Sequence stratigraphy was applied to the Early Permian (Sakmarian to Ufimian) sedimentary succession of Rio Grande do Sul State, southernmost Brazil. The research was based on data acquired from 120 entirely cored boreholes and several outcrops. The facies framework of the lithostratigraphical units Itarare, Rio Bonito, Palermo and basal Irati is shown. Eight facies associations are recognised, varying from glacio-continental to glacio-marine settings at the base (Sakmarian) to shoreface environment (Artinskian) and epicontinental sea (Artinskian-Ufimian). The facies are presented within a chronostratigraphical framework, linked by systems tracts, which in turn are limited by flooding surfaces and sequence boundaries. Four third-order depositional sequences are recognised, bounded by a type 1 unconformity (between sequence I and II) and a type 2 unconformity (between sequences II/III and III/IV). Four palaeophysiographic stages have been recognised: fjords, fluvial plain, coastal plain and epicontinental sea.
La succession sedimentaire Eo-Permienne (Sakmarien-Ufimien) de l'Etat du Rio Grande do Sul a ete etablie a partir de l'application des concepts de la stratigraphie sequentielle. Outre l'etude a l'echelle d'affleurement, la recherche aete effectuee sur 120 temoins de forages. La reconnaissance de huit associations facioogiques a permis d'etablir le cadre faciologique des unites Itarare/Rio Bonito/Palermo/Irati. Ces donnees ont conduit a l'etablissement a une histoire de depots glacio-marins et glacio-continentaux a la base (Sakmarien) passant a un depot cotier (Artinskien) et ensuite a un depot de mer epicontinentale (Artinskien/Ufimien). Ce cadre faciologique est presente dans un contexte chronostratigraphique, groupe dans des systemes de depots et relies a des corteges de systemes, delimites par des surfaces d'inondation et des discordances. Quatre sequences depositionelles de troisieme ordre ont ete reconnues, delimitees par des discordances de type I (entre les sequences I/II) et de type II (entre les sequences II/III et III/IV). Quatre sequences de depots de troisieme ordre ont ete reconnues: fjords, plaine fluvio-deltaique, plaine cotiere et er epicontinentale.