The paper discusses aspects of metallogenic classification of W, Sn, and Mo deposits and considers their affinities corresponding to different geodynamic settings. Most large W deposits correspond to the tungsten-polymetallic and tungsten-molybdenum metallogenic types and were formed in post-subduction (post-collisional and transform margin) settings. Tin-polymetallic deposits could be formed in post-subduction (post-collisional) and within-plate settings as well as in subduction settings, the latter, however, associated with steep-dipping subduction and asthenosphere mantle upwelling yet at the subduction stage. Consistently, this made the geodynamic regime similar to that in post-subduction (post-collisional) setting. Large W–Sn deposits more distinctly formed in post-subduction (post-collisional) settings. Rare metal-tin-tungsten, Sn-polymetallic, and W-Mo deposits formed also in the transitional (to within-plate) post-collisional and actual within-plate settings. Molybdenum deposits formed in subduction (Cu–Mo–Au deposits), post-collisional (Mo–W deposits), transitional, and within-plate (Mo, Mo–Au, and Mo–U deposits) settings. In the areas of polycyclic tectonic development, which included within-plate regime, polychronous W, Sn, and Mo deposits could be formed. Two evolutionary trends (“series”) of metallogenically-related W, Sn, and Mo deposits can be distinguished: (1) a “series” of molybdenum-free deposits (W-polymetallic, W–Sn, Sn-polymetallic and rare metal–Sn–W deposits), and (2) a “series” of deposits with significant Mo mineralization (Cu–Mo–Au, W–Mo–Cu–Au, Mo–W, Mo, and Mo–U deposits), with the respective differences of magmatic sources of productive intrusions. These evolutional trends of deposits are spatially separated in different metallogenic belts and segments, which correspond to belts/segments of ilmenite- and magnetite-series granitoids, respectively. In this regard, molybdenum-free deposits formed mostly in turbidite terranes of the accretion prism, whereas deposits with significant Mo mineralization formed in cratonic terranes with thick continental (cratonic granitic-gneissic) crust. W, Sn and Mo deposits are associated dominantly with magmatic complexes of mixed mantle-crust affinity including “hybrid” granitoid complexes, monzonitoid complexes of shoshonitic series, and anorogenic (A-type) granitic complexes. Melting of the Earth’s crust with various thickness and compositions could have been induced by deep-seated sources both in the oxidized metasomatized lithospheric mantle and in the reduced asthenospheric mantle, with their respective redox differences affecting the redox-potential of the final hybrid magmas.
The Xiangyangshan Pb-Zn deposit, situated in the eastern Xicheng ore field of the West Qinling region, extends the Changba-Lijiagou Pb–Zn mineralization. This deposit lies within a major Chinese polymetallic belt rich in Pb, Zn, and other metals. To clarify its poorly understood genesis, we conducted geological surveys, LA-ICP-MS trace element analysis, and sulfur isotope studies on sphalerite from different mineralization stages. Results show that later-generation sphalerite (Sp2) is enriched in Mn, Fe, Cu, Co, and In, while earlier Sp1 is richer in Cd and Ag. Geochemical indicators, including Zn/Cd and Zn/Fe ratios coupled with principal component analysis, suggest a moderate-temperature ore-forming environment, with Sp2 forming at higher temperatures (299–304°C) than Sp1 (254–263°C). Trace elements like Fe, Cd, and Ag enter the sphalerite lattice mainly via isomorphism. Sulfur isotopes indicate that sulfur originated from seawater sulfate or reduced sulfur in strata, with thermochemical sulphate reduction (TSR) as the primary reduction mechanism. The geological features of the Xiangyangshan deposit and the trace element distributions in sphalerite are consistent with characteristics of sedimentary exhalative (SEDEX) deposits. However, the ore bodies exhibit significant post-mineralization tectonic and metamorphic deformation. Taken together, the deposit is interpreted as a hydrothermal exhalative sedimentary-hydrothermal superimposed transformation deposit.
The distribution of platinum-group elements (PGE) in a newly identified type of high-Rh ores from the three Norilsk deposits (Norilsk 1, Norilsk 2 and Talnakh) have been investigated using inductively coupled plasma mass spectrometry with laser ablation (LA-ICP-MS) and scanning electron microscopy. The high-Rh pyrrhotite ores are distinguished by the elevated contents of Rh, Ir, Os, Ru (Rh + IPGE) > 2 g/t, low Pd/Rh < 10 and Cu/Ni < 2 ratios, compared to other types of the Norilsk ores, and form the spatially distinct parts within the orebodies. More than 80–90
The territory of Southeastern Eurasia includes areas of Russian Transbaikalia, Mongolia and China, where hydrothermal and infiltration uranium deposits are widespread, formed in the Mesozoic–Cenozoic period in the area of postplatform tectonic-magmatic activation or, in terms of plate tectonics, in an “extensive rift system.” It is shown that the accumulation of ore-bearing volcanogenic-sedimentary strata and uranium mineralization of different genesis is synchronized in time with the processes of rifting and magmatism, which in turn are a consequence of the interaction of the Eurasian, Indian, and Pacific plates. The stretching conditions ensured the emergence of depressions in which sedimentary basins and volcano-tectonic structures were formed. The successive alternation of orogenic uplifts and riftlike depressions in the Mesozoic–Cenozoic period created favorable hydrodynamic conditions for the emergence of uranium mineral systems in this area, from Late Jurassic to Early Cretaceous hydrothermal to late Cenozoic infiltration systems. Hydrothermal and infiltration uranium systems of Southeastern Eurasia are characterized by multifluidity associated with a variety of processes of formation of solutions circulating in the depths of the territories of development of tectonic-magmatic activation. In these systems, due to the emergence of hydraulic gradients as a result of relief differentiation, cold meteoric waters capable for carrying uranium entered from the surface. Thermal fluids formed above magmatic chambers and thermal brines formed in deep horizons of sedimentary basins came from the basement or depths of the basins to the same systems. The potential of uranium volcanogenic ore genesis is associated with the development of thermoconvective circulation of uranium-transporting fluids whereas the potential for infiltration formation of exogenous mineralization was most fully realized in the arid climate zone. High-grade uranium mineralization was formed in areas where solutions of different genesis were mixed, which indicates such an important characteristic of mineral systems as multifluidity.
The chemical composition, zonation, and crystallization sequence of minerals of the columbite and wodginite groups in quartz-albite-potassium feldspar-muscovite pegmatites, albitites, quartz-muscovite rocks and muscovite-lepidolite glimmerites of the Vishnyakovskoye rare metal pegmatite deposit were studied. The Ta/(Ta + Nb) (Ta*) = 0.39‒0.50 and Mn/(Mn + Fe) (Mn*) >0.80 ratios in the first crystallized columbite-(Mn) show that the pegmatite melt underwent deep differentiation before its emplacement and was enriched in fluorine. The evolution of the composition of columbite-group minerals is reflected in the increase of Ta* values from 0.80 to 0.91 with an increase in Mn* to 1.00. Wodginite is represented by a Sn- and Mn-rich variety with Sn/ΣB = 0.59‒0.82, Ti/ΣB < 0.20, and Mn/ΣA = 0.88‒1.00. The shape of the grains, their zonation, and the evolution of the chemical composition indicate a predominantly magmatic genesis of the columbite-group minerals and wodginite in quartz-albite-potassium feldspar-muscovite pegmatites. In the albitization and greisenization zones, the columbite-group minerals (CGM) are largely inherited from the pegmatites; in the quartz-muscovite zone, partial dissolution of tantalite-(Mn) and removal of Ta and Nb occur, and in the muscovite-lepidolite glimmerites, tantalite-(Mn) and wodginite are again formed. Wodginite-group minerals (WGM) from different zones of pegmatite veins have highly variable compositions, indicating an important role of post-magmatic processes in their genesis. In muscovite-lepidolite glimmerites, Ta- and Mn-rich wodginite with Ta/ΣB = 0.50‒0.70 and Mn/ΣA = 0.90‒1.00 (tantalowodginite) is formed, after which wodginite itself with Sn/ΣB = 0.50‒0.82 crystallizes. In albitites, wodginite is replaced by Ti- and Fe-rich wodginite and ferrotitanowodginite with Ti/ΣB = 0.52‒0.76 and Mn/ΣA = 0.29‒0.49. The albitization and acid leaching processes manifested in pegmatites do not significantly affect the distribution of ore components, but anomalous accumulation of Ta, Sn, and Nb is noted in locally developed muscovite-lepidolite glimmerites.
The results of geological, petrographic, mineralogical, and geochemical studies of the iron-manganese ore occurrence found in the Upper Ordovician siliceous-carbonate deposits of the Sopchinsky formation are presented. The ore-bearing stratum is represented by an alternation of stratified bodies of iron and manganese ores separated by zones of ore-bearing dolomites. Iron ores predominate in the section and are represented by silicate-oxide (stilpnomelane-magnetite and quartz-stilpnomelane-hematite) varieties. Quartz-rhodochrosite-pyroxmangite and rhodochrosite-friedelite-tephroite associations are distinguished among carbonate-silicate manganese ores. The distribution spectra of trace elements of all ore-bearing rocks are of the same type and are characterized by increased concentrations of Zn, As, Sb, Ba, and Pb, as well as Cs and Mo for iron ores. Manganese ores are characterized by low contents of rare earth elements and a positive cerium anomaly. The established characteristics indicate that the mineralization belongs to the manganese deposits of the Parnok type, which confirms the potential of the Pai-Khoi region in relation to manganese ores. The deposits of the slope facies of the Middle-Upper Ordovician stratigraphic level are the most promising for the detection of ore accumulations.
The Khuglannakh gold occurrence is located in the Ayan–Yuryakh anticlinorium of the Yana–Kolyma fold belt within the eponymous Late Jurassic granitoid stock, which is an NW-extending dike-like body of complex morphology (5.5 km long and up to 1.5 km wide) intruding Late Permian deformed sediments (diamictites, siltstones, and sandstones). The ore field contains 12 ore zones. The main gold resources are concentrated in five ore zones (the Khuglannakh ore occurrence proper). Based on sampling results, four of them are linear quartz–sulfide stockworks, while one zone (ore zone 3) is an axial quartz–sulfide vein with feathering veinlets. The ore zone 3 steeply dips to the southwest (80–85°), oppositely to other zones. The ore zones of the occurrence are confined to a dike-like granodiorite-porphyry apophysis, which are exposed on the surface separately from the main stock body. They are enriched in gold and saturated with quartz–sulfide veins and veinlets. Host rocks are strongly altered and contain up to 3–5
Various possible technogenic and natural autochthonous and allochthonous sources of oil manifestations in the soil cover were examined using the example of the Namarusky uranium ore deposit of Khiagda ore field of the Vitim uranium ore region. Data on the predominantly natural allochthonous deep origin of oil in soils were presented. It is assumed that the main environment for hydrocarbon transport are deep-seated tectonic disturbances of the extension type. Increased volcanic and seismic activity facilitate the migration of hydrocarbons from the granite basement to the daylight surface. The coincidence of the projections of ore bodies onto the daylight surface with anomalies of hydrocarbons in the upper layer of the soil cover is a possible new prospecting criteria for identifying uranium deposits of the Vitim type.
Within the Rassokha terrane, located in the North-East of Russia in the interfluve of Moma and Kolyma, there is a unique section of Ordovician sedimentary volcanogenic formations that is not typical of the North-East of Russia. The Agyndzha ore occurrence is associated with Ordovician volcanics and, according to a number of features, belongs to the Chilean manto type. Deposits of this type have industrial copper and silver contents and are localized in island-arc sedimentary and volcanic deposits of different ages. The most famous of these deposits are located in Chile, Peru, Iran, and China, while in Russia they are practically unknown. The paper presents the first structural data obtained for the Agyndzha ore occurrence, which made it possible to link the processes of structure formation with regional tectonic stages, and also provides the description of copper-bearing rock complexes. Based on the structural analysis, five deformation stages have been identified. The ore mineralization at the Agyndzha occurrence has a pronounced structural control, localized in sub-accordance with the zones of tectonic extension formed during the thrust paragenesis and in the shear environment during the later transpression regime. Subsequently, the latter kinematics was followed by the strike-slip kinematics during the later transpression regime. The tectonic compression environment provided the emplacement of main potential ore bodies with pyrite-chalcopyrite ore mineralization, while at the extension stage, chalcopyrite-bornite mineralization zones were formed. The Valanginian tectonic-thermal ore-generating activation has been established, expressed in the intrusion of trachytes and trachydolerites into the Ordovician rock complex.
Mineral intergrowths, associations, chemistry, and phase relations of the principal sulfide minerals in hydrothermal vein Ag–Pb–Zn sulfide ore deposits [galena, fahlore (Cu,Ag)10(Fe,Zn)2(Sb,As)4S13 – x, x = sulfur vacancies), (Zn,Fe)S sphalerite, and associated sulfides and sulfosalts] are explored utilizing recent developments in mineral thermochemistry. Retrograde reactions in PbS–αAgSbS2–αAgBiS2 galena lead to crystallization of a plethora of lower temperature materials close to the PbS–AgBiS2 binary join in the Prognoz Ag–Pb–Zn deposit (Western Verkhoyanye, Yakutia, Russia). A retrograde reaction involving the removal of the AgSbS2 component in galena explains the production of the highest-Ag fahlores in the Coeur d’Alene mining district (ID, USA) and retrograde AgSbS2 depletions in galenas account for the fact the Ag-rich Sb fahlores from the Keno Hill mining district (Yukon, CA) have compositions consistent with the temperatures of the main stage mineralization but their galenas are nearly pure PbS today. Sb fahlores with intermediate Zn/(Zn + Fe) ratios in two quartz druses from the Mangazeyskoye Ag–Pb–Zn deposit (Yakutia, Russia) have molar Ag/(Ag + Cu) and Zn/(Zn + Fe) ratios which cluster over the miscibility gaps calculated for (Cu,Ag)10(Fe,Zn)2Sb4S13 fahlores. An empirical geothermometer developed for fahlores with sulfur vacancies demonstrates that the temperatures of these fahlores are slightly above the temperatures calculated for these gaps. This suggests that these fahlores were in Landau’s critical regime where the minima in the Gibbs energy surface flatten out as the temperature decreases towards the critical temperature, providing an explanation for this compositional clustering. Strong indirect support for the existence of these miscibility gaps is also provided by the freibergite fahlores from the Xiayingfang Au–Ag deposit (North China Craton), as well as by the direct evidence summarized here. We recognize the importance of retrograde reactions in unraveling the paragenetic sequences of Ag–Pb–Zn deposits and of fahlore and other sulfosalts in recording their operation.
The article summarizes previous studies of the so-called “pyrope-bearing tuffs” of the Sivikagna volcanotectonic structure (Afanasiev et al., 1999, 2010), which suggested the existence of kimberlites within this structure, and recent studies of a kimberlite sample and a metamorphic rock sample from this area, which definitively confirmed this assumption. The article substantiates the existence of a field of Mesozoic kimberlites that penetrated the Lower Triassic tuffs of the trap formation in the Sivikagna River basin in the territory of the Tunguska syneclise. A prerequisite for the search for kimberlites in this area was the discovery of kimberlite indicator minerals in the tuff sequence. There are two groups of indicator minerals: (1) completely “fresh” minerals, corresponding to their state in the kimberlite; (2) minerals with signs of erosion and hypergenic corrosion, corresponding to the state of indicator minerals in intermediate reservoirs. The first group of minerals is present in kimberlites that broke through tuffs of the trap formation. The second group of minerals was captured from the Upper Palaeozoic intermediate reservoir located under these rocks. A kimberlite sample found on the tuff surface and a metamorphic rock sample (metapelite) were studied in detail. The following formations were established in the territory of the Sivikagna volcanotectonic structure: (a) Mesozoic kimberlite bodies, which broke through tuffs; (b) an Upper Palaeozoic intermediate reservoir of indicator minerals of Middle Palaeozoic kimberlites beneath the rocks of the trap formation; (c) the crustal section beneath the Sivikagna volcanotectonic structure contains metamorphic strata of the crystalline basement of the North Asian craton, which includes the West Aldan granite-greenstone terrane and the Tunguska tonalite-trondhjemite-gneiss terrane with the Archean consolidation.
The Nineh deposit is a Pb–Zn deposit hosted by Lower Cretaceous limestone as stratabound and epigenetic mineralization. Based on microthermometery results of fluid inclusions trapped in calcite and barite, a mean homogenization temperature of about 169 and 127°C, and a mean salinity of 5.7 and 13.9 wt
The solubility of mixed sulfides AgAuS + Ag3AuS2 (+Ag2S) at 110, 175, and 220°C and the saturated vapor pressure was experimentally studied in the acidic pH region depending on the concentration of H2S (0.05 – 3.2m, mol(kg H2O)–1). It was found that the main forms of Au are complexes AuHS(aq) and AuHS(H2S)(aq). The equilibrium constant of the reaction AuHS(aq) + 3 H2S(aq) = AuHS(H2S)3(aq) was determined: logK° = –1.03 ± 0.36 at 110°C, 1.26 ± 0.33 at 175°C, and 1.02 ± 0.59 at 220°C. The values of the standard thermodynamic properties and parameters of the Helgeson–Kirkham–Flowers model for the AuHS(H2S)3(aq) complex are calculated. The stability of the AgHS(H2S)3(aq) complex is significantly lower than that of its Au analogue. The AuHS(H2S)3(aq) complex can transport Au in the temperature range of 150–300°C at a high concentration of sulfide sulfur >0.3m (1 wt
Antimony mineralization in western Türkiye is preferentially constrained by NW-SE and NE-SW structures, extending diagonal to the main direction of the extensional zones. Metamorphic schists, volcanic rocks, altered limestone and serpentine are the primary hosting rocks for Sb mineralization, which occurs as veins, irregular pockets, lenses, narrow discontinuous veins, space fills, and occasionally disseminations in silicified rocks. Silicification is a common alteration while argillic and phyllic alteration, limonitization, pyritization and rarely carbonatisation have also been documented in mineralizing zones. Geochemical analyses show that the antimony is accompanied by variable abundance of As, Pb, Zn, Ag, Hg, Au, Cu and Ba. The homogenization (Th) temperature ranges from 150 to 310°C and salinity ranges 0.8–9.0, wt
The paper presents the first U–Pb data (LA-ICP-MS method) on zircon from rocks of the intrusive massifs of the Middle and Southern Tien Shan associated with tungsten deposits of various metallogenic types. Age frontiers of the intrusion emplacement in different tectonic segments of the Tien Shan orogenic belt are established. These age frontiers correspond to certain variations of the tectonic settings, which occurred during the Late Carboniferous-Permian post-collisional stage of the development of this orogenic belt. In particular, the emplacement of the high-potassic intrusions associated with tungsten-molybdenum-copper-gold deposits in the Naryn and Terskey segments of the Middle Tien Shan occurred in the post-collisional setting soon after the termination of active subduction, in the intervals of 325–302 Ma to 303–283 Ma, with the notably younger dates in the western direction. The high-potassic intrusions associated with similar tungsten mineralization in the Kurama segment of the Middle Tien Shan were formed in the similar age interval (298–290 Ma) and significantly later than the high-potassic igneous suites accompanied by copper-molybdenum-gold porphyry mineralization. In the southern (Gissar and Zeravshan) segments of the Southern Tien Shan, two age intervals are distinguished for the intrusions associated with tungsten-polymetallic(-gold) deposits: (i) Late Carboniferous-Early Permian (from 307–298 Ma to 292–284 Ma) and (ii) Early Permian (in the order of 293–281 Ma). Tungsten-tin deposits are present in the same mineralized districts, with their intrusions also varying from the Late Carboniferous (305–300 Ma) to mostly Early Permian (296–290 Ma). The latter highlights a different metallogenic specialization of nearly coeval igneous suites at the post-collisional stage, with the participation of magmatic chambers formed in a different protolith in relation to magmatic sources at different crustal and upper mantle levels. The intrusive massifs associated with tungsten-molybdenum deposits in the northern (Nurata) segment of the Southern Tien Shan were formed during the total interval of 282–266 Ma that corresponds to a more mature post-collisional stage.
The paper presents mineralogical characterization of antimony ore occurrences of the Iyul’skoe group within the boundaries of the Tyrgetui-Zhipkosh area (Eastern Transbaikalia), which are localized in terrigenous rocks of Late Permian and Early Triassic age. Low-temperature antimony mineralization is associated with tectonic breccias, which spatially tend towards zones of crushing and argillization of the host rocks. The main ore mineral of breccias is stibnite, which in near-surface conditions (in the zone of hypergenesis) is replaced by “antimony ochres” represented by minerals of the romeite group; the cement of breccias consists of quartz and rare carbonates of calcite–dolomite series. According to the results of microprobe analysis of ore minerals, primary ore mineralization in breccias with quartz and carbonate–quartz cement includes four different mineral associations: bertierite–stibnite, arsenopyrite–marcasite, arsenopyrite–pyrite, and pyrite–tetrahedrite. Analyses of sulfur isotopes in stibnite indicate the participation of organic source in the formation of ore mineralization, and a significant range of obtained values indicates the participation of two or more sources of sulfur in the ore formation process.
Detailed mineralogical and petrogeochemical studies of gabbro–dolerites of the Dlinnoe ore occurrence (Pai-Khoi, Nenets Autonomous District, Russia) were carried out. Three main rock types are identified within the ore occurrence: (1) porphyritic quartz-bearing fine- to medium-grained gabbro–dolerites, (2) quartz medium- to coarse-grained gabbro–dolerites, and (3) leucocratic quartz fine-grained gabbro–dolerites (3) with schlierens and lenses of medium- to coarse-grained diorites. Petrographic and petrochemical studies suggest that the rocks have formed as a result of differentiation of a single magmatic melt, with porphyritic quartz-bearing gabbro–dolerites of the eastern part being early differentiates and quartz and leucocratic gabbro–dolerites and diorites of the western part being late formations. In early differentiates—quartz-bearing gabbro–dolerites—sphalerite–pentlandite–chalcopyrite–pyrrhotite schlierens and nested disseminated mineralization was identified. Telluride, bismuthotelluride and sulfoantimonide mineralization also gravitates to these rocks. Late differentiates—quartz gabbro–dolerites—are associated with pyrite–sphalerite–chalcopyrite–pyrrhotite nested and vein-embedded mineralization. Hessite, altaite, melonite, vavřínite, volynskite, kochkarite, rucklidgeite, and ullmannite were detected for the first time at the ore occurrence. For the first time, Raman spectra for volynskite and kochkarite were obtained by spectroscopic methods, and the determination of rucklidgeite and vavřínite was confirmed by Raman spectroscopy. It was noted that the greatest diversity of mineral species is characterized by early differentiates, where Ni content prevails over Co.
The article presents the results of studies of the composition, morphology, and relationships of rock-forming minerals of phoscorites—magnetite, apatite, biotite, and carbonates—which made it possible to determine the conditions of their formation. The morphology and relationships of minerals were studied on the core material of boreholes 801 (177 running meters) and 59 (150 running meters) by optical and electron scanning microscopy. The chemical composition was determined by microprobe analysis for 100 magnetite–ilmenite pairs, 132 biotite grains, and 163 apatite grains. For magnetite with structures of solid-phase decomposition of ilmenite and biotite, the formation temperature of 850–530 and 750–550°C, respectively, was obtained using geothermometers. Based on the studied characteristics, conclusions were drawn about the participation of magmatic, metasomatic, and hydrothermal stages in the formation and transformation of the Tomtor massif phoscorites. Within the massif of ultramafic alkaline rocks and carbonatites, an ore occurrence of apatite–magnetite ores, Onkuchakh, was discovered, with iron resources of about 1 bln t and P2O5 resources of about 500 mln t. Apatite–magnetite ores (phoscorites) of the Tomtor massif form vein and lens-shaped bodies, dipping at an angle of 75°–80° in the direction of the carbonatite core and in contact with rocks of the silicate complex (foidolites, alkaline syenites) in the immediate vicinity of the carbonatites.
Three ore stages have been identified for the gold-copper-porphyry mineralization of the Despen ore field, associated with granites of the Bice-Serlig massif of the Early–Middle Cambrian Tannuola complex. The I-st gold-bornite-chalcopyrite-quartz ore stage is represented by chalcopyrite, bornite, pyrite, galena, molybdenite, cassiterite, gold, and electrum; the II-nd gold telluride–palladium-sulfide–quartz ore stage–by gold, electrum, keithconnite Pd20Te7, temagamite Pd3HgTe3, telluropalladinite Pd9Te4, kotulskite Pd(Te,Bi), mertiite Pd8(Sb2.5As0.5)3, Au and Ag tellurides selenides; and the III-rd gold-telluride-sulfide-quartz ore stage–by gold, electrum, acanthite, Ag and Bi tellurides, native Bi, alloclasite, cobaltite, barite and ankerite. Fluid inclusion data in quartz (microthermometry, Raman spectroscopy) showed that the I-st ore stage minerals were formed at P 0.4–0.5 kbar from CO2H2O chloride (Na) fluid with a salinity of 18.2–34.8 wt
The Anna gold deposit is a new industrial facility explored between 2006 and 2016 within the oldest Nevyansk–Berezovsky gold-bearing district of the Middle Urals. It is located 45 km north of Yekaterinburg and is confined to the subvertical Verkhotursky meridional oblique-slip fault, occurring among meta-ultrabasic rocks of the Pervomaysky massif. The latter has an arched anticline shape and is cut by some Late Paleozoic granitoid intrusions. The weakly gold-bearing sulfide mineralization of the deposit is associated with quartz veinlets in listvenites. It is represented by native gold, pyrite, chalcopyrite, galena, and fahlore. The productive mineralization of the deposit is associated with a columnar, steeply dipping eastward body of quartz metasomatites (quartz >90
