Journal of Geochemical Exploration最新文献

{"title":"The effect of FeP coupling on arsenic species in sediments during the ice-bound period of lakes in cold regions","authors":"Wenjing Shi ,&nbsp;Xinya Zhao ,&nbsp;Yizhe Liu ,&nbsp;Haoran Xu ,&nbsp;Changwei Lü ,&nbsp;Weiping Li","doi":"10.1016/j.gexplo.2025.107903","DOIUrl":"10.1016/j.gexplo.2025.107903","url":null,"abstract":"<div><div>The redox behavior of iron (Fe) significantly impacts the biogeochemical cycle of arsenic (As), with iron minerals serving as major reservoirs for phosphate (P). The cycle of As inherently associates with its species. However, the effect of Fe<img>P coupling on As species in lake sediments remain largely unknown, especially during the ice-bound period. The novelty of this study is to explore the effect of Fe<img>P coupling on As speciation during an ice-bound period using PLS-SEM model based on As、Fe and P species as well as environmental factors monitoring in sediments. Our findings revealed that Fe<img>P coupling accounts for 95.7 % of As speciation variability, playing a pivotal role in As transformation and partitioning, particularly in labile As pool that contained adsorbed As, moderately labile As pool that closely related to iron species, and pyrite-coprecipitated As. The significant influence of Fe<img>P coupling on the reductive transformation and re-distribution of amorphous and crystalline iron oxides, which in turn affects As adsorption-desorption processes. This interaction subsequently influences the speciation of Fe and P, as well as the release and ecotoxicity of As. Notably, exchangeable phosphorus, iron-bound P fraction and organic P fraction (OP) were identified as the primary P species mediating the effects of Fe<img>P coupling on As speciation. Interesting, OP also play the major role in the effect of Fe<img>P coupling on As species, potentially releasing As adsorbed on crystalline Fe hydroxides during organic matter mineralization. Results emphasize the importance of Fe(hydro)oxides and P in controlling As partitioning, with iron (hydro)oxides being particularly critical in P behavior and its interaction with As. This work provides insights into the cycling of As and the enrichment of P and As in sediment-water systems, providing a reference for environmental monitoring and remediation in sedimentary environments facing dual risks of As pollution and eutrophication.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107903"},"PeriodicalIF":3.3,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046587","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":"Trends of Cu and Co contaminated sediment dispersal along the Kafue River, the Zambian Copperbelt","authors":"Ondřej Bábek ,&nbsp;Ondra Sracek ,&nbsp;Vojtěch Ettler ,&nbsp;Jaroslav Kapusta ,&nbsp;Bohdan Kříbek ,&nbsp;Martin Mihaljevič ,&nbsp;Imasiku Nyambe ,&nbsp;Vít Penížek ,&nbsp;Aleš Vaněk ,&nbsp;Gabriel Ziwa","doi":"10.1016/j.gexplo.2025.107900","DOIUrl":"10.1016/j.gexplo.2025.107900","url":null,"abstract":"<div><div>Rivers are important pathways for metal(loid) contamination in mining areas. The Kafue River flows through the Zambian Copperbelt with nearly a hundred-year history of Cu and Co mining. Nine cores down to 2.5 m deep were drilled in fluvial sediments along a 750-km long river section and analysed for grain size, elemental composition, and mineralogy using extraction tests and scanning electron microscopy with an aim to investigate the spatial and temporal contamination patterns. The silty and fine- to coarse grained sandy sediments were deposited in natural levees, semi-abandoned meanders, and channel bars. They are heavily polluted by Cu reaching ore grade (up to 1.9 %) and Co, with UCC-based enrichment factors (EF) as high as 704 and 60, respectively, which is more than an order of magnitude higher than the most severely impacted large European rivers, and slightly polluted by Pb, As, U and other elements. The main carriers of Cu are malachite, pseudomalachite, secondary Fe oxyhydroxides (ferrihydrite, goethite), sulphides, and Cu-bearing grains of kaolinite, chlorite, and mica. This Cu contamination is traceable (EF up to 13) in sediments 750 km downstream of the Kafue River inflow to the Copperbelt. The contaminated sediments are ~100 cm to ~220 cm thick and their average sediment accumulation rates ~12 to ~27 mm/yr indicating that the contaminated suspended particulate matter can be rapidly deposited along the river, representing a potential environmental hazard. Arsenic and Pb can be scavenged to Fe oxyhydroxides and accumulate in capillary fringe above groundwater level during early diagenesis.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107900"},"PeriodicalIF":3.3,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096901","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":"Multistage genesis of the carbonate-hosted Tuokesai Pb–Zn deposit, West Tianshan, NW China: Synsedimentary strata-bound mineralization and hydrothermal remobilization","authors":"Shunda Li ,&nbsp;Wenjiao Xiao ,&nbsp;Chuan Chen ,&nbsp;Miao Sang ,&nbsp;Qigui Mao ,&nbsp;Lingling Gao ,&nbsp;Fang Xia ,&nbsp;Wei Wang ,&nbsp;Xiaofei Du","doi":"10.1016/j.gexplo.2025.107891","DOIUrl":"10.1016/j.gexplo.2025.107891","url":null,"abstract":"<div><div>The Tuokesai Pb–Zn deposit is located in the eastern section of the West Tianshan Orogen within Precambrian carbonate rocks. However, the genesis of the ore, including sedimentary exhalative and sedimentary-metamorphic types, remains controversial owing to varying interpretations of strata-bound and vein-type mineralization. In this study, we aimed to construct an innovative genesis model, focusing on two mineralization types, by analyzing fluid evolution, material sources, and trace element distributions. Three mineralization stages were identified, each with specific pyrite generation. Stage I pyrite–sphalerite–galena bands (Py-1 and Py-2) represent strata-bound mineralization. Stage II sphalerite–pyrite–quartz veins (Py-3) and Stage III pyrite–quartz–calcite veins (Py-4) represent vein-type mineralization. Fluid inclusion microthermometric and H–O isotopic analyses revealed that Stage I fluids are characterized by low temperatures (132–171 °C) and moderate salinities (11.8–17.3 wt% NaCl eqv.), and are derived from modified seawater. Conversely, fluids in Stages II–III are associated with moderate temperatures (165–267 °C) and variable salinities (2.1–35.3 wt% NaCl eqv.), being derived from a mixture of magmatic and meteoric water. The in situ S isotopic composition suggests that Py-1 and Py-2 (δ³⁴S = 9.46–12.20 ‰) originated from the thermochemical reduction of marine sulfate, whereas Py-3 and Py-4 (δ³⁴S = 0.85–3.85 ‰) originated from magmatic components. LA–ICP–MS analysis of trace elements in pyrite, combined with machine learning classification methods, indicated that Py-1 and Py-2 have a synsedimentary origin whereas Py-3 and Py-4 have a magmatic-hydrothermal origin. Overall, our findings support a novel multistage genesis model for the Tuokesai Pb–Zn deposit, suggesting that Neoproterozoic syngenetic strata-bound mineralization was overprinted by Late Paleozoic vein-type hydrothermal remobilization. This model highlights the importance of incorporating diverse geological events into our understanding of the ore-forming process to facilitate the exploration of carbonate-hosted Pb–Zn deposits within the West Tianshan Orogen.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107891"},"PeriodicalIF":3.3,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046585","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":"A review of Australian carbonatites and associated REE-Nb mineralisation","authors":"Ross Chandler ,&nbsp;Ignacio González-Álverez ,&nbsp;John Mavrogenes ,&nbsp;Luke Blais","doi":"10.1016/j.gexplo.2025.107870","DOIUrl":"10.1016/j.gexplo.2025.107870","url":null,"abstract":"<div><div>Australia has 16 known carbonatites, and two other occurrences of REE mineralisation interpreted as carbonatite-related. These are all located within Precambrian crust, and host known resources of c. 7.2 Mt. of rare earth oxides (containing c. 1.73 Mt. of Nd₂O₃ and Pr₆O₁₁), and c. 2.7 Mt. of Nb₂O₅.</div><div>Australia's carbonatites range from Neoarchean to Jurassic, and display extreme diversity in geological characteristics, ranging from large, multiphase intrusive complexes dominated by either carbonatite (e.g. Gifford Creek and Mt. Weld, Western Australia) or silicate rocks (e.g. Cummins Range and Cundeelee, Western Australia), to single phase and small volume carbonatite dykes (e.g. Yungal dykes, Western Australia). Studied occurrences show similarly diverse radiogenic isotopic signatures (Rb/Sr and Sm/Nd), indicating derivation from a variety of mantle sources ranging from HIMU through to EM1.</div><div>Significant rare earth element (REE) and niobium (Nb) mineralisation occurs in both fresh and weathered carbonatites throughout Australia, with markedly different mineralogical and grade characteristics. While weathering history and preservation are crucial to the formation of supergene enrichments in REE and Nb, analysis of whole-rock geochemical data for different carbonatite types from the Mt. Weld and Gifford Creek complexes suggest primary magmatic composition plays the strongest determinant in the magnitude of grade increase, with siderite-dominated carbonatites having less potential for supergene upgrade than dolomite, ankerite and calcite-dominated examples.</div><div>The distinct geophysical signatures of Australia's known carbonatites have aided exploration efforts leading to early discoveries of deposits within highly magnetic complexes such as Mt. Weld and Cummins Range. Recent discoveries of geophysically subtle complexes (e.g. Gifford Creek complex, West Arunta) suggests both alternative geophysical techniques and a comprehensive structural understanding are crucial to discovery.</div><div>Explorers should focus on areas of known carbonatite magmatism, with a particular focus on developing an understanding of the regional structures that can facilitate carbonatite intrusion. On a local scale, the selection of relevant carbonatite geophysical and exploration signatures leveraging previous local discoveries should be prioritised. The small number of known carbonatites in Australia compared to the other continents abundances indicates further carbonatites and associated mineralisation may be discovered with increased exploration.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"279 ","pages":"Article 107870"},"PeriodicalIF":3.3,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144996910","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":"Trace element and sulfur isotope constraints on the Genesis of Sb-(Au) deposits in Southern China: Insights from the Longkou deposit","authors":"Junwei Xu ,&nbsp;Xiangfa Song ,&nbsp;Degao Zhai ,&nbsp;Linyan Kang ,&nbsp;Xianghua Liu ,&nbsp;Kui Jiang ,&nbsp;Yulin Chen","doi":"10.1016/j.gexplo.2025.107892","DOIUrl":"10.1016/j.gexplo.2025.107892","url":null,"abstract":"<div><div>The Xiangzhong Metallogenic Province (XZMP) in southern China hosts the region's most extensive Sb-polymetallic mineralization system, comprising two principal deposit types: Sb-only and Sb–Au–(W). To investigate their genetic distinctions, we conducted in-situ LA-ICP-MS and sulfur isotope analyses on stibnite from the Longkou Sb<img>Au deposit in the Shaoyang Basin, and integrated these results with published data from the Xikuangshan, Daocaowan, Woxi, and Banxi deposits. Multivariate statistical analyses (PCA and PLS-DA) of stibnite trace elements reveal systematic geochemical differences between the two deposit types. Sb<img>Au deposits (e.g., Longkou, Woxi, Banxi) are enriched in Cu and Pb, whereas Sb-only deposits (e.g., Xikuangshan, Daocaowan) show elevated Hg and lower Cu<img>Pb concentrations. These patterns suggest that, while Sb in both deposit types was likely derived from Proterozoic basement rocks, metals such as Au, Cu, and Pb in Sb<img>Au deposits originated from deep magmatic-hydrothermal fluids. In contrast, ore-forming fluids in Sb-only systems were dominated by shallow-crustal or metamorphic sources, with limited magmatic input. The δ³⁴S values of stibnite are relatively uniform across most deposits, further supporting a shared sulfur source linked to basement lithologies. Trace element and sulfur isotope data point to two distinct mineralization mechanisms: in Sb<img>Au systems, magmatic-hydrothermal fluids transported metals from depth and leached Sb and S from basement rocks, while in Sb-only systems, magmatic activity primarily acted as a heat source, promoting the circulation of meteoric and metamorphic fluids that leached Sb and S from the basement. These findings provide a geochemical framework for distinguishing Sb deposit types and offer new insights into the metallogenic processes of Sb–(Au) systems in South China.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107892"},"PeriodicalIF":3.3,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046588","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":"Formation mechanism of high arsenic geothermal water in Gonghe basin, Northwest China","authors":"Zhen Wang ,&nbsp;Yongge Li ,&nbsp;Chuanxia Ruan ,&nbsp;Fu Wang ,&nbsp;Wenjing Lin ,&nbsp;Yu Yang ,&nbsp;Narsimha Adimalla","doi":"10.1016/j.gexplo.2025.107890","DOIUrl":"10.1016/j.gexplo.2025.107890","url":null,"abstract":"<div><div>The occurrence of high arsenic (As) concentrations in groundwater within overlying aquifers, influenced by deep geothermal activities, has been reported globally. However, its genetic mechanisms remain inadequately understood. In this study, forty-one water samples were collected to analyze the major and trace chemical compositions of water, along with isotopic signatures (δ¹⁸O, δD, δ¹³C, δ¹⁴C, δ³²S_SO4). Results show that As concentrations in NGW (with an average 452 μg/L) are significantly higher than in QGW (with an average 36.0 μg/L). Additionally, hydrochemical type of QGW gradually evolves from Na-HCO₃ to Na-SO₄ and Na-Cl·SO₄ along the flow path. The δ¹⁸O and δD isotopic results suggest that local atmospheric precipitation is the primary source of QGW, while glacial meltwater or high altitude atmospheric precipitation serves as the main source of NGW. The high temperature environment contributes to an oxygen drift in the δ¹⁸O of NGW. Results of δ¹³C indicate that the main sources of inorganic carbon in geothermal water are likely from the dissolution of carbonates and decomposition of organic matter. According to δ¹⁴C data, the average apparent age of QGW is 18.8 ka, with relatively older ages found in the south and southeastern parts of the study area, whereas NGW has an average age of 29.1 ka. The continuous upwelling of deep geothermal energy raises the temperature of hot storage aquifer, promoting the release and migration of As. Additionally, silicate weathering and microbial sulfate reduction play significant roles in As enrichment in both QGW and NGW. Furthermore, As desorption from QGW and NGW is another factor contributing to the elevated As levels in the investigated region.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107890"},"PeriodicalIF":3.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144989841","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 and economic evaluation of REE + Y potential in the fine-grained matrix of sedimentary phosphorites from the Tebessa region, eastern Algeria","authors":"Riadh Aouachria ,&nbsp;Rabah Kechiched ,&nbsp;Roberto Buccione ,&nbsp;Giovanni Mongelli ,&nbsp;Ouafi Ameur-Zaimeche ,&nbsp;Olivier Bruguier ,&nbsp;László Kocsis ,&nbsp;Rabah Laouar","doi":"10.1016/j.gexplo.2025.107889","DOIUrl":"10.1016/j.gexplo.2025.107889","url":null,"abstract":"<div><div>The Algerian phosphorites, deposited during the Paleocene-Eocene, are part of the Tethyan phosphogenesis along the southern paleo-Tethys margin. Located primarily in the Tebessa region, these deposits hold reserves exceeding 2 billion metric tons. Recent interest has grown due to their enrichment in rare earth elements plus yttrium (REY). While previous studies have examined whole-rock and grain-size fractions, the fine-grained matrix (&lt;45 μm) remains poorly explored. This study provides the first mineralogical and geochemical characterization of this fraction to assess its economic potential and paleoenvironmental significance. Twenty-two fine-fraction samples from four Tebessa localities were separated using humid grain-size classification. Mineralogical analysis was supported by X-Ray Powder Diffraction (XRD), whereas geochemical analyses were carried out using inductively coupled plasma optical emission spectroscopy (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS).</div><div>The XRD results show that the phosphorite fine-grained matrix is composed of calcite, dolomite, carbonate fluorapatite, glauconite, quartz, chlorite, and gypsum. Notably, glauconite occurs in higher amounts in southern deposits (Kef Essenoun), suggesting intensified glauconitization process. Geochemically, the fine fraction contains an average of 12.48 wt% P₂O₅, with REY concentrations ranging from 55 to 863 ppm. REY contents increase southward, with REEs ranging between 68 and 678 ppm (avg. 416 ± 198 ppm) and Y varies from 9 to 187 ppm (avg. 125 ± 56 ppm). The higher REY content is partly linked to glauconite phase abundance. Normalized REY contents indicate seawater-like patterns in the northern deposits, whereas the southern deposits show middle REE (MREE) enrichment patterns. High (La/Yb)_N ratios in the glauconite-rich samples suggest early-diagenetic adsorption under slow sedimentation rate and sub-reduced conditions. An enhanced glauconitization process occurred in the southern basin at the Paleocene–Eocene boundary, which is marked by global thermal event. These findings suggest that the fine-grained matrix, typically considered as waste during the treatment of raw phosphorites, holds economic potential due to its high REY content, presenting a promising resource for future exploitation.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107889"},"PeriodicalIF":3.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046586","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":"Large-scale polymetallic mineralization driven by long-lived magmatic-hydrothermal activity and subducted sediment influx: A case study from Toyoha, NE Japan","authors":"Mizuki Ishida ,&nbsp;Yuki Hieda ,&nbsp;Shuhei Araki ,&nbsp;Koichiro Fujinaga ,&nbsp;Toru Shimizu ,&nbsp;Masaharu Tanimizu ,&nbsp;Cindy Broderick ,&nbsp;Hitomi Nakamura ,&nbsp;Hikaru Iwamori ,&nbsp;Shiki Machida ,&nbsp;Shigekazu Yoneda ,&nbsp;Kentaro Nakamura ,&nbsp;Yasuhiro Kato","doi":"10.1016/j.gexplo.2025.107887","DOIUrl":"10.1016/j.gexplo.2025.107887","url":null,"abstract":"<div><div>Although there is increasing recognition that long-lived magmatic-hydrothermal systems are essential components of large-scale mineralization, relatively little is known about the source processes that enable such activity, especially in areas of average crustal thickness. To address this issue, we investigated the sources of ore-forming elements and drivers of prolonged ore-forming activity (&gt;1 million years) in the Toyoha polymetallic intermediate-sulfidation deposit, located at the northern end of the Northeast Japan Arc. We have presented Pb isotopic evidence that in the southeastern part of the deposit, where the hydrothermal activity lasted substantially longer (&gt;1 million years) than the nearby (&lt;10 km) volcanic activities, sulfide minerals from the ore had a specific metal source in addition to the wall rocks and the magmas observable as nearby extrusive rocks. The additional source was likely latent intrusions similar to the isotopically enriched volcanic rocks ~20 km southeast of the deposit, which incorporated abundant components from the subducting sediment. Based on regional geological, geochemical (major, trace elements and Sr-Nd-Pb isotopes) and geochronological data, we propose that seamount subduction induced the extra sediment input into the mantle wedge, which generated additional magma batches and helped to sustain magmatic-hydrothermal activity in the study area. The large tonnage, particularly of Pb, Zn, Ag, and In, in Toyoha was likely a result of the productive source, which enabled long-lived magmatic-hydrothermal activity, and an effective structure for the transport and trapping of ore-forming materials.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107887"},"PeriodicalIF":3.3,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027313","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":"The Bujinhei Pb-Zn deposit in the southern Great Xing'an Range, China: An example of the reduced hydrothermal vein type Pb-Zn mineralization system","authors":"Cheng-yang Wang ,&nbsp;Yun-sheng Ren ,&nbsp;Yi-cun Wang ,&nbsp;Zhen-jun Sun ,&nbsp;Li-juan Fu","doi":"10.1016/j.gexplo.2025.107888","DOIUrl":"10.1016/j.gexplo.2025.107888","url":null,"abstract":"<div><div>The Bujinhei deposit, a representative vein-type Pb-Zn mineralization, is situated on the western slope of the southern Great Xing'an Range (SGXR). The ore bodies of Bujinhei are primarily hosted within Permian sedimentary rocks and structurally controlled by nearly EW-trending faults. Three types of fluid inclusions (FIs), including gas-liquid two-phase inclusions (Type-1), CH₄ (±CO₂)-rich inclusions (Type-2), and pure CH₄-CO₂ inclusions (Type-3) can be recognized in hydrothermal veins. Laser Raman spectral analysis further confirmed that the gas phase of these fluid inclusions contained large amounts of CH₄. Petrographic analysis, microthermometry, and laser Raman spectroscopy of fluid inclusions suggest that the ore-forming fluids comprise a NaCl-H₂O-CH₄ ± CO₂ system, characterized by moderate temperatures and low salinity. Oxygen and hydrogen isotope data for quartz and carbonate from the ore-bearing veins fell between the fields of typical magmatic and meteoric water (δ¹⁸O_fluid = 4.0 ‰–7.2 ‰, δD_fluid = −123.1 ‰ to −112.7 ‰). The extremely low δD_fluid values of Bujinhei fluids could be due to water-rock reactions between ore fluids and carbonaceous strata. The δ¹³C _PDB value of the CH₄ in fluid inclusions ranged from −31.8 ‰ to −27.9 ‰, also suggesting the hydrolysis of organic matter in the sedimentary was involved in the mineralizing fluids. Sulfides from the Bujinhei show restricted δ³⁴S_CDT values of −3.2 to −0.7 ‰, without the diagnostic signature of sedimentary sulfur. These sulfides have ²⁰⁶Pb/²⁰⁴Pb = 18.200–18.285, ²⁰⁷Pb/²⁰⁴Pb = 15.519–15.623, and ²⁰⁸Pb/²⁰⁴Pb = 38.020–38.364, overlapping with most of the hydrothermal vein type deposits, which were sourced primarily from deep-seated magma. Genetically, the Bujinhei Pb-Zn deposit shows characteristics of a typical reduced hydrothermal system, which may be originally magmatic-related and dramatically influenced by carbonaceous-reducing rocks. The investigation results presented in this paper provide compelling evidence that carbonaceous wall rocks exert a substantial influence on the formation of reducing conditions in lead‑zinc ore-forming hydrothermal systems in the southern Great Xing'an Range.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"279 ","pages":"Article 107888"},"PeriodicalIF":3.3,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144916564","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":"Mineral system modeling of Lithium-Cesium-Tantalum (LCT)-type pegmatites: Regional-scale exploration targeting and uncertainty analysis in the Sanandaj-Sirjan zone, Western Iran","authors":"Majid Keykhay-Hosseinpoor ,&nbsp;Alok Porwal ,&nbsp;R. Kalimuthu ,&nbsp;Shanta Panja","doi":"10.1016/j.gexplo.2025.107885","DOIUrl":"10.1016/j.gexplo.2025.107885","url":null,"abstract":"<div><div>Granitic pegmatites, particularly lithium‑cesium‑tantalum (LCT) types, are vital sources of rare metals crucial for modern technologies, including sustainability, energy storage, and green energy applications. Exploring and targeting LCT pegmatites are essential to meet the increasing demand for critical metals like lithium in green technologies. Mineral prospectivity modeling provides a systematic approach to identifying these deposits, especially in regions such as western Iran, where the Sanandaj-Sirjan Zone (SaSZ) is the potential host of LCT pegmatites. This study aims to model the prospectivity of LCT pegmatites in the SaSZ, with three primary objectives: (i) to construct a mineral systems framework that defines the critical processes controlling the genesis of LCT pegmatites and their mappable proxies, (ii) to identify high-priority exploration targets using knowledge-driven approaches, and (iii) address uncertainties stemming from limited data availability (epistemic) and from the integration of multiple models (systemic) to improve exploration reliability. To achieve these objectives, three well-known knowledge-based algorithms—fuzzy inference systems, continuous fuzzy gamma, and geometric average—were employed using publicly available geo-exploration datasets to generate prospectivity models based on the mineral systems approach. These were subsequently combined into a final predictive model using a majority voting (MV) ensemble technique. A confidence index (CI) was incorporated to quantify and mitigate uncertainties associated with the multi-algorithm approaches, delineating low-risk, high-confidence zones for future exploration. The results show high prospectivity zones (~2 % of the study area) in the northern and southern parts of the SaSZ, particularly near the Alvand complexes, predominantly located farther from their host plutons and within metamorphic aureoles. This study highlights the efficacy of integrating mineral systems frameworks with geospatial modeling to optimize exploration strategies. Future research should prioritize acquiring high-resolution geophysical and geochemical data and conducting systematic ground-truthing to validate and refine these targets, ensuring economic feasibility and resource-efficient exploration.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"279 ","pages":"Article 107885"},"PeriodicalIF":3.3,"publicationDate":"2025-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896090","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}