Journal of Geochemical Exploration最新文献

{"title":"Driving factors of soil selenium accumulation in regional enrichment area at selenium-deficient soil belt of China: An enlightenment of Moran's index and machine learning","authors":"Yuanli Qin ,&nbsp;Li Zhang ,&nbsp;Qiaolin Wang ,&nbsp;Yuntao Song ,&nbsp;Min Peng ,&nbsp;Hangxin Cheng","doi":"10.1016/j.gexplo.2025.107746","DOIUrl":"10.1016/j.gexplo.2025.107746","url":null,"abstract":"<div><div>Selenium (Se) is one of the most indispensable trace elements for human beings, known as the ‘longevity element’ in the 21st century. Due to the complexity of the global geological environment, the distribution of soil Se varies significantly across the world. Understanding the distribution pattern and driving factors of soil Se enrichment is crucial for land resource development and addressing “hidden hunger”, especially in regions where soil Se is abundant. Therefore, a soil geochemical survey was conducted in the Baoshan area of southwest China, which is located at the Se-deficient soil belt yet exhibited characteristics of soil Se enrichment. Combined with Moran's I analysis and machine learning (ML), the enrichment and distribution characteristics, and driving factors of soil Se in this region were revealed. Specifically, we quantify the feature importance of each key factors. Additionally, distribution of soil Se demonstrated strong spatial dependence. The results from Bivariate Moran's I analysis, back-propagation artificial neural networks (BP–ANN) and random forest (RF) models indicated that soil organic carbon (SOC), pH, manganese (Mn), weathering eluvial index (ba), land use and parent materials are the primary driving factors of soil Se retention at the regional scale in Baoshan. In contrast, climate and topography, which are common factors affecting Se distribution at global and continental scales, were found to have no effect on Se retention at this regional scale. Based on the RF model, the relative importance of key driving factors are SOC (24.5 %), land use (21.1 %), pH (15.5 %), ba (15.2 %), parent materials (12.0 %), and Mn (11.9 %). These findings provide valuable guidance for agricultural managements planning and for adjusting agricultural planting structures in marginal and soil Se-rich regions of the traditional Se-deficient soil belt in China.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"274 ","pages":"Article 107746"},"PeriodicalIF":3.4,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143621497","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":"Metallogenesis of the sediment-hosted copper deposits in the Miocene sandstones from Upper Red Formation, Zanjan, NW Iran","authors":"Ghasem Nabatian ,&nbsp;Mohammad Ebrahimi ,&nbsp;Osvaldo Rabbia","doi":"10.1016/j.gexplo.2025.107745","DOIUrl":"10.1016/j.gexplo.2025.107745","url":null,"abstract":"<div><div>The Chehrabad, Qezeljeh, and Sarikand copper deposits, located in the Zanjan district in northwestern Iran, are classified as sediment-hosted copper (SHC) deposit. These deposits mainly consist of fine-grained, disseminated base-metal sulfides cementing grey sandstones from the thick sequences of Miocene red beds (Upper Red Formation: URF). The ore-hosting grey sandstones contain carbonaceous materials (fossil plants) and fine-grained, disseminated framboidal pyrite. Copper, lead, zinc, and iron sulfides replace primary organic material as well as framboidal pyrite. Ore minerals such as chalcocite, galena, sphalerite, argentite, covellite, pyrite and minor chalcopyrite and bornite occur as replacement in organic matter and cement of the host sandstone. Geochemical analyses of the SHC deposits in the Zanjan district show an average of 5 wt% Cu, 6 wt% Pb and 3 wt% Zn, ~0.7 to 128 ppm for Ag, and ~ 0.1 to 821 ppm for Cd in the grey sandstone. This research aims to enhance the comprehension of the genesis of the SHC deposits in the Zanjan district, thereby providing direction for future exploration efforts in the area.</div><div>Electron probe micro-analysis (EPMA) was used to determine the mineral chemistry and occurrence of copper, lead, zinc, and silver in sulfide and carbonate minerals. The results reveal that argentite is associated with Cu-bearing minerals (mainly chalcocite and covellite). Furthermore, the presence of montetrisaite mineral, along with minor amounts of cadmium, has been identified. The studied samples from Zanjan SHC deposits show a range of δ³⁴S values from −1.90 ‰ to +12.9 ‰ values, indicating sulfur might have originated from framboidal pyrite, organic matter, evaporite layers, and salt diapirs of URF. The sulfide ore is vertically zoned, with Cu sulfides at lower stratigraphic levels and Pb-Zn-rich ore at the upper part. Ore-stage sulfide minerals were likely formed by the infiltration of ore-forming fluids originating from the underlying red beds into the grey sandstone layers during the Miocene, following the deposition of these rocks. The oxidized, low-temperature, metalliferous brine responsible for mineralization originated from highly porous and permeable sediments expelled during diagenetic events in the basin. Mineralization occurred within a favorable reducing environment, mainly provided by organic matter, framboidal pyrite, and reduction of the oxidized, low-temperature brine in the grey sandstone horizons. The timing of these deposits is typically late diagenetic. Concerning host rock lithology, mineral assemblages, fabric and structure of the ores, and the overall genetic interpretation, they are similar to the sediment-hosted stratiform copper deposits elsewhere such as Lisbon Valley (Utah, USA) and Nacimiento (New Mexico).</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"274 ","pages":"Article 107745"},"PeriodicalIF":3.4,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610332","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":"Assessment of LUNAR, iForest, LOF, and LSCP methodologies in delineating geochemical anomalies for mineral exploration","authors":"Shahed Shahrestani ,&nbsp;Christian Conoscenti ,&nbsp;Emmanuel John M. Carranza","doi":"10.1016/j.gexplo.2025.107737","DOIUrl":"10.1016/j.gexplo.2025.107737","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Geochemical anomaly detection and delineation are crucial in mineral exploration, but they are challenged by high-dimensional data, complex inter-variable dependencies, and scarcity of ground truth labels for anomalies. Traditional outlier detection methods, including density-based and nearest-neighbor approaches, often misclassify anomalies close to the edges of the background data distribution, while ensemble methods face limitations in combining detectors effectively. Generic and global combination procedures frequently neglect local patterns in the data, leading to suboptimal detection of nuanced outlier characteristics, and the absence of robust selection processes can compromise ensemble performance due to underperforming detectors. To address these issues, this paper presents LUNAR (learnable unified neighborhood-based anomaly ranking), a novel outlier detection method that integrates graph neural networks with nearest neighbor analysis, and LSCP (locally selective combination in parallel outlier ensembles), which emphasizes local data structures and leverages pseudo-ground truth to optimize detector selection and improve score stability. This study also explored the efficacy of outlier detection methods, namely local outlier factor (LOF) and isolation forest (iForest) in detecting geochemical anomalies within the Varzaghan area, situated in the Ahar–Arasbaran zone of the Alborz–Azerbaijan Magmatic Belt. This region hosts diverse mineral occurrences, including porphyry Cu&lt;img&gt;Mo deposits (e.g., Sungun), epithermal base metal veins (e.g., Zaylik), and Fe&lt;img&gt;Cu skarn deposits (e.g., Sungun and Anjerd). Compared to the LOF and iForest, for the analysis of a trace element geochemical dataset from 1067 stream sediment samples, the LUNAR exhibited the highest relative percentage of delineated deposits along with superior AUC (area under curve) from ROC (receiver operating characteristic) analysis for both mineral occurrences and mineralized samples. The LOF-detected outliers for elements like As, Sb, and Ti, whereas the iForest-detected outliers for Ti, Pb, and Co, and the LUNAR-detected outliers for Au and pathfinder elements like As, Bi, and Sb. Employing a graph neural network, the LUNAR efficiently captured intricate outlier relationships within the multivariate geochemical dataset, surpassing the LOF. Spatial analysis uncovered a correlation between LSCP variants and the LUNAR in detecting geochemical anomalies and their association with known deposits. Based on AUC values, the LSCP_A (average) demonstrated relative superiority over the LSCP_AOM (average of maximum), LSCP_MOA (maximum of average), and LUNAR. Among the LSCP variants, the LSCP_A showcased superior performance, leveraging average scores, and detecting outliers of pathfinder elements for gold like As and Bi, along with lithologically-influenced elements like Cr and Ti, and the significant role of Cu. The mapping of clr-transformed Bi data aligned closely with mineral","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"273 ","pages":"Article 107737"},"PeriodicalIF":3.4,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143549610","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":"Silicon isotope behavior during silica diagenesis recorded by silica sinters in a geothermal system, Xizang, China","authors":"Wei Wang ,&nbsp;Shao-Yong Jiang ,&nbsp;Hai-Zhen Wei ,&nbsp;Wen Zhang","doi":"10.1016/j.gexplo.2025.107744","DOIUrl":"10.1016/j.gexplo.2025.107744","url":null,"abstract":"<div><div>Silica sinters formed in geothermal systems represent an ideal geochemical archive for studying silicon (Si) isotope (δ³⁰Si) behavior during early diagenesis. Understanding diagenetic processes, including the preservation of Si isotope compositions, is crucial in the matter of paleo-environmental reconstruction. We conducted an investigation in the Dagejia geothermal system located in Xizang, China. This study presents silica diagenetic sequences that span from active geothermal fluids, transitioning from modern and fresh (MF) opal-A to modern and fresh (MF) chalcedony at temperatures ranging from 70 °C to 85 °C and high alkalinity. During diagenesis, the Si isotope values of chalcedony exhibit significant centimeter-scale variations, ranging from −1.89 ‰ to −0.35 ‰. From the top layer MF opal-A to the bottom layer MF chalcedony, the δ³⁰Si values decrease, and the Δ³⁰Si _{chalcedony-opal-A} increases from −1.65 ‰ at 70 °C to −1.05 ‰ at 85 °C.</div><div>In this process, the Si concentration of the pore fluid and the Si isotopic composition of the silica sinter were modeled via C.O model and Rayleigh model, respectively. The results show that the Si concentration of pore fluid is controlled by opal-A precursor dissolution and diagenetic depth. These variations in MF chalcedony are caused primarily by kinetic fractionation and are influenced by the temperature and Si concentration of the pore fluid. In this study, we demonstrate that silica diagenetic processes, coupled with isotopic changes in natural siliceous deposits, heavily depend on specific conditions during the formation of silica sinters. Furthermore, they may effectively preserve the initial information present after the formation of silica sinters. These interlinked controls on Si isotopic compositions are crucial for the application of Si isotopes in cherts for paleo-environmental reconstructions.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"273 ","pages":"Article 107744"},"PeriodicalIF":3.4,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519250","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, geochronology and Fe-Mg-S isotopic composition of the Liaoshang gold deposit, Jiaodong Peninsula, China: Implications for ore-forming processes and mineral exploration","authors":"Yuan-lin Chen ,&nbsp;Huan Li ,&nbsp;Shang-yi Gu ,&nbsp;Scott A. Whattam ,&nbsp;Chao-yang Zheng ,&nbsp;Li-gong Wang ,&nbsp;Da-dou Li ,&nbsp;Liu-an Duan","doi":"10.1016/j.gexplo.2025.107738","DOIUrl":"10.1016/j.gexplo.2025.107738","url":null,"abstract":"<div><div>The Liaoshang Au deposit in North China is distinguished by gold occurrence in pyrite-dolomite veins and characterized by large Au endowment (about 69 t Au @ 3.3 g/t), representing a novel gold deposit type within the Jiaodong gold province. To date, the mineralization age and metallogenic mechanism remain controversial, limiting the in-depth understanding of ore-forming processes. The Liaoshang Au mineralization differs from classic orogenic Au metallogeny in close relationships with the occurrence of ore-stage pyrite and dolomite. Here, we use syn-ore stage monazite U-Pb geochronology to constrain the ore-forming age. We also measured Fe and Mg isotope compositions in pyrite and dolomite associated with gold mineralization, combined with in situ LA-(MC)-ICP-MS elemental mapping and S isotopes in pyrite to decipher the iron, magnesium, and sulfur source(s), aiming to provide new insights into the ore-forming processes. Petrographic observation shows that gold in pyrite-dolomite veins mainly occurs as micro-grains (20–100 μm) within pyrite. Elemental mapping and in situ S isotope measurements for pyrite indicate that the main Au mineralization is associated with elevated concentrations of Cu, Ag, As, and Bi, as well as heavy sulfur isotope values (δ³⁴S ~13.6 ‰, compared to ~8.0 ‰ in the early stage). This is attributed to the addition of sulfur with high δ³⁴S from the basement Jingshan Group. The δ⁵⁶Fe values of ankerite and pyrite present a narrow range with an average of −0.21 ‰ and +0.56 ‰, respectively. The inverse enrichment of iron isotopes between ankerite and pyrite may be attributed to thermodynamic equilibrium fractionation in an open system. The δ²⁶Mg values of ankerite yields a wide range from −3.02 ‰ to −0.80 ‰. By comparing the Fe and Mg isotopic signatures of ores with those of local granites and basement rocks, we argue that the Jingshan Group contributed Fe and Mg to form auriferous pyrite and dolomite. The U-Pb dating of monazite in Au-bearing pyrite yields an age of 118.8 ± 1.7 Ma, which may represent the mineralization age of the deposit. The ore-forming fluid sourced from metasomatized mantle lithosphere leached Fe, Mg, and some heavier sulfur from the Jingshan Group to precipitate pyrite and dolomite in Liaoshang, forming pyrite‑carbonate veins. This is a critical gold mineralization mechanism for forming the Liaoshang-type gold deposits in the Jiaodong Peninsula, North China, which is different from that of the Jiaojia-type (disseminated stockwork-altered wall-rock type) and Linglong-type (quartz-sulfide vein type) gold deposits.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"273 ","pages":"Article 107738"},"PeriodicalIF":3.4,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511214","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":"Fluid and mineral inclusions of charoitite deposit in the Murun alkaline-carbonatite complex, Eastern Siberia, Russia","authors":"Emilia Yu. Dokuchits,&nbsp;Shao-Yong Jiang,&nbsp;Suo-Fei Xiong,&nbsp;Aleksandr Stepanov,&nbsp;Irina Zhukova,&nbsp;Wen-Tian Li","doi":"10.1016/j.gexplo.2025.107735","DOIUrl":"10.1016/j.gexplo.2025.107735","url":null,"abstract":"<div><div>The Murun alkaline‑carbonatite complex in Eastern Siberia, Russia, is known as a unique <em>gem</em> deposit of scenic purple charoitite rocks that consist of up to fifty different minerals, most of which are rare in nature. Charoitites occur in the rocks, which were identified as fenites. Rock-forming minerals of charoitites include charoite, pyroxene, K-feldspar, amphibole, and quartz; various (Ca)-(K)-(Na) silicates often present in large amounts. Apatite, carbonate minerals (mainly strontianite and barytocalcite), baryte, steacyite, dalyite, and various sulfides are typical accessory minerals in charoitites. Several transparent minerals from charoitites were studied in this paper, with special attention given to fluid and mineral inclusions. Fluid inclusions (FIs) are observed in quartz, apatite, tinaksite, dalyite, amphibole, pyroxene, and K-feldspar, including monophase [V (vapor) and L (liquid)], two-phase [L + V (liquid+vapor) and V + L (vapor+liquid)], multicomponent (L + V + S), and solid crystalline inclusions, which are represented by both single grain and composite mineral inclusions. The Raman spectra showed that most two-phase FIs are aqueous with minor N₂ and sometimes contain abundant CH₄ in the vapor phase. Using Raman spectroscopy, the daughter phases in multiphase inclusions were identified as sulfates (baryte and thenardite) and carbonates (witherite and calcite). The following crystalline phases in mineral inclusions were recorded: carbonates (witherite, calcite, barytocalcite, burbankite), sulfates (baryte), sulfides (sphalerite, galena and others), and silicates (quartz, aegirine, amphibole, and some Ca-(K)-(Na) silicate minerals). High-temperature polyphase melt inclusions were found in K-feldspar and tinaksite; however, only partial dissolution was achieved, and total homogenization could not be measured due to decrepitation. The studied fluid inclusions record a complex post-magmatic history, which includes the trapping of an aqueous fluid. The measured total homogenization temperatures (<em>T</em>_h) of FIs in quartz (180–441 °C), apatite (152–364 °C), tinaksite (218–404 °C) and dalyite (264 °C) suggest a secondary origin for all two-phased FIs, while the high-temperature fluid and melt inclusions (<em>T</em>_h &gt; 400–460 °C) recorded in these minerals formed during the magmatic stage. The coexistence of different types of fluid inclusions in transparent minerals associated with charoite, as well as wide ranges of homogenization temperatures, could be evidence of boiling occurring during the formation of charoitites. Fluid evidence and petrographic observations indicate that both magmatic and hydrothermal processes contributed to the formation of the Sirenevyi Kamen charoite deposit.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"274 ","pages":"Article 107735"},"PeriodicalIF":3.4,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143561718","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 high-performance extreme gradient boosting outlier detection framework for integrating the outputs of diverse anomaly detectors for detecting mineralization-related geochemical anomalies","authors":"Sheng He,&nbsp;Yongliang Chen","doi":"10.1016/j.gexplo.2025.107741","DOIUrl":"10.1016/j.gexplo.2025.107741","url":null,"abstract":"<div><div>In geochemical exploration, the geochemical anomalies identified in the same area by different unsupervised anomaly detection models are often quite divergent. How to combine these divergent geochemical anomalies into reliable mineral prospecting targets is a problem worth studying. In this regard, the extreme gradient boosting outlier detection (XGBOD) framework was adopted to integrate the anomaly scores produced by diverse unsupervised anomaly detection models to construct a high-performance semi-supervised anomaly detection ensemble for detecting mineralization-related geochemical anomalies. In the XGBOD framework, various unsupervised anomaly detection models are built and used to transform input variables into the transformed outlier scores (TOSs), and the important TOSs are then selected and added into the original input data to train the extreme gradient boosting (XGBoost) model, and a high-performance semi-supervised XGBoost model is established finally for detecting mineralization-related geochemical anomalies. The superiority of the XGBOD framework was demonstrated by a case study implemented in the Baishan area (Jilin, China). The <em>K</em>-nearest neighbor, local outlier factor, histogram-based outlier score, one-class support vector machine and isolation forest were used to transform element concentrations to TOSs, and the TOSs were used as the input data of the XGBoost model together with the original input element concentration data. The XGBoost model was finally established to detect mineralization-related geochemical anomalies. The results show that the semi-supervised XGBoost model performs significantly better than the five unsupervised anomaly detection models. Therefore, the XGBOD framework is a viable tool for combining diverse anomaly scores produced by various anomaly detectors to build a high-performance semi-supervised ensemble for detecting mineralization-related geochemical anomalies.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"273 ","pages":"Article 107741"},"PeriodicalIF":3.4,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508828","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 use of EDTA leaching method to predict arsenic and antimony Neutral Mine Drainage from the Eleonore tailings","authors":"Vincent Marmier ,&nbsp;Benoît Plante ,&nbsp;Isabelle Demers ,&nbsp;Mostafa Benzaazoua","doi":"10.1016/j.gexplo.2025.107734","DOIUrl":"10.1016/j.gexplo.2025.107734","url":null,"abstract":"<div><div>The prediction of neutral mine drainage (NMD) is difficult using classical kinetic techniques due to the sorption and precipitation processes that retain the contaminant within the material, hiding the actual geochemical behaviour. A method for NMD prediction using sorption experiments and modified kinetic experiments with a complexing agent such as ethylenediaminetetraacetic acid (EDTA) was developed to predict metal leaching in mine waste. The objective of this study was to assess the applicability of the leaching procedure to oxyanions such as As and Sb as well as the evolution of the risk of Eleonore mine tailings towards As and Sb leaching in the long-term. The study found that the Eleonore tailings contained 527 mg/kg of As and 59 mg/kg of Sb, mostly found within löllingite and arsenopyrite. The leaching of As and Sb through complexation with EDTA was found to be effective in kinetic experiments for prediction purposes, despite EDTA's classification as a cation complexing agent. The tailings sorption capacity for As was estimated to be between 43 and 76 mg/kg. By comparing the sorption capacity and the metalloid content, the ratio sorption/metalloid content was found to be below 1 (0.07–0.13), indicating a high risk towards NMD. Furthermore, no notable change in sorption capacity was observed over the course of the column experiments, suggesting that sorption is unlikely to influence the As leaching dynamic. However, it is probable that As retention in the tailings is not primarily driven by sorption; given the high iron (Fe) loadings, coprecipitation may be the dominant mechanism.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"273 ","pages":"Article 107734"},"PeriodicalIF":3.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511212","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":"The impact of buried historical copper slags on contemporary soil contamination","authors":"Krzysztof Kupczak ,&nbsp;Rafał Warchulski ,&nbsp;Vojtěch Ettler ,&nbsp;Martin Mihaljevič","doi":"10.1016/j.gexplo.2025.107743","DOIUrl":"10.1016/j.gexplo.2025.107743","url":null,"abstract":"<div><div>This study focuses on the impact of historical metallurgical slags on contemporary soil and soil pore water contamination, and potential phytoavailibility of metal(loid)s based on the example of the former smelter (16th–18th century) in Miedziana Góra (Holy Cross Mountains, Poland). The slags buried in soil exhibit elevated concentrations of Pb (57,400 mg·kg⁻¹), Zn (9000 mg·kg⁻¹), Cu (8890 mg·kg⁻¹), and As (325 mg·kg⁻¹). Mineralogical analysis reveals that the main carriers of these metal(loid)s are sulfides (Cu, As), metallic phases (Cu), and glass (Pb, Zn). Based on leaching tests using deionized water, it was found that the metal(loid)s contained in the slags are hardly mobilized. Similarly, the pH-static leaching tests indicate that, under natural soil pH conditions (~ 6.5), contaminants leaching from slag is limited, with metals stabilizing primarily in secondary phases, mainly in the form of oxides, carbonates, and phosphates. Despite the limited mobility, surrounding soils show high concentrations of Pb (up to 31,200 mg·kg⁻¹), Cu (up to 13,900 mg·kg⁻¹), Zn (up to 11,800 mg·kg⁻¹), and As (up to 985 mg·kg⁻¹). Leaching tests on soil samples using CaCl₂ as a leaching agent reveal mobilized concentrations up to 19.1 mg·kg⁻¹ Zn, 7.20 mg·kg⁻¹ Cu, and 6.40 mg·kg⁻¹ Pb, with Sb (1.81 % of the total) and Cd (1.56 % of the total) showing the highest mobility. A Pb concentration exceeding 100 μg·l⁻¹ in the tested pore water sample indicates poor water quality, underscoring the significant environmental impact of historical metallurgy on present ecosystem.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"273 ","pages":"Article 107743"},"PeriodicalIF":3.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511216","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":"Ore genesis of the Baishizhang Mo(-W) deposit in the Nanling Range, South China: Constraints from wolframite geochronology and chemical composition","authors":"Yue Hou ,&nbsp;Huan Li ,&nbsp;Thomas J. Algeo ,&nbsp;Jianjun Liu ,&nbsp;Zhekai Zhou ,&nbsp;Zhaoyang Luo ,&nbsp;Weidong Ren","doi":"10.1016/j.gexplo.2025.107733","DOIUrl":"10.1016/j.gexplo.2025.107733","url":null,"abstract":"<div><div>The South China Block (SCB), as one of the most important molybdenum metallogenic provinces in China, contains &gt;40 Mo deposits including porphyry, skarn, and quartz-vein systems. In this work, we examine the ore geology and wolframite chemistry of the Baishizhang (BSZ) quartz vein-type Mo(-W) deposit in the Nanling Metallogenic Belt, using in-situ laser ablation-inductively coupled plasma-mass spectrometric (LA-ICP-MS) analysis of U-Pb isotopes and trace elements. The hydrothermal history of the BSZ deposit can be divided into three stages (i.e., quartz-wolframite, sulfide, and calcite), the first two of which are the two main mineralization stages and wolframite shows petrological evidence for these two stages. Wol(I) yielded a U-Pb age of 154.0 ± 1.2 Ma (1σ; <em>n</em> = 20; MSWD = 0.86) and Wol(II) ages of 150.8 ± 0.5 Ma (Wol(II-1);1σ; <em>n</em> = 19; MSWD = 1.0) and 146.1 ± 2.3 Ma (Wol(II-2); 1σ; <em>n</em> = 12; MSWD = 2.6), bracketing the transition from the quartz-wolframite stage to the sulfide stage. The Wol(II-1) mineralization may be genetically related to emplacement of biotite K-feldspar granite (150.3 ± 1.1 Ma), and the large-scale Mo mineralization may be related to deep concealed granites at BSZ. Our results show that the composition of wolframite was constrained by both crystallochemical effects and the composition of the mineralizing fluid, and that the substitution mechanisms controlling the chemical compositions of Wol(I) and Wol(II) were different. Wol(II) exhibits changes in composition and Eu anomaly from the core to the rim, likely reflecting the influence of an external reducing fluid enriched in Sn and Mo from concealed granites that caused Mo mineralization. A metallogenic model of the BSZ deposit can be applied to better interpret the various formation processes of the two main mineralization stages.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"273 ","pages":"Article 107733"},"PeriodicalIF":3.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143488407","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}