Carboniferous deglacial record in Paraná Basin (Brazil) and its analog in Paganzo Basin (Argentina): a comparison between Pennsylvanian and Permian sections

VICTORIA VALDÉZ; PAULO PAIM; SOUZA, PAULO ALVES; DI PASQUO, M.M.

San Pablo

Congreso; 6th Latin American Congress of Sedimentology; 2013

universidad federal de sao paulo

Paganzo and Paraná are two basins of South America that received glacially-derived sediments immediately after the mid Carboniferous glaciation of Gondwana. Whereas in the PaganzoBasin the glacio-sedimentary record is more complete, involving Mississippian to Pennsylvanian strata, in the Paraná Basin these deposits range from late Pennsylvanian to Early Permian. At least four Pennsylvanian glacial/deglacial cycles are recorded in the Paganzo Group in the Cerro Bola and Sierra de Maz areas of the Paganzo Basin. The typical glacial/deglacial cycle consists of alternating proglacial and postglacial marine strata, including deltaic and turbidite sandstones, black shales, and mass-transport deposits (resedimented diamictites). Outcrops of the Mafra and Rio do Sul formations of the Itararé Group in the Paraná Basin constitute the record of the Gondwana Early Permian glaciation in Santa Catarina State, southern Brazil. In the Doutor Pedrinho area, four glacial/deglacial cycles are recorded. These cycles are characterized by conglomeratic outwash deposits, sandy turbidites and diamictites associated with resedimentation. Whereas the sandy turbidites of the Dr Pedrinho area are related to the LST, in the Cerro Bola area similar turbidites are included in HST strata. Mudstones and other fine-grained deposits constitute the most common facies of the TST. Besides sedimentary descriptions, palynological results (palynofacies and preliminary age determination) derived from the analyses of shales or siltstones (with and without dropstones) sampled at different flooding surfaces within distinct TST and HST from both basins are also presented.