The evaluation of some geochemical and mass transport characteristic of surface waters of Serra Geral basaltic formation, in the Paraná State (South Brazil), was the aim of this study. Hydrochemical, hydraulic and sedimentologic data in the hydrografic basin of Jacutinga stream, were evaluated. To complement and to improve the discussion of those data, informations from other hidrographic basins, of the basaltic region, were used. The main process of alteration that was observed in this region was the monossialitization and relative mobility of the major ions, including silica, was K+ Na+ Ca2+ Mg2+ SiO2. It was determined the materials in suspension (46t/km2.year) from these basalts, and also the specific chemical outflow for each of the major cations an silica. The mean rates of the basaltic alterations (1.9 x 10-5 m/year) and mechanical erosion rates(5.6 x 10-5 m/year) were evaluated in the Jacutinga basin.The evaluation of some geochemical and mass transport characteristic of surface waters of Serra Geral basaltic formation, in the Paraná State (South Brazil), was the aim of this study. Hydrochemical, hydraulic and sedimentologic data in the hydrografic basin of Jacutinga stream, were evaluated. To complement and to improve the discussion of those data, informations from other hidrographic basins, of the basaltic region, were used. The main process of alteration that was observed in this region was the monossialitization and relative mobility of the major ions, including silica, was K+ Na+ Ca2+ Mg2+ SiO2. It was determined the materials in suspension (46t/km2.year) from these basalts, and also the specific chemical outflow for each of the major cations an silica. The mean rates of the basaltic alterations (1.9 x 10-5 m/year) and mechanical erosion rates(5.6 x 10-5 m/year) were evaluated in the Jacutinga basin.