Journal of Geochemical Exploration最新文献

{"title":"Isolation and identification of anaerobic molybdenum(VI)-reducing bacteria in molybdenum mine sediments in Korea","authors":"Vo Anh Khoa Nguyen ,&nbsp;Hyeop-Jo Han ,&nbsp;Jong-Un Lee","doi":"10.1016/j.gexplo.2025.107711","DOIUrl":"10.1016/j.gexplo.2025.107711","url":null,"abstract":"<div><div>This study was conducted to isolate and identify anaerobic molybdenum(VI)-reducing bacteria from sediments and soils collected from molybdenum mine areas in Korea. Molybdenum, a trace element vital for biological systems, can pose environmental risks when present in high concentrations, particularly in mining areas. Soil and sediment samples were collected, and the physicochemical properties including pH and metal content were analyzed. Two bacterial strains, identified as <em>Klebsiella aerogenes</em> and <em>Klebsiella oxytoca</em>, were isolated and exhibited significant molybdenum(VI) reduction under anaerobic conditions, reducing over 90 % of the molybdenum within 72 h at an initial concentration of 15 mM. The study further explored the effects of alternative electron acceptors and donors, revealing that nitrate and sulfate did not inhibit Mo(VI) reduction, while acetate had little effect. The reduction likely occurred via fermentative processes rather than respiratory reduction, as evidenced by the absence of oxygen consumption, the preferential use of glucose as an electron donor, and the lack of competition from alternative electron acceptors such as nitrate and sulfate under anaerobic conditions. These findings suggest that microbial Mo(VI) reduction in mining environments could play a critical role in the geochemical cycling of molybdenum and provide a foundational basis for developing bioremediation strategies specifically tailored for mining-affected ecosystems.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"272 ","pages":"Article 107711"},"PeriodicalIF":3.4,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metallogeny and distribution of critical and strategic metals in the polymetallic vein mineralization at Kolchiko, Vertiskos Unit, northern Greece","authors":"Christos L. Stergiou ,&nbsp;Grigorios-Aarne Sakellaris ,&nbsp;Vasilios Melfos ,&nbsp;Panagiotis Voudouris ,&nbsp;Lambrini Papadopoulou ,&nbsp;Nikolaos Kantiranis ,&nbsp;Irena Peytcheva ,&nbsp;Alexandros Chatzipetros ,&nbsp;Dimitrina Dimitrova ,&nbsp;Elitsa Stefanova","doi":"10.1016/j.gexplo.2025.107708","DOIUrl":"10.1016/j.gexplo.2025.107708","url":null,"abstract":"<div><div>The Kolchiko polymetallic vein-hosted mineralization is part of a broad mineralization system in the Vertiskos crustal unit in northern Greece, which includes several gneiss- and mica-schist-hosted gold, copper and antimony bearing quartz veins. Mineralization includes gold-bearing arsenopyrite and pyrite, chalcopyrite, sphalerite occurring in massive to disseminated forms in quartz-veins, as well as quartz-pyrite veins. The mineralized veins are enveloped by hydrothermal halos related to sericitization of the mica-schist host rocks. Arsenopyrite and pyrite are the most abundant ore minerals, while enrichment in bismuth (&lt;992 ppm) and tellurium (&lt;3 ppm) are related to the variable occurrence of galenobismuthinite, hessite, tellurobismuthite and native bismuth. Particularly gold is enriched (&lt;9.2 ppm) in the massive veins. The ore parageneses, the mineral chemistry analysis and the fluid inclusions imply that the mineralization formation was characterized by two stages of magmatic-hydrothermal activity: 1) an early higher temperature (<em>T</em> = 300 to 444 °C) Fe-As-sulfide rich stage that produced the arsenopyrite- and pyrite-dominated polymetallic massive veins, and 2) a later lower temperature stage (<em>T</em> = 160 to 300 °C) characterized by the formation of Bi-sulfosalts and tellurides in the polymetallic quartz and quartz-pyrite veins. It is suggested that the gold-polymetallic mineralization at Kolchiko was developed under regional retrograde greenschist facies metamorphism and was structurally controlled by the onset of the late Oligocene to early Miocene dextral strike-slip fault zone, which is documented along the western edge of the Vertiskos Unit.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"272 ","pages":"Article 107708"},"PeriodicalIF":3.4,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143379138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemistry of the Oligocene-hosted manganese ores and the host sediments in the Thrace Basin, Türkiye: Implications for genesis and exploration of the Paratethyan Mn deposits","authors":"Hüseyin Öztürk ,&nbsp;Zeynep Cansu ,&nbsp;Feridun Hacılar ,&nbsp;Barrie Bolton","doi":"10.1016/j.gexplo.2025.107707","DOIUrl":"10.1016/j.gexplo.2025.107707","url":null,"abstract":"<div><div>The Early Oligocene Binkılıç Mn deposit occurs within the laminated clays and clayey carbonates of the Thrace Basin, NW Türkiye. Carbonatic and oxidic ores generally alternate with greenish to brownish grey laminated clays. The Mn-bearing laminated clays are unconformably overlain by deltaic Miocene sediments consisting of clay, sand and lignite.</div><div>Trace element and REE contents of the Mn oxides and the laminated host Oligocene clays of the Binkılıç Mn deposits are quite similar. Mn-bearing Oligocene clays and Mn oxides typically show enrichment in Ni, U, Tl, Mo, Co, W, As, Hg, Cu and V relative to PAAS. While Sr and Ba extremely enriched in Mn oxide ore relative to PASS, such enrichment is not observed in the Oligocene clay. A similar trace element enrichment of the Mn oxides and the host Oligocene clays indicates that both were formed under similar geochemical conditions. The fact that the oxidic manganese ore is rich in these trace elements, but the carbonate ore is poor, may indicate that a local reducing environment developed as a result of organic matter decomposition, and that Mn carbonates were formed secondarily in the post-burial stage.</div><div>Trace elements are highly enriched in Mn oxides and clays, are clearly organophylic elements and indicate that the bioproductivity of Paratethyan sea was high in the early Oligocene and that the Mn deposit was formed by anoxic processes as a result of the development, precipitation and decomposition of organic substances. Organic matter-rich sediments at the bottom of deep basins must have ensured the continuity of reducing conditions while transferring the high amount of organophylic trace elements to the seawater. Mn and other anoxia proxy elements were concentrated in the anoxic water column and then carried to shallow marine environments by upwelling deep currents, where they may have been precipitated as Mn oxides in the early Oligocene. In addition to Mn, we propose that a trace element association consisting of Ni, U, Tl, Mo, Co, W, As, Hg, Cu, V anomaly of the Oligocene clays can be used as a prospecting tool for Oligocene-hosted manganese deposits around the Paratethyan Basin.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"272 ","pages":"Article 107707"},"PeriodicalIF":3.4,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assimilation of the chronology of mineral system components in prospectivity analysis procedure for mineral exploration targeting: Adaptation of recurrent neural networks","authors":"Soran Qaderi ,&nbsp;Abbas Maghsoudi ,&nbsp;Mahyar Yousefi ,&nbsp;Amin Beiranvand Pour","doi":"10.1016/j.gexplo.2025.107706","DOIUrl":"10.1016/j.gexplo.2025.107706","url":null,"abstract":"<div><div>Ore deposits are the end product of a series of complex geological processes that operate over time and scales. Given the importance of the time- and scale-dependent processes, this study aims to develop a mineral prospectivity modeling method through contribution of the chronology of ore deposition processes. To achieve this goal, three different architectures of recurrent neural networks (RNNs), i.e., simpleRNN (SRNN), long short-term memory (LSTM), and gated recurrent unit (GRU), were examined to integrate layers of mineral system-based exploration criteria for prospectivity mapping. To compare the time sequence-based prospectivity modeling method (TMPM), which was generated using RNNs, with existing MPM approaches that don't consider the sequence of the ore-forming geological events in the modeling procedure, we generated two prospectivity models using convolutional neural network (CNN) and a classical fuzzy gamma operator. The results obtained demonstrated excellent performance of the three RNN methods over the CNN and fuzzy approaches. To illustrate and demonstrate the method proposed we used a data set of Mississippi Valley-type (MVT) Pb<img>Zn mineralization in the west of Semnan province, Iran.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"272 ","pages":"Article 107706"},"PeriodicalIF":3.4,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cassiterite features and lifespan of Limu granite Ta-Nb-Sn-W ore-forming system in Guangxi, South China","authors":"Liuyun Ouyang ,&nbsp;Wenting Huang ,&nbsp;Jing Wu ,&nbsp;John Mavrogenes ,&nbsp;Juan Liao ,&nbsp;Jian Zhang ,&nbsp;Huaying Liang ,&nbsp;Shuang Yan ,&nbsp;Xiaoping Xia","doi":"10.1016/j.gexplo.2025.107696","DOIUrl":"10.1016/j.gexplo.2025.107696","url":null,"abstract":"<div><div>Rare metal deposits are clearly related to highly evolved granites. The Limu Li<img>F granite complex hosts early quartz vein-hosted W<img>Sn ore and late stage disseminated Ta-Nb-Sn ± W ore. To elucidate unique characteristics of cassiterite from Ta-Nb-Sn-W ore-forming system and the link between magmatic evolution and Nb<img>Ta mineralization, we analyzed textures and trace element compositions of cassiterites from both ore types, and conducted LA-ICP-MS U<img>Pb dating on cassiterites and columbite group minerals (CGMs). Both vein and disseminated cassiterites exhibit low Fe and high (Nb + Ta) contents with molar (Nb + Ta)/Fe ratios (&gt;7), significantly exceeding those of typical Sn-granite cassiterites (&lt;2). Late disseminated cassiterite displays high Nb and Ta oscillatory zoning eroded by low Nb<img>Ta domains, and intergrows with CGMs indicating a dissolution-reprecipitation process via hydrosilicate liquid during crystallization. Contrastingly, low and constant Zr/Hf (~4) suggest Zr and Hf remain stable in the hydrosilicate liquid. We proposed that high molar (Nb + Ta)/Fe ratios and eroded structures in cassiterites may indicate the potential Nb<img>Ta ore. Early quartz-vein cassiterites yielded ages of 215.5 ± 3.5 Ma, while late disseminated ores produced ages of 214.3 ± 2.4 Ma (cassiterite) and 212.7 ± 1.1 Ma (CGMs). Combined with previous zircon ages from early-stage granite (230–227 Ma), the Limu magmatic-hydrothermal system spans 15–16 Myrs. This long-lived magmatic-hydrothermal system depleted in Fe and enriched in (Nb + Ta), driven by continuous mantle-derived heat, likely underwent early fluid exsolution, triggering quartz vein W<img>Sn ores, followed by further melt evolution forming Nb-Ta-rich hydrosilicate liquid, which we consider a prerequisite for Nb<img>Ta enrichment and evolved to generate the late disseminated Ta-Nb-Sn ± W ore.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"273 ","pages":"Article 107696"},"PeriodicalIF":3.4,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143479887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Uncertainty quantification of geochemical data imputation using Monte Carlo dropout","authors":"Vladimir Puzyrev ,&nbsp;Paul Duuring","doi":"10.1016/j.gexplo.2025.107695","DOIUrl":"10.1016/j.gexplo.2025.107695","url":null,"abstract":"<div><div>Machine learning models have shown their promise in geochemical data imputation tasks. However, being black-box solvers, these models require more confidence in their predictions. Using uncertainty quantification methods for deep neural networks can increase the reliability of their predictions. In this paper, we use Monte Carlo Dropout to estimate uncertainty in geochemical data imputation. Multiple forward passes with different dropout configurations yield a predictive distribution for the unknown analytes. The mean of this distribution is used as the prediction, while the standard deviation expresses the uncertainty of the neural networks. Two different scenarios, namely the WACHEM and WAMEX databases containing multi-element geochemical data for rock samples, illustrate the predictive accuracy of the method and its capability to measure the associated uncertainty. Dropout values of 0.1–0.2 were identified as a good balance in prediction accuracy and model uncertainty.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"272 ","pages":"Article 107695"},"PeriodicalIF":3.4,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monazite chemistry and timing of mineralization at Paramanahalli, Chitradurga Greenstone Belt, Dharwar Craton, India: Implications for gold exploration","authors":"Manju Sati ,&nbsp;Rajagopal Krishnamurthi ,&nbsp;Sakthi Saravanan Chinnasamy","doi":"10.1016/j.gexplo.2025.107688","DOIUrl":"10.1016/j.gexplo.2025.107688","url":null,"abstract":"<div><div>Paramanahalli gold deposit, Chitradurga greenstone belt in the Western Dharwar Craton, is a shear zone-hosted/ structurally controlled, mineralization confined to carbonated metabasalt and Banded Iron Formation. Chlorite (Fe-rich) + quartz + ankerite + rutile + monazite ± pyrite ± gold is the mineral association found in the mineralized zone. Monazite from carbonated metabasalt (intensely altered rocks; proximal alteration zone) is interpreted as hydrothermal in origin, based on its mode of occurrence, texture, and chemical composition, particularly its low ThO₂ content, whereas monazite grains from schistose metabasalt (least altered rocks; distal alteration zone), found to be metamorphic. Hydrothermal monazite from the mineralized zone is enriched in light rare earth elements LREEs (La₂O₃ + Ce₂O₃ &gt; 51 wt%) and exhibits low ThO₂ concentrations (&lt;1.5 wt%) classified as anomalous values, in contrast to metamorphic monazite, contain lower LREEs (La₂O₃ + Ce₂O₃ &lt; 45 wt%) and higher ThO₂ (&gt; 1.5 wt%) identified as background values. The ratios such as Ce/Pr, La/Nd, La/Pr, along with REE trends, serve as diagnostic tools to target and exploration of orogenic gold deposits. This study highlights the utility of monazite as a geochemical tool to unravel mineralized zones, thereby enhancing exploration strategies for orogenic-type gold mineralization in the Dharwar Craton and similar terranes. Notably, we are the first to report the timing of a hydrothermal event related to gold mineralization at Paramanahalli by estimating the chemical ages (CHIME) of monazites through Electron Probe Micro Analysis. The study reveals two distinct ages: 2622 ± 08 Ma (older) and 2510 ± 12 Ma (younger), corresponding to metamorphism and <em>syn</em>-ore hydrothermal alteration/mineralization events, respectively. The Neoarchean mineralization event at Paramanahalli (2510 ± 12 Ma) aligns closely with ages estimated for gold mineralization in Ajjanahalli (2520 ± 9 Ma) and Gadag (2522 ± 6 Ma) within the Western Dharwar Craton. Our findings indicate that gold mineralization across the WDC is attributed to a regional tectono-thermal event around 2520 Ma, characterized by extensive fluid flux into the crust.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"271 ","pages":"Article 107688"},"PeriodicalIF":3.4,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143224581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrothermal alterations, geochemical vectoring, and their implications for the world-class Sossego IOCG deposit exploitation, Carajás Mineral Province, northern Brazil","authors":"Antonio Fabricio Franco dos Santos,&nbsp;Carlos Marcello Dias Fernandes","doi":"10.1016/j.gexplo.2025.107692","DOIUrl":"10.1016/j.gexplo.2025.107692","url":null,"abstract":"<div><div>The IOCG-type world-class Sossego deposit is a complex within the Carajás Mineral Province, Amazonian Craton (northern Brazil), with high Cu<img>Au contents (Cu &gt; 0.9 wt%) usually related to intensively hydrothermalized rocks. This deposit has the Pista, Sequeirinho/Baiano, and Sossego/Curral exploratory sectors. Their prevalent host lithologies are deformed or metamorphosed granitoids, felsic and mafic metavolcanics, and ultramafic rocks. Multivariate statistical analyzes of a broad whole-rock geochemical dataset (7834 samples) allow the characterization of the signatures of IOCG-style mineralization and constrain the conspicuous lithogeochemical units observed at the complex. Data treatment encompasses various diagrams based on the mineralogical association of these sectors and major and trace chemical elements that define parameters and limits for the characterization. The Pista sector reveals five lithogeochemical units, highlighting those with high silica and sodium and low iron values in areas closer to the ore zone. At the Sequeirinho/Baiano, nine units appear, where the distal portions to the ore zone reveal high sodium values; gradually changing to median values of sodium and calcium at the intermediate portion; and reaching high values of iron, calcium, and manganese closer to the mineralization. The Sossego/Curral sector has seven lithogeochemical units, where the more distal units to the mineralization zone have high sodium values, whereas those closer to the ore reveal enrichment in potassium, manganese, iron, and calcium. Implicit software-based 3D modeling and the AIOCG 1 and AIOCG 2 geochemical indices materialize these lithogeochemical units within vectors and visually show an enhanced geological overview of hydrothermal flows, their probable mineralogical paragenesis, and correlations with the mineralized zones. Hence, these results contribute to the Sossego Complex exploration, providing data for geometallurgical studies, mine operations improvement and predictability, safety increases, and better ore processing routines with expenditure reductions.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"271 ","pages":"Article 107692"},"PeriodicalIF":3.4,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Whole rock and zircon geochemistry of the Tieshan pluton in Daye region, Eastern China: Implication for petrogenesis and Fe-Cu-Au-(Co) mineralization","authors":"Bao Zhou ,&nbsp;Guang Wen ,&nbsp;Run-Jie Zhou ,&nbsp;Yue Sun ,&nbsp;Chang-Xiong Wu ,&nbsp;Jin Zhu ,&nbsp;Zhi-Jun Qin ,&nbsp;Xiao-Yang Liu ,&nbsp;Xiao-Zeng Cheng","doi":"10.1016/j.gexplo.2025.107687","DOIUrl":"10.1016/j.gexplo.2025.107687","url":null,"abstract":"<div><div>The Tieshan pluton is situated in the Daye region of the Middle-Lower Yangtze River Valley metallogenic belts. It consists mainly of quartz diorite and host abundant mafic microgranular enclaves (MMEs) and is associated with the renowned Daye Fe-Cu-Au-(Co) skarn deposit. The presence of disequilibrium textures in MMEs, including quenched margins, acicular apatite and elongated amphibole, provides evidence that the pluton underwent magma mixing involving mafic and felsic magma. In comparison with the Fe (4.20 wt% on average), Cu (28 ppm on average) and Co (10 ppm on average) concentrations in the quartz diorite, the Fe (7.26 wt% on average) and Cu (57 ppm on average) concentrations are doubled and Co (29 ppm on average) are tripled in MMEs. The recharge of mafic magma, therefore, likely adding significant amount of Fe, Cu and Co metals into the felsic magma, therefore enhancing the fertility of the Tieshan pluton.</div><div>Zircons from quartz diorite of the Tieshan pluton exhibit U-Pb ages of 138.2 ± 1.6 Ma and 136.9 ± 1.6 Ma, respectively. The zircon ε_Hf(<em>t</em>) values of the Tieshan quartz diorite (ranging from −17.6 to −16.1) closely match to those of the Cu-Fe-Au fertile granitoids in the Daye region. Zircons from the Tieshan quartz diorite display Eu/Eu* and Yb/Dy values ranging from 0.4 to 0.6 and 3.6 to 4.2, respectively. These ratios suggest substantial amphibole fractionation with minimal plagioclase fractionation and indicate high magmatic water contents. This is corroborated by the zircon oxybarometer-hygrometer analysis, which estimates the melt H₂O content to be between 8.3 and 10.3 wt%. The zircons from the Tieshan quartz diorite exhibit Ce⁴⁺/Ce³⁺ ratios of 67 to 201 and oxygen fugacity (log<em>f</em>O₂ values of ΔFMQ) from ΔFMQ+2.1 to ΔFMQ+2.8. The calculated zircon Ce⁴⁺/Ce³⁺ ratios and oxygen fugacity (log<em>f</em>O₂) for the quartz diorite from Tieshan pluton are comparable to the values of Tonglushan Cu-Fe-Au related fertile quartz diorite, indicating the similar oxygen fugacity of the Cu-Fe-Au ore-related magmas in Daye region. Our research demonstrates that the geochemistry of whole-rock and zircon is a powerful tool for identifying granitoids with potential for skarn Fe-Cu-Au-(Co) mineralization.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"271 ","pages":"Article 107687"},"PeriodicalIF":3.4,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143182833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mineralogy, geochemistry, and S isotope investigation of seafloor massive sulfides from the Yunzang hydrothermal field, South Atlantic Ridge","authors":"Wen-Sheng Li ,&nbsp;Pei Ni ,&nbsp;Xue-Fa Shi ,&nbsp;Bing Li ,&nbsp;Shao-Wen Liu ,&nbsp;Stefano Albanese ,&nbsp;Fei-Peng Fan ,&nbsp;Guan-Hua Wang ,&nbsp;An-Qi Hong","doi":"10.1016/j.gexplo.2025.107684","DOIUrl":"10.1016/j.gexplo.2025.107684","url":null,"abstract":"<div><div>Research on the ore-forming model of modern seafloor hydrothermal sulfide deposits is of significant economic and scientific importance. The limited research on recently discovered seafloor sulfide deposits has resulted in a vague comprehension of water-rock interactions, metal origins, and the subsequent metal deposition process. The Yunzang hydrothermal field is located on the South Mid-Atlantic Ridge and represents a newly discovered seafloor hydrothermal sulfide deposit. However, the geological features, primary mineral assemblages of ores, and the source regions of metals in the hydrothermal field remain unclear. In this study, sulfides were analyzed using a TESCAN Integrated Mineral Analyser (TIMA) and in-situ laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to investigate trace element distributions and S isotope compositions. Analysis by TIMA shows that the Yunzang hydrothermal field is mainly composed of pyrite, chalcopyrite, and sphalerite. Two types of ore with distinct characteristics were identified, one rich in chalcopyrite and the other in sphalerite. Within these ores, two different types of pyrite were identified, namely colloform and euhedral pyrite. Colloform pyrite formed at low temperature in outer margins of the chimney is enriched in Mn, V, Ag, Tl and Cd. Euhedral pyrite formed at high temperature in inner zone of the chimney is enriched in Co, Se, Cu and Sn. The variation in trace elements within pyrite is primarily governed by the synergistic effects of fluid conditions (such as temperature and redox state) and the influx of ambient seawater that accompanies the chimney formation process. The higher concentrations of Mo and V in the pyrite found in the outer wall of the chimney indicate significant interactions between seawater and hydrothermal fluids. The lower Au/As ratio in pyrite proves that gold exists within the lattice of pyrite rather than in nano-particles. The lower concentrations of Sn and Bi in chalcopyrite suggest that ore-forming materials may primarily originate from leaching of the surrounding rocks, with a lack of magmatic volatile components. The Fe/Zn ratio in sphalerite indicates that the Yunzang hydrothermal field belongs to sediment-starved SMS, with the formation temperature of sphalerite ranging from 242 to 262 °C. The positive δ³⁴SV-CDT values of pyrite (1.0 ‰–3.7 ‰) suggest 83 %–96 % of S was derived from the leaching of basement basalts, 4 %–17 % from oxidation of seawater sulfate. Based on these analytical results, the growth history of chimney and the fluid source in the Yunzang hydrothermal field are proposed.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"271 ","pages":"Article 107684"},"PeriodicalIF":3.4,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}