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  • Trace element systematics o...
    Keith, Manuel; Häckel, Florian; Haase, Karsten M.; Schwarz-Schampera, Ulrich; Klemd, Reiner

    Ore geology reviews, January 2016, 2016-01-00, Letnik: 72
    Journal Article

    Submarine hydrothermal sulfide ores occur at mid-ocean ridges, intra-oceanic arcs and in back-arc basins associated with host rocks of highly variable composition. Pyrite is the dominant sulfide mineral in most samples presented within this study, and thus the trace element composition of pyrite may reflect the different metal sources and precipitation processes. Here, we report on a systematic study of minor and trace element contents in pyrite from active and inactive submarine hydrothermal vent fields at different plate-tectonic settings including the Indian and Mid-Atlantic Ridges, the Tonga–Kermadec intra-oceanic arc, the Lau back-arc and the central Okinawa Trough. Our results show that the trace element contents of pyrite from different locations vary significantly but for most elements without any systematic correlation to the concentration in the magmatic host rocks. Only As appears to be depleted in pyrite from ultramafic-hosted vent systems that are affected by serpentinization. These As depleted pyrites preferentially host Au 0 micro- or nano-particles. Bismuth is enriched in pyrite from hydrothermal systems that contain a sedimentary component and micro-inclusions of sphalerite are either due to fluid–sediment interaction or phase-separated fluid venting. Pyrites from individual locations have highly variable concentrations of elements like Au, Co, Cu, Se, Mo, Ag and Sb that are most likely related to fluid evolution and changes in fluid composition. Sub-seafloor hydrothermal fluid–seawater mixing influences the distribution of Au, Co, Cu, Se and Mo in pyrite. Elements like Au, Ag, Sb and Pb often have a characteristic affinity to As, while Cd correlates closely with Zn. A magmatic volatile contribution to the Hine Hina hydrothermal system may result in the precipitation of Cu-enriched pyrite. Our results show that the concentrations of most trace metals in pyrite are a function of the physicochemical parameters of the fluid phase rather than a reflection of the magmatic host rock composition. •Global data base of trace element pyrite chemistry.•Most trace elements in hydrothermal pyrite are independent of the magmatic host rock composition.•Fluid–sediment interaction and serpentinization processes affect the composition of hydrothermal pyrite.•Fluid temperature variations control the trace element composition of pyrite.•Phase separation and magmatic volatiles also influence the pyrite composition.