Gülay Sezerer Kuru

Economic Geologist, QP, CPG, EFG, UMREK-CP

Preliminary Findings on Epithermal Au Mineralization of Bayındır, Kaman, Kırşehir, Turkey

The Bayındır epitheımal Au deposit, Kaman, Ku-şehir, Turkey, has historic and active fluorite mining records. The present work aims at understanding of petrographic and alteration clıaracteristics of host rocks and quartz veins, and detennining the microthemometric properties of gold mineralization. Kırşehir metamoıphic rocks, consisting of schist, gneiss, quartzite, marble, and migmatites, form the basement in the area. The metamoıphic rocks are intıuded by Late Cretaceous-Paleocene plutonic rocks composed of syenite, alkali feldspar gravite, monzonite, and diorite. The metamoıphic and intrusive rocks are unconformably overlain by Tertiaıy continental to slıallow marine sedimentaıy sequences. The fluorite mine and Au mineralization is hosted by quartz-clay–altered and moderately silicified syenite poplıyıy. The purple, light puıple to green fluorite is hosted by subparallel quartz-bante veins within clay-serite–altered syenite porphyry. The alteration and fluorite mineralization appears to be associated with emplacement of aplitic syenite into the syenite poıphyıy. The gold mineralization occurs as NW-SE– and NE-SW–trending quartz and quartz-fluorite veins cutting the altered syenite porphyıy and as disseminated to stockwork-type veinlets, plus as cementing the fault breccia. The quartz veins display banded, comb quartz textures common in low-sulfidation epithennal gold deposits. The veins are 5 to 35 cm thick and contain 3 ppm average Au. The gold mineralization is locally accompanied by pyrite, pyrrhotite, chalcopyrite, sphalerite, galena, arsenopyrite, and iron oxihydroxides. Microthermometric analyses were canied out on quartz crystals. The fluid inclusion pegtrography enabled the recognition of three types of inclusions: (1) three-phase inclusions (FIA1), (2) inclusions with CO2 (FIA2), and (3) two-phase (liquid-gas) inclusions (FIA3). The lıomogenization temperatures are as follows: FIA1-260°C, FIAlb-310°C, FIA2a-380°C, FIA2b-337°C, FIA3a-270° C, FIA3b-224°C, and FIA3c-190°C. The salinity values range between 6 and 20 % NaC1 equiv. The CO2 gas phase and relatively high homogenization temperatures and salinity suggest that there may have been a magmatic fluid contribution.

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