Mineralogical Journal

03-24

Authors: V.I. Pavlyshyn

This article discusses the state of mineralogical research in independent Ukraine in the period from 1991 to 2021. The main achievements in various Earth sciences disciplines, including regional, systematic and genetic mineralogy, the chemistry and physics of minerals, mineralogical crystallography, bio- and nanomeralogy, experimental, space and applied mineralogy, and technical studies are considered. Four world-famous research groups and disciplines are notable. They are: i) regional and mineralogical led by academician Yevhen Lazarenko, ii) thermobarogeochemical studies led by professor Mykola Yermakov, iii) crystal chemistry led by academician Oleksandr Povarennykh, and iv) mineral physics led by professors Ivan Matyash, Oleksiy Platonov, and Arkady Tarashchan. Problems facing mineralogy including personnel, scientific, and applied are briefly discussed in the "Conclusion" section.

42-53

Authors: H.O. Kulchytska, V.M. Belskyi, O.A. Vyshnevskyi, S.G. Kryvdik

A millimeter-sized fluorite crystal found in leucocratic syenite of the Velykovyska massif on the Ukrainian Shield became the object of study. This is a crystal of irregular shape with smoothed corners, broken by a system of contraction cracks inlaid with basnäsite-(Ce). The latter is characterized by a REE content of 57± 5 wt. %, CaO - of 3.3 ± 0.25 wt. % and Ce2O3 : : La2O3 : Nd2O3 ratio of 6 : 4 : 1. A detailed study using microprobe JXA-733 and an electron microscope JSM-6700F, equipped with EDS JED-2300, showed the presence of other mineral phases in the inlays. The middle of the cracks is filled with ferrous aluminosilicate without REE. On the opposite side, a siderite rim was found around the basnäsite and single crystals of calcite were found nearby in the fluorite. Fluorite inlaid with basnäsite is considered as a product of crystallization of the carbonate-fluoride melt drop that separated from silicate melt due to their immiscibility. Subsequent stratification of the melt inside the drop led to formation of fluorite rimmed by carbonates of REE and Fe and displaced to the cracks of Fe-aluminosilicate. Crystallization of the separated carbonate-fluoride melt took place in an isolated volume without any exchange of components with the surrounding Na-K-feldspar. Fluorite, as well as carbonates and mica are less common in the Velykovyska massif than other similar syenite massifs on the Ukrainian Shield. It is assumed that this is caused by the high temperature of the syenite melt, which contributed to evaporation of volatile components (F2, CO2, H2O), and by processes of liquation. The immiscibility between salt and silicate melts contributed to formation of drops of carbonatefluoride melt and their movement to the apical parts of the massif and outside. The discovery of inlaid fluorite increases the prospects of the Velykovyska massif for the detection of REE ore occurrences in syenites and surrounding rocks. In addition, the finding confirms the existence of carbonate-fluoride melts in nature. These melts are paternal for fluorite-carbonate veins with REE mineralization.

62-72

Authors: L.M. Stepanyuk, T.I. Dovbush, V.M. Belskyi, O.B. Vysotsky, O.V. Bilan, I.M. Kotvitska

The Haisyn complex rocks (sobites (Shcherbakov, 2005)), consisting of diorite-like rocks and amphibolites, which biotite granites develop, is outcroping near the village of Shumyliv along the South Bug river and in an abandoned open pit mine (on South of Shumyliv). The rocks are characterized by high magnetization according to magnetic survey results. A linear magnetic anomaly extends in the north-east direction (NE 69º) with a distance of more than 35 km. Entin et al. (2019) proposed that this magnetic anomaly is caused by a dyke with a felsic or intermediate composition. The internal structure of accessory zircon crystals from quartz diorite and granite were studied. In both types of rocks, zircon crystals are complex and consist of three different generations. The first generation consists of fractured nuclei of light pink color, which apparently grew in rims of zircon of the 2nd and/or 3rd generation. Zircon of the second generation is light pink in color. It forms rims around the first generation of zircon, but also occasionally occurs the interior core areas of crystals. Third generation zircon forms rims around the first two generation zircons, or growth episodes. As usually, the heads of crystals have a light brown to brown color. The age of formation of monazite in the granite and titanite in the quartz diorite was determined by the uranium-lead isotope method. The two endogenous geological processes have ages of 2049 ± 6 million years and 2005 ± 2 million years, respectively.

85-90

Authors: L.V. Shumlyanskyy, M. Hofmann, B.V. Borodynya, G.V. Artemenko

Results of U-Pb dating of zircons from the Middle Devonian sandstones of the Mykolaivka Suite, taken from the junction zone between the Azov Domain of the Ukrainian Shield and Donets basin, are reported. The rocks are taken from a drill core and they occur beneath a 210 m sequence of mafic and ultramafic volcanic rocks that belong to the Antonivka (D2-3) and Mykolaivka (D2) suites. In total, 28 U-Pb isotope analyses were performed. The predominant population (18 grains) of zircons yielded a concordant age of 2075 ± 9 Ma (MSWD = 0.64). The second largest population consists of zircon crystals with concordant to nearly concordant ages ranging from 3130 to 2830 Ma. These results indicate a local origin for the detrital zircons. The occurrence of coarse-grained terrigenous sediments, derived from local rock sources, indicates significant erosion of the Precambrian basement that might have been caused by differential vertical movements during the Middle Devonian period. In the Donets basin, rifting and uplift started ca. 10 Myr before that of other parts of the Prypyat-Dnieper-Donets Paleorift.

104-112

Authors: M.N. Daragan, O.V. Mytrokhyn

The results of a petrographic investigation of 80 stone spheroids from a Scythian burial near the village of Krasnyi Podol are presented. The results indicate that all the stone spheroids were made from the same type of metamorphic rocks, namely actinolitites. The petrographic characteristics of the actinolitites indicate that the initial raw material was obtained from a single deposit. The Middle-Dnieper Region of the Ukrainian Precambrian Shield is considered as the probable place for their mining. The authors do not exclude that the natural outcrops of actinolitites could initially have had spherical jointing due to the processes of physical weathering. This jointing provided an opportunity to obtain roughly spherical blanks directly at the mining site. But most of the studied stone spheroids have got their spherical shape by artificial firing. The latter manifests itself in the surface desquamation and oxidation of the outer parts of the stone blanks. At least some of the stone blanks were ground to varying degrees after the firing. Stone abrasive materials were used for this purpose. The listed facts allow us to postulate that stone spheroids found in the Krasnyi Podol burial illustrate the successive stages of their processing. The owner of the stone spheroids likely possessed special knowledge regarding their mining, production and use.