Late paleozoic faunal and floral successions in the Paraná Basin, Southeastern Brazil

Abstract

The stratigraphicaldjstribution of the Late Paleozoic marine fauna and megafIora is examined with respect to the available biostratigraphic framework for part of the Upper Paleozoic sequence of the Paraná Basin, Brazil (Tubarão Group) possibly spat:lning the Upper Carboniferous-Lower Permian intervalo ' Within this interval the megaflora succession shows a transition from assemblages with incidence of northem forms to others in which the Glossopterids are more frequent and finally predominate.The invertebrate megafauna (mollusks and brachiopods) succession shows a high frequency of cosmopolitan forms associated with Gondwanic forms in the early assemblages, followed later by more typical gondwanic faunal assemblages.The evidence at hand for the correlation of the studied sequence with the Caroniferous-Permian boundary is discussed. RESUMOo presente trabalho inclue uma análise de distribuição e composição da megafIora e megafauna marinha (moluscos e braquiópodes) do Grupo Tubarão; tendo em vista o arcabouço bioestratigráfico (palinológico) disponível para o Paleozóico Superior da Bacia do Paraná, Brasil. A sequência estratigráfica examinada abrange, possivelmente, o intervalo Neocarbonífero-Eopermiano .. A sucessão de megafIoras do Grupo Tubarão inicia-se com assembléias contendo formas "nórdicas", passando a outras em que as glossopterídeas são mais frequentes, ou mesmo predominantes, na parte superior da sequência investigada.A megafauna de invertebrados marinhos, por sua vez, abrange, inicialmente, assembléias com proporção relativamente alta de formas cosmopolitas, associadas a gêneros gondvânicos, às quais se seguem assembléias de caráter mais tipicamente gondvânico.Analisam-se, ainda, criticamente, as evidências disponíveis para o reconhecimento do limite Carbonífero-Permiano no Brasil e América do Sul.

Permian bivalves of the Taciba Formation, Itararé Group, Paraná Basin, and their biostratigraphic significance

“…Therefore, new SHRIMP U-Pb zircon ages (RochaCampos et al, 2011, p. 9, Figure 6) from tuffs recorded at the top of the Itararé Group (Rio do Sul Formation) indicate that this portion of the Late Paleozoic succession of the Paraná Basin was deposited during the Asselian. Hence, the age of the section containing the studied fauna is sound with the age and biocorrelations with the Bonetian fauna of Argentina, as already suggested by other authors (Rocha-Campos and Rösler, 1978;González, 1997;Simões, Anelli, RochaCampos, 1998;Pagani, 1998Pagani, , 2000. Finally, based on their mutual faunal content, both the Butiá and Baitaca assemblages are, indeed, an evident record of members of Eurydesma-fauna within the Late Paleozoic succession of Paraná Basin.…”

“…Hence, the Butiá and Baitaca assemblages are correlated to the "Eurydesma fauna" of the Bonete Formation (Asselian-Sakmarian) and with the fauna of the Amotape Formation (Middle Pennsylvanian) of Peru (Newell, Chronic, Roberts, 1953), as indicated by the common occurrence of Aviculopecten multiscalptus (Rocha-Campos, 1970;Rocha-Campos and Rösler, 1978 Our findings in Itararé succession of a bivalve species, which is typical of Bonetian fauna, open new avenues to better constrain the age of the marine intercalations recorded at the top of Itararé succession. In the Eastern Argentina, the Piedra Azul and Bonete Formations contain members of the typical Eurydesma fauna, and they are associated with the post-glacial transgression of the end of Gondwana Ice Age (Dickins, 1985;González and Saravia, 2007, Anelli et al, in press).…”

“…Contrary to Argentina, where thick lower carboniferous up to Permian sequences yield abundant and diversified marine fossiliferous records (González and Saravia, 2007;Pagani and Taboada, 2010), coeval occurrences in the Brazilian portion of the huge, up to 1,600,000 km 2 (Holz et al, 2010), foreland Paraná Basin are rare and poorly diversified (Rocha-Campos and Rösler, 1978;Simões, Rocha-Campos, Anelli, 1998).…”

“…Among those, the Butiá assemblage, known since Rocha-Campos (1966), in the upper most portion of the Itararé Group is of particular interest to regional correlations. This assemblage is associated with a short transgressive-regressive episode at the end of the Late Paleozoic glaciation in the Paraná Basin (Simões, Anelli, Rocha-Campos, 1998), and record the first appearance of typical Gondwanian marine bivalves in the basin (Rocha-Campos and Rösler, 1978;Simões, Anelli, RochaCampos, 1998). Therefore, the aim of this contribution was to describe, by the first time, the bivalve species of the Butiá assemblage found in the Taciba Formation in the top of Itararé succession at the State of Santa Catarina, Southern Brazil.…”

“…However, some of these are key faunas for interbasinal correlations since data on checklists available (Rocha-Campos, 1970;Rocha-Campos and Rösler, 1978) indicate that such assemblages at the top most portion of the Rio do Sul or Taciba Formations (upper third of Itararé Group) may show affinities with the Lower Permian bivalves, from the Bonete Formation, Sierras Australes, Buenos Aires Province, in Argentina (Harrington, 1955;Pagani, 2000). Rocha-Campos (1966) had listed (but not described or illustrated) the presence of marine invertebrates (e.g., brachiopods and mollusks) associated with glaciogenic rocks (e.g., diamictites) at the top of Itararé succession, in the Butiá Quarry.…”