Relações entre filões de fluorita, rochas da Bacia do Paraná e lineamentos de direção NW-SE no Sudeste Catarinense: implicações para a prospecção

The tertiary-mesozoic fluorite veins in the Santa Catarina fluorine mining district are associated to NNE-SSW lineaments. Along these lineaments, the fluorite ore veins are mainly located at the intersections with NW-SE lineaments and near to Paleozoic relicts rock of the Parana Basin, even in uplifted areas further east. The aim of this study is to understand the relationships among these lineaments and associated sediments and fluorite veins. The use of sequence stratigraphy in sediments associated to the Urussanga lineament (NW-SE) allowed the identification of three cronostratigraphycs surfaces and seven facies associations. The tectono-sedimentary evolution observed indicates that the sedimentation basin in the district area was essentially controlled by the NW-SE structures which generated areas with thicker sedimentary cover, a necessary condition for the formation of fluorite deposits. The hydrothermal fluids migration in greater deep was mainly controlled by the NW-SE structures. After rising up to the basal level of the sedimentary cover, the fluids migrated longitudinally along the NNE-SSW structures, depositing fluorite and establishing geochemical gradients that controlled the formation of deposits at a local scale.