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This paper reports the first finding of oriented triphylite (LiFe2+PO4) rods in fluorapatite. This observation was made in the contact zone between a metamorphosed rare-element pegmatite and its amphibolite wall rock at the Stankuvatske Li-ore deposit in the Ukrainian Shield. This contact zone consists of an exocontact, in which hornblende was altered to biotite, and an endocontact, which comprises four parallel mineral zones (aplitic, apatite, triphylite, and transitional). The needle-shaped triphylite inclusions were observed in greenish-blue apatite within the apatite zone. They are oriented parallel to structural nanochannels along the c-axis in apatite and were formed due to the infiltration of Li-rich, pegmatite-derived fluids into the apatite zone. Small amounts of pyrite, U-Th-rich and Fe-rich phases, as well as small mono-phase fluid inclusions of CO2, CO, and N2 are associated with the oriented triphylite inclusions and record the character of fluid. The exo- and endocontacts were formed as a result of interaction between metasomatic fluids derived from the pegmatite (enriched in K, Na, Li, Rb, F, P, and Mn) with the host amphibolite. At the contact, the amphibolite was altered into the biotite zone during the first metasomatic stage; alteration of hornblende and plagioclase released Ca, Fe, and Mg toward the pegmatite, where these elements reacted with P, Li, and Mn to produce the apatite and triphylite zones during the second metasomatic stage. Acting like a geochemical barrier, the apatite zone in the endocontact inhibited the further escape of Li from the pegmatite, which now is a Li-ore deposit. The metasomatic processes observed in the Stankuvatske Li-ore deposit represent an example of apatite and triphylite formation at the contact between a pegmatite and a metabasite, which has metallogenetic implications. [ABSTRACT FROM AUTHOR]

The results of the analysis and generalization of geological, hydrogeological and hydrochemical data for four cities of Ukraine with a population of 107,000 inhabitants (Nikopol) to 370,000 inhabitants (Vinnytsia), located within the Ukrainian Shield, are presented. The availability of their approved operational groundwater reserves or forecast resources is determined. For local water supply of these cities, it is necessary to attract from 770 to 2600 m³/day of groundwater and surface water. Recommendations are provided for the creation of an extensive system of local (pump-station) water supply in case of extraordinary natural and man-made events in particular the introduction of martial law. The research is funded by the National Academy Sciences of Ukraine. Their implementation is planned for 2023-2025. The reliability of drinking water supply in cities is increased by creating a branched system of pump-station water supply with autonomous power supply of pumps and portable water purification systems where necessary. When assessing and subsequently designing and constructing pump stations, depending on the type of development, we can proceed from estimates that for 2-5 thousand people in a microdistrict, from 10 to 35 m³ of water per day is required, with a reserve of up to 50 m³. The construction of pump stations must be carried out in protected areas. Using groundwater, it is possible to organize a local water supply network in the cities of Vinnytsia, Kropyvnytskyi, Nikopol and Bila Tserkva. Local water supply of the cities of Zaporizhzhia, Kryvyi Rih, Dnipro, Zhytomyr and Kremenchuk should be based on the use of surface water with partial involvement of groundwater. These issues will be considered in the next issue of the journal. [ABSTRACT FROM AUTHOR]

The article presents a mineralogical, petrographic, and geochemical characterization of the rare earth mineralization of the Kotlyarivka ore occurrence, which was discovered by drill hole 114 in the south-western part of the Krynychky plagiogranite-migmatite dome during geological exploration of the southern part of the Verkhivtseve greenstone structure and its granitoid framing. Rare earth elements (REE) are critically important minerals for many countries, including EU, USA, Canada, and Australia, and other developed countries. The Ukrainian Shield is one of the largest REE metallogenic provinces in Europe. In particular, the Middle Dnipro megablock is a prospective but under-explored region for the discovery of new REE deposits. Its prospects are associated with subalkaline and alkaline Mesoarchaean granitoids and metasomatites of the Tokivske, Mokra Moskovka, and Demuryno complexes. Comprehensive studies of core samples from primary and weathered rocks of the Kotlyarivka occurrence have revealed that monazite is the mine mineral concentrator of REE and yttrium. It was determined that monazite underwent two main stages of alterations: endogenic hydrothermal-metasomatic and hypergenic associated with weathering crust formation. Other minerals, such as apatite, zircon, and leucoxene, also contain lanthanides and yttrium. The findings highlight the critical need for the development of the mineral resource base for REE, involving the re-evaluation of known deposits and the search for new ones. This usually requires scientific support and modern laboratory equipment to accurately determine the composition and genetic features of productive mineralization. Despite some challenges, such as the limited number of samples available for study, the research provided new important data that contributed to the understanding rare earth elements mineralization in the studied Kotlyarivka occurrence and the Middle Dnipro region as a whole. Continuing such studies and conducting comprehensive full-scale research on REE mineralization in the Central Dnipro region will yield high theoretical and practical results. [ABSTRACT FROM AUTHOR]

The article presents a mineralogical, petrographic, and geochemical characterization of the rare earth mineralization of the Kotlyarivka ore occurrence, which was discovered by drill hole 114 in the south-western part of the Krynychky plagiogranite-migmatite dome during geological exploration of the southern part of the Verkhivtseve greenstone structure and its granitoid framing. Rare earth elements (REE) are critically important minerals for many countries, including EU, USA, Canada, and Australia, and other developed countries. The Ukrainian Shield is one of the largest REE metallogenic provinces in Europe. In particular, the Middle Dnipro megablock is a prospective but under-explored region for the discovery of new REE deposits. Its prospects are associated with subalkaline and alkaline Mesoarchaean granitoids and metasomatites of the Tokivske, Mokra Moskovka, and Demuryno complexes. Comprehensive studies of core samples from primary and weathered rocks of the Kotlyarivka occurrence have revealed that monazite is the mine mineral concentrator of REE and yttrium. It was determined that monazite underwent two main stages of alterations: endogenic hydrothermal-metasomatic and hypergenic associated with weathering crust formation. Other minerals, such as apatite, zircon, and leucoxene, also contain lanthanides and yttrium. The findings highlight the critical need for the development of the mineral resource base for REE, involving the re-evaluation of known deposits and the search for new ones. This usually requires scientific support and modern laboratory equipment to accurately determine the composition and genetic features of productive mineralization. Despite some challenges, such as the limited number of samples available for study, the research provided new important data that contributed to the understanding rare earth elements mineralization in the studied Kotlyarivka occurrence and the Middle Dnipro region as a whole. Continuing such studies and conducting comprehensive full-scale research on REE mineralization in the Central Dnipro region will yield high theoretical and practical results.

The results of the analysis and generalization of geological, hydrogeological and hydrochemical data for four cities of Ukraine with a population of 107,000 inhabitants (Nikopol) to 370,000 inhabitants (Vinnytsia), located within the Ukrainian Shield, are presented. The availability of their approved operational groundwater reserves or forecast resources is determined. For local water supply of these cities, it is necessary to attract from 770 to 2600 m³/day of groundwater and surface water. Recommendations are provided for the creation of an extensive system of local (pump-station) water supply in case of extraordinary natural and man-made events in particular the introduction of martial law. The research is funded by the National Academy Sciences of Ukraine. Their implementation is planned for 2023–2025. The reliability of drinking water supply in cities is increased by creating a branched system of pump-station water supply with autonomous power supply of pumps and portable water purification systems where necessary. When assessing and subsequently designing and constructing pump stations, depending on the type of development, we can proceed from estimates that for 2–5 thousand people in a microdistrict, from 10 to 35 m³ of water per day is required, with a reserve of up to 50 m³. The construction of pump stations must be carried out in protected areas. Using groundwater, it is possible to organize a local water supply network in the cities of Vinnytsia, Kropyvnytskyi, Nikopol and Bila Tserkva. Local water supply of the cities of Zaporizhzhia, Kryvyi Rih, Dnipro, Zhytomyr and Kremenchuk should be based on the use of surface water with partial involvement of groundwater. These issues will be considered in the next issue of the journal.

Detrital zircons from two samples of metasandstones from the Lykhmanivka Syncline, Middle Dnieper Domain of the Ukrainian Shield (Skelevate Formation of the Kryvyi Rih Group), have been dated by the LA-ICP-MS U-Pb method. Metasandstones from the northern part of the syncline yield zircons belonging to four age groups: 3201 ± 12 Ma, 3089 ± 11 Ma, 2939 ± 8 Ma, and 2059 ± 4 Ma. All three Archean groups originated from similar rock types that crystallized at different times from the same mafic source (lower crust) with a 176Lu/177Hf ratio of about 0.020. In contrast, zircon from metasediments from the southern end of the Lykhmanivka Syncline fall within two age groups: 3174 ± 13 Ma, and 2038 ± 9 Ma. In terms of Hf isotope compositions, the detrital zircons from the two oldest age groups in both samples are very similar. The source area was dominated by rocks of the Auly Group (3.27–3.18 Ga) and the Sura Complex (3.17–2.94 Ga). The proportion of zircons dated at 2.07–2.03 Ga, which reflects the timing of metamorphism, is 5%. The metamorphic nature of the Paleoproterozoic zircon allows us to define the maximum depositional age of the metasandstones of the Lykhmanivka Syncline at ca. 2.9 Ga, which is in good agreement with the earlier results from the metaterrigenous rocks of the Kryvyi Rih–Kremenchuk Basin. Our data also indicate the local nature of sedimentation and the absence of significant transport and mixing of detrital material within the basin. [ABSTRACT FROM AUTHOR]

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The geological structure of the Inhul Domain of the Ukrainian Shield is dominated by granites that develop after supracrustal rocks of the Inhul-Inhulets Group. The Group is subdivided, from the bottom to the top into the following Formations: Zelena Richka, Artemivka, Rodionivka, Kamyano-Kostuvate (and coeval Spasivka), and Roshchakhivka (and coeval Checheliivka). In this paper we report the results of the optical-microscopic study of the anatomy of crystals of accessory zircon from two-pyroxene plagioclase gneiss, and the results of U-Pb dating of zircon, hafnium isotope composition and trace element concentrations determination that were performed using the split-stream LA-ICP-MS technique. The results of multigrain monazite fraction U-Pb dating using the TIMS technique are also presented. It has been established that zircon has a complex internal texture with variable cores and thin overgrowths. The isotope age of the cores and overgrowths is the same — 2068±22 Ma, while the age-corrected weighted average εHf value is –2.1±1.1. Based on the microelement composition, zircon from the studied gneisses can be defined as magmatic and epimagmatic, with a weighted average crystallization temperature of 765 °С. The igneous rocks represented the protolith of the gneiss. The age of monazite crystallization (2017.2± ± 2.1 Ma) is a bit younger than the age of monazite from the main rock types of the Novoukrainka massif. The crystallization of monazite in the gneiss was related to the metasomatic processes caused by residual after Novoukrainka granite crystallization fluids. [ABSTRACT FROM AUTHOR]

The purpose. The aplitoid biotite granites with traces of rheomorphic transformations lying among gneisses and crystalline schists of the Central-Priazovska series of the Ukrainian shield, as well as the anatomy of accessory crystals of zircon and monazite from these granites, were researched. Method. The time of granite intrusion was determined by the uranium-lead isotope dating method based on multi-grain measurements of accessory monazite. The anatomy of zircon crystals was studied in artificial slices by optical microscopy methods. The results. The age of monazites was determined by multigrain weighing based on the 207Pb/206Pb isotopic ratio. The interest in these granites is related to the fact that they form a vein that breaks through the gneisses and crystalline slates of the Сentral-Priazovska series, discovered by the Oldcrimean granite quarry. The structure of the granite is heterogeneous, with grain sizes ranging from 0.1 to 3.5 mm. Based on the ratio between mineral grains and their shapes, the structure is identified as allotriomorphic and flattened. The configuration of the grains and their relationships indicate the coexistence of relict primary magmatic structure with dynamoblastic and brittle-plastic features caused by rheomorphism. These elements include granuloblastic phenomena and the flattening of quartz crystals; granuloblastesis of primary plagioclase grains; myrmekitization of early and crystallization of newly formed feldspars; microclinization of relict orthoclase and crystallization of newly formed microcline, and deformation of biotite flakes. Currently, the granites consist of (in %) acidic plagioclase - 30, microcline + orthoclase - 25, quartz - 45, chloritized dark mica - 1-5. Secondary transformations include biotite chloritization, as well as sericitization and pellitization of newly formed plagioclase. Accessory minerals are represented by zircon, monazite, apatite, possibly magnetite, and rutile, which forms during the replacement of biotite by chlorite. Weathering minerals include clay minerals, iron hydroxides, and carbonates. The anatomy of accessory zircon and monazite crystals has been studied. According to mineralogical research, zircon crystals have a complex structure. Zircon in synpetrogenic granites grows on heterogeneous cores of relict zircon, usually in the form of thin shells. A small number of crystals without cores are also present, consisting exclusively of fine-zonal zircon shells.The monazite is represented by two varieties: large (>0.1 mm) brownish-brown, dark brown to nearly black unevenly colored opaque crystals and small light brown, brown-yellow transparent crystals. Scientific novelty and Conclusions. The age of the granite was determined using the uranium-lead isotope method on multi-grain samples of dark opaque monazite crystals. The weighted average age, based on the 207Pb/206Pb isotope ratio, is 1978.8 ± 6 million years. The age obtained from multi-grain samples of light brown and brown-yellow transparent crystals is 1959 ± 18 million years and theoretically represents the minimum timing of rheomorphism processes.

Abstract—A collection of igneous rocks of the Ukrainian Shield sampled from the Korsun-Novomyrhorod pluton (age interval 1760–1735 Ma, Ingul Domain) and from the Korosten pluton (age 1760–1750 Ma, North-Western Domain) is studied. The magnetic and thermomagnetic properties of samples were studied and X-ray diffraction analyses were carried out to obtain reliable determinations of paleointensity (Banc), It is shown that the carriers of the characteristic component of natural remanent magnetization are single- and small pseudo-single-domain magnetite grains. Banc was determined by two methods: through the Thellier‒Coe procedure with pTRM checks and by Wilson method. Paleointensity determinations are obtained from five sites and shown to meet quality criteria. For all sites, Banc and the virtual dipole moment (VDM) values are extremely low, varying within the ranges 3.6–9.76 μT and (0.92–2.43) × 1022 Am2, respectively. The analysis of the data from the paleointensity world database (WDB) indicates that the geodynamo operation mode in the Proterozoic can be characterized by an alternation of strong and weak dipole regimes, but the validity of this conclusion entirely depends on the reliability of data reported in the literature and presented in the WDB. [ABSTRACT FROM AUTHOR]

The nepheline syenites of the Pokrovo-Kyriyivo massif in the junction zone of the Dnieper-Donets Rift and the Priazoviаn block of the Ukrainian Shield contain numerous of rare-metal minerals, among them götzenite is the most common. The nepheline syenites are divided into malignites (melanocratic, early) and juvites (leucocratic, late) based on their mineralogical characteristics. In both varieties, the götzenite is presented as euhedral or subhedral grains with a poikilitic texture (numerous rounded inclusions of nepheline). Among rock-forming minerals are observed feldspar, annite, aegirine (± alkaline amphibole), titanite, strontianite ± sodalite ± cancrinite ± Sr-apatite ± ± calcite ± natrolite. Usually götzenite in malignites has a "patchy" zonation due to the presence of metasomatically altered areas in the central parts, which have a lower content of Ca, Na, Sr and F, and a higher Si, relative to the outer parts. In comparation to juvite, the götzenite of malignite is more enriched in Zr, Nb and REE, with a low Y content in both types of rocks. A notable feature of the götzenite is high Sr content (up to 3 wt. % SrO), but low Nb (often up to 1.3 wt. % Nb2O5) and REE (often up to 2.4, rarely up to 5.6 wt. % REE2O3). The occurrence of götzenite in nepheline syenites of the Pokrovo-Kyriyivo massif is related with the early stage of the alkaline silicate melt differentiation with increasing activity of Na and volatile components, especially F. During götzenite crystallization the majority of REE and HFSE remained in the fluid as soluble complexes and precipitate own minerals at the postmagmatic stage. This is confirmed by presence of fine inclusions of fluorobritholite-(Ce), strontianite and burbankite in cleavage fractures, in miarole-like inclusions — aeschynite-(Ce), pyrochlore group mineral, bastnaesite, burbankite, etc. The Sr enrichment of götzenite can be explained by early crystallization from an Sr-enriched alkaline silicate melt and the absence of another Ca-rich rock-forming minerals or by external introduction of CO2-F fluids enriched in Sr and REE separated from a carbonatite melt. [ABSTRACT FROM AUTHOR]

Purpose. Mantle density models are key tools for understanding the fundamental geological and physical processes occurring within the Earth and are essential to our scientific and applied understanding of the planet. Methodology. The tasks were solved by a complex research method, including analysis and generalization of literary and patent sources, analytical, experimental studies, using computer and mathematical modelling methods. Findings. One-dimensional models simplify the mantle density distribution by assuming that it is uniform only in the vertical direction. This limitation does not allow for horizontal variations in mantle density, which may be important on a regional scale. 3D models are more complex and require more data and computational resources, so their use may be limited. In this study, we present a quasi-three-dimensional model of mantle density beneath the Ukrainian Shield. This 3D model is obtained using a basic set of one-dimensional seismic tomographic velocity models calculated for 21 mantle domains in the depth range from 50 to 2,600 km. The process of converting the P-wave velocity model into a density model includes the following stages: 1) determining seismic boundaries in the mantle based on P-wave velocity curves for each mantle domain; 2) creating a synthetic mantle model beneath the Ukrainian Shield for the P,S-wave velocity curves; 3) solving the Adams-Williamson equation for each domain, considering polynomial corrections to extract heterogeneities during its solution; 4) analysing existing models by comparing the calculated gravitational potential at the central point of the Ukrainian Shield as the standard reference for selecting one of 5 reference models. Here, we focus on the final stages of constructing the mantle density model by: 1) balancing the mass of the upper and lower mantle for each domain when determining density using the Adams-Williamson equation and introducing polynomial corrections; 2) calculating densities for each of the 21 mantle domains and their 3D integration. Originality. The obtained mantle-density model of the Ukrainian Shield aligns well with the division of the mantle into three main layers: lithosphere, upper mantle, and lower mantle. Each of the mantle’s structural layers has its representation pattern in density heterogeneities. Anomalies of decreased density in the lithosphere of the Ukrainian Shield correlate with thermal anomalies, whereas anomalies of increased density correspond to tectonic zones dividing its megablocks. Practical value. Regions of increased density gradient are associated with mantle thrust faults, which in some cases can be boundaries between different petrological formations and serve as channels for magma ascent into the Earth’s crust at certain stages of geological development of the Ukrainian shield and, in turn, be sources of minerals. [ABSTRACT FROM AUTHOR]

The presence of numerous native gold deposits of the Ukrainian Crystalline Shield (UCS), as well as the spread of placer gold manifestations, determines the high probability of the formation of precious metal placers with industrial parameters here. The main factors and geological conditions that contribute to the formation of gold placers are manifested in the UCS. An important reason for the failures of previous geological works is the outdated scientific and methodological platform, which involved the search for typical gold-bearing deposits with metal of gravity classes of size. The possibility of significant movement of placer gold in the clayey water flow and the formation of long-distance placers was not taken into account. The traditional slack method used in the study did not make it possible to determine the actual gold content when particles with a size smaller than 0.25 mm predominate in the sample, which is precisely the particle size of the primary sources of the UCS. The applied means of research could not be effective in the absence of the necessary analytical base for determining the gold content, modern methods of studying the geological structure and tectonics of the territories. The negative results did not provide any real grounds for further specialized large-scale research and prospecting for placer gold. Today, it is becoming obvious that placer gold of small and fine grades can easily move over considerable distances in the water flow and form accumulations not only in boulder-pebble material, but also in pelite sediments. As a result of repeated changes in the tectonic plan of block movements, gold-bearing accumulations could be eroded and redeposited in secondary reservoirs. In this aspect, neotectonic studies (using materials from space surveys) become the main predictive and prospecting method for identifying promising areas of placer gold concentration in the region. Field work should be carried out using drilling and modern methods of laboratory analysis of samples for gold. The results of many years of research give hope for the discovery of real placer gold deposits in the Northern Black Sea region in the near future.

Statement of the general problem. The analysis of the geological structure of Europe indicates a wide development of Laramian (post-Cretaceous - pre-Cenozoic) deformations in non-Alpine regions. They are traced by the regional angular unconformity between the folded Mesozoic and non-folded Cenozoic from the Caspian Sea to Great Britain. The area of development of the Laramie folding of Europe also covers the Ukrainian shield. An unsolved part of the overall problem. The Ukrainian crystalline shield is described as "uplift of the crystalline foundation of the East European platform", where Precambrian rocks come to the surface. But the same rocks can also be traced far beyond its borders. The question arises - what structural position does the Ukrainian shield occupy in the structure of the Laramie folded region? Analysis of recent research and publications. On the geological maps of the pre-Cenozoic formations of Ukraine, the northern border of the Laramie folded region can be traced along the Chernihiv-Lysychansk line. Mesozoic folds and an angular unconformity in the Cenozoic basement disappear further north. To the south, the Laramie deformations intensify, but unevenly. The purpose of the article is identification of modern structural position of Ukrainian crystalline shield. Research materials and methods. Were involved more than 120 geological maps of Ukrainian regions and author's digital geological model of East Ukraine. Presentation of the main research material. A band of Mesozoic folds and NW vergence thrusts tens to hundreds of kilometers long is developed immediately south of the border of the folded region. The amplitude of the folds is 1.5–2 km. The band of development of these folds and thrusts with a width of about 100 km limits the Ukrainian shield from the northeast. To the south of the Ukrainian Shield, on the shelves of the Black and Azov Seas and in Northern Crimea, a sub-latitude band of Laramie thrusts and folds with a width of 150–200 kilometers has been established. Amplitudes of thrust folds reach 1–2 km, amplitudes of separate thrusts reach 8–10 km. This band of folds and thrusts limits the southern slope of the Ukrainian shield from the south. These Laramie folds and thrusts are overlain by Cenozoic sediments. To the south, in the Mountainous Crimea, the deformations are still intensifying. Folds and thrusts are replaced by wide and extended mélange zones of northwestern vergence. The Ukrainian shield is bypassed by the development of folds and thrusts from the northeast, east, and south. On the slopes of the Ukrainian shield, Mesozoic fold deformations subside, and the Mesozoic there lies gently sloping and monoclinally. Such poorly deformed blocks within folded regions are called middle massifs. This middle massif of the Laramie fold region within Ukraine has an anteclise structure. In the core of the anteclise, Precambrian metamorphic and igneous rocks emerge from under the sedimentary cover. The western wing of the anteclise is overlain by younger thrusts of the Carpathian folded structure of Attic (post-Miocene) age. Scientific novelty. In the modern geological structure, the Ukrainian shield is the core of the anteclise of the middle massif in the Laramie folded region. Conclusions. As a tectonic uplift, shield was formed in the Paleocene. In the Late Cretaceous, it was still buried under shelf carbonate deposits. Erosion of this uplift formed the Cenozoic deposits of Ukraine with a specific mineragenic specialization. Taking into account the Laramian folding allows us to reconcile the diverse geological phenomena of the region into a single system without contradictions.

The results of uranium-lead dating of zircons from syenites of the Velykovyska massif (Korsun-Novomyrhorod pluton) of the Ingul megablock of the USh are given. The Velykovyska massif, located in the southern part of the Korsun-Novomyrhorod anorthosite-rapakivi granite pluton, in the area of the village Velyka Vyska, composed of fayalite-hedenbergite syenites. Syenites are small isolated intrusive bodies that are conventionally united in the Velykovyska massif. Several varieties of syenites are distinguished by textural-structural features and mineral composition — fine-grained, medium-grained (predominant), mesocratic (10-15% of dark-colored minerals, occasionally 20-30%), leuco- and melanocratic (present in subordinate quantities) syenites according to alkali content belong to the normal series. The anatomy of zircon crystals from a sample (217/862) of syenite discovered by well 862 was studied. Zircon crystals from the Velykovyska syenite massif are quite diverse — from transparent yellow and lilac to slightly transparent brown, cracked. Zircon crystals in the syenites of the Velykovyska massif crystallized from magmatic melt, probably with a short break in crystallization. The age of the syenites of the Velykovyska massif was determined by the uranium-lead isotope method based on three size fractions of multi-grain weights of zircon crystals from the fayalite-hedenbergite syenite, sample (217/860) and two size fractions of multi-grain weights of zircon crystals of the sample (158/860) St. 860. The discordia intersects the concordia at two points: the upper crossing corresponds to the age of 1774±18 Ma and the lower one — –129±955 Ma. Taking into account the slight discordance (0.9-1.6), the weighted average value of the age based on the 207Pbr /206Pbr isotopic ratio was calculated to be 1776.2±2.8 Ma, which coincides within the margin of error with the age calculated from the upper intersection of concordia with discordia and which we take the time of crystallization of zircon crystals and the age of the syenite of the Velykovyska massif. [ABSTRACT FROM AUTHOR]

The data of mineralogical studies of carbonatite veins and exocontact fenites in the open pit near the Khlibodarivka occurrence (Donetsk region, Volnovaha district) are presented. The thickness of carbonatite veins is neglegible, rarely exceeding 30 cm, and are mainly composed of calcite, alkaline amphibole and albite are the most common silicate minerals. Accessory minerals are more often represented by monazite, apatite, columbite, minerals of pyrochlore group, zircon, and opaque (ilmenite, rutile, magnetite, sulfides). In addition to the above-mentioned minerals, except for the minerals of pyrochlore group, chlorannite, aegyrine, REE-carbonates, baryte, allanite-(Ce), REE-apatite were found in the fenite haloes and veinlets. The reactionary interaction of the carbonatite melt enriched in alkalis and volatiles with the hosted enderbites caused the appearance of fenite halos both around the veins of carbonatites and the thin "net" of veinlets without a visible connection with carbonatites. The significant thickness of the fenite halos (usually twice as much in comparison to the thickness of the carbonatite veins), albitization of the surrounding rocks and saturation of the alkaline femic minerals of the carbonatite veins and fenites indicate that the initial carbonatite melt contained a significant amount of Na and volatile components (H2O, F, CO2, possibly Cl), and also had a more ferruginous composition of carbonates due to the presence of siderite or ankerite components (in the melt). As a result of the dissociation of primary carbonates, iron, as well as alkalis, was concentrated in the fluid phase and subsequently included in aegirine and alkaline amphiboles. The fenitization of host rocks took place in several stages. At the initial stage, the alkali-enriched fluids, mainly Na, F, and possibly Cl, were separated, while the later ones fluids were Fe-enriched and existing in more oxidized conditions. The fluids genetically related to carbonatites were penetrating into the host rocks caused the redistribution of trace elements. Barium, Th, and partly LREE were carried out from carbonatites most intensively, while Sr, Nb and a significant part of REE remained immobile due to the early crystallization of their host minerals and lack of subsequent autometasomatic alteration. Geochemistry of carbonatite veins (high content of incompatible elements such as Sr (117 777 ppm), increased REE (1624 ppm), elevated Nb, chondrite-normalized pattern of REE, high (La/Yb)cn = 24.7 and absence of negative Eu anomaly (Eu* = 1.03) and endogenous ratios of isotopes of Sr (0.703), C and, partially, O) testify to their magmatic origin. It is possible that the insignificant thickness of the carbonatite veins and the intensive interaction of juvenile fluids with the host granitoids and meteoric fluids caused the enrichment of carbonatites with 18O (δ18O 8.4÷20), but with the preservation of primary δ13C (–8 ÷ –6.5). Currently, the increased concentrations of rare metals were not found in carbonatites of the Khlibodarivka village. However, the presence of carbonatite veins in association with fenite halo, spatial connection to the Oktyabrsky massif of alkaline rocks, as well as numerous fenite occurrences in this area, increase the prospects of this area for such mineralization. [ABSTRACT FROM AUTHOR]

The article is dedicated to the investigation of orange garnets from Miocene-Pliocene deposits of the Balta suite and the Sarmatian stage in the Vinnytsia area. The Vinnytsia area is located on the southwestern slope of the Ukrainian Shield. The crystalline basement on most of the area is represented by granitoids of the Berdychiv complex of Paleoproterozoic age, and to a lesser extent by enderbites and charnockites of the Lityn complex of Neoarchean age. Among these, there are mafic and ultramafic bodies ranging from 0.5 to 2 meters in thickness. The sedimentary cover with a total thickness of up to 20 m is represented by sands and clays of the middle Sarmatian, Balta, and Quaternary sediments. These deposits are enriched with mantle minerals, predominantly pyrope, and four diamond crystals have also been discovered. We studied the chemical composition (253 crystals) and morphology (278 crystals) of the orange garnets. The studied samples are mostly represented by garnets of pyrope and pyrope-almandine composition, a small part is represented by grossulars. Most of the garnets are unrounded crystal fragments ranging in size from 0.2 to 0.6 mm, exhibiting signs of intense hypergene changes. These are evident in the development of positive (block) and negative relief features, appearing as drop-shaped, cone-shaped, small hilly microrelief and various forms of etching channels. The morphological features suggest that these garnets were probably relocated a short distance from their primary sources and had been present in the weathering crust for an extended period. The original sources of garnets are most likely Precambrian and located on active tectonic zones, which led to their destruction. According to chemical composition data, among orange garnets low-chromium websterite and lowcalcium eclogite varieties, as well as garnets of high-iron mantle pyroxenites are dominated. The presence of titanium impurities in many garnets indicates the possible diamond-bearing nature of some primary sources. [ABSTRACT FROM AUTHOR]

The purpose. The aplitoid biotite granites with traces of rheomorphic transformations lying among gneisses and crystalline schists of the Central-Priazovska series of the Ukrainian shield, as well as the anatomy of accessory crystals of zircon and monazite from these granites, were researched. Method. The time of granite intrusion was determined by the uranium-lead isotope dating method based on multigrain measurements of accessory monazite. The anatomy of zircon crystals was studied in artificial slices by optical microscopy methods. The results. The age of monazites was determined by multigrain weighing based on the 207Pb/206Pb isotopic ratio. The interest in these granites is related to the fact that they form a vein that breaks through the gneisses and crystalline slates of the Сentral-Priazovska series, discovered by the Oldcrimean granite quarry. The structure of the granite is heterogeneous, with grain sizes ranging from 0.1 to 3.5 mm. Based on the ratio between mineral grains and their shapes, the structure is identified as allotriomorphic and flattened. The configuration of the grains and their relationships indicate the coexistence of relict primary magmatic structure with dynamoblastic and brittle-plastic features caused by rheomorphism. These elements include granuloblastic phenomena and the flattening of quartz crystals; granuloblastesis of primary plagioclase grains; myrmekitization of early and crystallization of newly formed feldspars; microclinization of relict orthoclase and crystallization of newly formed microcline, and deformation of biotite flakes. Currently, the granites consist of (in %) acidic plagioclase - 30, microcline + orthoclase - 25, quartz - 45, chloritized dark mica - 1-5. Secondary transformations include biotite chloritization, as well as sericitization and pellitization of newly formed plagioclase. Accessory minerals are represented by zircon, monazite, apatite, possibly magnetite, and rutile, which forms during the replacement of biotite by chlorite. Weathering minerals include clay minerals, iron hydroxides, and carbonates. The anatomy of accessory zircon and monazite crystals has been studied. According to mineralogical research, zircon crystals have a complex structure. Zircon in synpetrogenic granites grows on heterogeneous cores of relict zircon, usually in the form of thin shells. A small number of crystals without cores are also present, consisting exclusively of finezonal zircon shells.The monazite is represented by two varieties: large (>0.1 mm) brownish-brown, dark brown to nearly black unevenly colored opaque crystals and small light brown, brown-yellow transparent crystals. Scientific novelty and Conclusions. The age of the granite was determined using the uranium-lead isotope method on multi-grain samples of dark opaque monazite crystals. The weighted average age, based on the 207Pb/206Pb isotope ratio, is 1978.8 ± 6 million years. The age obtained from multi-grain samples of light brown and brown-yellow transparent crystals is 1959 ± 18 million years and theoretically represents the minimum timing of rheomorphism processes. [ABSTRACT FROM AUTHOR]

This paper investigates the monazite grains from the Dibrova rare-earth-thorium-uranium (U-Th-REE) mineral deposit within the Azov Megablock of Ukrainian Shield. U-Th-REE mineralization is associated with K-feldspar-quartz metasandstones and metagritstones (hereafter quartzites) and pegmatoids. The latter possibly represent products of ultrametamorphism/granitization of initially sedimentary clastic rocks during tectono-magmatic activation during the Paleoproterozoic. Ores are composed of quartz as a principal mineral, feldspar, sillimanite, muscovite, monazite, brannerite, uraninite, zircon, rutile, and sulfides. The purpose of this work was to obtain insights into the genesis of the mineral deposit by studying the monazite grains, their chemistry, and ages. Petrographic research work was carried out that included studying/analyzing the monazites from various monazite-bearing rocks (quartzites, pegmatoid, and biotite schist samples). A variety of methods and tools were used, including optical microscopy study, X-ray fluorescence (XRF) mapping of selected samples, as well as scanning electron microscope (SEM) and electron microprobe (EPMA) characterization of monazites, including U-Th-Pb monazite chemical dating. U-Pb-Th chemical electron microprobe dating of the monazites yielded two major distinct monazite age groups at 3.0–2.8 Ga and 2.2–2.0 Ga. The first age group corresponds to the time of formation of the Archean granitoids, which served as a source of monazite for its clastic sedimentation during the Paleoproterozoic in the Dibrova suite sediments. The second age group corresponds to the reprecipitation (i.e., remobilization) of monazite during the Paleoproterozoic tectono-magmatic activation. The location of the mineral deposit within the deep mantle-crustal Devladivska shear zone is another favorable factor for the remobilization and transport of metals. New data on the age of mineralization yield a more complete understanding of the geological history and formation of the complex polyphase rare-earth-uranium-thorium Dibrova mineral deposit. [ABSTRACT FROM AUTHOR]

One of the important results of the state geological mapping is the understanding of tectonics and the history of the geological development of the surveyed areas. According to their purpose, they should be the main synthesizing result of the work performed and, at the same time, the scientific basis for further predictive metallogenic studies. Meanwhile, in modern literature there are still no clear definitions of the content and methodology of regional geotectonic studies, including during the state geological mapping. This is reflected in the completeness of the collection, use and generalization of the necessary data, especially when studying the Early Precambrian crystalline basement of the shields of ancient platforms, including the Ukrainian Shield. This article provides a detailed definition of regional geotectonic studies and their components – geotectonic analysis and synthesis. In the development of these definitions, a methodology is proposed – a technological scheme for geotectonic analysis in geological mapping, consisting of a number of sequential operations. They are aimed at revealing the structural and material features of the study area, due to tectonic movements and related processes. The results of geotectonic analysis form the basis of geotectonic synthesis, the purpose of which is to create a geoevolutionary model for the development of the studied area. The issue of geotectonic periodization of the Early Precambrian, on which this model should be based, is specially considered. Modern data on the composition and structural position of the main stratigenic metamorphic complexes of the shields make it possible to distinguish two major stages of the Early Precambrian evolution of the Earth's crust: eogean – the stage of indistinct (pre-geoblock) geotectonic differentiation, and protogean – the stage of distinct geoblock geotectonic differentiation. The proposed method was tested in compiling overview tectonic maps of the basement of the Ukrainian Shield. It is the first experience of an unbiased regional geotectonic study of the Lower Precambrian and can be used in state geological mapping as a supplement to existing instructions.

The article discusses the problematic issues of the geological structure of the Bilozersky synclinorium of the Ukrainian Shield, its stratigraphic structure, formation composition and absolute age of the rock associations that compose it. The interrelationships of interregional correlation of the Bilozerska and Kryvyi Rih series of the Ukrainian Shield are considered. Significant adjustments to the current stratigraphic scheme of the Bilozerska series are proposed. The necessity of abolishing the upper metasedimentary stratum (Pereverzevska Suite) and returning to the traditional twoshell structure of the Bilozerska series, which consists of a sub-iron-bearing essentially terrigenous and iron-bearing terrigenous-chemogenic ferruginous-siliceous suite, is noted. The author's interpretation of the folded structure of the central zone of the Bilozerska structure is proposed, which allows to explain all the complexities of its stratigraphy in a consistent manner, to reconcile the stratigraphic position of the Teplivska Association of the Bilozersky synclinorium with the position of the Talc Horizon of the Kryvyi Rih series, and to show a complete correspondence in the general sequence of stratons between the sediments of the Bilozerska and Kryvyi Rih series. The complete lithologic, stratigraphic, and formational correlation of the Bilozerska series with the section of the Kryvyi Rih series within the Skelyuvatsko-Saksagan sedimentary cycle is shown by a set of features. It is recommended to unite the Kryvyi Rih and Bilozerska series into a single supra-regional and superserial taxon - the Kryvyi Rih-Bilozersky complex. [ABSTRACT FROM AUTHOR]

The Ingul Megablock of the Ukrainian Shield is an area of mostly Paleoproterozoic continental crust located between the Dniester-Buh and Middle Dnieper Archean cratons. Its central part is occupied by the KorsunNovomyrhorod anorthosite-rapakivigranite massif, which is 1757-1740 Ma, and the Novoukrainskyi massif, which is 2037-2034 Ma. A wide range of granitoids (biotite, garnet-biotite, hypersthene-garnet-biotite porphyry, trachytoid granites, granosyenites, and quartz syenites) participates in the geological structure of the Novoukrainskyi massif; medium and basic rocks of the monzonite series (quartz monzonites, monzonites, monzodiorites) play a significantly smaller role, gabbromonzonites) and gabbroids (norites and gabbronorites). The article presents the results of the optical-microscopic study of the internal structure of zircon crystals and uranium-lead isotopic dating of monazite from trachytoid granite (sample Bo-1) and from the xenolith of giant-grained biotite-hypersthene granite (sample Во-2a) of the Novoukrainskyi massif, exposed by the Voynivskyi block stone. For trachytoid granite, sample Bo-1, an age of 2035.3±2 Ma was obtained, for the age of monazite from a xenolith of coarse-grained granite, sample Bo-2a, we take the weighted average age value according to the 207Pb/206Pb isotopic ratio —2035.2±1.8 Ma. Isotopic age values for monazites from trachytoid granite and coarse-grained granite xenolith expanded in the Voynivskyi block stone quarry completely coincide with the results of determining the age of gabbroids (according to zircon) and granitoids according to monazite: 2037.4±0.6 million years and 2034.8±0.6 million years, respectively. Thus, the time of formation of the crystalline rocks of the Novoukrainskyi massif (2037-2034 Ma) completely coincides with the time of formation of granitoids of the Kirovohrad complex (2040-2020 Ma), which, taking into account the anatectic nature of the granitoids of both the Novoukrainskyi and Kirovohrad complexes, gives grounds for uniting the granitoids both complexes into one, for example, the Kropyvnytskyi complex, leaving only gabbroids as part of the Novoukrainskyi complex. [ABSTRACT FROM AUTHOR]

Traditionally, feldspars are characterized in the following order: Volyn chamber pegmatites — Perzhansky ore node — kamyano-mohyla (stone grave) complex of Azov region — Kruta Balka rare-metal deposit — Shevchenkivske rare-metal deposit — rare-metal pegmatites of Inhulsky megablock. Feldspars in the chamber pegmatites of the Volyn are represented by maximum microcline-perthite, rarely by intermediate orthoclase and albite. Widely developed feldspars with close regularity, but different symmetry. The form of discharge is granular aggregates and polyhedral crystals. The outline of potassium feldspar crystals is varied. Crystals of only two morphological types have a clear arrangement: I — early high-temperature bar-like individuals, concentrated in the cavities of the graphic zone; II — columnar pseudohexagonal crystals in sinkholes. Among albite crystals, three morphological types are distinguished, depending on acidity-alkalinity and crystallization temperature. Feldspars of chamber pegmatites are well studied by radio spectroscopic, luminescent and genetic methods. Within the boundaries of the Perzhansky ore complex, multi-grained polygenic microcline-perthite dominates, the structural state of its potassium phase corresponds to a high degree of ordered distribution of Si and Al (maximum microcline). The evolution of the twin structure of potassium feldspars is briefly covered and illustrated. Pure microcline and amazonite (probably the purest on the Ukrainian Shield) were found in the perzhansky metasomatites. Feldspars are the leading minerals of the stone-burial complex of the Azov region, represented by microcline and microcline-perthite. A characteristic feature of the microcline rocks of the complex is the unique giant dendritic crystals of pink microcline. Feldspars in the Kruta Balka rare metal deposit are represented by albite, albite-oligoclase and microcline. Two feldspars — microcline and albite (in the form of perthites in microcline and independent aggregates) were diagnosed in the Shevchenkivske deposit. Microcline makes up 15-20% of the volume of pegmatites and represented by three generations. The mineralogy of feldspars in the pegmatites of the Inhulsky megablock is different. They are represented by monoclinic orthoclase, microcline and plagioclase (mostly albite, occasionally oligoclase). Their content in rocks is mostly >50%, but albite >potassium feldspar. In general, these feldspars have features uncharacteristic of rare-metal pegmatites: 1) high symmetry (monoclinic) and low order (t 1 > 0,7); 2) microperthite decay structure; 3) the initial and middle stages of monodomainization are manifested. These and other features of minerals area consequence of the specific origin of pegmatites, which represent a new genetic type of deposits of rare elements — metapegmatites. [ABSTRACT FROM AUTHOR]

Statement of the general problem. The analysis of the geological structure of Europe indicates a wide development of Laramian (post-Cretaceous - pre-Cenozoic) deformations in non-Alpine regions. They are traced by the regional angular unconformity between the folded Mesozoic and non-folded Cenozoic from the Caspian Sea to Great Britain. The area of development of the Laramie folding of Europe also covers the Ukrainian shield. An unsolved part of the overall problem. The Ukrainian crystalline shield is described as "uplift of the crystalline foundation of the East European platform", where Precambrian rocks come to the surface. But the same rocks can also be traced far beyond its borders. The question arises - what structural position does the Ukrainian shield occupy in the structure of the Laramie folded region? Analysis of recent research and publications. On the geological maps of the pre-Cenozoic formations of Ukraine, the northern border of the Laramie folded region can be traced along the Chernihiv-Lysychansk line. Mesozoic folds and an angular unconformity in the Cenozoic basement disappear further north. To the south, the Laramie deformations intensify, but unevenly. The purpose of the article is identification of modern structural position of Ukrainian crystalline shield. Research materials and methods. Were involved more than 120 geological maps of Ukrainian regions and author's digital geological model of East Ukraine. Presentation of the main research material. A band of Mesozoic folds and NW vergence thrusts tens to hundreds of kilometers long is developed immediately south of the border of the folded region. The amplitude of the folds is 1.5– 2 km. The band of development of these folds and thrusts with a width of about 100 km limits the Ukrainian shield from the northeast. To the south of the Ukrainian Shield, on the shelves of the Black and Azov Seas and in Northern Crimea, a sublatitude band of Laramie thrusts and folds with a width of 150–200 kilometers has been established. Amplitudes of thrust folds reach 1–2 km, amplitudes of separate thrusts reach 8–10 km. This band of folds and thrusts limits the southern slope of the Ukrainian shield from the south. These Laramie folds and thrusts are overlain by Cenozoic sediments. To the south, in the Mountainous Crimea, the deformations are still intensifying. Folds and thrusts are replaced by wide and extended mélange zones of northwestern vergence. The Ukrainian shield is bypassed by the development of folds and thrusts from the northeast, east, and south. On the slopes of the Ukrainian shield, Mesozoic fold deformations subside, and the Mesozoic there lies gently sloping and monoclinally. Such poorly deformed blocks within folded regions are called middle massifs. This middle massif of the Laramie fold region within Ukraine has an anteclise structure. In the core of the anteclise, Precambrian metamorphic and igneous rocks emerge from under the sedimentary cover. The western wing of the anteclise is overlain by younger thrusts of the Carpathian folded structure of Attic (post-Miocene) age. Scientific novelty. In the modern geological structure, the Ukrainian shield is the core of the anteclise of the middle massif in the Laramie folded region. Conclusions. As a tectonic uplift, shield was formed in the Paleocene. In the Late Cretaceous, it was still buried under shelf carbonate deposits. Erosion of this uplift formed the Cenozoic deposits of Ukraine with a specific mineragenic specialization. Taking into account the Laramian folding allows us to reconcile the diverse geological phenomena of the region into a single system without contradictions. [ABSTRACT FROM AUTHOR]

Results of a geochemical and geochronological study of the Paleoproterozoic rock assemblage in the Haisyn block of the Ros-Tikych Domain of the Ukrainian Shield are reported. Within the block, the Haisyn Complex comprises granitoids, including pyroxene-bearing diorites, quartz diorites, granodiorites, amphibole-biotite and biotite granites, and aplite and pegmatite granites. Monazite U-Pb isotope age of charnockitic syenite belonging to the Haisyn Complex was defined at 2027 ± 6 Ma. This age coeval with the time of granulite facies metamorphism and emplacement of numerous granitic intrusions in the area. The Sm–Nd apatite isochron yielded an age of 2100 ± 150 Ma. The εNd isochron value of − 5 indicates a long crustal residence time of the crustal protolith. Geochemical data do not indicate any enrichment of the studied rocks in relation to the Eoarchean and Neoarchean charnockites developed in the same area. So, if the model of partial melting of the older crustal protolith is involved then the degree of melting must be quite high. However, deep negative anomalies of Sr, Eu, Zr, and Ti indicate that plagioclase, zircon, and Fe–Ti oxides probably remained unmelted in the source. The Haisyn block was buried in the lower crust at high temperature and pressure conditions in the Paleoproterozoic time. Such a situation resulted in partial melting of the existing crust and formation of melts, containing undigested zircon and bearing ancient Nd isotope signature. [ABSTRACT FROM AUTHOR]

Abstract—The paper reports mineral chemistry, whole-rock major and trace element composition, structure, and geological setting of the phlogopite peridotite lens within the Bug granulite–gneiss terrane of the Dniester–Bug Province, Ukrainian Shield. Geochemical features of the studied peridotites and minerals indicate a complex evolution of the lens. The early stage is marked by the crystallization of olivine + spinel (Al-chromite) cumulus from melt of supposably picritic composition, and further crystallization of clinopyroxene. The melt shows signs of hybridization by host gneissic enderbite. Orthopyroxene crystallized later and frequently replaces clinopyroxene. The phlogopite cystallization is likely related to the fluid activity and the growth of potassium potential in the fluid. Granulite-facies metamorphism accompanied by ductile deformations affected the mineral asseblage and chemical compositions of peridotites and orthopyroxenites. At the final stage, the rocks and minerals experienced retrograde metamorphism and local foliation of the rocks. [ABSTRACT FROM AUTHOR]

A palaeomagnetic study of rocks for two Palaeoproterozoic anorthosite-mangerite-charnockite-granite (AMCG) complexes in the Ukrainian Shield was done to put additional constraints on the interpretation of palaeogeography of Fennoscandia and Volgo-Sarmatia in the Palaeoproterozoic. With this study, 5 sites of Korsun-Novomyrhorod and 3 sites of Korosten AMCG complexes in central and north-western parts of the shield, respectively, were chosen for palaeomagnetic sampling given the geological, modern geochronological and previous palaeomagnetic data. Primary remanent magnetization was isolated on samples of anorthosites, Gabbro, and monzonites within a narrow time interval of U-Pb geochronology dataset of 1.76—1.75 Ga. The palaeomagnetic poles calculated for Korosten and Korsun-Novomyrhorod complexes are almost identical, which indicates that the Volyn and Ingul Domains developed within a single structure of the Ukrainian Shield since at least 1.75 Ga. The new palaeomagnetic pole calculated for all 8 sites (Plat=22.7 °N, Plon=167.4 °E, A95=3.3°) agrees well with previous studies by Elming et al. [2001, 2010]. The selection of the most reliable palaeomagnetic poles for Fennoscandia and Volgo-Sarmatia of this time indicates that the present position of the Ukrainian Shield relative to Fennoscandia is not the same as for about 1.75 Ga, when Fennoscandia occupied a subequatorial position within palaeolatitudes of 5—20 °N, and Volgo-Sarmatia was located close to the equator and rotated relative to Fennoscandia counterclockwise by about 40° compared to its present position.

The name «Bug Series» was introduced into the Precambrian stratigraphic scheme of the Ukrainian Shield more than half a century ago. During this period, ideas about the composition and age of the series changed several times, but at the same time, until recently, the opinion of various studies about its stratigenic nature remained unchanged. In recent years, a number of publications have appeared in which other views on the origin of the «Bug series» are expressed. Initially, they concerned only individual petrographic groups, such as carbonate and magnetite-bearing rocks, which were attributed to endo­genous (magmatic) origin. Later, an opinion was expressed about the nonstratigenic origin of the entire «Bug Series», and some authors propose to abandon the dismemberment of the Early Precambrian granulite complexes into suites altogether. These ideas are based only on the materials of the study of local objects obtained by drilling and geophysical methods, and they do not take into account the results of regional geological and stratigraphic studies. Simultaneously with new ideas about the genesis of the «Bug series», an attempt is being made to link its origin with faults and to revise its age. In order to discuss the problem of the «Bug series», a series of publications has been prepared, in which the main generalized data of many years of regional geological and thematic studies on the composition, structure, stratigraphic and structural position of the units belonging to the «Bug series» are presented. The cycle consists of three separate articles. The first article [Kyrylyuk, 2022a] characterizes the composition of subdivisions and rock associations included in the «Bug series» in the current Precambrian stratigraphic scheme of the Ukrainian Shield. In the second article of the series [Kyrylyuk, 2022б], the ideas about the structural position of the «Bug series» and its subdivisions are considered. This final article is devoted to consideration of ideas about the primary nature of the «Bug series» and its age. As for the Kosharo-Aleksandrovskaya and Khashchevo-Zavalyevskaya suites, the composition, structure, and structural-stratigraphic position of these suits in the stratotype region unambiguously testify to their original stratigenic nature. The problem is only the origin of the rock association of magnetic anomalies, which are erroneously included in the Khashchevo-Zavalievskaya suite. But this association, according to the sum of the signs that are given in the article, also has the most probable lithogenic origin. All subdivisions of the «Bug series» are part of the unified Pobug granulite-gneiss complex of the Lower Archean. Its «stratigraphic age» is not younger than 3.8 Ga, and all younger dates indicate a long-term granulite metamorphism of the complex up to 2.0—1.9 Ga.

Complex geomagnetic and tectonophysical studies were performed in order to characterize in detail the heterogeneity of the Earth’s crust of the Zvenyhorod-Bratskfault zone and to clarify its internal structure and kinematics. Based on the results of magnetometric studies, maps of the different wavelength components of magnetic anomalies were obtained, the sources of which are associated with different layers of the crust; the magnetization of the upper, middle and lower parts of the crust was estimated; 2D and 3D magnetic models of individual structures and areas were developed; geological and tectonic interpretations were performed. The Zvenyhorod-Bratskfault zone is clearly manifested in the regional component of the geomagnetic field, separating its maxima and minima zones, and is also reflected by linear anomalies and bands of the short-wavelength component of the upper part of the crustal section. At the same time, it separates areas of the Earth’s crust with fundamentally different types of sources and their magnetization values: in the west, linear sources of the upper and middle crust of the GSZ are characterized by significant magnetization (up to 3—6 A/m) in contrast to the oval-shaped sources of the Ingul block with magnetization up to 1 A/m m. Tectonophysical measurements of structural and textural elements of rocks were carried out at four sites along the rivers Velyka Vys’, Kilten’, Suhyi Tashlyk and Mertvovid. Processing and interpretation of field measurements of structural textural elements of rocks were done by the structural-paragenetic method of tectonophysics for III-IV depth levels using the Stereonet program. It was established that the Zvenyhorod-Bratskfault zone was formed ≤2.45 billion years ago and consists of rectilinear shear zones related to different stages of fault formation. However, the main factor in the formation of the fault zone is the Pervomaisk stage, during which the L-shears with a strike azimuth of 345° and R-shears with a strike azimuth of 357° were formed. The presence of Archean phases of shear in it can testify to the earlier formation of the Zvenyhorod-Bratskfault zone relative to the Pervomaysk one. The Proterozoic cycle of activation (~2.1—1.70 billion years ago) contributed to the formation of deposits and ore manifestations of minerals within the Zvenyhorod-Bratskfaults zone.

The stratigraphic dismembrement of the Lower Precambrian has always been inextricably linked with the study of metamorphism. The degree of metamorphism of the complexes was even used for some time as an indication of their relative age. This sign was not confirmed by isotope dating and was no longer taken into account in the stratigraphic dismembrement of the basement of the shields, including the preparation of official stratigraphic schemes of the Precambrian of the Ukrainian Shield. The authors of the article believe that the degree of metamorphism can still be used in developing the stratigraphy of the Ukrainian Shield. The possibility of such use of metamorphism is considered in a series of publications. The first article describes the stratigraphy and metamorphism of all megablocks of the Ukrainian Shield. It is shown that older stratigenic complexes in each of the megablocks are characterized by higher temperature metamorphism. At the same time, the distinctive features of the composition and metamorphism of the stratigenic complexes, according to the authors, are a reflection of large successive stages of the geological development of the Ukrainian Shield in the Early Precambrian and can serve as the basis for compiling a regional stratigraphic scheme on a historical-geological basis. A version of the regional stratigraphic scheme of the Ukrainian Shield on a historical-geological basis, compiled at the level of complexes, proposed in the second article of the series. In this final article of the cycle, the conditions and duration of lithogenesis and accompanying metamorphism of various sequentially formed stratigenic complexes of the Lower Precambrian are considered. The idea is put forward that the initial pre-metamorphic composition of the complexes and their metamorphism are determined by the temperature state of the upper shells of the Earth and their directed thermal evolution at the early stages of geological history. The existence of hydrospheric, early thermohydrospheric, late thermohydrospheric and normohydrospheric global stages of lithogenesis, lasting from 300 to 700 Ma, and continuous metamorphism from 3.8 to 2.0–1.9 Ga are assumed. During this time, a single metamorphic (paleotemperature) zoning of the basement of the Ukrainian Shield was formed, in which all stratigenic complexes of different ages participate. [ABSTRACT FROM AUTHOR]

Rapakivi of the Korsun-Novomyrhorod pluton (KNP), being the latest Precambrian granites of the central part of the Ukrainian shield, contain older acidic and intermediate rocks as xenoliths, the geochemical features of which reflect the Early Proterozoic geodynamic situation. Rapakivi granites, their differentiates and three types of xenoliths in them, represented by plagiogneiss, pink granite and charnockitoid (mangerite), were selected in the northwestern part of the KNP for geochemical studies. Analysis findings were compared with the geochemical characteristics of similar rocks of igneous and metamorphic Precambrian complexes that surround the KNP and could serve as a source of xenoliths. Based on distribution patterns of rare earth elements, lithophile elements content and their ratios relations in the rocks, taking into account their petrographic composition, it was established that plagiogneiss belongs to the upper part of the Inhul-Inhulets series, pink granite belongs to the Kirovohrad complex, and charnokitoid belongs to the intermediate rocks of the Tashlyk complex. In the latter, acid charnockitoids (enderbites) are probably younger than intermediate ones and were formed in another geodynamic setting. Pink granite, like the granites of the Kirovohrad complex, shows collisional geochemical features, in contrast to the rapakivi granites containing these xenoliths, which have predominantly within-plate geochemical characteristics. Thus, in the form of xenoliths in rapakivi those rocks were preserved that had been generated before and during the collision that occurred about 2 billion years ago and constructed a crust thickening at the site of the Inhul megablock, under subsequent extension of which about 1.75 billion years ago the KNP was intruded. Acid charnockitoids of the Tashlyk complex and rocks of the Novoukrainian complex, which are absent in xenoliths, probably were formed after the collision. [ABSTRACT FROM AUTHOR]

Introduction. The relevance of this publication is associated with the problem of foundation and developing a raw material base of phosphate raw material in accordance with the demand of the national agro-industrial complex. The purpose of the publication is to develop a preliminary digital structural-lithological model (DSLM) of the Kopytkivsky deposit, as a tool for information support of its development, as well as geological and genetic characteristics of the object as a basis for specifying the criteria for predicting deposits of this type. This goal covers the following tasks: - presentation of methodology and research methods; - presentation of the database; - demonstration of derivatives of the created digital structural-lithological model (DSLM) and their interpretation;- representation of functional and cognitive characteristics of the object (Kopytkivsky phosphorite deposit). Materials and Metodology. The studies are based on two methodological principles: traditional lithological, paleofacial, paleogeographic studies and the author's development - digital structural and lithological modeling, dialectically combined in the form of a single predictive-paleoreconstructive retrospective-static model. Main Results. Kopytkivsky deposit belongs to the Zdolbunovskiy district of the Zdolbunovskiy-Ternopil zone of the Volyn-Podolsk Cretaceous basin of the phosphorite-bearing province of the East European platform. The indicated zone refers to the Volyno-Podilllya plate, i.e the western slope of the Ukrainian shield. In the area of the Kopytkivsky deposit, layers of inoceramic limestones represent the lower stratigraphic subdivision of the Cretaceous system, lying directly on the pre-Mesozoic basement. The DSLM of the Kopytkivsky field has been developed, intended for information support for further work on its development (detailed exploration and operation). The DSLM database is represented by a description of 567 geological exploration wells. Conclusions. Based on the constructed DSLM, a number of derivatives (including visualizations) were obtained that reflect the structural and material - industrial characteristics of the field - a number of maps, profiles, as well as a block diagram of the central part of the field. The description of the most informative visualizations are given: Map of the hypsometry of the bottom of the "productive horizon", Map of the hypsometry of the roof of the "productive horizon", Map of specific reserves and others. The model derivatives reflect the spatial (areal and hypsometric) configuration of phosphorites ore bodies and the distribution of specific reserves of P2O5. Based on the methodological principles of formation analysis and the methodological approaches adopted by us for predictive-paleoreconstructive retrospective-static modeling of the object, a geological and genetic characteristic of the stage of formation of layers of inoceramic limestones has been obtained. The mechanism of phosphorite formation is considered. The presented DSLM is intended for information support of detailed and operational exploration, with the prospect of the current development of the model (as a permanent one) with the addition of new data during exploration and operational work.

The SW-NE directed wide-angle reflection-refraction (WARR) SHIELD'21 profile crosses entire width of Ukraine. It targeted the structure of the crust and uppermost mantle in the southwestern part of the East European Craton (EEC), between Carpathians and Voronezh Massif, across Ukrainian Shield and Dnieper-Donets Basin. The ∼660 km-long profile is an extension of the RomUkrSeis profile in Romania and Ukraine. SHIELD'21 experiment, using TEXAN and DATA-CUBE short-period seismic stations, provided high-quality seismic sections from 10 shot points. This allowed construction of a ray-tracing P-wave velocity model, supplemented by V p /V s ratio, for the upper part of the lithosphere in the Sarmatia segment of the EEC and constraining geodynamic processes that led to the formation of the Ukrainian Shield and its margins since Archean times. The velocity distribution in the crystalline crust indicates a rather uniform structure, with velocity changing from 6.0 km/s near the surface to 6.8 km/s at the Moho. The entire section shows the lack of a high-velocity lower crust (V p > 6.8 km/s), presumably resulting from delamination of the primitive mafic lower crust during early evolution of a juvenile continental crust. The seismic boundaries in the upper crust reflect a Paleoproterozoic extensional detachment system below the SW flank of Dnieper-Donets rift basin, initiated in the Devonian. At larger depths, a wide dome of the lower crust with velocities of 6.5–6.8 km/s in the SW-central segment of the profile, probably represents an enormous Palaeoproterozoic(?) granitoid batholith. In the southwesternmost part of the profile, the crystalline crust shows exclusively low velocities. The prominent Moho is undulating and varies in depth between 32 and 50 km. It is underlain by high-velocity bodies (V p : 8.36–8.40 km/s), against the background of 8.16–8.25 km/s in the mantle. The velocity model corresponds with the anomalies of potential fields and zones of high electric conductivity. • Ray-tracing P- and S- wave velocity model was presented for Ukrainian Shield. • Vp in crystalline crust increases gradually with depth from 5.97 to 6.85 km/s. • Large wave-form variations in Moho depth (from 32 to 50 km) are observed. • High velocity bodies (Vp >8.35 km/s) up to 15 km thick were found below Moho. • At depths of ∼60–75 km inclined reflecting horizons occur in the mantle. [ABSTRACT FROM AUTHOR]

A network of long-period magnetotelluric and magnetovariational data (124 sites) in the period range of 9—16 to 2500—6400 s made it possible to explore the geoelectric structure of the Erth’s crust and upper mantle of most of the Dniester-Bug and adjacent megablocks of the Ukrainian shield. Based on the resistivity cross-sections along the profiles (with 2D inversion), a three-dimensional matrix was created for the territory limited by coordinates 27.7—30.4° E and 47.7—49.4° N, which included the spatial coordinates of each grid node on each profile, the power of the model cells, and the resistance value in the cell. As a result, geoelectrical anomalous structures were identified at different depths from 3 to 100 km. The entire block of rocks 200×200 km down to a depth of 100 km is characterized by high resistivity, against which objects of reduced resistivity (LRO) are identified. The resulting distribution of high-resistivity rocks over the entire depth of the model is in good agreement with the laboratory dependencies obtained both for the rocks of the Ukrainian Shield and other data. Model data show a significant difference in resistivities in the upper 14—16 km (above 105 ohm), lower crust (about 104 ohm), and upper mantle (103 ohm). Against a general decrease in resistance with depth in the Earth’s crust, three regions were identified in which anomalously high (for a given depth) resistances extend to the entire thickness of the crust. These high-resistivity objects are consistent with positive Bouguer anomalies. Against the background of high-resistivity rocks, LROs stand out, the resistance of which does not exceed 120 ohm·m. The spatial dimensions of the LRO zones indicate their locality and do not form a continuous layer. An analysis of the distribution of LROs in space and depth suggests a genetic relationship between mantle LROs and crustal LROs. Comparison of mantle LROs with the Beltska zone of modern activation on the territory of Ukraine shows their good agreement both vertically and horizontally. To explain the lower LRO resistivity in the upper mantle, overheating of the rocks to solidus and 2—3 % melting and/or the presence of fluids is necessary [Gordienko, 2017]. In recent studies discussing the influence of thermobaric conditions and the fluid content necessary to explain the presence of increased conductivity in the upper mantle, the authors of [Blatter et al., 2022] concluded that an anomalously large amount of volatiles is needed with small amounts of melt. The assumption that mantle LROs are related to crustal LROs has been tested by comparing LROs with fault zones. The presence of LROs in the mantle, their vertical extent, and their connection with rejuvenated fault systems can serve as a basis for the deep migration of fluids enriched in volatiles.

A special class of local small sizes of subisometric magnetic field anomalies (AMF) of the Ukrainian Shield (USh) is considered here. Such AMF are united by the volcanogenic-intrusive-tubular origin of the sources associated with the assumed source-channel manifestations of pulsed plutonic-degassing processes of the Earth. The geological study of such anomalies indicates the enrichment of their sources with mineralization of dark, noble, non-ferrous and rare metals. Some of these AMF (Zhdanivska group, Rivnenska) in general contours coincide with local gravitational minima due to decompaction and grinding of the rocks that cause them, despite the basic-ultrabasic composition. Other anomalies, on the contrary, fully correspond to the maxima of gravity due to the enrichment of rocks with magnetite (Pischansk AMF) or ilmenite (Stremigorodsk AMF) on an industrial scale. In the section, all the studied sources of anomalies have a funnel-shaped (sometimes fungal-shaped) or stock-like shape, which indicates the focal-channel type of their genesis. A characteristic feature of some of the studied AMF are peculiarities of the magnetization vector of their sources, which has variable directions in the section and is often subhorizontal (Kalyniv group of anomalies, Rivne and Stremigorod AMF), which is unusual for the USh latitudes. This indicates a multiphase and separation in time formation of the sources of these anomalies from the Archean-Proterozoic time of formation of the surrounding USh rocks. This time may be either Proterozoic (Stremigorod AMF), or Phanerozoic (Rivnenska AMP — early Paleozoic). A number of similar in size and concentrically-zonal shape of Cenozoic AMF has been established, for example, within the TransCarpathian fault zone. The obtained results show that within the Ukrshield there is a certain number of small-sized structures associated with different-age focal-channel manifestations of pulsed intrusive and plutonic-degassing processes of the Earth, which are much more widespread than it has been supposed. This does not only extend the prospecting possibilities for new types of minerals associated with the processes of magmatism and degassing of the Earth, but also contains a new additional information in the context of the universal history of the Ukrshield formation and its ore potential

The materials of several articles and reports published in 2022 by the authors of this work and V.P. Kirilyuk (Kirilyuk, 2022 a,b), who discussed the structure and stratigraphy of the Вug area granulite complex of the Ukrainian Shield. The authors, relying on their geological, geophysical and geochemical studies, isotopic geochronology data, as well as on the world experience in studying the Early Precambrian complexes of the Canadian and Australian shields, argue that during 3.8—1.7 Ga, the Bug area granulite complex underwent at least a threefold structural metamorphic processing. Its modern structural plan, as well as, to a large extent, the composition and structural and textural features of metamorphic rocks, are of Early Proterozoic age. Therefore, its division into suites of primary sedimentary-volcanogenic rocks and their vertical distribution by age does not make sense. Only a division into two series is possible — the Dniester-Bug and the Bug, between which there is a tectonic contact. Contrary to this, V.P. Kirilyuk, relying on the experience of his stratigenic-metamorphogenic studies and the authority of the well-known school of L.I. Salopa, E.M. Lazko et al., defends the point of view on the stratigenic nature of the Bug area granulite complex, in which the primacy and stability of the position of strata-formations relative to each other were preserved throughout the entire time. According to V.P. Kirilyuk, there are no breaks and disagreements between the suites, so he proposes to abandon the identification of the early Precambrian USh Bug Group. And the seven suites identified by him, the youngest of which is 3.8 billion years old, are proposed to be attributed to a single Dniester-Bug series. The authors of both alternative points of view apply to the National Stratigraphic Committee of Ukraine with a proposal to revise the stratigraphic scheme of the Early Precambrian of the USh.

The wide-angle reflection and refraction (WARR) SHIELD’21 profile carried out in 2021 crosses from SW to NE the main tectonic of Ukraine. The SHIELD’21 targeted the structure of the Earth’s crust and upper mantle of the southwestern margin of the East European Craton with overlying Neogene Carpathian Foredeep and Vendian-Paleozoic Volyn-Podolian Monocline, Archaean and Paleoproterozoic segments of Ukrainian Shield and Late Paleozoic Dnieper-Donets Basin. The ~650 km long profile is an extension of realized in 2014 RomUkrSeis line in Romania and Ukraine from Apuseni Mountains to southwestern Ukrainian Shield. The field work performed in 2021, included the deployment of autonomous seismic stations and drilling-explosive works. A total of 264 seismic receivers were deployed (160 DATA-CUBE and 104 TEXAN stations) with the average spacing between the observation points about 2.65 km. The sampling interval for all stations was 0.01 s. Seismic energy was generated by 10 shot points with ~50 km of distance between them and total charge in all wells 5775 kg. The SHIELD’21 experiment using TEXAN and DATA-CUBE short-period seismic stations provided high-quality seismic records. The main recorded seismic waves are the refractions of P- and S-waves in sediments, basement, crust and upper-most mantle, and reflections from crustal boundaries, Moho interface and boundaries in the uppermost mantle. Correlation of travel time arrivals of seismic waves provides calculation of the velocity model for both P- and S-waves. The main objective of the SHIELD’21 project is to get new seismic data that increase our knowledge on the lithosphere structure as well as geodynamics of the oil-and-gas-bearing and ore regions of Ukraine.

The aim of the study, the results of which are presented in this article, is to study changes in the composition of hydrothermal fluid ore systems of the early Precambrian on the example of gold and uranium ore deposits of the Ukrainian shield in connection with the evolution of exo- and endogenous processes in the outer shells of the Earth. The method used is a complex isotope-geochemical study of the composition of gas-liquid inclusions of hydrothermal fluid of ore systems. Based on experimental isotope-geochemical studies of the fluid of gas-liquid inclusions in the minerals of Precambrian deposits of uranium and gold of the Serednoprydniprovsky and Ingul megablocks of the Ukrainian Shield, a consistent change in the quantitative and isotopic composition of hydrothermal fluids of mineral formation from Mesoarchean to Paleoproterozoic was established. The content of H2O and CO2 was investigated and the isotopic composition of carbon CO2 fluids in quartz, pyrite, and feldspar were studied. The age range of the studied deposits is 3200—1750 million years. A decrease in the carbon dioxide content in the hydrothermal mineral-forming fluid of the Precambrian occurred in the Neoarchean, that is, before the Great Oxygen Event (Great Oxidation Event) — an increase in the oxygen content in the atmosphere in the Paleoproterozoic and is probably associated with the processes of exogenous and endogenous hydration of ultramafic rocks during the formation of the protocontinental crust. Molar fraction of CO2 in the mineral-forming fluid, in the Precambrian correlates to some extent with atmospheric pressure. The increase in the content of the carbon-12 isotope in the Paleoproterozoic in the mineral-forming fluid occurred due to the oxidation of organic matter with an increase in the oxygen content in the atmosphere.

Stratigraphic complexes of the Lower Precambrian are everywhere metamorphosed. Therefore, the stratigraphic subdivision of the Lower Precambrian has always been inextricably linked with the study of metamorphism. For some time, the degree of metamorphism of the complexes was even used as an indication of their relative age. With the beginning of the use of isotopic dating, this sign was not confirmed, after which the degree of metamorphism was no longer taken into account in the stratigraphic dismemberment of the shields basement. The degree of metamorphism of the complexes was no longer taken into account for a long time when compiling official stratigraphic schemes of the Precambrian of the Ukrainian Shield, which, in the opinion of many geologists, led to distortions of the real stratigraphy of the basement of this region. The authors of the article believe that the degree of metamorphism can still be used in the development of the stratigraphy of the Ukrainian Shield and, above all, in the stratigraphic study of individual megablocks. The possibility of such use of metamorphism is considered in the cycle of publications. This is the second article in the cycle. The first article describes the stratigraphy and metamorphism of all megablocks of the Ukrainian Shield. A number of conclusions have been made about the regularities of the manifestation of metamorphism. It is shown that older stratigenic complexes in each of the megablocks are characterized by higher temperature metamorphism. This pattern provides a basis for establishing the relative stratigraphic sequence of complexes within individual megablocks based on the degree of their metamorphism. At the same time, the distinctive features of the composition and metamorphism of the stratigenic complexes, according to the authors, are a reflection of the successive stages of the geological development of the Ukrainian Shield in the Early Precambrian and can serve as the basis for compiling of the regional stratigraphic scheme on a historical and geological basis. In this second article of the cycle, modern approaches to the geochronological periodization of the Precambrian are considered: a) geochronometric, adopted for the International "The Geological Time Scale" and b) historical-geological, which is the basis of the "General Stratigraphic Scale of the Lower Precambrian of Russia". The current "Correlation Chronostratigraphic Scheme of the Early Precambrian of the Ukrainian Shield" is based on the geochronometric approach, which the authors, like many other researchers, consider unacceptable for practical use. The article proposes a variant of the regional stratigraphic scheme of the Ukrainian Shield on a historicalgeological basis, compiled at the level of complexes, which in the final version of the scheme can be divided into series and suites. [ABSTRACT FROM AUTHOR]

In order to consistently highlight the distribution and forms of finding lithium in the subsoil of Ukraine, its geochemistry and mineralogy, genetic types of deposits and ore occurrences, mineralogical criteria and methods of their search and evaluation, the authors have planned a series of articles. The first part quantitatively and qualitatively analyzed the distribution and forms of Li occurrence in existing and prospective objects — the Volyn deposit, the Perzhansky ore district, rare-metal granites of the Azov region and the Korosten pluton, rare-metal pegmatites of the Azov region and the Shpolyansk-Tashlytsky ore region (Inguletsky megablock), hydrothermal of the Nagolny ridge (Donbas). The lithium-concentrating minerals in these objects, according to our data, are the following: spodumene, petalite, evcryptite, tourmaline, holmquistite, Li-Al micas of the isomorfic series (muscovite-lepidolite), Li-Fe micas of the isomorphic series (anite (lepidomelane) or siderophyllite, protolithionite, zinnwaldite, cryophyllite, lepidolite), margarite, donbasite, kukeite, polylithionite (?), tainiolite, tryphyllite, amblygonite, simferite. [ABSTRACT FROM AUTHOR]

The article continues the discussion of the origin of the leucogranulite formation of the Buh Area granulite complex and the possibility of its isolation as an independent stratigraphic unit – zelenolevadivska suite – in the scheme of the dismemberment of the Lower Precambrian of the Ukrainian Shield. This topic was unexpectedly raised in an article by a team of authors [24] after prolonged active use of these units in scientific literature and geological practice. The authors expressed the opinion that the leucogranulite formation is not a stratigenetic formation, but was the result of dynamometamorphism and the accompanying processes of diaphthoresis and quartz-feldspar metasomatism. In this regard, according to the authors, the zelenolevadivska suite should be excluded from the stratigraphic scheme of the Precambrian of the Ukrainian Shield. The arguments of the authors of the published article do not seem convincing. The zelenolevadivska suite and granitoids that replace it are widespread in the basement of the south-western part of the Ukrainian shield and occupy about half of its territory. That is why ideas about the origin and structural position of these formations are important for the geological mapping of this region and for understanding its geological structure and evolution. In this regard, this publication presents previously known and new grounds that confirm the initial priority conclusions about the stratigeneous origin of the leucogranulite formation (zelenolevadivska suite) [17]. It has been shown that the leucogranulite formation is represented mainly by leucocratic two-feldspar gneisses and by their subordinate variety of related rocks. On the basis of the differences in the composition of the accompanying rocks, the formation is clearly divided into two parts: the lower, including magnetite-bearing rocks, and the upper – dominant leucocratic gneisses, often transformed into various-looking granitoids. In the stratigraphic scheme of the Ukrainian Shield, these parts of the leucogranulite formation are shown as separate subdivisions – pavlivska (lower) and zelenolevadivska (upper) strata.

The article examines the results of research carried out by the methods of reflected waves and common depth point (MRW-CDP) on the «Granit» geotraverse, which crosses the whole of Ukraine from the southwest to the northeast and passes through the territories of Odesa, Mykolaiv, Dnipropetrovsk, and Kharkiv regions, west of Belgorod region of Russia. In structural and tectonic terms, the geotraverse crosses large geological structures: the marginal part of the Scythian Plate (SP), the Ukrainian Shield (USH), the Dnieper-Donetsk Basin (DDB) and the southern slope of the Voronezh Crystalline Massif (VCM). The analysis of the features of the registered wave field and the completed structural constructions of the consolidated crust and upper mantle in the section of the «Granite» geotraverse shows a complex heterogeneous structure with certain spatially correlated regularities, against the background of which there are numerous inhomogeneities characteristic of both individual blocks and their individual intervals. The cross-sections of all the studied geostructures are characterized by a high level of saturation with non-extended, unevenly distributed reflective elements, which occupy positions from subhorizontal to steeply sloping in space. With all the diversity of the mutual location of both individual boundaries and their groups, a fairly strict correlation is established, which primarily provides information about the nature of stratification, deformations, and the stress state of the structures of the consolidated crust and upper mantle. In the modern structure of the crust, a significant role belongs to faults and tectonic plates, the vast majority of which are manifested as inclined zonal bodies with different orientations. Systems of faults and plates form a complex hierarchical interdependence. The «crust-mantle» transition zone is a complex, laterally variable area, with a thickness of 3 to 7 km, caused by systems of subhorizontal stratification, expressed by the concentration of reflective elements. The largest homogeneous and contrasting region of the transition is manifested in the structures of ancient consolidation, with a thickness of the crust of about 40 km. As a result of the research, more detailed information on the structure of individual tectonic elements was obtained, and some general principles of the structure of the transition zone from the ancient continental platform to the active folded belt were clarified.

Stratigraphic complexes of the Lower Precambrian are everywhere metamorphosed. That is why the stratigraphic dismemberment of the Lower Precambrian has always been inextricably linked with the study of metamorphism. For some time, metamorphism was even used as a sign of the relative age of stratigenic metamorphic complexes according to the principle - "the higher the degree of metamorphism, the older the complex". The high-temperature complexes of granulite and amphibolite facies belonged to the Archean, while the less metamorphosed complexes belonged to the Proterozoic. But already at the beginning of the widespread use of methods of isotope dating of metamorphic shield complexes, the most ancient age determinations were obtained from weakly metamorphosed complexes. After that, the degree of metamorphism was no longer taken into account in the stratigraphic dismemberment of the shield basement. The degree of metamorphism of the complexes has not been taken into account for a long ago when compiling official stratigraphic schemes of the Precambrian of the Ukrainian Shield, in which isotope dating plays a leading role. This led, according to many geologists, to distortions in the schemes of the real stratigraphy of the basement of the region. The authors of the article believe that the degree of metamorphism can still be used in the development of the stratigraphy of the Ukrainian Shield and, above all, in the stratigraphic study of individual megablocks. The possibility of such use of metamorphism is considered in the cycle of publications in which this is the first article. The article presents the characteristics of stratigraphy and metamorphism of all megablocks of the Ukrainian Shield. In the structure of the megablocks of the Ukrainian Shield, as well as all the shields of ancient platforms, the following stratigenic metamorphic complexes of the Lower Precambrian have been established, differing in the type and degree of metamorphism: a) granulite-gneiss, b) amphibolite-gneiss, c) greenstone (metavolcanogenic), d) ferruginoussiliceous-shale (metavolcanogenic-chemogenic-terrigenous), e) gneiss-shale (metacarbonate-terrigenous). It has been established that in all megablocks granulite-gneiss complexes are represented and are the most ancient, and all younger complexes are always less metamorphosed than the previous ones. Thus, the relationship between the degree of metamorphism and relative age in individual megablocks is preserved, but this feature cannot be extended to the entire shield. Coeval complexes of neighboring megablocks may have different degrees of metamorphism, and younger complexes of one of the megablocks are sometimes more intensely metamorphosed than older ones in the neighboring megablock. [ABSTRACT FROM AUTHOR]

The Dobropil granitoid massif is confined to the junction of the Gulyaipil and Remiv blocks of the Azov region. The granitoids of the massif intrude the Kosivtsiv greenstone structure. The massif is represented by a fairly wide range of rocks connected by gradual transitions (quartz diorites, granodiorites, quartz monzonites, monzo-diorites, tonalites, plagiogranites, granites). A characteristic feature of the granitoids of the massif is the presence in them of various amounts of small xenoliths of rocks of different composition (amphibololites/metapyroxenites, amphibolites, quartz diorites and granitoids of the normal series). According to geological data, the formation of the massif took place in two stages, which correspond to the formation of two corresponding phases of granitoids. The article presents the results of uranium-lead dating of various generations of accessory zircon from tonalites of the second phase of the massif intrusion using the SHRIMP-II ion-ion microprobe. It is shown that zircon crystals are composed of three generations. Zircon of the first generation is represented by heterogeneous cores on which magmatogenic zircon actually grows — the second generation. Zircon of the third forms rather thin shells on the first two, its crystallization is due to the processes of post-magmatic kalishpatization, which took place, most likely, at the pneumatolite stage of the evolution of the silicate melt. According to the results of uranium-lead ion-ion dating, it was found that among the zircon of the first generation, a fairly wide range of numerical age values (according to the 207Pb/206Pb ratio) is noted, from 3.6 to 2.8 billion years. The age of 2078 ± 20 million years ago was obtained for the upper intersection of the concordia with the discordia, constructed on the basis of analytical data obtained for thinzoned shells (zircon of the 2nd generation) and zircon shells of the third generation, which corresponds to the time of rooting of the tonalites of the second phase of the intrusion. [ABSTRACT FROM AUTHOR]

Two species types of basic rocks contrasting in chemical and mineral composition were investigated within the Korsun-Novomyrhorod anorthosite-rapakivigranite pluton (KNP) of the Proterozoic age. In comparison to more typical basic rocks of KNP, the investigated rocks are presented by the extremely Fe-rich fayalite gabbroids and the most MgO enriched biotite gabbronorite. The first of them occupy a deeper level of the Horodishche massif in the central part of KNP. According to a high-Fe association of minerals and reduced or low An content in plagioclase they may represent the crystallization of a highly evolved basic melt (after anorthosite and gabbronorites separation), which were crystallized under abyssal conditions and low oxygen fugacity. Preliminary geochemical data indicate that trace elements concentration and negligible negative Eu-anomalies (0.72-0.95) are similar to most distributed basic rocks but unlike the last it is slightly differed by decreasing La/Yb and enriched in Sc (up to 118 ppm). Thus, we suppose those rocks might be crystallized as a result of mixing highly differentiated (iron and alkali enriched) melt with the early generation of anorthitic plagioclase, with subsequent dissolution of the last. Enrichment in iron of the mafic minerals and increasing of alkalinity of plagioclase in the basic rocks is consistent with the appearance of ferrodioritic melts as a product of prolonged crystalline differentiation of the initial melt. In contrast to fayalitic gabbroids, the pyroxene-biotite gabbronorites from the border zone in according to increased Mg# of the mafic minerals and rocks are obviously the least differentiated varieties of the anorthosite-gabbronorite series. The regularities in chemical composition in such type of rocks are consistent with the liquid line of dissent for basic rocks in KNP, which implies their crystallization at an earlier stage of magma ascending. By composition, such melt can be formed at an intermediate stage from slightly differentiated melt. This is indicated by enrichment in Sr (453- 881 ppm) and Ba (910-930 ppm), Eu/Eu* (0.85-1.10), increased content MgO (up to 8 wt. %), Cr and V (59-193 and 169-350 ppm respectively). At the same time these rocks are enriched in Zr and Hf (378-478 and 10.3-12.02 ppm respectively), highly enriched in Rb (169-192 ppm), with moderate Nb and Ta content (14.6-18.1 and 0.91-2.84 ppm respectively) that point out to interaction and partial assimilation by crust material. Summarizing geological data of the deep drill-holes, it is possible to reveal a general direction of the mafic minerals evolution in the basic rocks and the evidences of cryptic layering. The last are quite clearly manifested both in the large gabbro-anorthosite massifs and individual intrusive bodies. We suppose that the evolution trend of mafic mineral composition are consistent with the tholeiitic trend differentiation of the primary melt with gradual increasing of iron content (under low oxygen fugacity) during differentiation and ascending in the upper crust. According to this interpretation of the inner structure of gabbro-anorthositic massifs, on the modern erosional level of KNP are often exposed the fragments of the upper (or lateral) layered series (Fe-enriched), less often the drill-holes reach up to the heads of the lower layered series. [ABSTRACT FROM AUTHOR]

A scheme of the staging and thermobaric regime of the formation of the Balka Shyroka deposit gold mineralization (Middle Dnieper megablock of the Ukrainian Shield) was constructed, and the sequence and thermobaric intervals of ore formation were determined. Mineral paragenesises are combined into four mineral associations that form a series of mineral complexes: pre-productive magnetite-quartz, productive polysulphide, which includes two productive gold-bearing associations (arsenopyrite-pyrite-quartz with gold and gold-sulphosalt) and post-productive carbonate (quartz-calcite mineral association). Gold-producing associations were formed in a rather narrow range of temperature and pressure changes of the ore-forming environment specific to its composition and aggregate-density state. This affected the phase typomorphism of the respective families of fluid inclusions. Carbon dioxide-water inclusions with different phase ratios are common: Г—РСО2 —РН2О, РСО2 —Г—РН2О, РСО2 —РН2О, Г—РСО2. The most optimal temperature for homogenization of gas-liquid inclusions (according to the first type) is 210-290 °С. In minerals, there are families of two-phase and one-phase CO2 fluid inclusions with wide variations in its density (from 0.65 to 0.87 g/cm³) and homogenization into the liquid phase. These typomorphic features are thermo-barogeochemical search criteria and evaluation signs of gold mineralization. Equally important is the definition of the paleotemperature gradient and the spatial extrapolation of its change with depth, which makes it possible to calculate the vertical extent of mineralization, the level of its erosional section, and the depth of thinning out. [ABSTRACT FROM AUTHOR]

The uranium-lead isotope method is used to date titanites from granitoids of the Ros’-Tikych megablock of the Ukrainian Shield (middle reaches of the Ros’ river, below Bila Tserkva). Their isotopic behavior is analyzed along with published results, of other titanites found in crystalline rocks of the Ukrainian Shield. Titanites of granitoids from the Ros’-Tikych megablock contain impurity lead and this leads to an abnormal isotopic composition. The overestimation in age values calculated by methods that do not require correction for ordinary lead (method normalized, agreed differences and the slope of the regression line on the graph in the coordinates 207Pb/204Pb — 206Pb/204Pb) is up to several tens of millions of years, compared to, calculated on the model of Ahrens-Wetherill. The influence of impurity lead of anomalous isotopic composition on the distortion of the calculated values of the isotopic age, in the ratio 207Pb/206Pb is modeled. It was found that the entry into the isotope system, 2.0 billion years old, of ordinary lead with a modern isotopic composition, even with a ratio of impurity lead to radiogenic lead 1 : 1, will reduce the age by 207Pb/206Pb by only 4 million years. Significantly greater distortions (overestimations) of the isotopic ages is will be caused by impurity lead, in the isotopic composition of which there is an ancient (for example, 500 million older than the age of crystallization of titanite) radiogenic lead. Thus, when the ratio share of impurity lead is 20%, the overestimation of age is more than 50 million years, and it reaches 235 million years for at a ratio of 1 : 1 (50%). The numerical values of the isotopic age will be even more inflated at the ratio of 207Pb/206Pb in cases when impurity lead contains radiogenic lead of older age, even with a smaller share of it in the composition of impurity lead. [ABSTRACT FROM AUTHOR]

Trace element concentrations (REEs, Y, Sr, Th, U) in apatites from the most typical rocks of the KorsunNovomyrhorod anorthosite-rapakivi pluton (KNP) were measured. Apatite was the last liquidous phase to crystallize in all the studied rocks because of the low P2O5 content in the primary melts. In the basic rocks, apatite is the main source of REEs, especially LREEs, except for Eu and Y. In intermediate and acidic rocks, apatites have minor influence on REEs concentrations, but they are more enriched in Th and U. All chondrite-normalized REE patterns of apatite show large negative Eu-anomalies (Eu/Eu* 0.03-0.21). This anomaly as well as increased Sr contents is less prominent (0.39) only in apatite from the norite of the external part of the pluton. With increased magmatic differentiation, apatite becomes more enriched in REEs, but Sr is depleted in the basic and intermediate rocks. In addition, all apatites from these rocks are LREE enriched and depleted in HREE and Sc which is consistent with earlier clino- or orthopyroxene fractionation, considering the minor amounts of in REE in plagioclase. REE patterns normalized to the primitive mantle indicate LREE enrichment ((La/Lu)N = 10.8-36) of apatites from all types of rocks with pronounced negative anomalies of Sr and Eu. This is the result of their low compatibility with apatite compared to other REEs. Inasmuch as the distribution of Eu is related to oxygen fugacity, we think that such unusually low Eu-anomalies reflect the initial melt differentiation under abyssal conditions. Thus, ubiquitous strong negative Eu-anomalies in apatites of all types of rocks are a result of two factors occurring during parent melt fractionation, namely early intensive plagioclase fractionation and highly reduced conditions during melt differentiation. By similar trace elements concentration and similarity of REE distribution in apatites it is pro­bably that basic rocks and monzonitesare are derived from the same primary melt. At the same time, apatites from granites and syenites show maximum enrichment of REEs, especially HREE and Y. This indicates crystallization from residual differentiated melts (for syenites) or partial interaction of melts of various composition (basic and acidic) with migration of enriched LILE and REE solutions into acidic melts. The low content of P2O5 in ore-bea­ring rocks and ores of KNP, as well as the absence of Ti-magnetite and high iron enrichment of mafgic minerals and the unusually strong and negative Eu-anomalies in apatites, clearly distinguishes them from the Fe-Ti-P ores of the Korosten pluton. This suggests differences in the chemical composition of primary melts as well as the physical conditions of their differentiation. [ABSTRACT FROM AUTHOR]

There are seven meteorite craters and several Neogene placers in the Ukrainian Shield containing impact apographitic diamond. In this work impact diamonds from the Bilylivka meteorite crater and from the Samotkan' Neogene titanium-zirconium placer were studied in detail. The results of a comprehensive study of impact diamond crystals — morphology, microtopography, microstructure, carbon isotope composition, photoluminescence, optical, infrared, and Raman spectroscopy — are presented. The size of the impact diamonds is up to 0.5 mm. Impact diamond crystals are mostly two- or three-phase polycrystalline aggregates (diamond, lonsdaleite, graphite). They show external morphological and internal microstructural features of solid-state phase transition of graphite to diamond during impact shock metamorphism – they are paramorphoses on graphite crystals. Microstructural features of the graphite-diamond transition in the studied crystals of impact diamonds are their polysynthetic (11 2 ¯ 1) twinning and the polycrystalline structure of the twins themselves. The carbon isotopic composition of impact diamonds ranges: for Bilylivka diamonds – from –14.80 to –21.84 ‰ δ13C VPDB, with an average value of –17.21 ‰ δ13C and for Samotkan' diamonds – from –10.35 to –23.06 ‰ δ13C VPDB, with an average value of –17.64 ‰ δ13C. The photo luminescent and spectroscopic features of the studied diamonds indicate the absence of nitrogen defects in crystals that are characteristic for mantle diamond. The location of the source rocks and potential routes how diamond have been incorporated into the Samotkan' placer are discussed. [ABSTRACT FROM AUTHOR]