Antimony isotopes in the primary ores of the Pezinok and Pernek deposits

The Sb ore deposits of Pezinok-Kolarsky vrch, Trojarova and Pernek-Kriznica are unique on a global scale due to their mineral parageneses, from strongly reduced (pyrotitgudmundite-antimony), through the main sulfide ores (antimonite-berthierite), to late remobilization products with primary sulfoxides and oxides Sb (kermesite-valentinite-schafarzikite) or Sb silicates (chapmanite). The isotopic composition of antimony in all hydrothermal minerals was measured using multi-collector ICP-MS analysis. In the younger, oxidic paragenesis, the same trend is observed, but it starts at low values of δ¹²³Sb. The authors hypothesize that the antimony in Sb oxide minerals originates from the remobilization of older ores by oxidized fluids. A similar effect of remobilization is also observed in chapmanite, which was formed only locally, under limited conditions, apparently also by mobilization of Sb from older sulphide ores. Determined trends in the isotopic composition of Sb indicate that each paragenesis originated from a single fluid reservoir that gradually lost antimony as the temperature decreased or during reduction in the black shale environment. With the estimated or measured temperatures of mineral formation and the estimated rate of cooling of Variscan rocks, the total time of formation of such a deposit could be up to 5 million years. The authors assume that the crystallization of Sb minerals was episodic and that the fluid reservoir with Sb, S, and other elements was more or less preserved in the rock environment throughout this time. (authors)