The trace element (TS) composition of isocubanite, chalcopyrite, pyrite, bornite, and covellite from oxidized Cu-rich massive sulfides of the Ashadze-2 hydrothermal field (12°58′ N, Mid-Atlantic Ridge) is studied using LA-ICP-MS. The understanding of TE behavior, which depends on the formation conditions and the mode of TE occurrence, in sulfides is important, since they are potential sources for byproduct TEs. Isocubanite has the highest Co contents). Chalcopyrite concentrates most Au. Bornite has the highest amounts of Se, Sn, and Te. Crystalline pyrite is a main carrier of Mn. Covellite after isocubanite is a host to the highest Sr, Ag, and Bi contents. Covellite after pyrite accumulates V, Ga and In. The isocubanite+chalcopyrite aggregates in altered gabrro contain the highest amounts of Ni, Zn, As, Mo, Cd, Sb (166 ppm), Tl, and Pb. The trace element geochemistry of sulfides is mainly controlled by local formation conditions. Submarine oxidation results in the formation of covellite and its enrichment in most trace elements relative to primary sulfides. This is a result of incorporation of seawater-derived elements and seawater-affected dissolution of accessory minerals (native gold, galena and clausthalite).
Petrogenesis of Mid-Atlantic Ridge Basalts at DSDP Leg 37 Holes 332A and 332B from Major and Trace Element Geochemistry
