Arcabouço Cronoestratigráfico do Eopermiano da Bacia do Paraná na Região Centro-Oeste do Rio Grande do Sul

Abstract

The chronostratigraphic framework of the Rio Bonito and Palermo formations (Artinskian-Kungurian) of the Paraná Basin in Southern Brazil presented here was based on the Sequence Stratigraphy approach. This interval was subdivided into four 3rd order (2-3Ma) depositional sequences (A, B, C and D). these sequences, as a whole, include facies associations interpreted as transitional depositional systems (lowstand systems tract) which were progressively overlain by shallow marine systems (transgressive systems tract) until a relative stability was achieved and deeper marine conditions were established (highstand systems tract). All depositional sequences are bounded by unconformities which are related to the glacioeustasy with some local tectonic influence. Third order transgressions were probably superimposed to a larger scale basement rocks, during the deposition of the middle portion of depositional sequence C.