The most important molybdenum mineralization of the Middle Dnipro province is limited to the Mesoarchean (3,1–2,9 Ga) Greenstone belts or structure (GSS). These are next occurrences: East-Sergiivka, Solone in the Sura GSS and Gannivka (district “Chervona”) in the Kryvyi Rih GSS. They have spatial combining or closeness with well-known gold deposits and occurrences: East-Sergiivka and Solone occurrences are located on the Eastern flanks of the Sergiivka and Balka Zolota deposits, respectively, in the sublatitudinal ore-bearing zones. From the West to the East gold mineralization gradually changes to gold-molybdenum and molybdenum. Gannivka molybdenum and Zhovtіanka gold occurrences are adjacent and localized in the submeridional zone of the Kryvyi Rih-Kremenchuk fault, and not spatially combined. However, similar to the etalon Lobash deposit, they can be combined as elements of a common ore-generating system related to a submeridional-extended granite massif undiscovered by erosion. In the process of previously performed geological surveys and related research, these ore prospects were studied and evaluated separately for each type of minerals. It is proposed to carry out further geological research in the context of spatially and genetically combining of gold and molybdenum mineralization. First of all it concerns deposits and occurrences of Sura GSS, where it is rationally to place two complex gold-molybdenum deposits: Sergiivka and Balka Zolota. This approach, which involves carrying out mining and exploration works on a joint scientific and technical base for molybdenum and gold ores, will undoubtedly have good economic efficiency and, ultimately, substantially increase the investment attractiveness of one or another deposit, facilitate the early launch industrial exploitation.

The article is devoted to molybdenum mineralization of the Eastern flank of Au-Mo Serhiivka deposit, located in the Middle Dnipro megablock of the Ukrainian Shield (USh). The generalized description of mineralization is performed on such important questions: discovery and exploration history, structure and composition of the host rocks, metamorphic and metasomatic alteration of rocks, structural position and localization conditions of molybdenum mineralization, ore composition, description of major ore minerals, morphology of mineralization and the most widespread views about its genesis. Molybdenum ores were discovered and named East-Serhiivka occurrence for the first time in 1974, before the discovery of gold mineralization, which occurred in 1985. Serhiivka deposit consists of two Mesoarchaean volcanic-plutonic associations (VPA) of different composition: the early mafic and the late felsic. The Eastern flank of the deposit, where the molybdenum mineralization is concentrated, is a structural knot similar to the lying letter “T”. It is formed by complex joint of the sub-latitudinal Serhiivka and sub-meridional Solone subvolcanic bodies and the East-Serhiivka massif of plagiogranitoids of the late VPA, which intrude basic rocks of early VPA. Molybdenum mineralization is localized in linearly elongated zones with a chaotic network of thin quartz, carbonate-quartz veinlets and poor (2–5 %) sulfide impregnation, including molybdenite. About 20 vein-impregnated ore zones have been recovered with up to 100–150 m thickness and 0,01 to 0,3 %, sometimes more than 1 % average molybdenum grade. The ores are subdivided into two major mineral types: 1) quartz-molybdenite; 2) quartz-sulfide-gold-molybdenite. The main components of ores molybdenite and native gold are associated with pyrite, chalcopyrite, magnetite, occasionally – pyrrhotite, arsenopyrite, scheelite, bismuth telluride, silver and others. Typical non-metallic minerals are quartz, carbonate, feldspar, chlorite, amphibole, biotite, sericite. It is supposed hydrothermal-metamorphogenic genesis of molybdenum (and gold) ores. Molybdenite and gold are rarely detected in the same intersections, which indicates separate genesis of these minerals. According to the accepted classification molybdenum mineralization is systemized as linear stockwork. Molybdenum ores of Serhiivka deposit are mostly considered as independent, separate from gold mineralization, potentially workable mine. It is the most prospective one in the Middle Dnipro region, USh and Ukraine in general. We suggest a comprehensive approach to studying, resource and reserves evaluation of Serhiivka deposit, taking into account the potential of both molybdenum and gold mineralization, as well as concentrations of rhenium and osmium in molybdenite. Geological exploration on the base of this approach will increase investment prospects of Serhiivka gold-molybdenum deposit.

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