Mineralogical features and formation conditions of the Zafar copper-gold deposit (Lesser Caucasus, Azerbaijan)

Abstract


 
 
 The Zafar copper-gold deposit is located in Gadabay ore district, 3.5 km northwest of the Gadabay gold mine and 2 km southwest of the Ugur mine. This newly discovered cop- per-gold deposit contains 6.8 million tonnes of measured resource (0.5% Cu, 0.4 ppm Au and 0.6 % Zn, according to Zafar JORC Mineral Resource Estimate Update Report 2022). SEM analyses were carried out via «JSM-6610LV Scanning Electron Microscope» manufactured by JEOL USA. Petrographic studies were carried out using a ZEISS microscope with ZEN 2.3 imaging software. In this stage of the research we defined mineralogical properties of rocks and gold bearing mineralization type. According to the SEM analysis, gold mineralization formed in the pyrite, chalcopyrite (their derivatives too) stages. Based on the mineralogical study, the main ore minerals consist of pyrite, chalcopyrite, enargite, sphalerite, arsenopyrite, galena, baryte, pyrrhotite and sternbergite (silver mineral) based on polished section results. The main gangue minerals are quartz, baryte and carbonate. Quartz crystals in bands are euhedral to anhedral, vary in size from microcrystalline to coarse grained. The Zafar deposit was formed by two events. The first event is the formation of the «massive pyrite» related to small Later Bajocian sub-volcanic rhyolite-dacite bodies. The second event is assumed to be «copper-pyrite» and «copper-zinc» mineralization and is reported to be formed by the post-magmatic activity of the Gadabay diorite intrusive. This study has demonstrated new ideas about the formation and genesis of the Zafar deposit. The K-rich calc-alkaline composition of various rocks indicates that subduction-related magmatism occurring along Lok-Karabakh belt had a crucial role in forming this deposit. The information given in the article is of practical importance for regional predictive metallogenic constructions, prospecting and evaluation of epithermal Au–Cu deposits.