Mineral Belt Research Articles

Pyrite trace metal and sulfur isotopic compositions track metalliferous fluid circulation within the Ordovician/Silurian organic-rich black shales in the eastern Sichuan Basin, southwestern China

Depicting metalliferous fluid flows in sedimentary basins has a remarkable implication for understanding the formation and evolution of organic-rich sediments. The Middle-Upper Yangtze region in South China hosts voluminous gaseous hydrocarbons and MVT-type ZnPb deposits. Natural gases are mainly distributed in the Sichuan Basin, yet ZnPb deposits are found in surrounding regions of the basin. Such a unique distribution pattern implies that the interplay between metalliferous fluids and organic-rich sediments may be extensive in the boundary of these two types of deposits. A typical Ordovician/Silurian (Wufeng/Longmaxi formations) organic-rich black shale outcrop occurs in the eastern boundary of the Sichuan Basin. Pyrites are frequently distributed across this section, providing an ideal opportunity to investigate features of metalliferous fluids and their potential impacts on organic-rich sediments. Pyrites associated with high-angle carbonate veinlets are recognized in the studied area, and this group of pyrites (“Group 2”) commonly display planar-laminated morphologies, moderate δ34S values (0.78 ‰–8.86 ‰), and elevated trace metal contents (Ni, Pb, Mn, Mo, Tl, and REE) than those not associated with carbonate veinlets. These features suggest that this group of pyrites may be precipitated via local metalliferous fluid flows. Besides, pyrites with relatively lower trace metal contents can be further divided into two groups, including a group of euhedral/subhedral pyrites with more depleted δ34S values (−18.06 ‰ – -1.15 ‰; “Group 1”) and a group of planar-laminated/cubic pyrites with enriched δ34S values (10.55 ‰–37.62 ‰; “Group 3”). Pyrites of Group 1 and Group 3 may be formed via bacterial sulfate reduction (BSR) and thermochemical sulfate reduction (TSR), respectively. The discovery of fluid-related, trace-metal-enriched pyrites implies that fluid circulation within organic-rich black shales has the potential to remobilize, transport, and re-deposit trace metals. Besides, metalliferous fluid may also promote organic matter maturation within the Sichuan Basin. The outcomes of this study, combined with previous findings of metalliferous fluid flows in the center of the basin and ZnPb mineralization belts surrounding the basin, imply that a widespread Ediacaran-Palaeozoic fluid circulation system may exist in the Middle-Upper Yangtze region.

Newly discovered Early Cretaceous Au mineralization overprinting Late Jurassic Pb-Zn-Ag mineralization in the Qin-Hang metallogenic belt (South China)

Magmatic and mineralizing events in South China were traditionally thought to be limited between 150 Ma and 130 Ma despite the numerous Mesozoic-aged magmatic-hydrothermal deposits in the region. This viewpoint is being reevaluated in light of new age data. Kangjiawan is a representative Pb-Zn-Ag-Au deposit in the Hengyang Basin in the Qin-Hang metallogenic belt of South China that contains 1.96 Mt of Pb-Zn resource with 4.70% Zn, 6.02% Pb; 2280.5 t of Ag resource with 108.23 g/t of Ag; and 58 t of Au resource with 3.25 g/t of Au. Its mineralization can be divided into four stages: (I) pre-ore quartz−pyrite, (II) quartz−pyrite−galena−sphalerite, (III) quartz−galena−sphalerite, and (IV) calcite−pyrite. Multiple generations of pyrite were identified at Kangjiawan. Generation I pyrite (Py1, formed in Stage I) is coarse-grained, texturally homogeneous, and contains abundant silicate inclusions (e.g., K-feldspar and titanite). Generation II pyrite (Py2, formed in Stage II) is generally fine-grained and exhibits a core-rim texture, with the porous, sphalerite−galena inclusion-bearing core (Py2a) having replaced Py1 and the rim (Py2b) being homogeneous. Generation III pyrite (Py3, formed in Stage IV) is subdivided into Py3a and Py3b, with the homogeneous Py3a often replaced by the porous Py3b. The low Co/Ni ratio of Py1, along with the abundant silicate inclusions, is suggestive of intense fluid-rock interaction during Stage I. Py2a is As-Cu-Pb-Ag-Au−rich, Co-depleted, and has elevated Ag/Co (average 3.24) and As/Co (average 10,217.14) ratios, which are suggestive of extensive fluid boiling during the formation of Py2a. This is also supported by the ubiquitous Py2-cemented hydrothermal breccia. In contrast, Py2b is depleted in As-Cu-Pb-Ag-Au but enriched in Co, which is indicative of non-boiling conditions. Subsequent sealing of fractures by veins may have caused the formation of coarse-grained sphalerite and galena in Stage III. The similar 207Pb/206Pb values among Py1 (average 0.849), Stage II galena (average 0.849), Stage III galena (average 0.849), and the nearby Shuikoushan granodiorite stock (corrected average 0.848) suggests that mineralization in stages I−III may represent distal skarn-type Pb-Zn-Ag mineralization genetically related to the Shuikoushan stock. This interpretation is supported by the similar ages of mineralization Stage I (apatite U-Pb: 159.4 ± 1.0 Ma) and Stage II (fuchsite 40Ar-39Ar: 158.1 ± 0.4 Ma) to the age of Shuikoushan stock (zircon U-Pb age: ca. 158 Ma). As the primary Au-hosting mineral at Kangjiawan, the As- and Au-rich Py3a occurs in sharp contact with porous Co-Ni-Se-Bi-Mo-As−poor Py3b, which commonly contains abundant fine-grained galena and sphalerite inclusions. This suggests that Py3b formed via coupled dissolution−re-precipitation of Py3a. This coupled dissolution−re-precipitation reaction favors the remobilization of Au from within the Py3a structure and its re-enrichment as Au inclusions in Py3b; this is supported by the anomalous Au peaks in time-resolved signal profiles from laser ablation−inductively coupled plasma−mass spectrometry (LA-ICP-MS) and the abundant outliers for Au concentrations in Py3b. The markedly distinct trace-element geochemistry of Py3 compared to those of Py1 and Py2, and the U-Pb age of Stage IV calcite (ca. 138 Ma), are indicative of an Early Cretaceous Au mineralization event. Published calcite C-O isotope data, coupled with the narrow range of δ34S values (0.6‰−2.2‰) of Py3, suggest that the Kangjiawan Au mineralization may be associated with a concealed Early Cretaceous pluton. We propose that the Kangjiawan deposit formed via the overprinting of Late Jurassic distal skarn Pb-Zn-Ag mineralization by Early Cretaceous magmatic-hydrothermal Au mineralization, which demonstrates that 150−135 Ma may also be an important period for the formation of the magmatic-hydrothermal mineralization belt.

Genesis and fluid evolution of the Hatu orogenic gold deposit in the West Junggar, Western China

The West Junggar in Xinjiang, western China, represents a significant gold mineralization belt hosting over 200 gold deposits, with the Hatu gold deposit being the largest among them. In this study, ore geology and fluid inclusion assemblages of quartz samples from the Hatu gold deposit were investigated in an effort to clarify the mineralization process and its relationship with the geodynamic settings. The mineralization process is delineated into early (pyrite-albite-quartz veins), middle-a (quartz-ankerite veins), middle-b (quartz-ankerite-sulfide-native gold veins), and late (quartz-calcite veins) stages. The early stage veins suggest a compressional setting while the middle-a and middle-b stage veins suggest a tensional shear setting. The late stage veins are typically filled fissures cutting through earlier veins. Scanning electron microscope-cathodoluminescence (SEM-CL) reveals that early stage quartz (Q1) exhibits concentric CL-oscillatory growth zoning, while middle-a stage quartz (Q2a) displays unidirectional zoning and ranges from CL-bright to CL-dark, middle-b stage quartz (Q2b) is CL-bright and weakly zoned, and late-stage euhedral quartz (Q3) shows sector zoning transitioning from CL-gray to CL-dark. Quartz that formed in these stages developed three types of fluid inclusions: pure CO2 (PC-type), CO2–H2O (C-type), and H2O–NaCl (W-type). The early stage quartz contains C- and W-type fluid inclusions homogenizing at 309–345 °C, while the late stage quartz contains only W-type fluid inclusions with homogenization temperatures of 164–229 °C. Microthermometry of fluid inclusion indicated the evolutionary of the metallogenic fluid from a high-temperature, CO2-rich, and minor CH4 metamorphic fluid to a low-temperature, CO2-poor meteoric fluid. From the early to middle-a stages, fluid boiling caused the unloading of ore-forming elements whereas fluid mixing led to the precipitation of polymetallic sulfides and gold in the middle-b stage. Trapping pressures in the middle-b stage were estimated using C-type inclusions, illustrating that gold mineralization took placed at depth of 8.0 km. We propose classifying the Hatu gold deposit as an orogenic deposit, originating from the collisional orogenesis between the Yili-Kazakhstan and Siberian continents in the Late Carboniferous.

Linking beryllium mineralization to fluid-rock reactions: A case study of the Madumeng quartz vein-type beryllium mineralization in the Southern Great Xing'an Range, Northeast China

The Southern Great Xing'an Range (SGXR) in Northeast China is a significant polymetallic mineralization belt. Although several beryllium (Be) deposits have been reported in the SGXR, the timing and mechanisms of Be mineralization are poorly understood. To determine the mechanisms of newly-discovered Be mineralization in the Madumeng area, we carried out monazite–zircon–apatite U–Pb dating, whole-rock and mineral geochemical, and monazite Nd isotopic analyses of the beryl-bearing quartz veins and host Late Permian–Early Triassic granite. Monazite from the beryl-bearing quartz veins yielded U–Pb ages of 138–137 Ma, and the host granite yielded zircon and apatite U–Pb ages of 251 ± 1 and 256 ± 27 Ma, which indicate that the Madumeng Be mineralization formed later than the host granite. Monazite in the beryl-bearing veins has similar εNd(t) values (−1.31 to +4.27) to those of Early Cretaceous highly fractionated granite related to Be mineralization in the SGXR, which suggests the ore-forming material was derived from exsolved fluids associated with Early Cretaceous, deep-seated, highly fractionated granites. Fluid-rock reactions had a key role in generating the Madumeng Be mineralization, and the intensity of these reactions was recorded by the whole-rock and mineral geochemistry. The alteration during fluid-rock reactions increased the pH and Ca contents of the fluids. Mica and beryl record the release of Ca and Fe from the granite into the fluid. The released Ca2+ ions combined with F− ions in the fluid, leading to instability of Be–F complexes and subsequent precipitation of beryl. Our findings indicate that the Early Cretaceous was an important period of Be mineralization in the SGXR and highlight the contribution of fluid-rock reactions to Be precipitation in quartz vein-type Be mineralization.

Control of magmatic halogen composition and redox state on the zonation of metal mineralization across active continental margins: Perspectives from the world-class South China metallogenic province

Active continental margins are the major sites of continental magmatism and associated hydrothermal ore deposits with a broad metal spectrum. Mineralization across active continental margins typically displays spatial zonation, with porphyry copper-(molybdenum‑gold) deposits in volcanic arcs and tin- and tungsten-dominated mineralization occurring further inland in a back-arc setting. Particularly, tin and tungsten commonly form separate deposits in back-arc regions, even though both metals exhibit similar lithophile behavior. The key factors governing this metallogenic zonation remain unclear. The world-class South China metallogenic province hosts over 50 % of the global tungsten resources, along with a significant amount of tin and copper resources distributed in different mineralization belts, making it an ideal location in which to study regional metal zonation. Here, we comprehensively integrate a very large dataset of the halogen volatile composition (F, Cl) and oxygen fugacity of granites related to tin, tungsten, and copper mineralization in the South China continental margin. Our compilation, derived from a substantial collection of zircon, apatite, mica, and whole-rock geochemistry data, suggests that lateral variations in granite magmatism (away from the trench), transitioning from chlorine-rich and oxic to fluorine-rich and reduced conditions, exert the primary control on copper versus tin‑tungsten mineralization in the arc and back-arc regions, respectively. Differences in oxygen fugacity have a minor impact on the decoupling of tin and tungsten mineralization despite tin granites being universally reduced (ΔFMQ = −1.8 to −0.1, where FMQ is the fayalite-magnetite-quartz redox buffer) and tungsten granites having a broader redox range (ΔFMQ = −1.5 to +1.2). Instead, the disparity in fluorine content plays a more crucial role in controlling the spatial separation of tin and tungsten mineralization observed in the back-arc setting. Nd-Hf and He-Ar isotopic modeling calculations suggest that magmas linked to tin mineralization have a more pronounced involvement of F-rich mantle components compared to those associated with tungsten. Elevated fluorine (ca. 650–8000 ppm) in tin-associated magmas allowed an extreme degree of magmatic differentiation and delayed fluid exsolution due to high H2O solubility in F-rich silicate melts, ensuring Sn enrichment in highly evolved melts. In contrast, early fluid exsolution under less F-rich conditions (ca. 100–700 ppm) led to early tin loss from the melts, ultimately resulting in tungsten-dominant mineralization. This work emphasizes the combined influence of halogen composition and redox state on the regional mineralization zonation in world-class metallogenic provinces, providing vectors for global metal exploration in both past and currently active continental margins.

PORPHYRY COPPER RECURRENCE IN THE ANDES OF CHILE AND ARGENTINA

Abstract Porphyry Cu deposits in the Chilean and Argentinian central Andes occur in a series of orogen-parallel magmatic arcs, which migrated episodically eastward since the Early Cretaceous. The three Cenozoic belts, corresponding to Paleocene-early Eocene, middle Eocene-early Oligocene, and Miocene-early Pliocene epochs, cut obliquely across a composite belt of subeconomic porphyry Cu mineralization formed at several times during the Late Carboniferous to Triassic interval. Based mainly on U-Pb zircon and Re-Os molybdenite ages, 10 Cenozoic porphyry Cu centers, including major deposits in all three of the Cenozoic belts, occupy the same sites as late Paleozoic-Triassic porphyry Cu mineralization where their respective magmatic arcs cross one another. The sites of recurrent porphyry Cu mineralization are believed to be underlain by long-lived dike conduits that were utilized at least twice—first in the late Paleozoic-Triassic and then again in the Cenozoic—to rapidly transmit hydrous magma from deep to shallow levels of the crust. Contenders for preferential dike localization include arc-oblique fault and subjacent ductile shear zones—transcrustal discontinuities—long hypothesized to be present in the region, particularly where they intersect magmatic arcs and associated porphyry Cu belts. Regardless of the controls on porphyry Cu recurrence, alteration zones hosted by late Paleozoic-Triassic volcanic and plutonic rocks in the central Andes of Chile and Argentina must be considered prime exploration targets for potentially large, high-grade Cenozoic porphyry Cu deposits.

Differentiating Jurassic Cu-, W-, and Sn (—W)-bearing plutons in the Nanling Range (South China): An integrated apatite study

The Nanling mineralization belt, South China, is well-known for widespread W-, Sn (—W), and Cu-polymetallic ore deposits. At present, how to better trace their magma sources and constrain their magmatic processes is currently a conundrum. As a resistant mineral, apatite has shown great potential in metallogenic studies. In this study, we present a comprehensive investigation of apatite from the Baoshan (BS) and Tongshanling (TSL) Cu-bearing granites, the Wangxianling (WXL) W-bearing granite, and the Qitianling (QTL) Sn-bearing granite in South Hunan, to trace the nature of parental magma and to establish apatite discrimination criteria to be used in regional prospecting. The U-Pb age dating of apatite indicates that these different types of ore-bearing granites were all formed in the Middle-Late Jurassic. The εNd(t) values results suggest that (1) Cu-bearing granites in the Nanling Range were formed by melting of meta-igneous rocks in the deep crust, (2) W-bearing granitic magmas were generated by melting of old continental crust, while (3) Sn-bearing granitic magmas were produced by melting of crust material with various input of mantle-derived components. Apatite from the BS and TSL plutons exhibits lower F/Cl ratios compared to those from WXL, and QTL plutons, with higher Cl contents in the BS and TSL plutons, implying that the crustal basement of the suture zone was metasomatized by a Cl-enriched fluid. We used a partial least squares discriminant analysis (PLS-DA) of trace element data in apatite to differentiate Cu-, W-, and Sn (—W)-bearing plutons. We find that the most influential elements for classification are Sr, Eu, Ga, Nd, and Li. Trace elements differences reveal distinguished degrees of fractionation, and redox conditions for different types of ore-bearing granites. A comparative study of apatite from different ore-bearing granites indicates that, apatite can be a useful mineral exploration tool to differentiate Cu-, W-, and Sn (—W)-bearing plutons in the Nanling Range and South China.

Sedimentary basins, hydrocarbons, graphite, coal, and Cu-Au deposits - from Mongolia to the Pacific margin: Interplay between the ubiquitous orthogonal fracture network and Global Wrench Tectonics

Mongolia is exceptionally rich in coal and copper-gold resources - with world-class deposits like Tavan Tolgoi, Oyu Tolgoi and Erdenet. Thus, the mining industry has a crucial importance for the national economy, yet most of the country remain very underexplored. Within today's global tectonics, an acceptable understanding of metal enrichments - including leaching, the internal hydrostatic-hydraulic pumping system, and surface emplacement mechanisms - has remained unresolved. However, a broader view of the structural situation in the Mongolia-China region shows a close link between orientation of elongate sedimentary basins, important mineral belts, and the fundamental orthogonal fracture/fault system. In the east the tectonic trend is dominantly northeast, while it is northwest in western areas. The main east Mongolian graphite deposits have northeast structural trends like numerous regional Cu and Au belts. A new theory of the earth, Global Wrench Tectonics, offers an exciting approach to better understanding the various facets of Earth's geological history and its surface resources. Earth’s degassing, dynamo-tectonic consequences, inertia-driven crustal wrench tectonics, as well as surface products such as water, hydrocarbons and ore deposits are given a coherent system explanation. Many hydrocarbons are products from the interior of our slowly degassing Earth, with massive hydrocarbon fields such as Songliao and the Yamal megaproject producing from the basement. Crustal thinning in the Songliao region is about the same as in southeast Mongolia, suggesting that they may have had similar degassing and crustal evolution histories. As such, it is not unlikely that the underexplored Mesozoic basins of southeast Mongolia - particularly at the deepest levels and/or in the adjacent crystalline basement - may have important hydrocarbon potential.

Crustal conductivity footprint of the Miocene porphyry copper polymetallic deposits in the Gangdese metallogenic belt, Tibetan Plateau

New evidence worldwide has linked the surface locations of mineral deposits and their crustal-scale electrical conductivity footprint. We examine the relationship between the Gangdese Miocene porphyry copper deposits, Tibetan Plateau, and the electrical conductivity signature from a three-dimensional model generated from 311 magnetotelluric measurements. The distribution of electrical resistivity throughout the crust and the conductance within the mid-lower crust (depth range of 25–70 km) is analyzed. The results clearly show that the large and ultra-large Miocene porphyry copper deposits coincide spatially with conductive zones and areas of very-high conductance (>10,000S) in the mid-lower crust. Computations are undertaken to determine the influence of water-bearing silicate melts and alkali-bearing (Na+ and K+) fluids on conductivity. Based on this, the bulk conductivity is interpretated to be caused by a system of alkali-rich volatile-rich partial melt. The alkali-rich volatile-rich magmatic-hydrothermal fluids facilitate the migration and concentration of metal ions originating in deep areas. The volumes necessary are much less than partial melt alone and can thus help to reconcile large conductivity variations with small seismic velocity variations. The electrical structure indicates the magma source area of anatexis in the lower crust, a multi-stage magmatic system with large mid-crustal and small upper-crustal magma reservoirs, and complex pathways related to rift zones. We determine that the conductive zones in the mid-lower crust have an influence on the development of the mineralization and the location of the mineral belt.

Extracting geological and alteration information and predicting antimony ore based on multisource remote sensing data in Huangyangling, Xinjiang

Introduction: China has the world’s largest amount of antimony resources and plays a vital role in the global antimony industry. The Huangyangling area in Xinjiang belongs to the Lazhulong-Huangyangling antimony mineralization belt; this area is rich in antimony ore resources, with potential for discovery of additional ore. This high-elevation mountainous area is located in the northwestern region of the northern Tibetan Plateau, with a harsh natural environment and poor transportation access; thus, the use of traditional geological exploration methods is limited, and remote sensing technology provides unique advantages.Methods: Using Landsat 8 OLI and Gaofen-6 (GF-6) data, we extracted stratigraphic, lithologic and fault information from the study area through information enhancement processing of the images. Based on Landsat 8 OLI, Sentinel-2 and ASTER images and the use of remote sensing image preprocessing and interference information masking, the spectral characteristics of limonite, as well as hydroxyl, carbonate, and silicified alteration minerals were utilized; the characteristics included reflection or absorption in specific spectral bands. The spectral characteristics were then combined with principal component analysis (PCA) and the band ratio method to extract the alteration information for the study area.Results: The stratigraphy and boundaries between stratigraphic and lithologic units extracted in this study were defined, and numerous small faults were identified based on a comparison with 1:250,000 geologic maps. And the overall distribution trends of the indicators of alteration extracted in this study were located along fault zones; additionally, the hydroxyl and carbonate alteration anomalies matched well with known deposits (occurrences). Thus, the alteration information is a good indication of antimony ore bodies. Based on the geological interpretation, alteration information extraction and geochemical exploration data, four prospecting areas were identified.Discussion: The method of extracting geological and hydrothermal alteration information by remote sensing has practical significance because it provides the possibility for geological work and mineral exploration in difficult high-elevation environments.

The composition and differences of antimony isotopic in sediments affected by the world's largest antimony deposit zone

Antimony (Sb) isotopic fingerprinting is a novel technique for stable metal isotope analysis, but the use of this technique is still limited, especially in sediments. In this study, the world's most important Sb mineralization belt (the Xikuangshan mineralization belt) was taken as the research object and the Sb isotopic composition and Sb enrichment characteristics in the sediments of water systems from different Sb mining areas located in the Zijiang River (ZR) Basin were systematically studied. The results showed that the ε123Sb values in the sediments of the ZR and its tributaries, such as those near the Longshan Sb-Au mine, the Xikuangshan Sb mine, and the Zhazixi Sb mine, were 0.50‒3.13 ε, 2.31‒3.99 ε, 3.12‒5.63 ε and 1.14‒2.91 ε, respectively, and there were obvious changes in Sb isotopic composition. Antimony was mainly enriched in the sediments due to anthropogenic sources. Dilution of Sb along the river and adsorption of Sb to Al-Fe oxides in the sediment did not lead to obvious Sb isotopic fractionation in the sediment, indicating that the Sb isotopic signature was conserved during transport along the river. The Sb isotopic signatures measured in mine-affected streams may have differed from those in the original Sb ore, and further investigation of Sb isotopic fingerprints from other possible sources and unknown geochemical processes is needed. This study reveals that the apparent differences in ε123Sb values across regions make Sb isotopic analysis a potentially suitable tool for tracing Sb sources and biogeochemical processes in the environment.

Using Stochastic Point Pattern Analysis to Track Regional Orientations of Magmatism During the Transition to Cenozoic Extension and Rio Grande Rifting, Southern Rocky Mountains

AbstractThe southern Rocky Mountains in Colorado and northern New Mexico hosted intracontinental magmatism that developed during a tectonic transition from shortening (Laramide orogeny, ca. 75 to 40 Ma) through extension and rifting. We present a novel approach that uses stochastic weighted bootstrap simulations of a large set of new and historical geochronology data to better understand how regional anisotropies responsible for focusing magma emplacement evolved through time. This technique can detect subtle trends in directional distributions, including multi‐modal orientations, and can be filtered from regional to local scales. Our results indicate that magmatism followed first the northeast trend of the Colorado mineral belt between 75 and 40 Ma and deviated afterward. These deviations vary depending on the scale of the analysis. At the smallest scale we evaluated (<75 km), the orientation of magmatism from 45 to 30 Ma rotated counter‐clockwise before aligning with the north‐south trend of the modern Rio Grande rift. Larger, regional‐scale analyses indicate magma centers between 40 to 35 Ma and 25 to 20 Ma were dominantly oriented southwest‐northeast, whereas magmatism between 35 and 25 Ma had north‐south orientation. The large areal footprint of magmatism and shifting regional patterns suggest that ancient zones of weakness in the North American lithosphere accommodated magma flow at different moments in time, rather than controlled by a retreating interface of the Farallon and North American plates.

Europe's economic geology generates exploitable critical mineral resources enabling to reduce its geopolitical dependence- Progress beyond state-of-the-art.

Mineral raw materials were for many years the missing link in the climate debate. It is now evident that climate goals can’t be met without them. Mineral-based lithium battery and neodymium magnets value chains are not in balance between upstream-downstream efforts e.g. electric vehicles boom when energy transition mineral resources are yet not secured, Considering the long period of time (from exploration to mining takes about 15 years) needed for the mineral value chains to be fully operational, the technologies addressing the implementation plan of climate change goals might not always readily available due to lack of the mineral resources needed. However, Europe’s opportunity to become self-sufficient in mineral raw materials supply from own sources and resources, is strongly favored by its geological setting and metallogenetic evolution. Critical and strategic mineral raw materials from European primary and secondary resources produced in Europe can be taken as a guarantee for high standards in social, environmental, and economic terms. Elements and practices related to circular economy, responsible sourcing and resource efficiency addressed by the new EU industrial strategy, should be particularly considered. Major European mineral belts, such as Fennoscandian, Iberian, Carpathian-Balkan, host highly potential exploration targets challenging the likelihood for discovery of new resources and feasible mining prospects. At this stage recycling is not significant resource provider for some of the critical and strategic mineral raw materials. For the EU and the rest of the world to develop mineral supply chains, less dependent on China, strengthening key technology value chains, including processing, refining and metallurgy facilities, seems to be a dominant target.

Quantifying uncertainty and improving prospectivity mapping in mineral belts using transfer learning and Random Forest: A case study of copper mineralization in the Superior Craton Province, Quebec, Canada

Mineral prospectivity mapping (MPM) involves identifying locations with a higher potential for mineral exploration based on a set of explanatory variables. In cases where there is a scarcity or absence of unfavorable sites that adequately represent the geological context for deposit discovery, generating synthetic negative data sets becomes necessary to employ a machine learning algorithm optimally. Moreover, when favorable sites are insufficient for deposit discovery within a geological zone, machine learning methods can potentially result in large and highly uncertain prospecting areas. This article proposed a concept based on transfer learning by applying the knowledge gained from mineral belt signatures in different geological zones to a related area. The positive training data were taken from five mineral belts distanced from each other, while the negative data were sampled using geological constraints based on the distance to occurrences and spatial associativity. The results demonstrate that transfer learning, combined with geological constraints applied to the creation of negative datasets, improves model performance and prediction of known deposits while significantly reducing uncertainties. Mineral prospectivity models for predicting potential copper formations were generated using data from the Quebec Government's spatial reference geomining information system, SIGEOM. The case study for this work focused on the geological province of the Superior Craton, which encompasses the vast majority of northeastern Quebec.

Fingerprinting Pb-Zn mineralization events in the SW Yangtze Block, South China: A case from Yuanbaoshan deposit

The southwestern Yangtze Block represents one of the world’s largest lead–zinc provinces, comprises more than 400 known carbonate-hosted Pb-Zn deposits and contains over 30 million tons (Mt) of total Pb + Zn reserves. The Pb-Zn deposits in this area have been studied extensively by economic geologists, but the origin and mineralization processes of these deposits are still controversial. The Yuanbaoshan deposit is a typical carbonate-hosted Pb-Zn deposit of medium scale (0.19 Mt P + Zn reserves @ 0.7–26.31 wt%), which is in the northern part of the Pb-Zn mineral belt in the southwest margin of the Yangtze Block. In this study, we have conducted LA-ICP-MS sulfides trace elements, S isotope analyses, together with gangue carbonate C-O stable isotope analyses and pyrite Rb-Sr dating. We present Rb-Sr isotopic data on the pyrite that yields an isochron age of 196.4 ± 2.3 Ma. The mineralization temperature at Yuanbaoshan, as determined by the Ga, Ge, In, Mn and Fe (GGIMF) in sphalerite geothermometer, ranges from 161 to 264 ℃ (Sp1) and 141 to 246 ℃ (Sp2). The δ13CPDB values range from −0.66 to 0.61 ‰, δ18OSMOW values range from 15.6 to 17.3 ‰. In situ S isotopes show that the δ34S values of sulfides range from −1.4 to 17.73 ‰. The field, petrologic, geochemical and isotopic data from our study lead to the following salient findings. (1) The dissolved carbon and oxygen of ore forming-fluids of these Pb-Zn deposits were mainly derived from sedimentary carbonate dissolution. (2) The reduced S in the sulfide of the Yuanbaoshan Pb-Zn deposit is mainly derived from the thermochemical sulfate reduction (TRS) and the reduced S produced by the pyrolysis of S-containing organic matter in the carbonaceous mudstone of the Ebian Group. (3) The large-scale Pb-Zn mineralization in the southwest margin of the Yangtze Block was influenced by the post-collision extension between the Indosinian Block and the South China Block during ca. 200 Ma.

Research progress of the boron mineralization belt in the Liaodong Peninsula

Research progress of the boron mineralization belt in the Liaodong Peninsula

Distribution of In, Sn, Ga, Ge, and other critical metals in sulfide ores from epithermal listvenite-associated Badovc Pb–Zn–Sb–Ni deposit (Kosovo): Insights from mineralogy and geochemistry

This work presents a mineralogical and geochemical study of sulfide ores from the epithermal listvenite-associated Badovc Pb–Zn–Sb–Ni deposit, which is located in the central part of the Kizhnica-Hajvalia-Badovc ore field, in the Trepça Mineral Belt (TMB) in Kosovo. Badovc is an example of one of many base-metal Pb–Zn–Ag deposits associated with the Serbo-Macedonian metallogenic province. There are three types of ores, the first two associated with polymetallic epithermal IS veins (massive-banded Pb–Zn–Sb and rhodochrosite-stibnite breccia) and disseminated ores associated with listvenites, which are hydrothermally altered mafic and ultramafic rocks. The mineralogy of these ores was described using EPMA in combination with reflected and transmitted light microscopy. The mineralogy of massive-banded Pb–Zn–Sb and rhodochrosite-stibnite breccia ores is relatively limited: sphalerite + rhodochrosite-siderite + pyrite/marcasite ± Pb–Sb sulfosalts ± stibnite. Listvenite Pb–Zn–Sb–Ni ores are more mineralogically variable due to the multi-stage formation of these rocks and the overprint of polymetallic mineralization. Apart from typical base-metal sulfides such as sphalerite, pyrite, galena, and chalcopyrite, the listvenite ores contain Fe–Mn carbonates, quartz, and Ni–Fe ± As ± Sb association (gersdorffite, ullmannite, millerite, and Ni–Fe thiospinels), Sn minerals (stannite and cassiterite). The LA-ICP-MS technique was used to determine critical metals occurring as minor and trace elements and substitution mechanisms in sphalerite, pyrite, stibnite, chalcopyrite and stibnite. The main critical metals, such as In, Sn, Ga, and Ge, are hosted by sphalerite in all types of ores. The highest concentrations of tin in sphalerite are observed in massive-banded Pb–Zn–Sb ores, which substitutes within the 3Zn2+ ↔ 2(Cu, Ag)+ + Sn4+ mechanism. The highest concentrations of indium are observed in sphalerites from listvenites, indicating the 2Zn2+ ↔ Cu+ + In3+ substitution. Low-temperature sphalerites from rhodochrosite-stibnite breccia exhibit elevated concentrations of Ga, Ge, and Ag, which incorporate into the structure through 2Zn2+ ↔ (Ag, Cu)+ + Ga3+, and 3Zn2+ ↔ 2(Cu, Ag)+ + Ge4+ mechanisms. The specific crystallization temperatures using GGIMFis for sphalerite are: 248–332 °C for massive-banded Pb–Zn–Sb ores, 208 °C for rhodochrosite-stibnite breccia, and 2112–344 °C for listvenite Pb–Zn–Sb–Ni ores. Additionally, stibnite from Badovc exhibits substitutions such as As3+ ↔ Sb3+ and (Cu+ + Ag+) + Pb2+ ↔ Sb3+ + □, and can incorporate various monovalent elements other than copper, including Ag+ and Tl+. Studies of epithermal listvenite-associated Badovc Pb–Zn–Sb–Ni deposits suggest that similar deposits spread across the Balkans may hold considerable prospectivity.

Feature detection of mineral zoning in spiral slope flow under complex conditions based on improved YOLOv5 algorithm

In actual processing plants, the quality and efficiency of the traditional spiral slope flow concentrator still rely on workers to observe the changes in the mineral belt. However, in realistic complex working conditions, the formation of mineral separation zones is subject to large uncertainties, and coupled with the limited efforts, experience, and responsibility of workers, it becomes important to free up labour and improve the efficiency and profitability of the beneficiation plant. Therefore, to solve the problem of difficult detection of fuzzy small target mineral separation point features in real scenes, an improved YOLOv5-based algorithm is proposed. Firstly, the dataset quality is well improved by image enhancement and pre-processing techniques, after that an innovative CASM attention mechanism is added to the backbone of the YOLOv5 model, followed by a multi-scale feature output and prediction enhancement in the neck part of the model, and an optimized loss function is designed to optimize the whole feature learning process. The improved effect of the model and the specific detection performance were tested using real mine belt image datasets, the ablation experiment verified the comprehensive effectiveness of the proposed improved method and finally compared it with the existing high-level attention mechanism and target detection algorithms. The experimental results show that the improved YOLOv5 algorithm proposed in this study has the best overall detection performance carrying a MAP of 0.954, which is over 20% better than YOLOv5. It is worth mentioning that the improvement to achieve this performance only increases the parameter values by 0.8M and GFLOPs by 1.8, moreover, in terms of the inference speed, it also achieves a respectable 63 FPS, implying that the proposed improved method achieves a better balance between the performance enhancement and the computational complexity of the model, the overall detection results fully satisfy the industrial requirements.

Oxygen Isotope Geochemistry as a Tool in the Exploration for BIF-hosted Iron Ore Occurrences within the Precambrian Mineral Belt of Southern Cameroon, Northwestern Margin of the Congo Craton: A Review

Oxygen Isotope Geochemistry as a Tool in the Exploration for BIF-hosted Iron Ore Occurrences within the Precambrian Mineral Belt of Southern Cameroon, Northwestern Margin of the Congo Craton: A Review

High-resolution X-ray fluorescence-based provenance mapping of Eocene fluvial distributary fans that fed ancient Gosiute Lake, Wyoming, USA

The Green River Formation of Wyoming, USA, is host to the world’s largest known lacustrine sodium carbonate deposits, which accumulated in a closed basin during the early Eocene greenhouse. Alkaline brines are hypothesized to have been delivered to ancient Gosiute Lake by the Aspen paleoriver that flowed from the Colorado Mineral Belt. To precisely trace fluvial provenance in the resulting deposits, we conducted X-ray fluorescence analyses and petrographic studies across a suite of well-dated sandstone marker beds of the Wilkins Peak Member of the Green River Formation. Principal component analysis reveals strong correlation among elemental abundances, grain composition, and sedimentary lithofacies. To isolate a detrital signal, elements least affected by authigenic minerals, weathering, and other processes were included in a principal component analysis, the results of which are consistent with petrographic sandstone modes and detrital zircon chronofacies of the basin. Sandstone marker beds formed during eccentricity-paced lacustrine lowstands and record the migration of fluvial distributary channel networks from multiple catchments around a migrating depocenter, including two major paleorivers. The depositional topography of these convergent fluvial fans would have inversely defined bathymetric lows during subsequent phases of lacustrine inundation, locations where trona could accumulate below a thermocline. Provenance mapping verifies fluvial connectivity to the Aspen paleoriver and to sources of alkalinity in the Colorado Mineral Belt across Wilkins Peak Member deposition, and shows that the greatest volumes of sediment were delivered from the Aspen paleoriver during deposition of marker beds A, B, D, and I, each of which were deposited coincident with prominent “hyperthermal” isotopic excursions documented in oceanic cores.