Search Results (49)

The North China Craton hosts abundant skarn iron resources, yet the regional large-scale mineralization mechanism remains incompletely understood. The Litun deposit is a newly discovered skarn iron deposit in the North China Craton. Integrated field geological investigations, petrographic observations, fluid inclusion microthermometry and stable isotope geochemistry are applied to constrain evaporite contributions to metallogenic processes. Four mineralization stages are identified: skarn, oxide, sulfide, and carbonate. Early skarn-stage fluids are iron-rich magmatic hydrothermal fluids with high temperatures (498 to >550 °C), high salinities (18.6 to 59.4 wt% NaCl eqv.), and magmatic δ¹⁸O values of 8.3 to 10.8‰. Subsequent oxide to late carbonate stages record continuous infiltration of meteoric water, supported by H–O isotopic trends of rising meteoric water proportions. Pyrite from the magnetite ores has δ³⁴S_V-CDT values between 12.0 and 15.0‰, significantly higher than those of pyrite in the Litun diorite (−0.8 to 1.1‰), indicating the contributions of sulfur from evaporites (δ³⁴S_V-CDT 26.9 to 28.6‰) in the mineralization process. Moreover, vein pyrite formed in later stages displays even higher δ³⁴S values (17.3 to 20.9‰), demonstrating progressive enrichment of evaporite-derived sulfur as hydrothermal activity evolves. Synchronous rises in meteoric water fraction and evaporite sulfur proportion indicate evaporites are delivered into the ore-forming system via meteoric water mixing. The mixing of meteoric water containing dissolved evaporites and iron-rich magmatic-hydrothermal fluids may be the major mechanism of magnetite precipitation in the Litun deposit. Full article

Titanite is a widespread accessory mineral in magmatic, metamorphic, and hydrothermal systems and can incorporate trace elements that are sensitive to ore-forming processes. Although titanite trace-element chemistry has been widely applied to individual ore systems and deposit comparisons, its potential for supervised machine-learning-based discrimination across multiple ore deposit types remains less systematically explored. In this study, we compiled a literature-based LA-ICP-MS titanite trace-element dataset comprising 1679 analyses from five major ore deposit types: porphyry, skarn, iron oxide–apatite (IOA), iron oxide copper–gold (IOCG), and orogenic Au deposits. A common feature set of 21 trace elements, including REE, Y, Zr, Hf, Nb, Ta, Th, and U, was used to evaluate six supervised machine-learning algorithms: K-nearest neighbors, support vector machine, random forest, XGBoost, TabMap, and TabPFN. Two-dimensional element and element-ratio diagrams showed substantial overlap among deposit types, whereas machine-learning models better captured deposit-type-related multielement patterns in the compiled dataset. TabPFN achieved the highest stratified 5-fold cross-validation performance, with an accuracy of 0.957 ± 0.011 and a macro-F1 score of 0.944 ± 0.012, followed by TabMap and XGBoost. SHAP and TabMap-SHAP interpretations suggest that deposit classification is mainly associated with coupled variations in REE-Y, Eu, HFSE, and Th-U systematics rather than with a single diagnostic element. These results indicate that titanite trace-element compositions may provide a useful quantitative and interpretable approach for deposit-type discrimination within compiled geochemical datasets, while broader application requires expanded standardized datasets and independent validation samples. Full article

The Yechangping super-large porphyry–skarn deposit is a key component of the East Qinling molybdenum metallogenic belt, central China. Magnetite is widely developed across all mineralization stages of this deposit, yet its systematic geochemical evolution and prospecting significance remain poorly constrained. This study presents in situ major- and trace-element analyses of magnetite via electron probe microanalysis (EPMA), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and elemental mapping, to unravel the ore-forming hydrothermal evolution and establish reliable prospecting indicators. Four magnetite generations are identified based on petrography and paragenetic relationships: late skarn stage (Mt1), oxide stage (Mt2 and Mt3), and polymetallic sulfide stage (Mt4). Magnetite has total iron contents (TFeO, total Fe calculated as FeO) of 82.72–95.46 wt.% (values above the 93 wt.% stoichiometric limit of pure magnetite stem from minor oxidation), with dominant isovalent Fe³⁺ and Al³⁺ lattice substitution supported by a significant negative Fe–Al correlation. Systematic stage-dependent geochemical variations are observed: Mt1 has the highest Ti (mostly >1500 ppm), V and Cr, while Mt2–Mt4 show progressive Ti depletion (mostly <100 ppm), recording continuous cooling of the hydro-thermal system. V and Cr contents decrease markedly from Mt1 to Mt3, with secondary enrichment in Mt4; Mo concentrations peak in Mt2 (average 5.06 ppm), coupled with elevated chalcophile metalloid Te, As, Pb and Bi. Elemental mapping results show that K occurs as discrete hotspots, which may be mainly derived from feldspar microinclusions, rather than lattice substitution in magnetite. These geochemical fingerprints record a transition from high-temperature magmatic–hydrothermal fluids to late contact-metasomatic fluids, with evolving fluid–rock interaction and oxygen fugacity. Our results demonstrate that magnetite chemistry is a reliable tool for discriminating mineralization stages and vectoring prospecting targets in porphyry–skarn Mo–W systems. Full article

Skarn deposits, as one of the most widespread ore deposit types, commonly contain economically subordinate Co, which can locally reach ore-grade concentrations in arsenide and sulfarsenide minerals. However, the partition behavior of Co during skarn mineralization and the key physicochemical factors governing its enrichment remain unclear. The Haisi Fe-Co deposit in the eastern segment of the East Kunlun Orogenic Belt is an ideal case for understanding Co mineralizing processes. Based on mineral paragenesis and texture observation, the chemical compositions of magnetite and Fe, Co-, and As- mineral phases were obtained using the EPMA and LA-ICPMS methods. Low Co concentrations (<7 ppm) in magnetite suggest a low partition coefficient of magnetite relative to skarn fluids. During the sulfide stage, abundant glaucodot, alloclasite, cobaltite, and Co-rich arsenopyrite were formed, following earlier native bismuth, safflorite, and löllingite mineralization. The observed paragenetic evolution from diarsenides to sulfarsenides likely records a progressive increase in oxygen fugacity (fO₂) and an increase in the S/As ratio of ore-forming fluids. Thermodynamic modeling using CHNOSZ corroborates that the continuous increase in fO₂ and sulfur fugacity (fS₂), coupled with a possible decrease in pH, promoted the sequential precipitation of diarsenides, sulfarsenides, and ultimately sulfides. These findings imply that dynamic redox and sulfur activity gradients are critical drivers for Co concentration in skarn systems. Full article

Sulfide-bearing iron oxide deposits consisting of magnetite and silicates are common within the greenstones of north-west Finland and northern Sweden. These iron oxide deposits have variable copper, gold, and uranium content and occur in association with tuffite, black schist, and dolomitic marble. The deposits have a resource size of up to 145 Mt and an iron content of 35%–50% (e.g., Stora Sahavaara). The total sulfur content of these deposits is typically in the range of 1%–5% but can have exceptional values up to 20.8%, and disseminated pyrite, pyrrhotite, and chalcopyrite are commonly present. The prediction of acid rock drainage and metal leaching potential requires a detailed understanding of the site-specific rates and mechanisms of weathering. This has been obtained through geochemical (multi-element analysis and acid–base accounting) and mineralogical characterization testing undertaken on representative materials, including multi-element analysis, acid–base accounting, net acid generation testing, and humidity cell testing. Despite the high sulfide content and low neutralizing potential of most rock types found in these deposits, the humidity cell tests showed a delayed onset to acid generation, which is primarily attributed to sulfide crystallinity and mafic silicate dissolution leading to slow oxidation and reaction rates. The need for long-term kinetic testing is evident from the Hannukainen amphibole and schist rock types. This study provides an overview of the environmental geochemistry of the skarn-hosted sulfide-bearing iron oxide deposits in Scandinavia. These deposits show potential for acid generation but due to the buffering reactivity of mafic silicates and the high crystallinity of the sulfides, the rate of acid generation is slow and the onset of these conditions delayed by mineral buffering. Full article

The Qulong–Jiama polymetallic ore concentration area, located in the eastern segment of the Gangdese metallogenic belt, is one of China’s most significant copper resource production zones. With the growing demand for copper resources, this area has become a key target for mineral exploration. The current study aims to explore the application potential of multispectral and hyperspectral remote sensing technologies in porphyry copper deposit prospecting, establish a hyperspectral remote sensing prospecting model tailored to this region, and provide technical support for prospecting prediction and resource exploration of similar deposits. Sentinel-2 and Landsat 8 data were used to outline major alteration anomalies at the regional scale, while GF-5 hyperspectral data enabled precision mineral mapping. Results show clear porphyry-style alteration zoning. Hyperspectral mineral identification reveals 33 mineralization- and alteration-related minerals, including muscovite, biotite, pyrophyllite, dickite, chlorite, epidote, and limonite. The ore concentration area exhibits a well-developed inner–middle–outer alteration sequence: (1) an inner potassic–silicic zone locally accompanied by skarn; (2) a middle phyllic and argillic zone dominated by quartz–sericite–pyrite assemblages; and (3) an outer propylitic zone of chlorite–epidote–carbonate with supergene iron oxides. These alteration patterns spatially coincide with known deposits and metallogenic structures such as faults, annular features, and intrusive contacts. Based on these spatial relationships, a hyperspectral remote sensing prospecting model was constructed. The model defines diagnostic mineral assemblages for each zone, highlights structurally altered overlapping areas as priority targets, and effectively predicts the distribution of ore-related alteration belts. The strong correspondence between remote sensing-derived anomalies and existing deposits demonstrates that hyperspectral alteration information is a reliable indicator of ore-forming systems. The proposed model not only provides a scientific basis for further prospecting and exploration in the Qulong–Jiama area but also serves as a reference for copper exploration in the Gangdese metallogenic belt and other similar porphyry–epithermal metallogenic systems. Full article

The Kavokta deposit in Russia contains gray and black dolomite-type nephrite, which is in high demand commercially. Although the fact that black nephrite has been found in several deposits, the reasons for its color are not well understood. The present study aims to identify the localization and mineral composition of gray and black nephrite, and to determine the reasons for its dark coloration. The mineral composition of nephrite was studied using a scanning electron microscope with energy-dispersive microanalysis (SEM-EDX) and X-ray phase analysis. Also, the isotopic composition of carbon in graphite in nephrite and in carbonates associated with nephrite in the surrounding strata was determined. The gray–black color in most samples from the southeastern part of the Kavokta deposit (lodes 17 and 28 of the nephrite-bearing zone 4 of the Medvezhy section and lode 6-1 of the nephrite-bearing zone 6 of the Levoberezhny section) is due to the presence of graphite. Syngenetic graphite formed both by the organic matter buried in dolomites and by the decomposition of carbon dioxide that is released during decarbonation under the influence of deep-seated hydrogen. The color of nephrite also depends on the iron content, changing from white to light green as the iron content increases. The gray color of tremolite–diopside nephrite is due to the development of chlorite aggregates that replace diopside and/or tremolite. The gray-green to black color of the nephrite in the northwestern part of the Kavokta deposit (lode 1 of the nephrite-bearing zone 1 of the Prozrachny section) is due to the high iron content in the tremolite–actinolite at the contact with the epidote–tremolite skarn formed after amphibolite. The identified patterns of black nephrite localization can be used in the process of geological exploration of similar deposits elsewhere in Russia and abroad. Full article

Skarn-type iron ore is economically significant, and numerous skarn ore deposits have been identified in the North China Craton. The newly discovered orbicular diorite in this region is distinguished from other analogous rocks due to the accumulation of large magnetite particles, which may shed new light on the genesis of this ore type. The magnetite in different parts of the orbicular structure exhibits distinct compositional differences. For example, magnetite at the edge has a small particle size (200 μm) and is associated with the minerals plagioclase and hornblende, indicating that it crystallized from normal diorite magma. By contrast, magnetite in the core has a relatively large particle size (>1000 μm), is associated with apatite and actinolite, and contains apatite inclusions as well as numerous pores. The size of magnetite in the mantle falls between that of the edge and the core. The syngenetic minerals of magnetite in the mantle include epidote and plagioclase. The magnetites in the cores of orbicules have a higher content of Ti, Al, Ni, Cr, Sc, Zn, Co, Ga, and Nb than those in the rim. The δ⁵⁶Fe value of the core magnetite (0.46‰–0.78‰) is much higher than that of the mantle and rim magnetite in orbicules. Moreover, the δ⁵⁶Fe value of magnetite increases as the V content of magnetite gradually decreases. This large iron isotope fractionation is likely driven by liquid immiscibility that forms iron-rich melts under high oxygen fugacity. The reaction between magma and carbonate xenoliths (Ca, Mg)CO₃ during magma migration generates abundant CO₂, which significantly increases the oxygen fugacity of the magmatic system. Under the action of CO₂ and other volatile components, liquid immiscibility occurs in the magma chamber, and Fe-rich oxide melts are formed by the melting of carbonate xenoliths. Iron oxides (Fe₃O₄/Fe₂O₃₎ will crystallize close to the liquidus due to high oxygen fugacity. These characteristics of magnetite in the Tanling orbicular diorite (Wuan, China) indicate that diorite magma reacts with carbonate xenoliths to form “Fe-rich melts”, and skarn iron deposits are probably formed by the reaction of intermediate-basic magma with carbonate rocks that generate such “Fe-rich melts”. A possible reaction is as follows: diorite magma + carbonate → (magnetite-actinolite-apatite) + garnet + epidote + feldspar + hornblende + CO₂↑. Full article

The study of the material composition, textural, and structural features of skarns and magnetite ores is of great importance for increasing the efficiency of iron ore mining and its subsequent processing and enrichment. In the northwestern Balkhash region of Central Kazakhstan, there is a reserve iron ore region represented by a series of skarn contact-metasomatic deposits: Bapy, Zhuantobe, Karaulken, Akchagyl, Ushtobe, Kiyik, Taitobe, Tomashev, Kyzyl-Sayak, and others. The results of field investigations and laboratory analyses have enabled the characterization of the mineralogical and petrographic composition of the skarns, as well as their material composition and textural–structural features. All these specified characteristics of skarns reflect the stage-by-stage nature of the contact-metasomatic processes of iron ore formation. The skarn formation model at the Zhuantobe deposit developed over several stages: (1) the formation of skarns during granitoid intrusion and the establishment of conditions for contact metamorphism (resulting in iron-poor, barren diopside hornfels and marbles); (2) early skarn stage, during which anhydrous, dark-colored endo- and exoskarns composed of pyroxenes, magnetite, and hematite develop; (3) late fluid–hydrothermal stage, during which hornblende, epidote, calcite, and sulfides (pyrite, chalcopyrite, sphalerite, and galena) form; (4) oxidative supergene stage under near-surface conditions, during which limonite and iron hydroxides form. The conducted comprehensive analysis of the material composition and textural–structural features of iron ores of the Zhuantobe deposit made it possible to establish the influence of these parameters on the technological properties of ores. The performed studies make it possible to more accurately identify promising iron ore zones in skarns and predict the technological behavior of ore during processing. Full article

Although skarn-type deposits represent significant hosts for Co resources, the distribution patterns and enrichment mechanisms of associated Co resources within these deposits have not been systematically investigated. This study summarizes relevant data on Co resources from representative skarn-type deposits in China to comparatively reveal the grade and reserve characteristics, spatiotemporal distribution patterns, and coupled enrichment mechanisms of Co across three principal skarn mineralization subtypes: iron-, copper-, and lead–zinc polymetallic-dominated deposits. Studies demonstrate that Fe-dominated skarn-type cobalt deposits exhibit widespread distribution, high Co grades (100–2000 ppm), and abundant Co reserves (4000–32,000 t), demonstrating significantly superior Co resource potential compared to Cu-dominated (Co grades: 20–200 ppm, Co reserves: 3000–10,000 t) and Pb-Zn polymetallic-dominated (Co grades: 140–853 ppm, Co reserves: approximately 3000 t) subtypes. In these skarn-type cobalt deposits, cobalt is mainly hosted in sulfide minerals. Influenced by tectonic settings, magmatic activity, and hydrothermal fluid evolution, associated Co resources in these skarn-type deposits exhibit both regional zonation and stage-specific differential enrichment patterns. In the formation of skarn-type cobalt deposits, mantle-derived magmas play a critical role in the pre-enrichment of Co. The injection of mafic magmas, assimilation of evaporite sequences, and the dissolution–reprecipitation mechanism of hydrothermal fluids collectively promote the re-enrichment of Co during magmatic evolution. These findings provide a theoretical foundation for targeted exploration, sustainable development, and comprehensive utilization of associated Co resources in skarn-type deposits. Full article

In the absence of appropriate tools and a knowledge base for exploring high-grade metamorphic terrains, felsic gneiss complexes at granulite facies have long been considered barren and have remained undermapped and understudied. This was the case of the Bondy gneiss complex in the southwestern Grenville Province of Canada which consists of 1.39–1.35 Ga volcanic and plutonic rocks metamorphosed under granulite facies conditions at 1.19 Ga. Iron oxide–apatite and Cu-Ag-Au mineral occurrences occur among gneisses rich in biotite, cordierite, garnet, K-feldspar, orthopyroxene and/or sillimanite-rich gneisses, plagioclase-cordierite-orthopyroxene white gneisses, magnetite-garnet-rich gneisses, garnetites, hyperaluminous sillimanite-pyrite-quartz gneisses, phlogopite-sillimanite gneisses, and tourmalinites. Petrological and geochemical studies indicate that the precursors of these gneisses are altered volcanic and volcaniclastic rocks with attributes of pre-metamorphic Na, Ca-Fe, K-Fe, K, chloritic, argillic, phyllic, advanced argillic and skarn alteration. The nature of these hydrothermal rocks and the ore deposit model that best represents them are further investigated herein through lithogeochemistry. The lithofacies mineralized in Cu (±Au, Ag, Zn) are distinguished by the presence of garnet, magnetite and zircon, and exhibit pronounced enrichment in Fe, Mg, HREE and Zr relative to the least-altered rocks. In discrimination diagrams, the metamorphosed mineral system is demonstrated to exhibit the diagnostic attributes of, and is interpreted as, a metasomatic iron and alkali-calcic (MIAC) mineral system with iron oxide–apatite (IOA) and iron oxide copper–gold (IOCG) mineralization that evolves toward an epithermal cap. This contribution demonstrates that alteration facies diagnostic of MIAC systems and their IOCG and IOA mineralization remain diagnostic even after high-grade metamorphism. Exploration strategies can thus use the lithogeochemical footprint and the distribution and types of alteration facies observed as pathfinders for the facies-specific deposit types of MIAC systems. Full article

The Mazenod Lake region of the southern Great Bear Magmatic Zone (GBMZ) of the Northwest Territories, Canada, comprises the north-central portion of the Faber volcano-plutonic belt. Widespread and abundant surface exposure of several coalescing hydrothermal systems enables this paper to document, without ambiguity, the relationships between geology, structure, alteration, and mineralization in this well exposed iron-oxide–copper–gold (IOCG) mineral system. Mazenod geology comprises rhyodacite to basaltic-andesite ignimbrite sheets with interlayered volcaniclastic sedimentary rocks dominated by fine-grained laminated tuff sequences. Much of the intermediate to mafic nature of volcanic rocks is masked by low-intensity but pervasive metasomatism. The region is affected by a series of coalescing magmatic–hydrothermal systems that host the Sue–Dianne magnetite–hematite IOCG deposit and several related showings including magnetite, skarn, and iron oxide apatite (IOA) styles of alteration ± mineralization. The mid to upper levels of these systems are exposed at surface, with underlying batholith, pluton and stocks exposed along the periphery, as well as locally within volcanic rocks associated with more intense alteration and mineralization. Widespread alteration includes potassic and sodic metasomatism, and silicification with structurally controlled giant quartz complexes. Localized tourmaline, skarn, magnetite–actinolite, and iron-oxide alteration occur within structural breccias, and where most intense formed the Sue–Dianne Cu-Ag-Au diatreme-like breccia deposit. Magmatism, volcanism, hydrothermal alteration, and mineralization formed during a negative tectonic inversion within the Wopmay Orogen. This generated a series of oblique offset rifted basins with continental style arc magmatism and extensional structures unique to GBMZ rifting. All significant hydrothermal centers in the Mazenod region occur along and at the intersections of crustal faults either unique to or put under tension during the GBMZ inversion. Full article

Metasomatic iron and alkali-calcic (MIAC) mineral systems form district-scale metasomatic footprints in the upper crust that are genetically associated with iron oxide–apatite (IOA), iron oxide and iron sulfide copper–gold (IOCG, ISCG), skarn, and affiliated critical and precious metal deposits. The development of MIAC systems is characterized by series of alteration facies that form key mappable entities in the field and along drill cores. Each facies can precipitate deposit types specific to the facies or host deposits formed at a subsequent facies. Defining the spatial and temporal relations between alteration facies and host rocks as well as with pre, syn, and post MIAC magmatic, tectonic, and mineralization events is essential to understanding the evolution of a MIAC system and to evaluating its overall mineral prospectivity. This paper proposes an ontology for MIAC systems that frames the key characteristics of the main alteration facies described and links it to a taxonomy and descriptive lexicons that allow the user to build an efficient data collection system tailored to the description of MIAC systems. The application developed by the Geological Survey of Canada for collecting field data is used as an example. The data collection system, including the application for collecting field data and the lexicons, are applicable to regional- and deposit-scale geological mapping as well as to drill core logging. They respond to the need for the metallogenic mapping of mineral systems and the development of more robust mineral prospectivity maps and exploration strategies for the discovery of critical and precious metal resources in MIAC systems. Full article

The Huanggang iron-tin deposit, located in the southern Greater Khingan Range, is one of the largest Fe-Sn deposits in Northern China (NE China). Iron-tin mineralization occurs mainly in the contact zone between granitoid intrusions and the marble of the Huanggang and Dashizhai formations. Six mineralization stages are identified: (I) anhydrous skarn, (II) hydrous skarn, (III) cassiterite-quartz-calcite, (IV) pyrite-arsenopyrite-quartz-fluorite, (V) polymetallic sulfides-quartz, and (VI) carbonate ones. Fluid inclusions (FIs) analysis reveals that Stage I garnet and Stage II–III quartz host liquid-rich (VL-type), vapor-rich two-phase (LV-type), and halite-bearing three-phase (SL-type) inclusions. Stage IV quartz and fluorite, along with Stage V quartz, are dominated by VL- and LV-type inclusions, while Stage VI calcite contains exclusively VL-type inclusions. The FIs in Stages I to VI homogenized at 392–513, 317–429, 272–418, 224–347, 201–281, and 163–213 °C, with corresponding salinities of 3.05–56.44, 2.56–47.77, 2.89–45.85, 1.39–12.42, 0.87–10.62, and 4.48–8.54 wt% NaCl equiv., respectively. The H–O–C isotopes data imply that fluids of the anhydrous skarn stage (δD = −101.2 to −91.4‰, δ¹⁸O_H2O = 5.0 to 6.0‰) were of magmatic origin, the fluids of hydrous skarn and oxide stages (δD = −106.3 to −104.7‰, δ¹⁸O_H2O = 4.3 to 4.9‰) were characterized by fluid mixing with minor meteoric water, while the fluids of sulfide stages (δD = −117.4 to −108.6‰, δ¹⁸O_H2O = −3.4 to 0.3‰, δ¹³C_V-PDB= −12.2 to −10.9‰, and δ¹⁸O_V-SMOW = −2.2 to −0.7‰) were characterized by mixing of significant amount of meteoric water. The ore-forming fluids evolved from a high-temperature, high-salinity NaCl−H₂O boiling system to a low-temperature, low-salinity NaCl−H₂O mixing system. The garnet U-Pb dating constrains the formation of skarn to 132.1 ± 4.7 Ma (MSWD = 0.64), which aligns, within analytical uncertainty, with the weighted-mean U−Pb age of zircon grains in ore-related K-feldspar granite (132.6 ± 0.9 Ma; MSWD = 1.5). On the basis of these findings, the Huanggang deposit, formed in the Early Cretaceous, is a typical skarn-type system, in which ore precipitation was principally controlled by fluid boiling and mixing. Full article

This study investigates the mineral chemistry and iron isotope composition of the Pertek Fe-skarn deposit in the Eastern Taurides, Turkey, to elucidate skarn formation and ore genesis through chemical and isotopic parameters. The deposit consists of substantial and dispersed magnetite ores formed by the intrusion of a dioritic suite into marbles. Mineral assemblages, including hematite, goethite, andradite garnet, hedenbergite pyroxene, calcite, and quartz, exhibit compositional variations at different depths within the ore body. Magnetite is commonly associated with hematite, goethite, garnet, pyroxene, calcite, and quartz. Extensive LA–ICP–MS analysis of magnetite chemistry reveals elevated trace element concentrations of titanium (Ti), aluminum (Al), vanadium (V), and magnesium (Mg), distinguishing Pertek magnetite from low-temperature hydrothermal deposits. The enrichment of Ti (>300 ppm) and V (>200 ppm), along with the presence of Al and Mg, suggests formation from high-temperature hydrothermal fluids exceeding 300 °C. Discriminant diagrams, such as Al+Mn versus Ti+V, classify Pertek magnetite within the skarn deposit domain, affirming its medium- to high-temperature hydrothermal origin (200–500 °C), characteristic of skarn-type deposits. Magnetite thermometry calculations yield an average formation temperature of 414.53 °C. Geochemical classification diagrams, including Ni/(Cr+Mn) versus Ti+V and TiO₂-Al₂O₃-MgO+MnO, further support the skarn-type genesis of the deposit, distinguishing Pertek magnetite from other iron oxide deposits. The Fe-skarn ore samples display low total REE concentrations, variable Eu anomalies, enrichment in LREEs, and depletion in HREEs, consistent with fluid–rock interactions in a magmatic–hydrothermal system. The δ⁵⁶Fe values of magnetite range from 0.272‰ to 0.361‰, while the calculated δ⁵⁶Fe_aq values (0.479‰ to 0.568‰) suggest a magmatic–hydrothermal origin. The δ⁵⁷Fe values (0.419‰ to 0.530‰) and the calculated 10³lnβ value of 0.006397 indicate re-equilibration of the magmatic–hydrothermal fluid during ore formation. Full article