Search Results (186)

As a potential strategic resource of critical metals, deep-sea cobalt-rich crusts represent one of the most promising metal reservoirs within oceanic seamount systems, and their metallogenic mechanism constitutes a frontier topic in deep-sea geoscience research. This review focuses on the cobalt-rich crusts from the Magellan Seamount region in the northwestern Pacific and synthesizes existing geological, mineralogical, and geochemical studies to systematically elucidate their mineralization processes and metal enrichment mechanisms from a microstructural perspective, with particular emphasis on cobalt enrichment and its controlling factors. Based on published observations and experimental evidence, the formation of cobalt-rich crusts is divided into three stages: (1) Mn/Fe colloid formation—At the chemical interface between oxygen-rich bottom water and the oxygen minimum zone (OMZ), Mn²⁺ and Fe²⁺ are oxidized to form hydrated oxide colloids such as δ-MnO₂ and Fe(OH)₃. (2) Key metal adsorption—Colloidal particles adsorb metal ions such as Co²⁺, Ni²⁺, and Cu²⁺ through surface complexation and oxidation–substitution reactions, among which Co²⁺ is further oxidized to Co³⁺ and stably incorporated into MnO₆ octahedral vacancies. (3) Colloid deposition and mineralization—Mn–Fe colloids aggregate, dehydrate, and cement on the exposed seamount bedrock surface to form layered cobalt-rich crusts. This process is dominated by the Fe/Mn redox cycle, representing a continuous evolution from colloidal reactions to solid-phase mineral formation. Biological processes play a crucial catalytic role in the microstructural evolution of the crusts. Mn-oxidizing bacteria and extracellular polymeric substances (EPS) accelerate Mn oxidation, regulate mineral-oriented growth, and enhance particle cementation, thereby significantly improving the oxidation and adsorption efficiency of metal ions. Tectonic and paleoceanographic evolution, seamount topography, and the circulation of Antarctic Bottom Water jointly control the metallogenic environment and metal sources, while crystal defects, redox gradients, and biological activity collectively drive metal enrichment. This review establishes a conceptual framework of a multi-level metallogenic model linking macroscopic oceanic circulation and geological evolution with microscopic chemical and biological processes, providing a theoretical basis for the exploration, prediction, and sustainable development of potential cobalt-rich crust deposits. Full article

Ataúro Island, located in the inner Banda Arc, provides a natural laboratory to investigate the interplay between magmatic evolution, hydrothermal circulation, and near-surface weathering in an active arc–continent collision setting. This study presents the first systematic island-wide geochemical baseline for Ataúro Island, based on multi-element analyses of stream sediments integrated with updated geological, structural, and hydromorphological information. Compositional Data Analysis (CoDA–CLR–PCA), combined with anomaly mapping and spatial overlays, defines a coherent three-tier geochemical framework comprising: (i) a lithogenic component dominated by Fe–Ti–Mg–Ni–Co–Cr, reflecting the geochemical signature of basaltic to andesitic volcanic rocks; (ii) a hydrothermal component characterized by Ag–As–Sb–S–Au associations spatially linked to structurally controlled zones; and (iii) an oxidative–supergene component marked by Fe–V–Zn redistribution along drainage convergence areas. These domains are defined strictly on geochemical criteria and represent geochemical process domains rather than proven metallogenic provinces. Rare earth element (REE) systematics further constrain the geotectonic setting and indicate that the primary geochemical patterns are largely controlled by lithological and magmatic differentiation processes. Spatial integration of geochemical patterns with fault architecture highlights the importance of NW–SE and NE–SW structural corridors in focusing hydrothermal fluid circulation and associated metal dispersion. The identified Ag–As–Sb–Au associations are interpreted as epithermal-style hydrothermal geochemical enrichment and exploration-relevant geochemical footprints, rather than as evidence of confirmed or economic mineralization. Overall, Ataúro Island emerges as a compact natural analogue of post-arc geochemical system evolution in the eastern Banda Arc, where lithogenic background, hydrothermal fluid–rock interaction, and early supergene processes are superimposed. The integrated geochemical framework presented here provides a robust baseline for future targeted investigations aimed at distinguishing lithogenic from hydrothermal contributions and evaluating the potential significance of the identified geochemical enrichments. Full article

The economic importance of Carlin-type gold deposits is complicated by the concealed nature of stratiform gold-bearing zones and their occurrence at depths of several tens of meters or more below the present-day surface. This necessitates the use of a wide range of technologies and unconventional, including cost-effective and environmentally friendly, exploration methods to delineate potentially prospective areas. This study explores the possibilities of applying remote sensing methods to organize prospecting and exploration activities for targeting Carlin-type deposits in a more efficient and cost-effective way. The location of Carlin-type gold deposits within areas of orogenic and post-orogenic magmatism, mantle plumes, and linear crustal structures—as demonstrated by previous research in the Nevada and South China metallogenic provinces—may serve as a basis for developing a conceptual model of their distribution. To this end, we developed the GeoNEM (Geodynamic Numeric Environmental Modeling) software in Python, which enables the analysis of the formation of fold and fault structures, melt emplacement and contamination, as well as the duration and rate of geodynamic processes. GeoNEM is based on the computational geodynamics “marker-in-cell” (MIC) method, which treats geological media as extremely high-viscosity fluids. Locations of the brittle deformations of the crust, the formation of which was simulated numerically, can be detected through lineament analysis of remote sensing images. The spatial distribution of such structures—lineaments—serves as a predictive criterion for assessing the prospectivity of territories for Carlin-type gold deposits. It has been demonstrated that remote sensing provides a modern level of efficiency, cost-effectiveness, and comprehensiveness in approaching the exploration and assessment of new Carlin-type gold deposits. This is particularly important in the context of rational resource utilization and cost reduction. Full article

Fluorite, a key accessory mineral associated with rare earth element (REE) deposits, exerts a significant influence on REE migration and precipitation through complexation, adsorption, and lattice substitution within fluorine-bearing fluid systems. It therefore provides a valuable archive for constraining REE enrichment processes. The Weishan alkaline–carbonatite-related REE deposit, the third-largest LREE deposit in China, is formed through a multistage magmatic–hydrothermal evolution of the carbonatite system. However, limited mineralogical constraints on REE enrichment and precipitation have hindered a comprehensive understanding of its metallogenic processes and exploration potential. Here, cathodoluminescence imaging and LA-ICP-MS trace element analyses were conducted on fluorite of multiple generations from the Weishan deposit to constrain the physicochemical conditions of mobility and precipitation mechanisms of this REE deposit. Four generations of fluorite are recognized, recording progressive evolution of the ore-forming fluids. Type I fluorite, which coexists with bastnäsite and calcite, is LREE-enriched and exhibits negative Eu anomalies, indicating precipitation from high-temperature, weakly acidic, and reducing fluids. Type II fluorite occurs as overgrowths on Type I, while Type III fluorite replaces Type II fluorite, with both displaying LREE depletion and MREE-Y enrichment, consistent with cooling during continued hydrothermal evolution. Type IV fluorite, which is interstitial between calcite grains and associated with mica, is formed under low-temperature, oxidizing conditions, reflecting REE exhaustion and the terminal stage of fluorite precipitation. Systematic shifts in REE patterns among the four generations track progressive cooling of the system. The decreasing trend in La/Ho and Tb/La further suggests that these fluorites record dissolution–reprecipitation events and associated element remobilization during fluid evolution. Full article

Xicheng is an important Chinese area enriched in lead–zinc polymetallic ore concentration area. Since the 1970s, substantial research achievements have been made in various domains, including the geological and geochemical characteristics of the deposits, metallogenic chronology, features of the marine basin during the initial mineralization stage, enrichment and precipitation of lead–zinc and other metallic ions, ore genesis, and metallogenic simulation experiments. Among these, the most representative findings focus on exhalative sedimentary reformation and the complexation of organic matter with lead–zinc metal elements during sedimentary processes. This review discusses the formation and evolution of sulfur-containing organic matter, especially H₂S, under Thermal Decomposition of Sulfate (TDS), Bacterial Sulfate Reduction (BSR), and Thermochemical Sulfate Reduction (TSR) conditions, and further summarizes the general characteristics of organic matter and lead–zinc (and other metal elements) adsorption–complexation–reduction. Subsequent research on organic lead–zinc mineralization in the Xicheng area has been grounded in ore deposit geology and geochemistry, adopting the perspective of organic fluids. These studies focus particularly on the formation process of Pb–Zn organic complexes and analyze the various stages and mechanisms of mineralization based on the characteristics and evolution of organic matter. This approach provides new insights for understanding both the general features and the unique attributes of lead–zinc mineralization in the Xicheng area. Full article

The Qingshan lead–zinc (Pb–Zn) deposit in northwestern Guizhou Province is a structurally controlled, carbonate-hosted system formed from basin-derived hydrothermal processes. Geology, fluid inclusion, and isotopic data reveal a multi-stage hydrothermal circulation after Emeishan Large Igneous Province (ELIP, ~260 Ma) tectono-thermal reactivation within the Sichuan–Yunnan–Guizhu triangle (SYGT) area. Fluid inclusion microthermometry indicates that ore-forming fluids were derived from deep sources influenced by enhanced crustal heat flow linked with possible thermal input from Indo-Caledonian tectonic activity after ELIP. Ore-stage calcite records mixed carbon derived from marine carbonates with additional inputs from organic matter and deep-sourced fluids, reflecting carbonate dissolution and fluid–rock interaction. Sulfide, together with fluid inclusion temperatures > 120 °C, indicates sulfur derived from evaporitic sulfate reduced by thermochemical sulfate reduction (TSR); the heavy sulfur signature and partial isotopic disequilibrium among coexisting sulfides reflect dynamic fluid mixing during ore deposition. Lead isotopes indicate metallogenic metals were leached mainly from Devonian–Permian carbonates with subordinate basement input. Ore precipitated by cooling, depressurization, and mixing of metal-rich, H₂S-bearing fluids in structurally confined zones where the carbonate–clastic interface effectively trapped ore-forming fluids, producing high-grade sphalerite–galena mineralization. Collectively, these data support a Huize-type (HZT) carbonate-hosted Pb–Zn genetic model for the Qingshan deposit. Full article

The northwestern Hubei region, primarily encompassing Shiyan City and Yunxi County in Hubei Province, constitutes a crucial component of the South Qinling Tectonic Belt. The Neoproterozoic Wudang Group in the study area exhibits Cu element enrichment, with ore deposit formation closely associated with stratigraphic and structural features. This study evaluates copper mineral resource distribution and metallogenic potential in northwestern Hubei by employing factor analysis, concentration-area fractal modeling, and the fuzzy weights-of-evidence method based on stream sediment data, aiming to construct a metallogenic potential model. Factor analysis was applied to process 2002 stream sediment samples of 32 elements to identify principal factors related to copper mineralization. Inverse distance interpolation was used to generate element distribution maps of principal factors, which were integrated with geological and structural data to establish a model using the fuzzy weights of evidence method. Prediction results indicate that most known copper deposits are located within posterior favourability ranges of 0.0027–0.272, constrained by stratigraphic and fault controls. The central northwestern Hubei region is identified as a priority target for future copper exploration. This research provides methodological references for conducting mineral resource potential assessments in north-western Hubei using innovative evaluation approaches. Full article

Sulfide geochemistry has been widely employed to constrain formation processes in various deposit types; however, its use in porphyry W-Mo metallogenic systems is still relatively scarce. The Sansheng porphyry W-Mo deposit (Mo 24,361 t @ 0.226% and WO₃ 17,285 t @ 0.569%), situated in eastern Inner Mongolia, northeastern China, features with quartz vein and veinlet-disseminated W-Mo orebodies primarily localized within the cupolas of an Early Cretaceous granitic intrusion. This contribution provides a comprehensive analysis of the deposit’s geology, in situ sulfur isotopic signatures, and geochemical characteristics of wolframite and sulfides to decipher the formation of the Sansheng deposit. A narrow δ³⁴S range (2.15‰–7.14‰) for sulfides, consistent Y/Ho (5.09–6.23) and Nb/Ta (7.20–19.96) ratios in wolframite, and pyrite Co/Ni (1–10) and As/Ni (>10) ratios collectively point to a shared source—the highly fractionated Sansheng granitic magma. Wolframite, pyrite, arsenopyrite, and chalcopyrite all host significant trace elements, though their enrichment patterns differ considerably among these minerals. Temporal variations in trace element concentrations in wolframite and sulfides reveal a decline in fluid temperature and oxygen fugacity from early to late stages. Greisenization is associated with tungsten mineralization, whereas sericitization facilitates Stage III sulfide precipitation. Full article

Integrating heterogeneous and multilingual geoscience texts into coherent knowledge graphs is challenged by semantic inconsistencies from terminology variations, diverse expressions, and data heterogeneity, hindering the construction of reliable mineral exploration knowledge systems. We propose a semantic-aware fusion framework that enables consistent and sustainable integration of mineral exploration knowledge. Built on a standardized geological knowledge schema defining core entities and their interrelations, the framework incorporates an incremental update paradigm via a schema-guided fusion mechanism that detects and resolves semantic conflicts while preserving provenance for traceable evolution. Evaluated on textual sources, the framework achieves an overall triple extraction F1-score of 0.82. Notably, for the critical task of entity extraction, it attains an F1-score of 0.88, outperforming BERT-BiLSTM and BERT-BiLSTM-CRF baselines by up to 11 points. Precision for key metallogenic elements exceeds 0.90. It identifies 1432 conflicts during fusion and generates a refined knowledge graph of 18,204 high-quality de-duplicated triples, retaining 87.3% of inputs. The resulting graph supports downstream applications, including case analysis, visualization, question answering, and mineral prospectivity prediction. Unlike conventional aggregation approaches, this work treats knowledge fusion as a semantically guided dynamic process, enhancing consistency, transparency, and adaptability. It provides a practical pathway toward intelligent and sustainable geoscience knowledge infrastructures. Full article

Magma oxidation state and water content are pivotal factors governing porphyry copper mineralization. The Xiongcun deposit, the only super-large porphyry copper deposit (PCD) formed in an oceanic subduction environment in the Gangdese belt, has been the primary focus of prior research, with limited systematic comparisons conducted among Xiongcun, weakly mineralized, and barren igneous rocks across the Jurassic Arc. Furthermore, the interaction between ore-controlling factors and deep-seated magmatic processes remains poorly understood. This study examines Xiongcun volcanic rocks, as well as weakly mineralized and barren volcanic rocks from the Jurassic Arc, with Dazi and Jiamagou samples from the eastern segment of Jurassia Arc (ESJA) and Xiongcun, Chucun, and Qinze samples from the western segment of Jurassia Arc (WSJA). All samples (168.0–184.8 Ma) are predominantly calc-alkaline, which is typical of arc magmas. Zircon Hf isotopic data reveal pronounced E-W variations but minimal N-S differences, dividing the arc into the WSJA and ESJA subzones. The WSJA volcanic rocks exhibit uniform Hf isotopic signatures (ε_Hf(t) = 11.2–16.3) and young crustal model ages (186–500 Ma), whereas the ESJA mantle source region is heterogeneous, reflecting greater retention of ancient crustal material. Compared to the ESJA, new data from WSJA samples display higher zircon Ce⁴⁺/Ce³⁺ ratios (454 vs. 145), lower T(Zr-Ti) values (716 °C vs. 779 °C), and elevated whole-rock Ba/La ratios. These differences suggest that mineralization contrasts between the two segments arise from varying fluid metasomatism in their source regions, leading to divergent magma oxygen fugacity and water content—critical controls on porphyry Cu formation. The WSJA magmas exhibit higher values in both parameters, while the ESJA lacks significant mineralization potential. Full article

Jiaodong Gold Province is a globally rare giant gold cluster, with ongoing debates regarding its metallogenic material sources and mineralization mechanisms. This study focuses on the Linglong quartz-vein-type gold deposit within the Zhaoping Fault Zone, conducting in situ trace element and S-Pb isotope analyses of pyrite from different mineralization stages. The trace element characteristics were investigated to explore the sources of metallogenic materials, the evolution of ore-forming fluids, and the mechanisms of gold precipitation. The main findings are as follows: (1) In the Linglong gold deposit, gold primarily enters the pyrite lattice as a solid solution (Au⁺) through Au-As coupling. From the Py1 to Py3 stages, Co and Ni contents significantly decrease, while Cu, As, Au, and polymetallic element contents continuously increase. Additionally, Cu mainly replaces Fe²⁺ in the form of Cu²⁺, whereas Pb predominantly exists as micro inclusions of galena. (2) The S isotope (Py1: δ³⁴S = +7.60‰–+8.25‰, Py2: δ³⁴S = +6.15‰–+8.15‰, Py3: δ³⁴S = +6.90‰–+9.10‰) and Pb isotope (²⁰⁶Pb/²⁰⁴Pb = 16.95–17.715, ²⁰⁷Pb/²⁰⁴Pb = 15.472–15.557, ²⁰⁸Pb/²⁰⁴Pb = 37.858–38.394) systems collectively constrain the ore-forming materials such that they are dominated by metasomatized enriched lithospheric mantle, with simultaneous mixing of crustal materials. (3) The ore-forming fluid underwent a continuous evolution process characterized by persistently decreasing temperatures and a transition from mantle-dominated to crust–mantle mixed sources. The Py1 stage was predominantly composed of mantle-derived magmatic fluids uncontaminated by crustal materials, representing a high-temperature, closed environment. In the Py2 stage, the fluid system transitioned to an open system with the incorporation of crustal materials. Through coupled substitution of “As³⁺ + Au⁺ → Fe²⁺” and dissolution–reprecipitation processes, gold was initially activated and enriched. During the Py3 stage, pyrite underwent dissolution–reprecipitation under tectonic stress and fluid activity, promoting extraordinary element enrichment and serving as the primary mechanism for gold precipitation. Concurrently, bismuth–tellurium melt interactions further facilitated the precipitation of gold minerals. Full article

The Early Permian Tarim Large Igneous Province is a prominent magmatic-metallogenic province in China, hosting significant Fe-Ti mineralized mafic-ultramafic intrusions. Among them, the Wajilitag Fe-Ti oxide deposit stands out, which is hosted by olivine pyroxenite, clinopyroxenite, and gabbro. In the present study, we have examined the mineralogical and geochemical characteristics of apatite to elucidate a deeper understanding of the magmatic evolutionary processes and source characteristics of the mafic-ultramafic intrusions in the Wajilitag area. Petrographic analysis revealed three distinct types of apatite: (1) an inclusion phase within pyroxene and plagioclase, (2) an intergranular phase associated with Fe-Ti oxides, and (3) a late-stage phase found in association with biotite and/or amphibole. Geochemical analysis showed that the inclusion and intergranular apatites exhibited high fluoride (F) and low chlorine (Cl) concentrations, while the late-stage apatite displayed the reverse. A negative correlation between F and Cl was observed, suggesting different formation conditions for each apatite type. The high F/Cl ratios (>3) and enrichment of light rare earth elements (LREEs/HREEs = 12.8–29.5) in the apatite, in conjunction with Sr/Th-La/Sm diagrams, indicated that the parent magma originated from an enriched mantle source, influenced by ancient subduction-related fluids. Furthermore, low sulfur content (0.01%–0.16%) in apatite, along with estimated melt sulfur concentrations (19–54 ppm), points to a low sulfur fugacity environment. These findings collectively suggest that the Wajilitag deposit formed from magma derived from partial melting of an enriched mantle, followed by extensive magmatic differentiation, crystallization of Fe-Ti oxides, and low sulfur fugacity conditions. Full article

The Nakexiuma area in the East Kunlun Orogen Belt hosts two spatially distinct mineralization systems: uranium-molybdenum (U-Mo) in schist and granitoid, and tungsten-molybdenum (W-Mo) in skarn and granitoid. To clarify their genetic relationship, we conducted U-Pb dating and trace element analyses on zircon, garnet, and uraninite. Zircon from granitoids yields a crystallization age of 250 ± 2.3 Ma, followed by W-Mo mineralization at 245 ± 2.1 Ma (garnet) and U-Mo mineralization at 235 ± 9 Ma (uraninite), indicating a prolonged magmatic-hydrothermal history spanning approximately 15 million years. Trace element data reveal a shift in fluid chemistry over time: Skarn garnets show high W contents, suggesting oxidizing, high-temperature fluids; uraninite displays REE depletion and negative Eu anomalies, precipitated from oxidizing fluids encountering a reducing environment. We propose that the W, U, and Mo mineralization in Nakexiuma is the result of this long-lived magmatic-hydrothermal system. The spatial separation of these mineralization systems is attributed to a multi-stage process involving host rock lithology and fluid redox evolution. Early oxidizing fluids from granitoids metasomatized carbonates to form W-Mo mineralization skarn. Later, meteoric water influx increased oxygen fugacity, generating U-rich, highly oxidizing fluids that precipitated uraninite and molybdenite upon interaction with the reducing meta-mafic rocks. These results highlight the roles of lithology and fluid chemistry in controlling spatially separated mineralization within the same system. Furthermore, they expand the Early Mesozoic metallogenic spectrum of the East Kunlun Belt, providing a refined model for polymetallic ore formation in a post-collisional extensional setting. Full article

The Lower Cambrian Niutitang Formation was deposited precisely during the Cambrian Explosion period, a short-lived interval marked by drastic shifts in oceanic chemistry and climate. This stratigraphic sequence preserves a comprehensive record of early-ocean evolution and constitutes a world-class reservoir for rare and precious metals, widely termed the “poly-metallic enrichment layer”. Despite its metallogenic prominence, the genetic model for metal enrichment in the Niutitang Formation remains contentious. In this study, we employed inductively coupled plasma mass spectrometry (ICP-MS), carbon and sulfur analyzer, and X-ray fluorescence spectrometry (XRF) to quantify trace-metal abundances, redox-sensitive element distribution patterns, rare-earth element signatures, and total organic carbon contents. Results reveal that metal enrichment in the Niutitang Formation was governed by temporally distinct mechanisms. Member I records extreme enrichment in As, Ag, V, Re, Ba, Cr, Cs, Ga, Ge, Se and In. This anomaly was driven by the Great Oxidation Event and intensified upwelling that oxidized surface waters, elevated primary productivity and delivered abundant organic matter. Subsequent microbial sulfate reduction generated high H₂S concentrations, converting the water column to euxinic conditions. Basin restriction imposed persistent anoxia in bottom waters, establishing a pronounced redox stratification. Concurrent vigorous hydrothermal activity injected large metal fluxes, leading to efficient scavenging of the above metals at the sulfidic–anoxic interface. In Members II and III, basin restriction waned, permitting enhanced water-mass exchange and a concomitant shift from euxinic to anoxic–suboxic conditions. Hydrothermal metal fluxes declined, yet elevated organic-matter fluxes continued to sequester Ag, Mo, Ni, Sb, Re, Th, Ga, and Tl via carboxyl- and thiol-complexation. Thus, “organic ligand shuttling” superseded “sulfide precipitation” as the dominant enrichment mechanism. Collectively, the polymetallic enrichment in the Niutitang Formation reflects a hybrid model controlled by seawater redox gradients, episodic hydrothermal metal supply, and organic-complexation processes. Consequently, metal enrichment in Member I was primarily governed by the interplay between vigorous hydrothermal flux and a persistently sulfidic water column, whereas enrichment in Members II and III was dominated by organic-ligand complexation and fluctuations in the marine redox interface. This study clarifies the stage-dependent metal enrichment model of the Niutitang Formation and provides a theoretical basis for accurate prediction and efficient exploration of polymetallic resources in the region. Full article

The Upryamoye ore field is located in the Chukotka metallogenic belt in Northeast Russia. The orebodies are hosted within Late Jurassic–Early Cretaceous greenschist-facies metamorphosed rocks and structurally controlled by NW-trending fold-and-thrust dislocations. Based on geological exploration, petrographic, mineralogical, and geochronological studies, new data on the geological structure and composition of gold–quartz mineralization of the Upryamoye ore field are presented. Optical and scanning microscopy were used to study the lithological features of the host rocks and determine the ore textures and the morphology and internal structure of native gold, auriferous pyrite, and arsenopyrite. Qualitative and quantitative characterization of the ore minerals was carried out using SEM-EDS and EPMA. To determine the age of the gold mineralization, Re-Os dating of arsenopyrite and U-Th/He dating of pyrite were performed. The results show that the orebodies comprise carbonate–quartz and sulphide–carbonate–quartz saddle reef veins in both the fold hinge and limbs, as well as mineralized shatter zones and mylonite zones that trace thrust faults. The main ore minerals are arsenopyrite and pyrite, associated with minor amounts of galena, sphalerite, chalcopyrite, tetrahedrite, and bournonite. Native gold is distributed extremely unevenly, forming thin and finely dispersed inclusions in pyrite and arsenopyrite. U-Th/He isotopic analyses of auriferous pyrites suggest that gold mineralization in the Upryamoye ore field occurred at 123 ± 4 Ma. The data obtained by Re–Os dating of auriferous arsenopyrite are inconsistent with direct geological observations but indicate that Os in the arsenopyrite was derived from the crustal source. According to a number of characteristic features of mineralization, the Upryamoye ore field is attributed to a metamorphic genetic type of orogenic low-sulphide gold–quartz deposits. The ore-forming process was long and multi-stage, occurring during the final collisional phase and the beginning of the extensional phase of the Chukotka orogen. Full article