Basin of Argentina and the Southern part of the Paraná basinof Brazil. The lithostratigraphic units involved are the San Gregorio, Tres Islas, Melo, and Yaguarí Formations. The fossil remains on which those proposals are based are palynomorphs, plant macrofossils, invertebrates and vertebrates. The palynological assemblage found in the San Gregorio Formation has been correlated with the Cristatisporites Biozone (Asselian?-Kungurian) of Argentina and with the Cannanoropollis korbaensis Biozone (Sakmarian-Kungurian) of Brazil, recently renamed as Vittatina Biozone. However, its fossiliferous assemblages of invertebrates and vertebrates suggest older ages. The palynomorph assemblage found in the Tres Islas Formation has been correlated with the same Biozones of Argentina and Brazil. The fossils of the Melo Formation have been correlated with the mentioned Biozones and with the Striatites Biozone (Kungurian?-Kazanian) of Argentina and the Lueckisporites virkkiae (Kazanian-Tatarian) ofBrazil. The invertebrates and vertebrates found tend to be congruent with an older assignation. Moreover, the taphoflora and the invertebrates and vertebrates faunas found in the Yaguarí Formation have been assigned to a Late Permian age.