ENVIRONMENTAL CHARACTERIZATION OF THE ITAÚ-ITAUNA QUARRY (PARANÁ BASIN, LOWER PERMIAN), SANTA CATARINA, BRAZIL

The Paraná Basin is located on center southern region of South America. It's a foreland basin with sedimentary deposition ranging in age from Neo-Ordovician to Tertiary.

The Rio do Sul Formation, an Early Permian sequence from Itararé Group is the main subject of studies carried out here. In order to understand the paleogeographical evolution of this formation, a series of stratigraphic, palinological and paleontological studies were performed in a key area, the Itaú-Itauna Quarry in Santa Catarina. The sedimentary rocks analysed are shales are milimetric cyclic deposits, tabular and continuous layers, graywisch colors and fine grains.

Using stratigraphic analyses were recognized the glacial influence of shallow marine environment with high stand sistems tract, low stand sistems tract and transgressive sistems tract.

Shallow marine environment also is suggested by petrographic studies, showed by the presence of eodiagenetic pyrite as well as by palinological data where Tasmanites spp. agree with this interpretation. It was possible to recognize more than 60 palynomorphs, standing out Vittatina subsaccata, Limitisporites delasaucei and Limitisporites rectus all of them of Kungurian age, Tasmanites spp. occurence show to marine water and Botryococcus braunii to fresch water influence.

The petrographic analysis of thin sections demonstrates dominance of thin granulometric sediments with angular intraclasts originated from muds and sands, mica levels, and eodiagenetic produts such as framboidal pyrite and siderite. The occurrence of mudy and sandy angular intraclasts demonstrates that these fragments were extracted near to depositional area. Mica levels also suggest a micacea-originated source for this depositional area.

Bioturbations represent a preferential standard of shifting where were noted ichnospecies Cruziana problematica, Diplichnites gouldi, Diplopodichnus biformis, Gluckstadtela isp., Helminthoidichnites tenuis, Hormosiroidea isp., Neonereites uniserialis, Rusophycos isp, Umfolosia longula e Umfolosia sinuosa. Distribution of these bioturbations, along of quarry levels, reflect environmental variations such as temperature, salinity and substract conditions which was occurring in Rio do Sul Formation.