Unusual PGE concentration in early disulfides of a low-temperature hydrothermal Cu-Ni-Co-Au deposit at Villamanin (Leon, northern Spain)

The early mineral assemblage of the Providencia mine in northern Spain includes metastable Cu-Ni pyrite-type disulfides with economic concentrations of Au and subeconomic concentrations of PGE in solid solution. High chondrite-normalized relations of Ir, Rh and Pt versus Pd, and the lack of Ru also characterize the ore. Our studies show that the ore-forming fluids were quasi-hydrostatic, low-temperature hydrothermal, and had a high salinity, and a high sulfur fugacity. The source of PGE remains unknown.