Türkiye Jeoloji Bülteni

Geology, Alteration and Geochemical Characteristics of Inlice (Konya-Turkey) High Sulphidation Epithermal Gold Deposit

Abstract: Inlice high sulphidation epithermal gold deposit is located in the Erenlerdağ-Alacadağ Volcanic Complex(EAVC), approximately 40 km southwest of Konya city centre. The volcanic and volcano-sedimentary rocks seen inthe study area are andesite, block and ash flow, basaltic andesite lava flow and andesite lava flow, from oldest to youngest. The youngest units unconformably covering the volcanic and volcano-sedimentary rocks are talus andalluvium. Four different alteration zones in the andesites moving from the centre of the alteration toward freshrock are i) silicified zones (consisting of vuggy-sugary and chalcedonic/opaline quartz veins), ii) advanced argillicalteration, iii) intermediate argillic and iv) propylitic alteration. In addition, a potassic alteration zone consisting of magnetite, quartz, biotite and anhydrite was identified in the deep part of the Merkez Zone. The mineralisationis commonly represented by pyrite, and to a lesser extent enargite, chalcopyrite, covellite, chalcocite, sphaleriteand marcasite. Petrographically, the fine-grained gold grains (between 2-6 µm) are only observed in areas where sulphide minerals are oxidised.The degree of geochemical variation in the alteration zones decreases from silicified zones to propylitic alteration,and this variation is largely consistent with the mineralogies observed in these zones. Moreover, enrichment in As,Sb, Bi, Ag and Au, and depletion in Zn and Ni are especially notable from fresh/least altered andesites towards advanced argillic alteration and silicified zones. In addition, studies showed that the high Pb value in chalcedonic/opaline textured quartz veins and low Rb/Sr value in advanced argillic alteration and silicified zones can be used asa geochemical guide, at least for the Inlice region.