Fluid inclusion and stable isotope studies in Sn-W deposits of western Spain

Abstract

Most of the Spanish Sn-W mineralizations are related to the syn- to late-tectonic Hercynian granites. Fluid inclusion and stable isotope studies have been carried out in quartz, cassiterite, scheelite and wolframite from different types of deposits : Sn diseminations in apogranites (Golpejas and Penouta), Sn pegmatite (Feli) and Sn, Sn-W, W quartz veins ( Teba, San Finx, La Parrilla and Virgen de la Penouta), Sn The fluids probably responsible for the Sn-W mineralizations belong to H₂O-NaCl-CO₂-CH₄-N₂-H₂S system with salinities below 15 Wi. % eq. NaCl and homogenization temperatures ranging between 240 and 430⁰C. With salinitIes below 15 wt. % eq. NaCl and homogenization temperatures ranging between 240 and 430⁰C. δ18 O (SMOW) %₀ values show small variations: from 9.4 to 15.6 in quartz, -3.8 to 7.3 in cassiterite, 5.8 to 6.9 in scheelite, 4.9 in wolframite, and -2.9 to 8.2 in waterof the metalliferous fluids. These fluids are mainly magmatic or with incorporation of other isotopically ligther waters.