Geology of the cretaceous Paraná Magmatic Province at the central portion of Torres Syncline, Southern Brazil

ABSTRACTGeological maps of tropical areas demand special challenges due to weathering conditions, mainly where relief has low variability. Most part of Paraná Magmatic Province is included in this scenario. An exception to this situation is the southeastern portion of the province, in the state of Rio Grande do Sul, Brazil. The stratigraphic disposition of volcanic units and the characteristics of erosion of each one caused the exposition of four identified plateaus, in which outcrop, from bottom to top: (1) basalts from Torres/Vale do Sol formations; (2) Caxias do Sul dacite; (3) Barros Cassal sequence; (4) Santa Maria rhyolite. The contacts were traced using SRTM images (through altitude and slope maps), integrating previously published semi- to detailed maps and geochemical database from our group. The resulting map (1:250,000) contributes to the volcano-stratigraphic knowledge of this huge province, and allows us to suggest the review of silicic units, initially called Palmas Formation.