High and Low Temperature Gold Mineralizations in the Fe–Cu–Zn Sulfide Deposits of Corchia Ophiolite, Northern Italian Apennine

摘要

Gold has been found in the Cyprus-type volcanogenic massive sulfide ore (VMS) deposits of Corchia ophiolite (Parma province, Italy) in the Cantiere Donnini, Speranza and Pozzo mining sites. At Cantiere Donnini and Speranza, the mineralization occurs at the contact between pillow lava and sedimentary rocks. The Pozzo mineralization is hosted by a serpentinite. Concentrations of gold up to 3070 ppb have been reported for the Cantiere Donnini and up to 6295 ppb in the Pozzo mine. According to the field relationships, gold composition, mineralogical assemblage and sulfur isotope data, we can conclude that two different types of gold mineralization have been recognized in the Corchia ophiolite: (1) formed at low temperature in submarine environment (Cantiere Donnini and Speranza) and (2) formed at high temperature in the oceanic mantle (Pozzo) by segregation of an immiscible sulfide liquid.