Characterization of ultramafic rocks from the Jinchuan nickel deposit in China by 57Fe Mössbauer spectroscopy

57Fe Mossbauer spectroscopy has been applied to the ultramafic rocks collected from the Jinchuan nickel deposit in China to elucidate their mineralization process. Their Mossbauer spectra consisted of two sextets ascribable to magnetite, two doublets ascribable to Fe2+ and Fe3+ in chromite, and one doublet ascribable to olivine. The closest sample to the ore body did not contain chromite and contained a doublet ascribable to pyrite and a sextet ascribable to pyrrhotite. The valence and site distribution of iron species suggested low oxygen fugacity for the formation of the Jinchuan nickel deposit.