Investiga on ore forming solutions in Karadere-İvrindi (Balikesir) low sulfidated epitermal gold-silver mine

A number of epithermal Au-Ag (high and low sulfidation/HS-LS), porphyry Au-Cu-Mo and base metal skarn deposits and mineralization are associated with Tertiary calc-alkaline magmatism in Western Anatolia. The Karadere deposit can be considered an Low Sulfidation Epithermal Deposit and mineralization area consists of Triassic metamorphic basement, Oligo-Miocene Kozak granodiorite and early-middle Miocene volcanic-subvolcanic rocks. Gold and silver mineralization are hosted by quartz veins confined to high to moderate angle normal faults traversing the andesitic domes, and overlying agglomerate-volcanic breccia in the early-middle Miocene volcanic, subvolcanic rocks. The mineralized veins are composed of sugary quartz and occasional bladed to brecciated textures. Fluid inclusion studies conducted of in quartz minerals showed that; the hydrothermal fluid is interpreted to have evolved during at least two stages: i) an early fluid, trapped in sugary quartz, with moderate ~7 eq. wt% NaCl salinity, and temperature is about 300°C; and ii) late-stage fluid trapped in recrystallized quartz with low ~0.3 eq. wt% NaCl salinity, and temperature is 180°C. The presence of bladed texture and of co-existing liquid-rich and vapor-rich inclusions in the ore-stage indicates a boiling event in the Karadere gold mineralization. The isotope results showed that; sulfur isotope results measured from sulfur mineral is are between 1.4‰ and these values indicate that the sulfur possibly originated from magmatic sources. Oxygen and hydrogen isotope geochemistry of quartz show that the ore forming solutions are formed mainly by the warming of the meteoric waters at deep depths and gain an isotopic composition which representing the meteoric-magmatic water due to passing through the magmatic-origin rocks.