Journal of Geochemical Exploration最新文献

{"title":"Redistribution of minor and trace elements in ore minerals in metamorphosed VMS deposits, Rävliden North, Skellefte district, Sweden","authors":"Jonathan Rincon ,&nbsp;Nils Jansson ,&nbsp;Helen Thomas ,&nbsp;Majka Christiane Kaiser ,&nbsp;Mac Fjellerad Persson ,&nbsp;Amir Morteza Azim Zadeh ,&nbsp;Yousef Ghorbani ,&nbsp;Christina Wanhainen","doi":"10.1016/j.gexplo.2025.107830","DOIUrl":"10.1016/j.gexplo.2025.107830","url":null,"abstract":"<div><div>The Rävliden North volcanogenic massive sulfide (VMS) deposit, in northern Sweden underwent polyphase deformation and greenschist to lower amphibolite facies metamorphism during the Svecokarelian orogeny. This caused remobilisation and recrystallisation of ore minerals, whose composition was analysed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and electron probe microanalysis (EPMA). Sphalerite, chalcopyrite, and pyrrhotite chemistry mirrors zonation of undeformed VMS deposits. Chalcopyrite-rich mineralisation contains higher Cu, Co, In, and lower Mn concentrations than sphalerite-rich mineralisation. Besides galena, Ag occurs in sulfosalts, tellurides, antimonides, and amalgams, which possibly formed through exsolutions from α-galena in <em>syn</em>- to post-tectonic structures. LA-ICP-MS imaging shows Ag-rich minerals in early syngenetic pyrite, in contrast to syn-metamorphic pyrite, indicating remobilisation during deformation. Despite sampling effects accounted for through linear mixed effects (LME) modelling, the results indicate that <em>syn</em>-metamorphic recrystallisation and remobilisation did not lead to substantial compositional changes in ore minerals. Instead, these processes partitioned Ga between sphalerite and chalcopyrite and enriched Ag, Cd, and Sb in minerals associated with younger parageneses. Zeolite-bearing veins in the hanging wall host sphalerite with the highest Ga, Ge, Cu, and Sb contents and galena with the lowest Bi, Te, and Tl contents. An origin potentially linked to far-field effects of the opening of the Iapetus Ocean or waning Timanian orogeny is discussed based on similarities to other vein- and breccia-hosted Zn<img>Pb deposits in Northern Sweden. This study provides the first multiple-mineral in-situ trace element dataset for a VMS deposit in the Skellefte district, enhances understanding of element redistribution during metamorphism, and identifies remobilised elements potentially vectoring mineralisation at depth. Moreover, this study enables tracing of penalty and by-product elements in downstream beneficiation processes.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"278 ","pages":"Article 107830"},"PeriodicalIF":3.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144288961","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":"Leaching behavior and mechanism of Cu and Cd in acid paddy soil under acid mine drainage","authors":"Yan Pan ,&nbsp;Yang Yang ,&nbsp;Qimo Liu ,&nbsp;Mengyu Fu ,&nbsp;Guining Lu ,&nbsp;Zhi Dang ,&nbsp;Chengfang Yang","doi":"10.1016/j.gexplo.2025.107847","DOIUrl":"10.1016/j.gexplo.2025.107847","url":null,"abstract":"<div><div>Heavy metal pollution seriously affects soil quality, especially in paddy soils that have been polluted for a long time by acid mine drainage (AMD). However, the underlying mechanisms of the complicated AMD flooding processes in paddy soil remain poorly understood. In this study, the leaching behaviors and speciation distribution mechanisms of Cu and Cd were investigated by batch and in-situ leaching experiments under simulated AMD irrigation conditions. The results suggested that continuous AMD flooding for 180 days caused a decrease in pH and Eh until these values stabilized, at day 84 and day 70, respectively. Between pH 4.5 and 6.5, more Cu than Cd was adsorbed which was consistent with the findings of the surface complexation model (SCM). The maximum adsorption capacities of the soil was 264.84 mg/kg towards Cu and 125.96 mg/kg towards Cd. Tessier's five-step extraction showed that most adsorbed Cd was present in exchangeable fraction (F1) and carbonate-bound fraction (F2) at different depths and time points, while Cu was mainly found in Fe/Mn-bound fraction (F3) and organic-bound fraction (F4). Correlation analysis showed that migration of Cu and Cd was most susceptible to the influence of pH, Eh, and Fe. In all assessed layers of the column, Cu was retained to a greater extent than Cd. The leaching of AMD significantly increased the mobility of soil Cd. The presented data improves our understanding of the impact of long-term exposure and leaching on the mobility of heavy metals in contaminated paddy soils and assist in developing appropriate management strategies.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"278 ","pages":"Article 107847"},"PeriodicalIF":3.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144470789","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":"Geochemical characteristics and petrogenesis of uranium-bearing and barren granites in the Miao'ershan Batholith, South China: Implications for U mineralization","authors":"Cui Yang ,&nbsp;Xilian Chen ,&nbsp;Deru Xu ,&nbsp;Shaohao Zou ,&nbsp;Hengsong Zhang ,&nbsp;Zihang Fan ,&nbsp;Longfei Luo","doi":"10.1016/j.gexplo.2025.107829","DOIUrl":"10.1016/j.gexplo.2025.107829","url":null,"abstract":"<div><div>The Miao'ershan batholith in South China is an important domain for granite-hosted uranium mineralization, comprising both uranium-bearing (Douzhashan) and barren (Yangqiaoling and Xiangcaoping) granites. However, the processes governing uranium enrichment in granitic systems, as well as the factors responsible for the contrasting fertility of these granites remain poorly understood. This study integrates zircon U<img>Pb geochronology, zircon trace element geochemistry, and in situ chemical analysis of both discrete apatite grains and apatite inclusions within zircon to elucidate the petrogenetic processes and physicochemical conditions that distinguish uranium-bearing from barren granite. Zircon U<img>Pb dating constrains the crystallization ages of the Yangqiaoling, Xiangcaoping, and Douzhashan granites to 218.6 ± 1.8 Ma, 223.3 ± 1.9 Ma, and 213.5 ± 1.8 Ma to 212.2 ± 1.6 Ma, respectively. Variations in apatite Cl/F ratios, combined with published whole-rock geochemical data, indicate that the Douzhashan granite is a strongly peraluminous S-type granite derived from the partial melting of meta-sedimentary rocks, whereas the Yangqiaoling granite reflects a mixed magmatic source involving both meta-sedimentary and meta-igneous components, and the Xiangcaoping granite exhibits intermediate characteristics. Apatite trace element compositions reveal that the Douzhashan granite underwent a higher degree of magmatic differentiation than the barren granites, as evidenced by lower concentrations of Sr, Th, and light rare earth elements (LREE), reduced (La/Yb)_N and (Sm/Yb)_N ratios, and elevated contents Y and Mn. Geochemical proxies from both zircon and apatite, including (Eu/Eu*)_N, Ce/Nd, and Y/ΣREE ratios, suggest that all three granites crystallized under low oxygen fugacity conditions. Therefore, uranium enrichment in the Douzhashan granite was driven by a combination of distinct source characteristics, advanced magmatic differentiation and reduced magmatic conditions, which collectively enhanced uranium solubility and retention in the melt. These results provide new insights into the petrogenetic controls on granite-hosted uranium mineralization and establish a geochemical framework for guiding future uranium exploration in similar geological settings.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"278 ","pages":"Article 107829"},"PeriodicalIF":3.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144271001","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":"Tourmaline and monazite chemistry reflects magmatic-hydrothermal evolution of the Xianghualing W-Sn-Nb-Ta (Li, Be) pegmatite and metasomatite, South China","authors":"Wenbo Sun ,&nbsp;Huan Li ,&nbsp;Thomas J. Algeo ,&nbsp;Mohammed Abdalla Elsharif Ibrahim ,&nbsp;Nuerkanati Madayipu ,&nbsp;Xiaojun Hu ,&nbsp;Annan Guan ,&nbsp;Bowen Zhu","doi":"10.1016/j.gexplo.2025.107859","DOIUrl":"10.1016/j.gexplo.2025.107859","url":null,"abstract":"<div><div>The Nanling Metallogenic Belt, one of the world's largest rare-metal mineralization provinces, contains the Laiziling W-Sn-Nb-Ta rare-metal deposit. Despite its economic importance, the Li and Be mineralization and associated hydrothermal history of this deposit have not been studied in detail and remain controversial. This study presents the first in situ U<img>Pb dating and Nd isotopic analysis of monazites, as well as chemical composition and B isotopic data of tourmalines, from Laiziling pegmatites and metasomatites. LA-ICP-MS U<img>Pb geochronology yields crystallization ages of 152.0 ± 1.1 Ma for magmatic monazite and 151.9 ± 3.0 Ma and 151.2 ± 2.1 Ma for hydrothermal monazites. These results indicate that the hydrothermal stage was synchronous with pegmatite emplacement, and that pegmatite crystallization was related to hydrothermal activity. Variable Eu anomalies in monazite suggest an increase in environmental oxygen fugacity during the hydrothermal stage. The εNd(t) values of magmatic monazite (−7.49 to −6.82) are slightly lower than those of altered monazite (−7.24 to −6.51), indicating a slight disturbance of the Nd isotopic system by hydrothermal processes. The tourmalines exhibit oscillatory zoning from core to rim (Tur-I to Tur-VI) with δ¹¹B values ranging from −13.6 to −11.7 ‰. This observation suggests that tourmaline was derived from a single continental crustal source. The δ¹¹B of tourmaline shows a gradual decrease from cores to rims. The variation in B isotopes and chemical composition of tourmaline may be related to the mixed of the original igneous components in the earlier stage of metasomatism. LA-ICP-MS mapping of the cross and longitudinal sections of tourmaline shows elemental variations during its crystallization, with Tur-IV used as an indicator of magma evolution into the hydrothermal stage. After entering the hydrothermal stage, exchange vectors gradually changed from □Al(NaMg)₋₁ to MgFe₋₁, with the tourmaline type transitioned from schorl to Mg-foitite. Although rare metal mineralization and pegmatite emplacement were synchronous, the multiple stages of magma evolution exhibit differences in mineralization. The mineralization of Nb<img>Ta during the magmatic period has been confirmed previously. Principal component analysis (PCA) was used to predict the geochemical behavior of Li-Be-W-Sn and to determine the chemical controls on tourmaline crystallization at different stages of magmatic evolution. Enrichment and precipitation of Li usually occur during the magmatic stage, while Be-W-Sn mineralization is typically related to late hydrothermal alteration. However, the Laiziling deposit is characterized by Li mineralization synchronously with pegmatite emplacement, and by Be-W-Sn mineralization with hydrothermal alteration after this emplacement event. Our findings provide new insights into the formation processes of rare-metal mineral deposits.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"278 ","pages":"Article 107859"},"PeriodicalIF":3.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572791","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":"Characterization of neutral fluids in the volcanic geothermal system under the Tatun Volcano Group, Taiwan","authors":"Yi-Chia Lu ,&nbsp;Chyi Wang ,&nbsp;Sheng-Rong Song ,&nbsp;Pei-Ling Wang ,&nbsp;Ting-Jui Song ,&nbsp;Sachihiro Taguchi ,&nbsp;Tsung-Ren Peng ,&nbsp;Li-Hung Lin ,&nbsp;Jian-Cheng Lee ,&nbsp;Hong-Chun Li","doi":"10.1016/j.gexplo.2025.107814","DOIUrl":"10.1016/j.gexplo.2025.107814","url":null,"abstract":"<div><div>The Tatun Volcano Group (TVG), located near the populated Taipei metropolitan area, is a promising geothermal energy source because of its active hydrothermal system. However, severe corrosion from acidic fluids hindered exploration in the 1970s. Given renewed global interest in renewable energy, this study examines the evolution and assesses the reservoir temperatures of neutral thermal fluids to mitigate corrosion-related challenges and facilitate geothermal exploration in the TVG. Water and carbonate samples were collected from hot springs, cores, cuttings, and outcrops along the TVG SW–NE corridor for geochemical analysis.</div><div>A clumped isotope thermometer was used to calculate carbonate precipitation temperatures, combining stable water isotope analysis (¹⁸O and ²H), this approach provides carbonate clumped isotope composition-based reservoir temperatures of 181–276 °C in three areas. Distinct fluid origins and multiple chemical reactions across the depth (temperature) zones were identified. A geothermal model was generated to demonstrate the life cycle of non-strongly acidic fluids, from their deep origins to their upward migration and chemical interactions. Based on water and carbonate analyses, non-strongly acidic zones suitable for geothermal drilling have been identified in the active volcanic region of the TVG.</div><div>Preliminary drilling data indicate that the vapor-dominated reservoirs in the TVG have significant potential for geothermal exploration and near-term development in conventional geothermal systems. This study further suggests that high-temperature, non-artesian well locations with carbonate deposits, which reflect a history of non-acidic environments, are excellent candidates for future enhanced geothermal systems, advanced geothermal systems, and superhot geothermal resource development.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"278 ","pages":"Article 107814"},"PeriodicalIF":3.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670184","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":"Host minerals of lithium in Jiujialu Formation Li–rich claystones in South China, and implications for the genesis","authors":"Jihua Yang ,&nbsp;Hanjie Wen ,&nbsp;Chongguang Luo ,&nbsp;Yuxu Zhang ,&nbsp;Wenxiu Yu ,&nbsp;Chuanwei Zhu","doi":"10.1016/j.gexplo.2025.107865","DOIUrl":"10.1016/j.gexplo.2025.107865","url":null,"abstract":"<div><div>Lithium is a critical metal, and recent discoveries have identified significant lithium enrichment in the Late Paleozoic Jiujialu Formation (C₁jj) of southwestern China. However, the specific mineral hosts of lithium remain a topic of debate. This study examines two representative sections of the Jiujialu Formation, utilizing major and trace element analysis, δ⁷Li, SEM-EDS, and XRD techniques. However, previous TOF-SIMS studies have shown that lithium is not enriched in K-rich illite. Furthermore, ion exchange experiments indicate that approximately 6 % of lithium can be exchanged by Na⁺. This finding, combined with δ⁷Li values, XRD patterns, and SEM–EDS data, supports further interpretation. In conjunction with a review of previous research on the formation and transformation of clay minerals, this study suggests that lithium is predominantly hosted in the smectite crystal lattice of illite-smectite mixed layers. It proposes a two-stage diagenetic process for the formation of lithium-rich claystones: the first stage involves the formation of lithium-rich smectite, and the second stage entails the transformation of this smectite into illite and chlorite during diagenesis. In the first stage, weathering of argillaceous dolomite created an alkaline, stagnant, and closed sedimentary environment that facilitated the formation of lithium-rich smectite. In the second stage, lithium-rich smectite, as a precursor, undergoes illitization and chloritization. While illitization leads to the formation of stable illite-smectite mixed layers, chloritization of smectite is less likely to form stable chlorite-smectite mixed layers. Consequently, claystones with higher illite content tend to have higher lithium concentrations. Furthermore, complete illitization and chloritization result in the formation of low-lithium claystones. This study resolves discrepancies in previous research and provides a new perspective on the relationship between the diagenetic processes of lithium-rich claystones and the variations in lithium content.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"278 ","pages":"Article 107865"},"PeriodicalIF":3.3,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144722420","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":"Delineating new targets in a komatiite-hosted magmatic nickel sulfide prospect - Emu Lake, Kalpini, Western Australia","authors":"Louise Schoneveld ,&nbsp;Walid Salama ,&nbsp;Stephen Barnes ,&nbsp;Catherine Spaggiari ,&nbsp;Margaux Le Vaillant","doi":"10.1016/j.gexplo.2025.107863","DOIUrl":"10.1016/j.gexplo.2025.107863","url":null,"abstract":"<div><div>This study tests the use of litho-geochemistry and indicator mineral analysis to delineate new exploration targets within the Emu Lake komatiite-hosted magmatic sulfide prospect within the Archean Eastern Goldfields Superterrane of Western Australia.</div><div>Massive sulfide was recently intercepted at the basal contact of a komatiite unit informally known as the Western ultramafic. The extent of this mineralisation is difficult to track along the ~15 km strike length of the ultramafic sequence due to multiple overlying and underlying barren komatiite flows and significant fault offsets. Whole-rock geochemistry shows that the Western ultramafic unit has distinctly lower Ni/Cr ratios than other ultramafic rocks in the sequence and sits firmly within the 50th percentile of channelised sheet flow komatiitic facies. This Ni/Cr ratio helps distinguish the nickel sulfide-bearing unit from the other komatiitic flows and was used to outline a new target where further drilling was successful in finding sulfide.</div><div>Indicator minerals within the Emu Lake prospect consist of arsenides and chromite. Chromites within the Western ultramafic have lower Ru contents than those within the other ultramafic units, marking interaction between silicate and sulfide melts. Arsenides are also present at Emu Lake and their Pd/Pt values signify arsenic-rich fluids interacted with magmatic sulfide accumulation along shear or fault zones. Surface samples collected above the mineralised area at the Emu Lake prospect contained sulfides (pentlandite and chalcopyrite). Primary sulfides sampled at the surface have the potential to be a powerful ex-situ indicator mineral and could be applied to magmatic sulfide exploration in greenfield terranes.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"278 ","pages":"Article 107863"},"PeriodicalIF":3.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144605454","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 genesis of skarn-related tungsten mineralization of the Salau Deposit, Pyrenean Axial Zone","authors":"Eric Gonzalez ,&nbsp;Huan Li","doi":"10.1016/j.gexplo.2025.107853","DOIUrl":"10.1016/j.gexplo.2025.107853","url":null,"abstract":"<div><div>This study investigates the trace element chemistry of scheelite and sulfides (chalcopyrite, arsenopyrite, pyrrhotite) from the reduced skarn Salau deposit, one of France's largest tungsten deposits, located in the Pyrenean Axial Zone, to unravel the interplay between Variscan granodiorite intrusion, fluid composition and evolution, and metal transport during deposit formation. Cathodoluminescence imaging and geochemical data identify multiple scheelite generations corresponding to different mineralization stages: an early-stage, high-temperature type (GB Sch I) characterized by negative Eu anomalies, and a later retrograde type (GB Sch II) with positive Eu anomalies, both exhibiting internally variable but globally low Mo content characteristic of reduced skarn. A third, late-stage scheelite generation (GD), influenced by Veronique Fault-derived fluids, exhibits LREE depletion and near absent Mo concentrations (&lt;2 ppm), forming in association with sulfide-rich mineralization (arsenopyrite: As &lt;51 wt%, Bi &lt;483 ppm; pyrrhotite: Co/Ni &gt;5).</div><div>Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of scheelite and sulfides provide new insights into fluid evolution and trace element partitioning in the Salau skarn system. Scheelite displays distinct trace element variations, with early-stage crystals (GB Sch I) characterized by a relatively higher Mo (though &lt;0.1 wt%) and negative Eu anomalies, while later scheelite generations (GB Sch II, GD) exhibit evolving REE patterns and elemental enrichments linked to fluid chemistry changes. Sulfides, including chalcopyrite, arsenopyrite, and pyrrhotite, show compositional differences that reflect variations in sulfur activity and metal transport mechanisms.</div><div>Trace element systematics (e.g., Sr²⁺, Mo⁶⁺, REEs) indicate a transition from high-temperature magmatic-hydrothermal fluids to lower-temperature, sulfur-rich hydrothermal phases. Under sustained reduced conditions, with Y/Ho correlations suggesting minimal fluid mixing. Geochemical signatures primarily reflect fluid evolution within this reduced skarn framework, recording progressive changes in temperature, salinity, and redox conditions.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"278 ","pages":"Article 107853"},"PeriodicalIF":3.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144522851","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 reduction process contributes to the generation of subduction-related Langmuri Cu-Ni sulfide deposits in the East Kunlun Orogen, Northern Tibetan Plateau","authors":"Xu Zhao ,&nbsp;Wanting Li ,&nbsp;Wenjun Li ,&nbsp;Chongwen Xu ,&nbsp;Hua Li ,&nbsp;Liang Li ,&nbsp;Yanning Wang ,&nbsp;Lebing Fu","doi":"10.1016/j.gexplo.2025.107843","DOIUrl":"10.1016/j.gexplo.2025.107843","url":null,"abstract":"<div><div>Ore-genesis of the subduction-related Cu-Ni sulfide deposits has not been well studied. This article focuses on the Langmuri Cu-Ni sulfide deposit in the East Kunlun Orogen (EKO) by studying the symbiotic ore-bearing olivine pyroxenite and ore-free gabbro. Twenty-seven Cu-Ni sulfide orebodies were defined in these ultramafic and mafic rocks in past years with Ni average grades up to 1.5 % and Cu average grades up to 0.18 %. The ore mineralization comprises sulfides (pyrite, chalcopyrite, pentlandite, and pyrrhotite) and oxides (chromite and magnetite). Zircon U-Pb dating shows that the Langmuri mafic-ultramafic rocks have similar emplacement ages (449.9 ± 3.9 Ma for the olivine pyroxenite, 450.8 ± 1.8 Ma for the gabbro), and they were generated during the northward subduction of the Proto-Tethys Ocean. These rocks were sourced from partial melting of a continuously enriched lithosphere mantle resulting from interaction with slab-derived fluids. The ore-bearing olivine pyroxenite had a basaltic parental magma. It underwent accumulation of olivine and minor chromite and crustal contamination during magmatic evolution, while the ore-free mafic rocks underwent fractional crystallization of olivine and chromite and the crustal contamination was insignificant. The oxidation state of the ore-bearing olivine pyroxenite at QFM-1 to QFM is lower than the values for normal arc magma and the ore-free gabbro, which should be associated with the crustal contamination. Based on these clues, we inferred that fractional crystallization of olivine and minor chromite occurred in a deep magmatic chamber, and these minerals accumulated locally to form olivine-rich ultramafic rocks. The magma that underwent fractional crystallization of these minerals is the parental magma for the ore-free gabbro, while the magma with accumulation of these minerals is heavier and transported more slowly, which makes it undergo significant crustal contamination during magmatic rising. The crustal contamination reduced the magma, resulting in the sulfur saturation in magma and the generation of Cu-Ni sulfide orebodies in the Late Ordovician subduction setting at EKO.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"278 ","pages":"Article 107843"},"PeriodicalIF":3.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144299038","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":"Exploring groundwater quality and subsurface characteristics using Vertical Electrical Sounding (VES) in the Basantar watershed of J&K India","authors":"Ajay Kumar Taloor ,&nbsp;Shailesh Bhatnagar ,&nbsp;Savita ,&nbsp;Ravi Sharma","doi":"10.1016/j.gexplo.2025.107851","DOIUrl":"10.1016/j.gexplo.2025.107851","url":null,"abstract":"<div><div>In the present study, 36 Vertical Electrical Sounding (VES) sites test have conducted in the Basantar watershed with maximum current electrode separation of 300 m to detect groundwater prospects. The integration of VES results and lithology data reveals valuable information about groundwater potential zones in various sites. In order to substantiate the results, VES were conducted in finer grid pattern. The data acquisition was conducted using the Terrameter SAS 300C. In certain locations, non-collinear spacing and surface moisture affected the reliability of the observed apparent resistivity values, resulting in irregular VES curves. After applying smoothing techniques, the interpretation of the VES curves became feasible. The results indicated a strong correlation between the resistivity data and lithological information, identifying VES points 6, 9, 10, 19, 20, 21, 22, 24, 27, 29, 31, and 33 as the most suitable sites for groundwater extraction. Further, fifty groundwater samples have been analyzed for hydrochemical analysis shows that hydrochemistry is dominated by the alkaline earth and weak acids. The Pollution Index of Groundwater (PIG) shows that 97 % of groundwater samples found in the insignificant pollution.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"278 ","pages":"Article 107851"},"PeriodicalIF":3.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144522849","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}