Mineralogy of the scheelite-bearing ores of Monte Tamara, SW Sardinia: insights for the evolution of a Late Variscan W–Sn skarn system

Abstract Southwestern Sardinia, Italy, hosts several skarn, W–Sn–Mo greisen and hydrothermal deposits related to a 289±1 Ma Late Variscan granite suite. Among them, the most representative scheelite-bearing skarns belong San Pietro Sinibidraxiu localities, in Monte Tamara area, Sulcis region. The deposit is typical calc-silicate skarn whereas sharply bounded orebody hosted marble unit. Optical petrographic observations compositional data of major trace elements were obtained for samples from both localities. suggests evolution an oxidising prograde stage (andradite–diopside, hematite scheelite), progressively more reducing conditions early retrograde (magnetite–cassiterite) late sulfide (arsenopyrite, stannite, molybdenite, Bi sulfosalts Zn–Cu–Pb–Fe sulfides); has diffuse carbonate–quartz intergrowths pseudomorphic over mineral assemblage with fibrous habit, followed by abundant ore precipitation under (scheelite, arsenopyrite Pb–Zn–Cu–Fe sulfides). Geothermometers indicate comprehensive temperature range 460–270°C stages deposits. differences between two might be controlled distance source intrusion coupled different reactivity host rocks. mineralogy represents proximal contrasting distal mineralogical chemical features characterising (lack Mo–Sn–Bi phases; LREE–MREE–HREE signature scheelite). This investigation contributes first time identification W–Sn system SW thereby suggesting area its surroundings as favourable further exploration.