Mineralogical Journal

3-13

Authors: I.M. Naumko, L.M. Stepanyuk, H.O. Zankovych, O.B. Vysotsky, I.M. Kotvitska

Тhe strontium isotope composition was determined for the first time for vein calcite in Oligocene deposits of the flysh formation, north-western part of the Krosno structural-facial unit of the Ukrainian Carpathians. The measured 87Sr/86Sr ratios vary from 0.70 864 to 0.71 030 and do not show any correlation with the location of veins in outcrops, sampling point, composition and age of host rock. They are plotted within the interval characteristic of continental crustal rocks and almost completely coincide with 87Sr/86Sr values (0.708—0.7095) typical of present-day seawater. At the same time they clearly differ from 87Sr/86Sr mantle values as well as values of continental carbonate rocks. It can indicate fundamentally different sources for these fluids and fluids from mantle and continental carbonate rocks. Veinlet-disseminated mineralization is treated to be associated with tectonic activization, influx of deep fluids and formation of mineral paragenesis in veinlets and disseminations by healing of cracks in zones of fracturing and crushing. Therefore fluids are enriched in radiogenic 87Sr up to typically crustal values, what reflects the essential importance of the crustal material in calcite formation. The range of values 87Sr/86Sr ratios obtained is similar to those determined for oil samples of collected from a number of pre-Carpathian fields (0.7084—0.7109). This fact additionaly proves the conjuncting nature of processes of vein filling, dissemination and of hydrocarbon formation within the Carpathian region. It also indicates common crustal source of deep migrating hydrocarbonrich fluids, which inflow into the so-called zones of the development of sealed reservoirs promotes formation of oil and gas fields in favorable geodynamic conditions.

20-31

Authors: K.V. Repina, T.P. Volkova, V.M. Zagnitko, V.S. Moroz, L.I. Proskurka

The article presents results of geochemical features of carbonate rocks and ore associations of the zone between the Donbas and the Priazov megablock of the Ukrainian Shield, in particular, the Novotroitsk deposit and adjacent areas. The Novotroitsk deposit consists of a number of blocks bordered by faults from all sides. The northern boundary of the deposit runs along the western ending of the South-Volnovakha fault zone. In the south, the site is bordered by sub-latitudinal Dolomite fault, and the western border coincides with the Velyko-Anadol fault. Ore mineralization in the deposit is represented by Cu, Pb, Zn, Mo and other sulfides. Sulfide mineralization occurs both in veins and as phenocrysts of pyrite, chalcopyrite, bornite, arsenopyrite, chalcosine in the groundmass of carbonate rocks. In quartz veins and breccia zones phenocrysts of molybdenite are present in association with chalcopyrite, galena, sphalerite. Fluorite mineralization was found in carbonate rocks of single wells of the Novotroitsk deposit, that are located near the Velyko-Anadol fault. Isotope-geochemical studies of carbonate veins, veinlets and host rocks, with taking into account various geochemical and mineralogical features, made it possible to identify several groups of carbonate paragenesis that correspond to the mineral formation stages. The first stage of mineral formation resulted from the dynamics of the marine regime occurred within the zone between the Donbas with the Priazov block in the Carboniferous. Samples of ordinary limestones of the Novotroitsk deposit have composition of stable oxygen and carbon isotopes that is typical of carbonates. The presence of negative δ13C values indicates a change towards more recovery conditions of marine regime, which is characteristic of the Early Visean C1 va. The second and third stages of mineral formation are associated with phases of tectonic-magmatic activization (during Devonian and Permian- Triassic). In general, medium- and low-temperature ore-forming hydrothermals prevailed. With increasing temperature, water was evaporates from carbonates, interacted with the host rocks and turned into a mineral-forming fluid. On passing through permeable fractured, brecciated carbonate rocks, it promoted the redeposition of carbonate material and the formation of ore minerals. The range of changes in the isotopic composition of these carbonates varies widely depending on the mineral formation temperature. The subsequent stages of mineral formation occurred during the processes of multiple dissolution-redeposition of carbonates. These carbonates are associated with tectonic block dislocations of the zone and the circulation of solutions in permeable areas. In this case, abiogenic redistribution of carbon isotopes occurred, when the heavy 13С isotope was accumulated in residual carbonates, and lighter fractions removed from mineralization zones.

46-62

Authors: L.M. Stepanyuk, L. Shumlyanskyy, A. Hoffmann, M. Hofmann, A. Kovalick, A. Bekker

Convincing geochronological data regarding the time of accumulation of deposits that fill the Kryvyi Rih structure, Ukraine, are still lacking, and in the current hronostratigraphic chart they are attributed to the Paleoproterozoic. Thus, dating of detrital minerals that allows determination of the maximum age of sedimentation, is especially important. The paper presents results of the U-Pb LA-ICP-MS dating of zircons from two quartzite and two phyllite samples from the Kryvyi Rih structure. Three of these samples are from metaterrigenous sediments of the Skelyuvatka Suite, whereas one sample was collected from the Saksagan Suite. The study was carried out applying LA-ICP-MS method. Most of the obtained results are highly discordant due to the high degree of metamictization caused by high concentrations of Th and U. Only results of U-Pb dating with the degree of concordance higher than 80% were further considered. Zircons from all four samples yielded ages that fall within a narrow interval of 2.9-3.3 Ga that corresponds to the age of the basement rocks of the Middle Dnieper Domain that underlies the Kryvyi Rih structure. The youngest measured age of ca. 2.9 Ga corresponds to the maximum sedimentation age of the Saksagan and Skelyuvatka Suites. Within error this age also corresponds to the age of detrital monazite (2.85 Ga) found earlier in sandstones of the Skelyuvatka Suite. It is somewhat younger than the age of metamorphosed basalts of the New Kryvyi Rih Suite (2.96 Ga), whose outpouring indicated initial formation of the Kryvyi Rih structure. The earlyer defined age of granites of the Hannivka massif (2.68 Ga) that cut through deposits of the New Kryvyi Rih and Saksagan suites, also confirms their at least Neoarchean age. Currently available geochronological data indicate Meso- to Neoarchean deposition age of the New Kryvyi Rih, Skelyuvatka and Saksagan suites.

74-89

Authors: О.М. Ponomarenko, E.М. Sheremet, М.А. Kоzar, L.V. Shpyliovuj, S.М. Strekozov, I.Yu. Nikolaev, S.G. Kryvdik,L.D. Sietaia

The geological structure of the Mazurov, Azov, and Anadol deposits (Ukrainian Shield, Eastern Azov region), the structural and tectonic conditions of ore localization and their mineralogical and geochemical types are presented. The distribution and concentration of rare elements including rare earths (REE) in ore bodies is given. The balance reserves of ores and the estimated resources of zirconium oxides, REE, niobium and tantalum in these deposits have been calculated. The technological aspects of ore enrichment and processing are considered. The results of the calculation of the expected technical and economic indicators of the development of deposits in the mining unit are presented. The feasibility and investment attractiveness of the creation of a mining association in the southeastern Azov region is economically justified. On the basis of the Donetsk chemical and metallurgical plant (DCMP, in the Donske, Volnovakha district) the creation of an industrial complex (mineral deposits association) is proposed, capable of processing stale tails of DCMP and ores of the Mazurovka deposit by means of "Tantalum-niobium enterprise" and its structural unit "Rare-earth mining enterprise" targeted for mining ores of Azov and Anadol deposits. The objective of the industrial complex is to carry out a complete closed cycle of work within the above mentioned ore deposits, starting with exploration, development, enrichment, production of commercial products in the form of concentrates, and ending with their deep processing to obtain the necessary final products, as well as their implementation in domestic and foreign markets. The creation of additional small exploration and production enterprises for the extraction of other types of raw materials is envisaged that ensure the work of technological processes of the industrial complex. The mineral deposits’ association will be the base enterprise for the creation of the REE industry of Ukraine, ensuring the use of strategic types of mineral raw materials — rare metals — as one of the important indicators of the level of development of the country’s economy.