Abstract— The Dudica deposit is located in the southern part of the Republic of North Macedonia (RNM), not far from the border with Greece in the Kozuf–Aridean volcanic region. The deposit is genetically associated with the Neogene igneous event (≥6 Ma, K/Ar), which is manifested at the intersection of northeast trending faults with the northwest trending Vardar fault zone. The REE spectrum of volcanic

Abstract— The sulfur isotope composition of single sulfide grains has been studied taking into account their paragenetic sequence in the samples collected from three hydrothermal fields (Logatchev, Krasnov, and Rainbow), located in the northern part of the Mid-Atlantic Ridge. The δ34S values of sulfides are +3.9 to +6, +7.1 to +9.8, and +2.1 to +8.4 ‰ in the Logatchev, Krasnov, and Rainbow fields,

Abstract— The major objective of the study investigation was to find the physicochemical conditions for U, Nb, and Ta mobilization into the solution from acidic melts similar in composition to rhyolitic inclusions in quartz at the unique Streltsovka Mo–U field (Eastern Transbaikalia). The experiments were performed with model homogeneous leucogranite glass (wt %): 72.18 SiO2, 12.19 Al2O3, 1.02 FeO

Abstract Preore metasomatites of epithermal gold–silver deposits are formed by various types of hydrothermal solutions—from highly acidic and oxidized (argillization, alunitization, secondary quartzites) and moderately acid (sericitization) to rather reduced and alkaline (adularia). The possible processes creating highly acid mineralizing fluids at shallow depths are: (a) the condensation of the acid

Abstract—More than 10 t of gold have been mined within the Vagran placer cluster (Northern Urals), and the identified primary sources are limited to single noneconomic ore occurrences. Our research has established the heterogeneity of placer gold, which reflects the multistage history of the cluster’s development and the diversity of bedrock mineralization owing to which placer deposits were formed

Abstract—Gold and silver are capable of forming stable natural compounds with different elements. For gold 36 minerals are known: 10 in the class “Native metals, intermetallic compounds” and 26 in the class “Sulfides (selenides, tellurides, arsenides, antimonides, bismuthides).” For silver, 194 minerals are registered in the MMA, presented in 8 classes. Compared to gold in the class “Native metals

Abstract New data on the geological structure and ore-bearing structural parageneses of the Uryakh gold ore field are presented. The formation of the deposit occurred in dynamic shear regime along ore-controlling deep-seated faults of the Syulban fault system and faults of the system transverse to it. The interaction of two duplex shear systems resulted in the block structure of the ore field. Tectonophysical

Abstract The Varvarinskoye copper–gold deposit, large in terms of Au and small in terms of Cu, was discovered in 1979 in the western part of the Torgai trough in Kazakhstan. It is composed of Devonian volcanosedimentary and intrusive rocks. Ore zones with a thickness from a few meters to a few tens of meters have been identified against a background of disseminated ore mineralization. They are composed

Abstract A study of the composition of fluid inclusions in ore minerals of the Davenda Mo–porphyry deposit and the Aleksandrovskoe sulfide–quartz–gold ore deposit, as well as of fluid inclusions in minerals of igneous rocks, showed that ore-forming fluids inherit the salt and gas composition of magmatic fluids generated during crystallization of ore-bearing rocks of the Amudzhikan–Sretensky Igneous

Abstract The Lipovka and Alabashka ruby occurrences in the Central Urals hosted in marble of the Murzinka–Adui Anticlinorium are considered. The field works were carried out; the chemical compositions of rocks and minerals and oxygen isotopic composition of corundum and silicates were determined; and micas were dated by the K–Ar method. These occurrences are similar in geological environment and mineral

AbstractIndividual fluid inclusions in quartz from ore veins of the Askold gold deposit, which was previously attributed to the epithermal type, are studied for the first time. It is established that gold mineralization of Askold Island derived from ore-forming fluids of carbon dioxide–water–salt composition, with a salt concentration of 2.8–4.1 wt % NaCl equiv and a high carbon dioxide concentration

AbstractOscillatory zoning in tennantite-(Fe) crystals found in carbonate–sulfide aggregates at the Darasun gold deposit has been studied. Similar elements have been distinguished in zoned crystals: core, “identical oscillatory rhythm,” rhythms with crystallographic and wavy oscillatory zoning, and rim with poorly defined fine oscillatory zoning. Oscillatory zoning is due to considerable variations

Abstract—The formation of present-day seafloor sulfide deposits is accompanied by their continuous oxidation and crystallization of insoluble Fe oxyhydroxides, which absorb metals (including heavy metals) (Fallon et al., 2017). Due to the high sorption ability of Fe oxyhydroxides, it is suggested that the removal of metals during submarine oxidation into ambient seawater is insignificant (Fallon et

Abstract—The limited literature data on gold-bearing albite–pyroxene rodingites are summarized for the Agardag ultramafic massif in southern Tuva. These data are supplemented by new mineralogical, geochemical, thermobarogeochemical, and isotopic–geochemical results in order to reveal the physicochemical mineral formation conditions and sources of ore matter and fluids on gold deposition in rodingites

AbstractThe article discusses the features of the composition, age, and genesis of gold–antimony mineralization of the East Sayan based on the example of the largest Tumannoe ore occurrence. It is shown that objects of this type are rare in the considered region. In the course of studies, it was found that stibnite, pyrite, and arsenopyrite predominate in ores; Bi minerals (tetradymite, cobaltite,

AbstractThe Valunistoe Au–Ag deposit is the third largest among epithermal deposits in Chukotka after the Kupol and Dvoinoe. It is located at the western closing of the East Chukotka flank zone of the Okhotsk-Chukotka volcanic belt. Volcanic domes (Pravogornenskaya, Zhil’ninskaya, Shakhskaya, Valunistaya, Shalaya, and Oranzhevaya, each is 3–6 km in diameter) have the main ore-controlling significance

AbstractExhalation ore mineralization is developing in the crater part of the active Kudryavy volcano. Lithogeochemical sampling results have revealed that Re, Au, Ag, As, Bi, Cd, Cu, Ge, In, Mo, Pb, S, Sb, Se, Sn, Te, Tl, W, Zn, Rb, and Cs accumulate in solid fumarole formations. These elements are transported by high-temperature volcanic gases and are deposited in mineral phases in the near-surface

AbstractBased on 5000 analyses of geological prospecting samples from four alunite deposits (Began’, Ukraine; Haft Sanduq, Iran; Bolshaya Kremenyukha and Kachar, Kazakhstan) and 6000 microprobe analyses of alunite, the features of changes in three parameters of alunite quartzite composition have been studied: (1) alunite content, (2) mole fraction of K in alunite, and (3) correspondence of the amount

Abstract—The recognition of the Fouta Djallon–Mandingo territory as an independent bauxite province is substantiated. It is confined to the morphostructure of the same name within a single geotectonic structure, the sedimentary cover of the Sahara Platform, in the tropical monsoon climate zone in West Africa. The bauxite exploration history, reserve and resource estimates, and production dynamics in

AbstractThe distributions of niobium mineral deposits and their resources on the geological time scale are analyzed. The sampling list includes 45 mineral deposits with their individual resources estimated not less than 105 tons of Nb2О5. The classification of deposits used includes three types, namely, alkaligranitic, foidic, and carbonatitic. The geohistorical variability in niobium metallogeny is

Abstract—Geochronological studies have been conducted for ore-hosting rocks (quartz rhyolites, felsitic rhyolites, porphyry granites) of some U deposits of the Yakshi-Yangistau complex within the Balkashino ore center of the Northern Kazakhstan uranium province. According to geological maps of various scales, the rocks were traditionally ascribed to the Early–Middle Devonian (quartz and felsitic rhyolites)

Abstract—This paper considers examples of “hydrogenic” commercial uranium deposits termed as “sandstone-hosted” in the English literature and characterized by so-called “reduced-type alterations.” In addition to the case when they are absent at the deposit, a few characteristic alterations are identified in different ratios, such as rock bleaching, iron redistribution, argillization, carbonatization

Abstract—Various hypotheses, including alternative ones, have been put forward in the literature about the sources of ore substance and ore-forming fluids in the deposits of the Streltsovka ore field, which hosts the world’s largest uranium reserves, in excess of 250 000 t U: (1) uranium transport by ascending flow of ore-forming fluids that have separated from a deep subcrustal or intracrustal uranium-bearing

Abstract—The characteristic features of the manifestations of acid magmatism and metasomatic hydrothermal alteration processes in Southeastern Transbaikalia, an important mining region in Russia, are discussed. The zoned or beltlike distribution of the ores of various metals, uranium in particular, and other mineral deposits is due to the general evolutionary trends of the geodynamic regimes of the

Abstract—The distribution of major gold deposits in the Earth’s history is discussed. The primary heterogeneity of the Archean crust in terms of gold mineralization is demonstrated. Characteristics of the main auriferous metallogenic epochs are given. The predominant associations of the orogenic gold deposits with volcanogenic massive sulfide and copper–nickel deposits during the early periods of the

AbstractThe global distribution of tantalum deposits and their resources on the geological time scale is analyzed. The analysis is based on the data for 65 deposits of the world with a resource estimate from 2000 t of Ta2O5, which are classified into five types: pegmatitic, granitic, alkaligranitic, foidic, and carbonatitic. Placers and ore-bearing weathering crusts are taken into account with their

AbstractHeterogeneous rhythmic–zonal aggregates of tennantite-IV partly or completely replacing early homogeneous Zn-tetrahedrite-I grains and euhedral (Fe–Zn)-tennantite-I crystal were found in ores of the Darasun gold deposit. The different stages of fahlore replacement were observed. This initiates at grain boundaries and is terminated by a complete transformation into pseudomorphic, newly formed

Abstract—The paper completes a series of works about the unique Schlema-Alberoda deposit. The data on sources of vein and ore minerals and their relation to the processes of regressive alteration of rocks from the contact metamorphism zone are refined. The correlation between stages of mineral formation and their directed change are shown. A general scheme for the sequences in formation stages of the

Abstract—The first results of optical microscopy, cathodoluminescence (CL), ultraviolet fluorescence (UV), electron-probe microanalysis (EPMA), and laser-ablation inductively-coupled plasma-mass spectrometry (LA-ICPMS) study of scheelite from quartz–molybdenite and quartz–carbonate–sulfide veins and veinlets (porphyry type), as well as the magnetite–sulfide massive, veinlets, and disseminated (skarn

AbstractThe Neoarchean subalkaline magmatism of the Keivy structure is expressed in the formation of the volcanoplutonic latite–monzonite–granite association (LMGA). The formation of LMGA magmas is assumed to occur due to melting of metasomatically altered mafic rocks during intrusion into the lower crust of basaltic melts initial for rocks of the dike complex and gabbro–labradorite massifs. The alkaline

AbstractThree hundred thirty-six diamonds from deposits of the Rassolninskaya depression and 144 crystals from recent alluvial placers of the Krasnovishersky district were studied by IR absorption and photoluminescence spectroscopy. It is shown that crystals from the Rassolninskaya depression have a close-to-normal distribution for the nitrogen concentration. The average nitrogen content is 725 ppm

AbstractSulfide-free mineral assemblages with the chalcophile element minerals from occurrences associated with altered rocks of Pelagonian massif, Republic of North Macedonia have been studied. The inputting sequence of various ore-forming constituents has been revealed on the basis of morphological features, zoning of the spinel-group minerals, and the högbomite supergroup minerals. Conclusions about

AbstractMagnetoplumbite-group minerals from various paragenetic assemblages, including a xenolith of altered garnet lherzolite from the Obnazhennaya kimberlite pipe in Yakutia, sulfide-free metasomatic Pb–Zn–Sb ore from the Pelagonian massif in the Republic of North Macedonia, and some other metasomatic occurrences have been studied with electron microprobe, as well as using IR and Raman spectroscopy

AbstractNamibite, Cu(BiO)2(VO4)(OH), has been found in a sample from the Alakurtti granite pegmatites for the first time in Russia. This sample has been deposited in the collection of the Museum of Geology and Mineralogy of the Geological Institute, Kola Science Centre, Russian Academy of Sciences. Bright green crusts and peels of namibite fill cavities and fractures in quartz. The mineral occurs as

AbstractThe pyrochlore-group minerals in ongonite and zwitter of the Verkhneurmiysky granite pluton in the Badzhal district, Russian Far East are reported. The composition, genesis, and crystallization sequence are characterized. Three rare species of pyrochlore, pyrochlore-I and pyrochlore-II in ongonite, and pyrochlore-III in zwitter are found for the first time in the Russian Far East. Pyrochlore-I

AbstractThe rare beryllium silicate, meliphanite, from nepheline syenite pegmatite of the Sakharjok massif, Kola Peninsula has been studied. The chemical composition of the mineral has been refined using infrared and Raman spectroscopy; bulk chemical, thermal, and electron microprobe analyses; and singe crystal X-ray diffraction. The obtained data unambiguously support the presence of H2O in the mineral

Abstract—Chromceladonite in chromitites of the Southern Sarany chromium deposit (the Urals) occurs in two mineral associations: as crusts of acicular grains on uvarovite crystals and in thin-scale aggregates together with quartz and chlorite in brecciated zones developed after chromitites. The chemical composition of chromceladonite (wt %) is K2O 9.4, MgO 6.8, Cr2O3 17.1, SiO2 51.7, Al2O3 8.5, CaO

AbstractZircon from granitoids of the multiphase Turga massif (Eastern Transbaikalia) shows various morphological features and compositions of trace elements. This granitoid massif of the Kukulbey complex is spatially associated with rocks of the Shakhtama monzonitoid complex, whose ages are about 133 and 158 Ma, respectively. Zircon from different granitoid phases of the Kukulbey complex demonstrates

AbstractThe comprehensive study (electron microscopy, mass-spectrometry of secondary ions, Raman spectroscopy) of zircon from harzburgite inclusion in granulites of the Bug complex (Ukrainian Shield) is carried out. Based on a number of features, the studied zircons are subdivided into three groups. Zircon from the first group is of igneous genesis and crystallized 2.8 Ga ago at the temperature of

AbstractThe chemical composition of chlorites from the rocks that are conventionally classified as the residual weathering mantle of the Kolskii ophiolite massif was studied. The chlorites exhibit high Mg/ (Mg + Fe) atomic ratio values (Mg#) of 0.78–0.96 and elevated Si content (2.95–3.74 apfu), but are relatively poor in Al (1.28–2.66 apfu). In terms of octahedral occupancy (RVI is 5.52–5.98 and [R3+]VI

AbstractPaleoreconstruction of events involved in the bottom sedimentation has been carried out on the basis of mineral composition of the section of the minor lake IV (Lake Fumarolnoe, Kamchatka) bottom sediments. The lower sediments are composed mainly of smectite in association with gypsum and jarosite; they are overlain by smectite–kaolinite with a large amount of framboidal pyrite and diatom shells

AbstractDalnegorskite, a new pyroxenoid with the crystal chemical formula Ca2Ca2MnCa(Si3O9)2 and simplified formula Ca5Mn(Si3O9)2, is a rock-forming mineral in the B-bearing calcic skarns in the Dalnegorsk borosilicate deposit (Dalnegorsk, Primorsky Krai, Russia). It belongs to the bustamite structural type and forms a continuous solid-solution series with isostructural ferrobustamite Ca2Ca2FeCa[Si3O9]2

AbstractThe chemical composition, substitutions, and zoning of minerals that concentrate arsenic in specific sulfide-free ore-bearing metasomatic rocks at the contact of the Early Paleozoic metarhyolites and aporhyolite schists with dolomite marbles and baryte schists in the Pelagonian massif, near the village of Nežilivo, Republic of North Macedonia, have been studied. These metasomatic rocks are

AbstractA variety of caryopilite enriched in Mg and Al from the goethite–neotocite–rhodochrosite ores of the Mazul manganese deposit in Krasnoyarsk Krai is described. The mineral occurs as sheaf-like and fibrous aggregates of fine-lamellar individuals intimately intergrown with goethite, hematite, rhodochrosite, and neotocite. The optical parameters of caryopilite are: Z = yellow, X = pale yellow,

AbstractCompositional variations of the epidote-supergroup minerals from the different magmatic, metasomatic, and metamorphic formations of the Pelagonian Massif (Republic of North Macedonia), the Urals (Russia) and the Eifel Mountains (Germany) were studied. The new data on isomorphism in these minerals were obtained. Nine potentially new mineral species belonging to the epidote supergroup including

AbstractThe present communication is focused on inclusions in topaz from the Mokrusha pegmatite deposit, Urals. These inclusions are intergrown fine crystals of manganocolumbite, cassiterite and a mineral compositionally corresponding to niobium tungstate with minor Mn, Ta, and Fe. Electron microprobe and X-ray diffraction study has revealed that this mineral is identical to that previously described

AbstractThe results of experimental modeling of the arsenic transition from natural arsenides to mobile oxidized species in the near-surface environment are discussed. The experiment has been carried out with the samples collected from the dump of the Schlema-Alberoda deposit. Arsenides (safflorite, löllingite, nickeline, rammelsbergite) have been dissolved in acidic and near-neutral oxidative media

AbstractFor the first time data on platinum group minerals (PGM) from the deluvial placer of the Veresovka River are given; their root source are dunites of the northern part of the Veresovoborsky massif. Among minerals typical of this type of placers, Pt–Fe minerals, Os–Ir–(Ru) intermetallic compounds, kashinite, bowieite, laurite, erlichmanite, and Ir–Rh thiospinels have been identified. Irarsite

AbstractIt was found that in minerals, 27 chemical elements are essential species-defining constituents in all tellurium-bearing mineral species known up to 2018 (166). The number of minerals containing these leading elements were calculated as follows (parentheses): O (85), H (47), Cu (42), Pb (39), Bi (30), S (26), Fe (20), Ag (18), Pd (15), Cl (13); Zn Au (11 minerals each); Ca, Se (7 minerals each);

AbstractA new Sc-bearing variety of tusionite has been found in the Eastern Pamirs, in the near-miarolitic Dorozhny granite pegmatite complex at the Kukurt pegmatite field (left bank of the Kukurt River, 45 km east of the settlement of Murghab, Gorno-Badakhshan Autonomous Oblast, Tajikistan). Miarolitic pegmatites are related to the alpine leucocratic granites of the Shatput intrusive complex and occur

AbstractEsseneite from ultramafic xenoliths in dacite flow of the Ten’-01 paleovolcano at the Lena–Vilyui watershed, East Yakutia has been studied. The empirical formula of the mineral has been obtained using electron microprobe analysis: \({\text{C}}{{{\text{a}}}_{{0.99}}}{\text{Fe}}_{{0.52}}^{{3 + }}{\text{M}}{{{\text{g}}}_{{0.32}}}{\text{Fe}}_{{0.06}}^{{2 + }}{\text{T}}{{{\text{i}}}_{{0.05}}}{\text{Mn}}_{{0

AbstractThe new data for the segregations, paragenetic assemblage, and composition of bismuthian jamesonite from gold–quartz mineralization at the Sredny Golgotai deposit located in the eastern part of the Mongolia–Okhotsk orogenic belt are reported. This mineral occurs as two varieties (I, II), which are slightly different in composition and chemically close to bismuthian jamesonite (“sakharovaite”)

AbstractDiamonds with garnet inclusions have been studied from the Udachnaya, Zapolyarnaya, Komsomolskaya-Magnitnaya, Yubileynaya, Komsomolskaya, Aikhal, Mir, and Mayskaya kimberlite pipes of the Yakutia diamondiferous province. A positive correlation has been revealed between the positions of the main peaks in the Raman spectra of garnets and their chemical composition. A method for determining the

AbstractA group of accessory ore minerals is revealed in rocks of the Galmoenan mafic-ultramafic massif (Koryak Upland, Kamchatka, Russia), represented by native metals (iron, copper, zinc, and silver), iron-nickel and cobalt-iron intermetallic compounds, sulfides (pentlandite, cobaltpentlandite, pyrrhotite, sphalerite, heazlewoodite, millerite, shandite, pyrite, chalcopyrite, and Cu3S2 phase), arsenides

AbstractThermal behavior of catapleiite, ideally Na2ZrSi3O9 ⋅ 2H2O, has been investigated with the X-ray diffraction, electroconductivity measurements using impedance spectroscopy, dynamic scanning calorimetry, thermal gravimetry, and infrared spectroscopy. The high-temperature transformation product of catapleiite obtained after annealing of catapleiite at 1000°C has been studied. This is a new microporous

Abstract—The Chernogorskoe gem-quality scapolite deposit, which is attributed to a new genetic type, is described. It is located in the Central Pamirs (Tajikistan), in the Sary-Dzhilga Formation of the Muzkol Group (PR1). Host rocks include metamorphosed mafic–ultramafic formations of the Kukurt complex, among which harzburgite was the first discovered. Albitite lenses host gem-quality scapolite mineralization

Abstract“Invisible” gold in hydrothermal ores is frequently scattered in the most abundant minerals of the Fe–As–S system. It is assumed that “invisible” gold does not incorporate into the mineral structure (nanoscale inclusions of the metal or its compounds) or is chemically bound (isomorphous substitution). The aim of this study is to determine the concentration range of “invisible” gold, species

Abstract—Integrated structural geological, minerogenic, and metallogenic studies with allowance for previous topical surveying, geological mapping and prospecting, and mineral exploration data has revealed that Upper Paleozoic and Early Mesozoic tectonomagmatic structures are widespread in the Selenga ore district. They are associated with the evolution of the transregional Upper Paleozoic Selenga–Vitim

AbstractThe paper presents data on the structure of the Okunevskoe fluorite–leucophanite deposit, located within the Early Paleozoic East Sayan rare metal metallogenic zone. The deposit is controlled by alkali granitoids, with ore mineralization concentrated at the contact between granitoids and host carbonates. Mineralization is represented by leucophanite–fluorite and pyroxene–fluorite ore types

Abstract—The paper presents the results of studying bentonite clays of the Akkalklan deposit (Southeast Kazakhstan). Four main bentonite types are distinguished based on mapping: light gray mudstone, dark gray laminar and rubbly, waxy light brown and pale laminar, and black plastic clays. Their mineralogical study revealed a relationship between the crystal morphological features of the major rock-forming