Mineral chemistry and oxygen isotope studies on Sn (& PLUSMN;W) mineralization from Pedra Branca Granite Massif, Central Brazil

Central Brazil hosts Paleo-Mesoproterozoic A-type granitic suites related to the Goias Tin Province (GTP) that contain Sn (& PLUSMN;W, Nb-Ta, REE) mineralization associated with greisen, veins, and small pegmatite bodies. The Pedra Branca granite massif (1.77-1.74 Ga) is the main representative of GTP, marked by important cassiterite (& PLUSMN;wolframite) contents. The cassiterite contains SnO2 = 96-100 wt. %, with the sum FeOtotal, TiO2, WO3, Ta2O5, Nb2O5, In2O3, and UO2 content below 4 wt.%, while wolframite contains WO3 = 71.5-74.5 wt.%, FeOtotal = 14.3-17.4 wt.% and MnO = 6.3-9.9 wt.%, as well as Sn, Ca, Ti, Ta, Nb, Pb, In, and U as trace elements. The 818O data on the quartz-cassiterite pair (quartz = 9.4-10.4%o, cassiterite = 2.6-2.9 %o) from greisen reveal a magmatic-hydrothermal signature with calculated crystallization temperatures between 410 and 485 & DEG;C. However, during the Neoproterozoic Brasiliano/Pan-African Orogeny (800-500 Ma), all lithologies and ore sites were subjected to flattening, fragmentation, and mylonitic deformation. Fluid inclusion data revealed the presence of low-salinity aqueous solutions with homogenization temperatures between 215 and 100 & DEG;C related to Neoproterozoic deformation. Finally, during the Phanerozoic, prolonged erosive produced Sn (& PLUSMN;W)-rich alluvium around the Pedra Branca granitic massif.