Mineralogical Journal

3-11

Authors: V.I. Pavlyshyn, D.K. Voznyak,

The Volyn chamber pegmatites in Korosten granites are continued to the zone in which the products of degassing of acid and basic fusions entered in chambers of free growth of crystals over a long period of time. Topaz is the most famous mineral in the Volynian pegmatites. The characteristic morphology of topaz from the Volynian pegmatites is of ten flattening of the crystals in a direction perpendicular to the prism face {110}. As a result, the extremal symmetry is not perfect (dissymmetrization). On the example of dissymmetrized topaz crystals, such a collision is clearly defined: the concept of a crystal, in the case of its dissymmetrization, loses the value of a mineral individual, acquires a heterogeneous structure, which corresponds to the loss of the main properties of the crystal — homogeneity and anisotropy. For such dissymmetrized crystals the term "anomalous monocrystal" is proposed — a visually homogeneous crystal whose individual growth pyramids belong to different spatial symmetry groups at the micro level. The theme "Fluid flows and morphology of mica and topaz" in the chamber pegmatites of Volyn’ is presented comprehensively through the prism of symmetry-dissymmetry. The conclusion is that the columnar crystals of Li-Fe mica (sometimes without pinacoid {001}) are a consequence of the active interaction of two symmetries (the Curie principle) — the fluid flow and the crystal. Dissymmetrization of topaz crystals was carried out under the conditions of one-sided flow of deep fluid flows with symmetry of the "arrow".

24-35

Authors: D.K. Voznyak, V.O. Syomka, V.M. Belskyi

By convention, the information about the PT-parameters of mineral formation obtained by fluid inclusions study is classified into basic and additional. The former is based on studying the genetic nature of inclusions of homogeneous and heterogeneous capture that are homogeneous and heterogeneous in origin (according to V.A. Kalyuzhnyi). It forms predominant data set on the PT-parameters of mineral formation. The latter, additional information substantially supplements the basic information. It is obtained by studying inclusions refilling and cracking , variations in chemical composition of the mineral substance re-deposited on the walls of the inclusion during the acquisition of the equilibrium form of the negative crystal as well as the study of inclusions with "cap". These are inclusions of new type that have indicator (typomorphic) value. It should be noted that, in general, there are rare examples of application of volatile components inclusions that are homogeneous in origin for reconstruction of PT-conditions of mineral formation. It is not easy to find a point on the isochore that corresponds to the inclusion content and it should be done in separate way by determination of either temperature or pressure. Sometimes there are cases of direct determination of the RT-condition of mineral formation. The solution of such cases might be done through estimation of fluid pressure at formation of metamorphic mineral; determination of the overheating degree of inclusions in quartz from Volyn chamber pegmatites and the depth of pegmatites formation; revealing the role of high-thermobaric CO2 fluid flows in the formation of the Mayske gold deposit; studying the genesis of quartz-albite-petalite pegmatites in the western part of the Ingul megablock as well as REE-U-Th ores of Dibrova deposit (Ukrainian Shield); formation of inclusions with a "cap".

49-65

Authors: O.V. Dubyna, S.G. Kryvdik, O.A. Vyshnevskyi

Alkaline granites and their hypabyssal and effusive varieties have a limited distribution on the Ukrainian Shield, unlike other Precambrian platforms and shields. Grorudite dikes in the Eastern Azov region have discrete chemical and mineral composition and are considered as analogues of alkaline granites — pantellerites (high-Ti or aegirine type) or comendites (low-Ti or amphibole type). High-Ti grorudites are highly enriched in incompatible elements (REE, Zr and Nb) in comparison to low-Ti type. As a result of high-Ti grorudite investigation, new for these rocks titanium minerals (titaniferous hematite with high MnO content, minerals of the FeTiO3–MnTiO3–ZnTiO3 series), previously unknown in these rocks Ca-Na-amphiboles, as well as structural relationships between aegirine and alkaline amphibole were revealed. Despite of high or increased content of HFSE in grorudites, information about their accessory minerals is quite restricted. In the aegirine-bearing varieties of grorudites, such rare elements minerals: monazite-(Ce), bastnäsite-(Ce), britholite-like mineral and REE-enriched apatite, zircon, a Na-rich mineral similar to calciocatapleiite, as well as unidentified zirconium minerals and minerals of the aeschynite group were recognized. In amphibole-bearing dikes zircon and Nb-bearing rutile were only found. These minerals are often very small in size, the largest of them can reach 15—20 μm in size; mostly do not exceed 10 μm. It greatly complicates their identification. An interesting and unusual fact is that many of rare minerals, especially bastnäsite-(Ce), aeschynite group minerals and zircon are present as inclusions in titaniferous hematite. It is assumed that a significant part of rare metals isomorphically incorporate to rock-forming minerals (alkaline pyroxenes and amphiboles). Some of rare minerals (especially zirconium ones) are secondary mineral and were formed as a result of replacement of primary Na (eudialyte, catapleiite, hilairite) or Ca (gittinsite, calciocatapleiite) Zr-silicates, which are more typical in peralkaline (agpaitic) rocks. Taking into account the petrological features and the nature of the rare-earth mineralization of grorudites of the Eastern Azov region, there is a reason to believe that such type of mineralization in these rocks occurs in course of differentiation of the initial magmatic melt(s). Such melts are similar to high-Ti basalts (characteristic rocks of this region) of Devonian age. Secondary hydrothermal processes are weakly manifested in the studied rocks and probably led to substitution of primary accessory minerals. Considering the increased or high concentrations of Nb in high-Ti grorudites and an insignificant amount of Nb-minerals, it is likely that differentiation conditions (low F, high f O2 and hypabyssal conditions of crystallization) did not promote prolonged crystallization with significant accumulation of rare-metal minerals. However, the presence of grorudites with high content of rare metals found in this region increases the prospects for discovery of small alkaline granite intrusions (holocrystalline analogues of grorudites) which may host deposits and/or occurrences of Nb, REE, Zr, Sn, Be.

76-85

Authors: V.O. Pryvalov, O.A. Panova, А.V. Pryvalov

The Donets Basin or Donbas frames one of the major late Palaeozoic coal-bearing basins in the world. Geologically, the basin stands out by its thick sedimentary column containing prolific coal-bearing measures. Within the domain of the Donbas Foldbelt, it is characterized by prominent inversion-folding patterns controlled by principal displacement zone (PDZ). Historically, the Donbas region has served as a heartland of Ukrainian industry including coal and mercury mining, multiple metallurgical and chemical processing plants. Because of tremendous amount of organic matter became thermally mature the basin hosts unconventional gas plays including "shale gas" and coal-bed methane resources, which may be served a resource base to cease the Ukrainian dependence on gas imports from the Russian Federation through unconventional gas developments. Nowadays, this geological and economic-geographical region suffers from military hostilities, which may have unpredictable consequences and threaten the security of adjoining regions. The aim of this publication is to ascertain the threat of a dramatically deadly combination of historically persistent man-made environmental damage and armed conflict which affected surface terrain and underground environment, urban and infrastructural facilities, lands and agricultural development within the Donbas region (Eastern Ukraine). We used the extensive dispersed long and short-term observation data collected and acquired in the Donets Basin in order to describe, classify and retrieve the most pressing environmental concerns, as well to delineate future goals for its forthcoming recovery. A scope of environmental problems is given with special stress on interval from 2014 up to the present time including delineation of risks related with specific geostructural position of "Cleavage" underground nuclear blast site and induced seismic activity reported within Khanzhonkovo site (Obyedinenyi settlement) of Makiivka region in 2019. Methods of detection and prevention are described and the potential size of the problem is assessed. The scopes of remedial measures that may be taken are discussed.