Geological, mineralogical, petrographical and geochemical properties of the dakhkasaman (North-West Azerbaijan) polymetallic gold deposit

It was aimed to investigate the geological, mineralogical, petrographic and geochemical characteristics of Dakhkasaman (North-West Azerbaijan) polymetallic gold deposit, one of the most important gold copper deposits in the west of Azerbaijan in this study. Dakhkasaman polymetallic Au deposit is located on the northwest slope of the Shahdag Mountain Range in the Lesser Caucasus region and just west of Ağstafa Province, northwest of Azerbaijan. Dakhkasaman Village and the mineralization zone of the same name are in the northwest of the structural-metallogenic region of Lök-Karabagh. Located in the Kazakh graben in the structural metallogenic region of the Lök-Karabagh region, the area covering Dağkesemen polymetallic gold deposit, and its surrounding formations has a very complex geological structure. Dakhkasaman polymetallic gold deposit is located in the Lesser Caucasus region which is one of the world's major gold and copper Tethyan Tectonic Belt province in the Pakistan, Iran, Azerbaijan, Georgia and extending to Turkey. Dakhkasaman polymetallic gold deposit on the spot were discovered in the early 19th century, but no production activity was carried out. During the Soviet period, geological, stratigraphic and geochemical studies were carried out. Azergold, who has been conducting research in the region since 2016, detected a significant amount of gold and silver, lead, zinc copper in the deposit. Due to the tectonic structure of the Dakhkasaman mine bad and especially the tectonic structure of the Kazakh graben and the magmatic activities in the region are more common in Cretaceous aged units, these units are represented by Upper Cretaceous clastic-carbonate, sedimentary-pyroclastic and volcanogenic rocks. Based on the petrographic and XRD studies the ore minerals are sphalerite, galenite, chalcopyrite, pyrite, bornite, digenite, cerussite, covellite, chalcocite, malachite, azurite, hematite, magnetite, ilmenite, and anglesite as the identified gangue minerals are quartz, calcite, dolomite, gypsum and fluorite. Plagioclase, chlorite, mica/illite, serpentine mineral, alkali-feldspar and clay minerals were commonly observed among the rocks and alteration samples related to mineralization. Among the main oxides in Dağkesemen polymetallic Au deposit, SiO2 has 57.1%, Al2O3 3.84%, Fe2O3 9.73%, CaO 1.46%, MgO 1.28%, K2O 1.08% and Na2O 0.47% average values. Average 190 ppb Au, 16.2 ppm Ag, 1.54% Cu, 8.31% Zn, 4.39% Pb, Cd reaching 2150 ppm, V reaching 189 ppm, Ba reaching 104 ppm and As reaching 148 ppm in the mineralization is important. Accordingly, Dağkesemen deposit was evaluated as a polymetallic Au deposit with an Au content of up to 1 ppm and an Ag content exceeding 50 ppm together with Fe, Cu, Pb, Zn and Cd. According to the S isotope analysis of sulfidic minerals collected from Dakhkasaman (North-West Azerbaijan) polymetallic Au deposit, δ34S values vary between -3.3 ‰ to -1.8 ‰ for chalcopyrite, -0.6 ‰ to -4.0 ‰ for sphalerite, -2.5 ‰ to -1.0 ‰ for pyrite and -3.1 to – 5.0 for galenites. The calculated δ34SH2S values of chalcopyrite, sphalerite, pyrite and galenite from ore are as follows: -3.1 ‰ to -1.6 ‰ for chalcopyrite, -2.7 ‰ to -0.8 ‰ for galenite, -4.4 ‰ to -1.0 ‰ for sphalerite, -2.5 ‰ for pyrites. According to the S isotope analysis performed, the solutions forming the mineralization indicate magmatic origin. Final Ice Melting Temperature (Tm-ice °C) and Homogenization Temperature (Th°C) of liquid inclusions were measured in microthermometric measurements made on sphalerite and quartz samples collected from Dakhkasaman polymetallic Au deposit. In the measurements made in SG-type inclusions, Tm-ice values were found to be between -0.4 and -4.1 °C. The final ice melting temperatures (Tm-ice) obtained were evaluated according to Bodnar's (1993) equation and % NaCl equivalent salinities were calculated. In microthermometric measurements, the homogenization temperatures (Th°C) of SG-type inclusions vary between 201 °C and 281.2 °C, and the salinities corresponding to Tm-ice vary between 0.7 % and 6.6 % NaCl and these data show Dakhkasaman polymetallic Au deposit were formed under meso-epithermal conditions. Keywords: Azerbaijan, Dakhkasaman, Geochemistry, Gold, Kazak Graben, Polymetallic, hydrothermal