Karakasi mines, Hermione, evolution of a Cyprus-type Cu-Zn deposit, Argolis, Greece

The Hermione Cyprus-type Cu-Zn deposits, Argolis, Greece, are hosted in Miocene ophiolites overlain by terrigenous turbidites with intercalations of limestones and manganiferous iron formations. The ore deposits form irregular lenticular or stratiform ore bodies, and veins. These ore bodies are associated with marginal volcanic activity in an arc-related Miocene palaeocontinent. Late N- to NNE-trending, sinistral, milky quartz-pyrite-calcite veins cut the host ophiolites. Alteration haloes of quartz-calcite, albite-sericite-chlorite, and chalcedony-epidote-clay minerals envelop the veins or develop in the lavas as concentric shells. The tellurium-bearing Cu-Zn mineralization is developed in two successive stages followed by a supergene stage. The Co-pyrite- chalcopyrite geothermometer defined two stages of sulphide equilibrium: 310° to 375°C (Stage I), and 220° to 260°C (Stage II). The calculated δ180 and \u3c5D compositions of the waters reflect the dominance of a magmatic component. The calculated δ3^Η^ fluid values also reveal a magmatic source for the sulphur, with minor contribution from submarine sediments, whereas tellurium is proposed to be derived from a mafic-ultramafic source. The physicochemical conditions of the hydrothermal fluids in the Hermione system were T=250°-300°C, P ~ 450 bars, pH =j61 to 530,fS2 HS aq) : = 10\u2711·6 to 10-12·4,fo2 = 10-35·5 to 10-38·3, logaH2S(aq) = 10\u273\u277 to 10\u2740, and loga = 10\u271 2·6 to 10-3·4