Problems of ore genesis
Due to the controversial nature of the problem of the genesis of ores of copper sandstones and shales, when developing prospecting and forecasting criteria and features, various geological factors are given decisive importance in the location and localization of mineralization, depending on the accepted genetic concept. In the sedimentary-diagenetic hypothesis, priority is given to such predictive and prospecting factors as stratigraphic, paleotectonic, paleogeographic, and mineralogical-geochemical control of mineralization, as well as metallogenic specialization of demolition areas. In the magmatogenic-hydrothermal hypothesis, the main ore-controlling role is assigned to deep faults, considered as ore-bearing channels, as well as folded structures and lithological composition of rocks. In the hydrogenic hypothesis, the main ore-localizing factors are considered to be the foci of discharge of metalliferous waters from artesian basins with developed red-colored formations, as well as various geochemical barriers. In the volcanogenic-sedimentary and hydrothermal-sedimentary hypotheses, mineralization is associated with volcanic apparatuses.
Based on the established patterns of placement and localization of ores of copper sandstones and shales, regardless of genetic concepts, the following geological forecasting and prospecting prerequisites, signs and criteria are outlined.
When identifying regions promising for the detection of mineralization such as coppery sandstones and shales, the most effective use of the following geological prospecting prerequisites is: the formation structure of sedimentary strata, the geotectonic position of territories, the geological age of formations and their stratigraphic division, paleogeography of epochs of accumulation of red rocks throughout the profile from sources of terrigenous material to basins of sedimentogenesis, metallogenic specialization of eroded rocks in the areas denudation, lithological and facies structure, and mineralogical and geochemical features of prospective stratigraphic levels in red-colored formations.
As noted in the previous sections, large deposits of copper-bearing sandstones and shales are represented by copper-bearing horizons composed of variegated carbonate-type formations accumulated in superimposed troughs of the outer belts of folded regions. in the late and final stages of their development, in intra—platform troughs - aulacogens and in the marginal parts of platforms near paleopods. Ore accumulations are located within the territories of the distribution of red flowers, located inside their strata or in marginal zones. The ores are localized in lagoon-delta and organically enriched bay-lagoon and shallow coastal-marine sandy and carbonate-clay deposits. Industrial mineralization is associated with elements of paleotectonics, coinciding with paleopods, domes, and sedimentation mulches. The mineralogical and geochemical prerequisites consist in the detection of copper mineralization in sedimentary strata, a relatively high content of copper and related components in them, as well as in the establishment of primary mineral and geochemical zonation. The ores are characterized by a pronounced stratification, which makes it possible to identify promising stratigraphic levels, taking into account the possibility of multi-tiered mining development.
Based on the analysis of geological prospecting prerequisites, the formation type of deposits (copper sandstones or shales) is determined and, by analogy with known deposits, a quantitative forecast assessment of territories by category is given. https://ambo.market/