Patterns of distribution and peculiarities of formation of gold ore mineralization in metamorphic and black shale strata of Azerbaijan

The article discusses the patterns of distribution and the peculiarities of the formation of gold mineralization in the metamorphic and black shale strata of Azerbaijan in order to determine metallogenic specialization. Mineragenic analysis of gold-bearing territories was carried out using numerous data of quantitative studies of the substance of the studied objects: ore-bearing sedimentary and metamorphic strata, ore bodies and processes ore genesis. The spatio-temporal relationships of gold-bearing mineralization of various material-morphological types, conditioned by lithological-geochemical conditions and time of manifestation of lithogenetic processes and metamorphism, have been determined. In the petrographic description of the studied rocks, two groups were distinguished: Early Paleozoic crystalline shales and Upper Paleozoic sedimentary rocks. It has been determined that the shales were initially enriched with gold during sedimentogenesis. In subsequent processes of metamorphism, part of the gold was removed from the shale and redeposited, and thus spread unevenly. Favourable zones of ore deposition could lead to the concentration of gold in shales in industrial conditions. In the studied crystalline shales, attention is drawn to the contents of Pt and Pd, the commonest elements of the platinum group. The Pt content in shales is 0.08 g / T on average, while the clarke for clayey shales is 0.03 g / t, i. e. almost three times higher than the clarke. Even more contrasting is the content of the platinum group element, palladium. In shales, the Pd content is 0.046 g / t. These data, together with the high gold content in the shales, can be considered as a typomorphic geochemical feature of the crystalline shales of the Asrikçay massif of the pre-Jurassic basement of the Lesser Caucasus. The studies have shown that during the formation of gold mineralization in metamorphic and black shale strata, an important role was played by the features of the host carbonaceous sedimentary complexes, which served as additional sources of noble and associated metals. Some of the ore elements in unaltered sediments have their own mineral forms.