Journal of Geochemical Exploration最新文献

{"title":"GEMAS: Novel continental-scale patterns revealed in the spatial distribution of Cr in European agricultural soil – A systematic method validation","authors":"Attila Petrik ,&nbsp;Gyozo Jordan ,&nbsp;Ahmed Abdelaal ,&nbsp;Alecos Demetriades ,&nbsp;Benedetto De Vivo ,&nbsp;Stefano Albanese ,&nbsp;Martiya Sadeghi ,&nbsp;The GEMAS Project Team","doi":"10.1016/j.gexplo.2025.107906","DOIUrl":"10.1016/j.gexplo.2025.107906","url":null,"abstract":"<div><div>Following the Ni-focused experimental investigation, it was clear that a critical advancement in digital image analysis of geochemical data sets required the validation of the procedures used with another element. Chromium was selected because its geochemical behaviour closely mirrors that of Ni in both lithological context and surface processes. Our current study, conducted with rigorous methodological precision, aims to assess a novel geospatial technique capable of capturing spatially variable continental-scale element distribution patterns. To reduce localised anomalies, we applied a moving average filter to the TIN-based interpolated Cr data set. The processed grid was then subjected to digital image analysis, which highlighted several continental-scale spatial orientations — NE-SW, E-W, and NW-SE — that closely resemble those found in the Ni study. Notably, prominent NE-SW and ENE-WSW linear Cr structures were identified, aligning with the known structural imprints of the Variscan and Alpine orogenic belts. Elevated Cr variable concentrations mainly occur in the Balkans and Alpine regions, consistent with exposures of mafic to ultramafic lithologies. A striking east-west trending Cr feature, with lower concentrations northwards, was also observed within the terminal zone of the last major glaciation, aligning with Cr-depleted glaciofluvial deposits. Chromium anomalies with a NW-SE trend also occur in regions such as Fennoscandia, Hellenic Republic, northern Italy, and the Pyrenees, aligning with those for Ni. Beyond confirming the efficacy of image analysis techniques in uncovering and describing new geochemical spatial patterns, this research also reinforces the approach by showing a pronounced continental-scale spatial correspondence between Cr and Ni distributions.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107906"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096903","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":"Chemical stability and environmental characterization of alkali-activated mine tailings generated using a MgCO3/MgO industrial residue","authors":"Antonio J. Diosdado-Aragón ,&nbsp;José Miguel Dávila ,&nbsp;Manuel A. Caraballo","doi":"10.1016/j.gexplo.2025.107886","DOIUrl":"10.1016/j.gexplo.2025.107886","url":null,"abstract":"<div><div>Mining tailings are commonly combined with ordinary Portland cement (OPC) and water to form a paste used for mine gallery backfilling (MGBF). Although OPC remains the most frequent choice, alternative alkaline reagents such as Mg(OH)₂ are being investigated due to several limitations: its high cost, a significant carbon footprint associated with its production, and limited long-term durability, especially because of its vulnerability to sulfate attack. This study examines how the use of a MgCO₃/MgO industrial residue affects the environmental behavior of alkali-activated pastes in a wide range of mine tailings (MTs), considering the results obtained from different tests: ABA test, leaching test according to UNE 12457-4 and uniaxial compressive strength (UCS) tests. Various paste formulations were generated using different MgCO₃/MgO concentrations and six very different types of MTs spanning a wide range mineralogical, chemical and acid potential characteristic. As a main conclusion, all alkali-activated pastes, when compared with the original MTs, showed a very important improvement of their environmental behavior, marked by a consistent reduction of their acid generation potential, a water quality improvement of their leachates and their new consideration of inert wastes according to the European regulation for waste acceptance at landfills. While dynamic long-term leaching experiments and reactive transport geochemical models are advisable to better understand the behavior of these type of mine residues under real conditions and in the long term (decades to centuries); the present study shows how the combined application of ABA and UNE 12457-4 tests can offers a reliable initial environmental characterization of alkali-activated mine pastes.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107886"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144989840","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 Hongjianbingshan W–Li–(Be) deposit in the Beishan Orogenic Belt is not related to carboniferous magmatic–hydrothermal events: Insights from multi-mineral U-Pb and zinnwaldite Rb-Sr geochronology","authors":"Yong Yin ,&nbsp;Heng-Feng Zhang ,&nbsp;Zhuang Duan ,&nbsp;Bing-Fei Yu ,&nbsp;Heng Luo ,&nbsp;Yan-Gang Fu ,&nbsp;David R. Lentz ,&nbsp;Tao Luo ,&nbsp;Ke-Yu Ren ,&nbsp;Zhe Ren ,&nbsp;Hao Hu","doi":"10.1016/j.gexplo.2025.107916","DOIUrl":"10.1016/j.gexplo.2025.107916","url":null,"abstract":"<div><div>The Hongjianbingshan (HJBS) W–Li–(Be) deposit in the Beishan Mineralization Belt of the Central Asian Orogenic Belt has significant potential for rare-metal mineralization and exhibits a close genetic relationship with extremely fractionated granites. Previous geochronological studies have established that the host granites (321.2 ± 2.7 to 306.3 ± 2.3 Ma) were formed during the Carboniferous. However, muscovite ⁴⁰Ar/³⁹Ar ages from greisen-type ores are ~216 Ma. Therefore, the precise age of the ore-forming and ore-related granites in the HJBS deposit remains uncertain. We present a comprehensive geochronological investigation of the primary ore minerals in the HJBS deposit. By integrating these results with zircon and monazite ages from the host rocks, we reassess the temporal framework of the magmatism and mineralization associated with this deposit. Our analysis indicates that both the magmatic and mineralization processes (232 ± 38 Ma) occurred during the Indosinian orogeny, in contrast to prior assumptions linking these events to Carboniferous magmatism. The mineralization history of the HJBS deposit closely resembles that of other rare-metal deposits across the Tianshan–Altay–Songpan–Ganzi–West Kunlun regions in western China. These deposits occur along the Paleo-Tethyan tectonic belt and formed during the closure of the Paleo-Tethys Ocean. This suggests that the HJBS deposit in the Beishan Mineralization Belt formed during the same tectonic events as other rare-metal deposits associated with extremely fractionated granites in western China. The closure of the Paleo-Asian and the Paleo-Tethys oceans, along with subsequent tectonic changes, led to significant magmatism and large-scale rare-metal mineralization in western China. Our study underscores the substantial impact of large-scale rare-metal mineralization events during the Indosinian orogeny on the Beishan Mineralization Belt, as exemplified by the HJBS deposit. These findings provide new insights into the geological evolution and mineralization processes in the Beishan area, revealing substantial potential for rare-metal mineralization. Furthermore, they establish a foundation for future exploration and exploitation of rare-metal deposits in the Beishan region.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107916"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145324551","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, enrichment mechanisms and geomedical assessment of fluoridated groundwater in some parts of the largest semi-arid sedimentary basin in Ghana","authors":"Emmanuel Daanoba Sunkari ,&nbsp;Onesimus D. Zeon ,&nbsp;Asare Asante-Annor ,&nbsp;Samuel Nunoo ,&nbsp;Abayneh Ataro Ambushe","doi":"10.1016/j.gexplo.2025.107924","DOIUrl":"10.1016/j.gexplo.2025.107924","url":null,"abstract":"&lt;div&gt;&lt;div&gt;This study investigated the hydrogeochemistry, spatial distribution, health risks, and underlying mechanisms of elevated fluoride (F&lt;sup&gt;−&lt;/sup&gt;) concentrations in groundwater across communities situated within the Voltaian Supergroup of the semi-arid Volta Basin in Ghana. This was achieved through a medical geology framework that integrates hydrogeochemistry, GIS-based spatial analysis, geochemical modelling, unsupervised machine learning, petrography, PXRD analysis, Monte Carlo Simulation, Sobol sensitivity analysis, probabilistic health risk assessment, and community-based health surveillance to investigate the geogenic sources, spatial distribution, and health implications of F&lt;sup&gt;−&lt;/sup&gt; in groundwater. Thirty-one borehole water samples were collected from Mion District, Karaga District, and Gushegu Municipality in the Northern Region of Ghana. Petrographic and PXRD analyses identified minerals such as quartz, albite, biotite, zeolite, illite, and opaque minerals in the reservoir rocks. Lithological evaluation of boreholes confirmed the reservoir rocks at depth. These minerals dissolve in groundwater, enriching it with various ions. The major cations in groundwater were found in the order: Mg&lt;sup&gt;2+&lt;/sup&gt; &gt; Ca&lt;sup&gt;2+&lt;/sup&gt; &gt; K&lt;sup&gt;+&lt;/sup&gt; &gt; Na&lt;sup&gt;+&lt;/sup&gt;, and the major anions in the order: HCO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt; &gt; SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2−&lt;/sup&gt; &gt; Cl&lt;sup&gt;−&lt;/sup&gt;. The groundwater is alkaline, with Mg&lt;sup&gt;2+&lt;/sup&gt; − HCO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt; as the common water type. Fluoride concentrations ranged from 0.23 to 19.5 mg/L, with an average of 4.71 mg/L, exceeding the World Health Organization's guideline value of 1.5 mg/L in about 87 % of the boreholes around the northeastern fringe of the study area. The high F&lt;sup&gt;−&lt;/sup&gt; levels are primarily due to natural sources and are influenced by water-rock interaction, weathering, ion exchange, and mineral dissolution and precipitation. Health risks associated with fluoridated drinking water were assessed using the US Environmental Protection Agency Model, Monte Carlo Simulation, and Sobol sensitivity analysis revealing non-carcinogenic risks such as dental and skeletal fluorosis, particularly affecting children, followed by adults, teenagers, and infants. Sobol sensitivity analysis reveals that body weight is the primary driver of the non-carcinogenic risk variability across the population, followed by water consumption and F&lt;sup&gt;−&lt;/sup&gt; concentration. However, age-specific patterns show that for infants and children, F&lt;sup&gt;−&lt;/sup&gt; levels and body weight are key contributors, while in teenagers and adults, F&lt;sup&gt;−&lt;/sup&gt; concentration alone dominates risk variability. Community-based health surveillance confirmed these findings. Due to the high F&lt;sup&gt;−&lt;/sup&gt; levels, the people now use polluted surface water for drinking and domestic purposes, leading to severe gastrointestinal infections. Therefore, urgent attention is needed by the stakeholders to curb the threat of ground","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107924"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416288","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":"2026-01-01","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":"Metallogenic constraints of sandstone-hosted uranium deposits in arid red beds: A case study from the northwestern Santanghu Basin","authors":"Hui Rong ,&nbsp;Jun Zhou ,&nbsp;Yu Zhou ,&nbsp;Yuchen Zhang ,&nbsp;Min Liu ,&nbsp;Kaiyu Chang","doi":"10.1016/j.gexplo.2025.107923","DOIUrl":"10.1016/j.gexplo.2025.107923","url":null,"abstract":"<div><div>The Changjihe Group in the northwestern Santanghu Basin can serve as a typical case for studying the uranium metallogenic regularity in arid red beds. The uranium reservoirs of the Changjihe Group comprise of red sandstone, yellow sandstone, gray mineralized sandstone, and primary gray sandstone. The red sandstone is characterized by the predominance of hematite, hydromica, and rhodochrosite, and the hematite predominantly occurs in colloidal and framboidal forms. The yellow sandstone primarily contains hematite and anatase, and the anatase is found within dissolved titanite pores and fractures. The gray mineralized sandstone is distinguished by the presence of pyrite, anatase, uranium-bearing minerals, and kaolinite. The pyrite frequently exhibits framboidal, colloidal, and euhedral granular textures, while the anatase occurs within dissolved titanite pores and fractures, often adsorbing uranium internally. The primary gray sandstone is dominated by pyrite and chlorite, and the pyrite chiefly appears as euhedral granules within biotite cleavage fissures. Uranium accumulation is fundamentally governed by redox interfaces (macro-scale) and precursor mineral reactivity (micro-scale). The redox transition zone hosts peak uranium mobility, with anomalies concentrated at advancing oxidation fronts. At the grain scale, uranium mineralization requires antecedent anatasization of titanite, wherein neoformed anatase provides a carrier for uranium enrichment. The Hanshuiquan uranium system exemplifies a tripartite control involving sedimentary architecture, epigenetic alteration, and basement unconformities. Titanite-to-anatase transformation in the mineralized sandstones emerges as a mineralization driver and indicator. These findings provide novel insights that fundamentally advance our understanding of metallogenic mechanisms and distribution patterns in sandstone-hosted uranium deposits.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107923"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362973","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":"Magmatic controls and chronology of tin mineralization in the Mengsong Deposit, Southern Lincang Batholith, SW China","authors":"Jiale Wang ,&nbsp;Xiaobo Si ,&nbsp;Mingjun Zheng ,&nbsp;Huanchao Xu ,&nbsp;Xiang Sun","doi":"10.1016/j.gexplo.2025.107902","DOIUrl":"10.1016/j.gexplo.2025.107902","url":null,"abstract":"<div><div>The Triassic Lincang granite batholith in southwestern Yunnan, China, hosts numerous granite-related tin deposits. This study investigates the Mengsong tin deposit, located in the southern part of the Lincang batholith, by integrating zircon U<img>Pb geochronology, Hf isotopic analysis, and trace element geochemistry. Zircon from the Mengsong deposit reveals crystallization ages of 225.5 ± 0.9 Ma (MSWD = 2.3, <em>n</em> = 20) for the muscovite granite and 224.7 ± 0.9 Ma (MSWD = 1.9, <em>n</em> = 25) for the two-mica granite. This indicates that the Mengsong granites was formed during the Triassic period. Zircon trace element signatures indicate that the Mengsong granites are highly fractionated and crystallized from magmas with low oxygen fugacity (ΔFMQ). Negative zircon ε_Hf(t) values (−14.3 to −1.5) indicate derivation from an ancient crustal source. We propose that reduced magmas were fundamental prerequisite for tin enrichment. This factor, in conjunction with highly magmatic differentiation of crustal melts generated during post-collisional extension after the Paleo-Tethys closure, created the ideal conditions for Sn mineralization. These results highlight the genetic relationship between tin mineralization and synchronous granitic magmatism in the Mengsong deposit and provide valuable insights for future exploration targeting Triassic tin systems in southwestern Yunnan.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107902"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096904","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":"Genesis and prospecting significance of the Xiaodonggou granites in the eastern Central Asian Orogenic Belt: Evidence from geochronology, geochemistry, and Hf isotope characteristics","authors":"Lele Qiu ,&nbsp;Peiwen Chen ,&nbsp;Renchang Mi ,&nbsp;Zhujun Liu ,&nbsp;Yong Fu ,&nbsp;Qingdong Zeng","doi":"10.1016/j.gexplo.2025.107928","DOIUrl":"10.1016/j.gexplo.2025.107928","url":null,"abstract":"<div><div>The Xiaodonggou granites are located in the southwestern part of the Xilamulun Mo Metallogenic Belt, within the eastern Central Asian Orogenic Belt. They are characterized by significant Mo mineralization and minor Pb<img>Zn enrichment. The pluton mainly consists of fine-grained granite (FG), coarse-grained granite (CG), granite porphyry (GP), and diorite. However, the genetic relationships among these lithologies and their tectonic implications remain unclear. To address this, we conducted an integrated geochemical, geochronological, and isotopic study to investigate the origin of the Xiaodonggou granites. Zircon U<img>Pb dating identifies two distinct magmatic events: Cretaceous granites (FG: 141.0 ± 0.86 Ma; CG: 140.9 ± 0.86 Ma; GP: 137.7 ± 0.75 Ma), formed during the lithospheric thinning of the North China Craton, and Permian diorite (273.3 ± 1.8 Ma), which was emplaced earlier than the Cretaceous granitic magmatism. The granites belong to the high-K calc-alkaline series and are characterized by high SiO₂ and low P₂O₅ contents. They show enrichments in Rb, Th, U, and Pb, and depletions in Nb, Ta, Ti, and P, with low Zr/Hf and high Rb/Sr ratios, suggesting strong fractional crystallization. The occurrence of amphibole and magnetite, combined with A/CNK values &lt;1.1, indicates I-type granite characteristics. Most granites display εHf(t) values ranging from −1.0 to +3.34 and <em>T</em>_DM2(Hf) ages of 979–1261 Ma, indicating that their primary magmas were largely derived from the juvenile lower crust. The ore-forming granites are characterized by increased oxygen fugacity (ΔFMQ = +2.84) and a high capacity for transporting ore-forming elements. The FG and CG were emplaced first, followed by the GP, which carried the majority of ore-forming materials and ultimately formed the Mo mineralization. Owing to the lower crystallization temperatures of Pb and Zn in the hydrothermal system, these elements migrated distally along the early-emplaced diorite dikes, leading to Pb<img>Zn mineralization. Based on the Early Cretaceous magmatic-metallogenic age, the Xiaodonggou porphyry system is interpreted to have originated from partial melting of the juvenile lower crust in an extensional setting driven by the rollback of the Paleo-Pacific Plate.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107928"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145568419","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":"2026-01-01","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":"Soil anomaly mapping in the Hattfjelldal area, Norway: Reconciling soil geochemical and geophysical properties within their spatial context","authors":"Pedro Acosta-Góngora ,&nbsp;Malin Andersson ,&nbsp;Terje Bjerkgård ,&nbsp;William A. Morris ,&nbsp;Tobias Kurz ,&nbsp;Madeline Lee ,&nbsp;Marie-Andre Dumais ,&nbsp;Aziz Nasuti ,&nbsp;Mikis van Boeckel ,&nbsp;Johannes Jakob ,&nbsp;Ana Carolina R. Miranda ,&nbsp;Aidian Crilly ,&nbsp;Ying Wang ,&nbsp;Behnam Sadeghi","doi":"10.1016/j.gexplo.2025.107911","DOIUrl":"10.1016/j.gexplo.2025.107911","url":null,"abstract":"<div><div>This study presents a multivariate framework for geochemical data processing and anomaly detection to support mineral exploration in the Hattfjelldal area, Norway. The workflow integrates data levelling, multivariate analysis, and spatial evaluation to improve the detection and interpretation of geochemical anomalies associated with volcanogenic massive sulfide (VMS) mineralization. Soil geochemical and magnetic susceptibility data were log-transformed and subsequently levelled using <em>Z</em>-score normalization by soil type and lithology. Both linear (principal component analysis, PCA) and non-linear algorithms (hierarchical clustering, isolation forest, and angle-based outlier detection) were applied to construct anomaly detection vectors. Hierarchical clustering proved particularly effective in defining element assemblages that refine anomaly detection, including associations of Type 1 (Ag, Mo, S, Sb, Bi, Pb); Type 2 A (Fe, Zn, Co, Mn) and Type 2B (Fe, Zn, Co, Mn, As, Cu). These groupings provide a robust geochemical and geological context within established VMS zoning models.</div><div>Magnetic susceptibility, although less reliable as a stand-alone exploration vector, enhances interpretation when integrated with geochemical anomalies. Fractal analysis applied to both, geochemical vectors and magnetic susceptibility data effectively distinguished background from anomalous values, delineating areas of potential economic interest. Spatial Feature Embeddings (SFE), derived from clustering radiometric, topographic, and spectral datasets, further improved the spatial characterization of anomalies. When combined with airborne magnetics, SFE enabled the refinement and prioritization of specific targets within broad anomaly zones.</div><div>Overall, this framework demonstrates the value of integrating statistical, geochemical, and geophysical methods within their spatial context, providing a transferable approach for exploration programs in Arctic environments.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107911"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362309","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}