SEM - EDS mineralogical study of the Cuaro Sill Tacuarembo dept. (Uruguay)

The Mesozoic magmatism exposed in the Norte basin of Uruguay is related with the tectono-magmatic events of the South Atlantic Ocean opening and, regionally is part of the Parana Magmatic Province (PMP). It is represented by basaltic flows correspondent to the Arapey Formation and by the associated intrusive rocks of the Cuaro Formation. The aim of this work is the mineralogical characterization of the Cuaro Sill (Department of Tacuarembo, NE Uruguay), using conventional petrographic techniques (polarized transmitted and reflected microscopy) and scanning electron microscopy (SEM-EDS). Based on the petrographic features observed, the dolerites of the Cuaro Sill are composed by: plagioclase (labradorite), pyroxenes (augite and pigeonite), Fe-Ti oxides (magnetite and ilmenite), relicts of olivine and apatite. It presents frequent glomero-porphyritic textures, with plagioclase/clinopyroxene phenocrysts, with lack of cumulate textures. Anomalous concentrations of guide exploration elements have not been observed despite the presence of traces of Mn and Cr within the ilmenites or the presence of sulfides (chalcopyrite). Therefore, a greater potential of these elements at deeper levels of the intrusion is not rule out