@article{3068461,
    title = "Trace Element Signatures in Pyrite and Marcasite From Shallow Marine Island Arc-Related Hydrothermal Vents, Calypso Vents, New Zealand, and Paleochori Bay, Greece",
    author = "Nestmeyer, M. and Keith, M. and Haase, K.M. and Klemd, R. and Voudouris, P. and Schwarz-Schampera, U. and Strauss, H. and Kati, M. and Magganas, A.",
    journal = "FRONTIERS IN EARTH SCIENCE",
    year = "2021",
    volume = "9",
    publisher = "Frontiers Media S.A",
    doi = "10.3389/feart.2021.641654",
    keywords = "Distillation;  Hot springs;  Pyrites;  Seawater;  Sediments;  Steam condensers;  Sulfide minerals;  Sulfur compounds;  Textures;  Trace elements, Element fractionation;  Elevated concentrations;  Epithermal systems;  Hydrothermal mineralization;  Microbial sulphate reduction;  Seasonal migration;  Thermochemical reduction;  Volcaniclastic sediments, Mineralogy, epithermal deposit;  hydrothermal vent;  mineralization;  pyrite;  shallow water;  sulfur isotope;  trace element;  volcaniclastic deposit, Greece;  New Zealand",
    abstract = "Fluid conditions of shallow marine hydrothermal vent sites (<200 mbsl) in island arcs resemble those of subaerial epithermal systems. This leads to a distinct mineralization-style compared to deeper arc/back-arc (>200 mbsl) and mid-ocean ridge-related environments (>2000 mbsl). At Calypso Vents in the Bay of Plenty and Paleochori Bay at the coast of Milos Island, fluids with temperatures <200°C are emitted through volcaniclastic sediments in water depths <200 mbsl. The hydrothermal mineralization from these fluids is dominated by pyrite and marcasite showing diverse textures, including colloform alternations, semi-massive occurrences surrounding detrital grains, vein-type pyrite, and disseminated fine-grained assemblages. Pyrite and marcasite from Calypso SE show elevated concentrations of volatile elements (e.g., As, Sb, Tl, Hg) implying a vapor-rich fluid phase. By contrast, elements like Zn, Ag, and Pb are enriched in hydrothermal pyrite and marcasite from Calypso SW, indicating a high-Cl liquid-dominated fluid discharge. Hence, vapor-liquid element fractionation induced by fluid boiling is preserved in the seafloor mineralization at Calypso Vents. Hydrothermal mineralization at very shallow vent sites (<10 mbsl), like Paleochori Bay, are affected by wave action causing a seasonal migration of the seawater-fluid interface in the sediment cover. The δ34S composition of native S crusts and crystalline S (0.7–6.7‰) is indicative for host rock leaching and thermochemical reduction of seawater sulphate. By contrast, the highly negative δ34S signature of native S globules in sediments (−7.6 to −9.1‰) is related to microbial sulphate reduction or a subordinate magmatic fluid influx. Alunite-jarosite alteration (Paleochori Bay) and a mineral assemblage consisting of orpiment, realgar, and native S (Calypso Vents) may also suggest a contribution by an oxidised (sulphate-rich) low pH fluid of potential magmatic origin. However, fluid boiling is pervasive at Calypso Vents and Paleochori Bay, and the condensation of vapor-rich fluids in a steam-heated environment may produce a similar alteration and mineralization assemblage without a significant magmatic fluid influx, as known from some subaerial epithermal systems. © Copyright © 2021 Nestmeyer, Keith, Haase, Klemd, Voudouris, Schwarz-Schampera, Strauss, Kati and Magganas."
}