Journal of Geochemical Exploration最新文献

{"title":"Constraining lithium-clay equilibria in sedimentary environments using a new thermodynamic dataset","authors":"Tiziano Boschetti ,&nbsp;Adedapo N. Awolayo","doi":"10.1016/j.gexplo.2025.107920","DOIUrl":"10.1016/j.gexplo.2025.107920","url":null,"abstract":"<div><div>Lithium-rich formation brines from sedimentary basins are emerging as key unconventional resources in response to the growing global demand for lithium. This study integrates geochemical data from diverse settings, including the Smackover and Edwards Formations (Gulf Coast, USA), the Alberta Basin (Canada), and Salsomaggiore (Northern Apennine, Italy), to investigate the role of diagenetic processes and clay mineral equilibria on lithium mobility and retention. A new thermodynamic dataset was developed for lithium-bearing clay minerals and jadarite, allowing the construction of activity diagrams, calculation of saturation indices, and modeling. Activity diagrams indicate progressive brine evolution from kaolinite to montmorillonite, and toward Mg-rich saponite/chlorite assemblages, consistent with advanced diagenetic stages and lithium uptake into octahedral sites. The transition from equilibrium with smectites to chlorite-like phases reflects increasing temperature and prolonged water-rock interactions. A hyperalkaline paleo-fluid in equilibrium with jadarite and associated phases was also modeled, indicating that lithium concentrations in the Jadar Basin may have reached levels comparable to those currently observed in the Salar de Atacama. These findings underscore the dual role of clay minerals as buffers and potential sources for lithium in sedimentary systems, providing new insights for exploration and geochemical modeling of lithium-rich formation brines.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107920"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145324859","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":"Petrography and chemical composition of tourmaline from the Xiazhuang uranium orefield, South China: Implications for magmatic-hydrothermal evolution and uranium exploration","authors":"Ming-Ji Zhang ,&nbsp;Jia-Yong Pan ,&nbsp;Yang Xu ,&nbsp;Mostafa Fayek ,&nbsp;Zhan-Shi Zhang ,&nbsp;De-Hui Zhang ,&nbsp;Cheng-Biao Leng","doi":"10.1016/j.gexplo.2025.107921","DOIUrl":"10.1016/j.gexplo.2025.107921","url":null,"abstract":"<div><div>Tourmaline is a reliable recorder of magmatic-hydrothermal evolution and ore mineralization. Numerous investigations on tourmaline from magmatic rocks and ore deposits have been conducted, while the links between tourmaline and granite-related uranium (U) mineralization systems remain poorly understood. This paper presents data of <em>in</em>-<em>situ</em> major and trace elemental compositions of tourmaline in the U-bearing and U-barren granitic plutons from the Xiazhuang U orefield by EPMA and LA-ICP-MS. Four types of tourmalines are identified by occurrences: (1) disseminated tourmaline (D-T) in the U-barren Luxi pluton; (2) interstitial tourmaline (I-T) in the U-bearing Maofeng pluton; (3) segregational tourmaline (S-T) in the U-bearing Xiazhuang pluton and (4) tourmaline veins (V-T) (including samples from the Zhushanxia U deposit (VZ-T), the Xiwang U deposit (VX-T) and the Luxi pluton (VL-T)). Tourmaline grains from the U deposits all display “cracked” appearance under the microscope, whereas those from the U-barren area remain intact. All the tourmalines are rich in Al (&gt;6 apfu), and belong to the alkali group and schorl endmember, falling into field 2 in the total Al-Fe-Mg ternary diagram. Petrographic and chemical composition data suggest that the D-T was primary magmatic in origin and formed in a late stage from the fractionated magma; the I-T and the S-T crystallized during the magmatic-hydrothermal transition; the V-T formed in magmatic hydrothermal fluids that may have been interacted with country rocks. The negative correlation of Fe and Mg from the D-T to the V-T demonstrates the MgFe₋₁ exchange vector, suggesting constant reduced crystallization environments from magmatic to hydrothermal fluids. Concentrations of V, Sr, Sc, Nb, Ta, and Mg/(Mg + Fe) ratios in tourmaline exhibit marked differences between the D-T and the V-T, and are considered as efficient discriminators for the magmatic and hydrothermal tourmaline. The gradually elevated contents of Sr and Mg/(Mg + Fe) ratios from the D-T, I-T to the S-T perfectly monitors fluid evolution from magmatic to magmatic-hydrothermal transition. The VZ-T and the VX-T from the U deposits show pronounced higher concentrations of Pb (&gt;10 ± 2 ppm) and lower Sn/Pb ratios (&lt;10 ± 1). The high anomaly of Pb in the hydrothermal tourmaline from the U-rich granites reflects accumulations of Pb in the magmatic hydrothermal fluids possibly through radioactive decay of U from the fertile granitic melts. The unique “cracked” appearance of the tourmaline in the U deposits is attributed to the alkaline hydrothermal alteration associated with U remobilization, which in turn may provide another sign for U-bearing fluid activity and the process of U enrichment at Xiazhuang. The “cracked” texture and Pb contents of tourmaline can serve as powerful and cost-effective vectoring tools for uranium exploration in similar granite-related systems globally.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107921"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362311","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":"Textural and geochemical constraints on the formation of the magmatic Fe–Ti oxide deposit at Boreum Island, South Korea","authors":"Ji-Hyun Lee ,&nbsp;Eui-Jun Kim ,&nbsp;Seok-Jun Yang ,&nbsp;Heonkyong Im ,&nbsp;Dongbok Shin","doi":"10.1016/j.gexplo.2025.107908","DOIUrl":"10.1016/j.gexplo.2025.107908","url":null,"abstract":"<div><div>This paper investigates the complex magmatic processes of the Boreum magmatic Fe–Ti oxide deposit through comprehensive field observation, petrography, and geochemistry. Located in the marginal zone of the Gyeonggi Massif, central-western Korean Peninsula, this deposit represents one of South Korea's most important Fe–Ti oxide provinces, providing an ideal natural laboratory for understanding ore formation mechanisms. The sill-like Boreum ultramafic rocks (30 m wide, 300 m long) intrude Paleoproterozoic Boreumdo schist and comprise three distinct phases: actinolite-, diopside-, and olivine-dominant. Cross-cut relationships indicate formation through multiple melt injections rather than single-melt fractionation processes. Iron–Ti oxide mineralization concentrates unevenly in the highly fractured olivine-dominant phase as sill-dyke networks. Magnetite and ilmenite are dominant, with subordinate pleonaste and perovskite (restricted to diopside-dominant phase). Magnetite shows complex exsolution textures indicating subsolidus re-equilibration during slow cooling. It is significantly enriched in compatible elements (Cr: 25,622–140,526 ppm; Ti: 18,160–87,919 ppm; V: 2421–18,433 ppm), plotting within magmatic Fe–Ti, V deposit compositional fields. Mineral chemistry reveals high-temperature magnetite crystallization (T_Mg-Mag = 885–607 °C, T_Ilm-Mag = 754–594 °C) under low oxygen fugacity conditions (ΔFMQ −2.60 to +0.69). Magnetite exhibits restricted δ⁵⁶Fe (+0.12 to +0.40 ‰) and δ¹⁸O (−0.75 to +2.89 ‰) values, consistent with magmatic origin. Fe–Ti oxide mineralization resulted from high-temperature magmatic melt migration into already solidified ultramafic rocks, not in situ crystallization or crystal settling. These findings provide new insights into magmatic processes forming Fe–Ti oxide deposits in mafic–ultramafic intrusions.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107908"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155534","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, mineral chemistry, and geothermometry of the Anbar-Kuh Fe skarn deposit, Tutak complex, Sanandaj-Sirjan Zone, Iran: Implications for the mineralization processes","authors":"Soqra Rasti ,&nbsp;Batoul Taghipour ,&nbsp;Alireza K. Somarin ,&nbsp;David R. Lentz","doi":"10.1016/j.gexplo.2025.107905","DOIUrl":"10.1016/j.gexplo.2025.107905","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The Anbar-Kuh iron deposit is situated in the Sanandaj-Sirjan Zone (SASZ) within the Tutak metamorphic complex, Iran. This complex includes metacarbonate, mica schist, greenschist, and orthogneiss, which hosts the iron ores. Metacarbonate and orthogneiss were simultaneously metasomatized by hydrothermal fluid premetamorphically. Locally preserved textural and mineral paragenesis indicate Fe mineralization occurs before, but also was locally remobilized during and after metamorphism and deformation processes. Magnetite mainly occurs as massive, cataclastic, lenticular, and disseminated ore associated with hematite and minor pyrite. Gangue minerals mainly include quartz, calcite, chlorite, amphibole, and K-feldspar. Two generations of magnetite ore are found: replacement bodies where coarse grains of magnetite replaced carbonate host rock during potassic metasomatism and the second generation of magnetite formed as veins and veinlets that formed during a later post-metamorphic retrograde stage. The Ni, Cr, and Co content of the deposit (average: Ni = 18 ppm, Cr = 9 ppm, and Co = 17 ppm) along with high Co/Ni ratio (average 3.54) suggest a typical hydrothermal skarn origin for this deposit. Metacarbonate and orthogneiss samples show distinct LREE enrichment relative to HREE. The host rocks are characterized by positive Eu anomalies in the metacarbonates and a negative Ce anomaly in schists. The fluid inclusion data on quartz preserved within retrograde and sulfide‑carbonate assemblages suggest that Fe-mineralization formed from the ore-bearing magmatic-hydrothermal fluid with an average salinity of 18.5 wt% NaCl equivalent that saturated at a temperature of 260 °C. Microthermometric data suggest that temperature and pressure decrease, fluid neutralization due to interaction with carbonate wall rock, and mixing of the hydrothermal fluid with meteoric water-controlled Fe precipitation in this deposit. A five-stage model is proposed for the genesis of the Anbar-Kuh Fe mineralization: I) potassic/alkali metasomatism; fluid-mineral interaction related to the subduction-related magmatism and volatile exsolution, resulting in potassic metasomatism of magmatic minerals, such as plagioclase, K-feldspar, amphibole, biotite, and secondary muscovite saturation of magnetite with partial saturation of Fe from the Fe-bearing hydrothermal fluid. II) Prograde skarn stage; the major mineral assemblage, including garnet and pyroxene, formed in the disseminated and banded Fe ores. During migration of hydrothermal fluids from the crystallizing granitoid intrusion (orthogneiss) to the surrounding limestone (now metacarbonate rocks), Ca and Mg were continuously added to the fluid as FeCl&lt;sub&gt;2&lt;/sub&gt; saturated. As fluid temperature dropped, Ca and Mg concentrations increased, forming Ca-Mg-rich skarn minerals. III) Post-metamorphic retrograde skarn stage; epidote, biotite, chlorite, magnetite, and hematite assemblages were developed. Ca pyroxene was replaced by a","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107905"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145325267","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":"Hydrochemical insights into lithium enrichment mechanisms in Southern Tibet's geothermal systems","authors":"Jiexiang Li ,&nbsp;Hankun Li ,&nbsp;Chuanxia Ruan ,&nbsp;Gideon Sagoe ,&nbsp;Guanghui Tian ,&nbsp;Shen Wang ,&nbsp;Wenjing Lin","doi":"10.1016/j.gexplo.2025.107929","DOIUrl":"10.1016/j.gexplo.2025.107929","url":null,"abstract":"<div><div>Some geothermal systems in Southern Tibet stand out for their exceptionally high lithium (Li) compared to other geothermal regions in Himalayan geothermal belt, yet the Li sources and enrichment processes remain underexplored. To fill this gap, hydrogeochemical data of 156 geothermal water samples from Chabu, Kawu, Laduogang, Mangre, Yangbajain, Targejia and Yangyi geothermal systems in Southern Tibet and of 23 geothermal water samples from Tengchong, Kangding and Litang in the Hengduan Mountains District (as a reference) were retrieved from the literature to investigate the occurrence and hydrogeochemical processes of Li. Using thresholds of 4 % molar proportion of sulfate (SO₄²⁻) in the anions and 10 mg/L Li concentration in the geothermal waters, the geothermal systems chosen in this study are categorized into four types. In the “Low-SO₄, High-Li” geothermal systems, such as Kawu, Yangbajain and Laduogang, the majority of the geothermal waters have high Li concentrations due to significant magmatic water input with limited Li enrichment from the surrounding rocks. The Laduogang geothermal waters exhibit unusually high Li concentrations, reflecting the combined effect of magmatic water mixing and intense concentration processes. Contrastingly, in the “High-SO₄, Low-Li” geothermal systems, including Chabu, Mangre, and Targejia, the geothermal waters have relatively low Li concentrations. These fluids likely originate from deep geothermal reservoirs, with minimal influence of water-rock interaction in the reservoirs and along the flow paths. They likely mix with a smaller proportion of magmatic water and traverse a longer flow path after leaving the reservoirs. During the ascent, S²⁻ oxidation elevates the levels of SO₄²⁻ and other solutes like magnesium. In the “High-SO₄, High-Li” geothermal system (i.e, Yangyi), the presence of high-Li geothermal waters may be attributed to water-rock reaction interactions rather than being solely due to the input of deep magmatic waters. All geothermal systems in HMD are classified as “Low-SO₄, Low-Li”, suggesting a different Li enrichment mechanism compared to Southern Tibet.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107929"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145516468","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 trace element composition in volcanogenic massive sulfide Cu-Zn-Pb and clastic-dominated Zn-Pb deposits with applications to mineral exploration","authors":"Eduardo Valentin ,&nbsp;Georges Beaudoin ,&nbsp;Bertrand Rottier ,&nbsp;John F. Slack","doi":"10.1016/j.gexplo.2025.107913","DOIUrl":"10.1016/j.gexplo.2025.107913","url":null,"abstract":"<div><div>Tourmaline from thirteen volcanogenic massive sulfide (VMS) deposits, three clastic-dominated (CD) Zn-Pb deposits, and four barren sediment-hosted tourmalinites were analyzed for major, minor, and trace elements to identify chemical criteria that distinguish tourmaline in VMS and CD deposits from other barren and mineralized environments. Tourmaline from VMS is mainly dravitic, with some deposits showing schorlitic and uvitic compositions, whereas CD Zn-Pb and barren tourmalinite tourmaline spans the schorl-dravite transition and dravitic compositions, with few exceptions showing uvitic and foititic compositions. Tourmaline major element composition from VMS and CD is governed by heterovalent coupled substitutions, reflecting local processes specific to each deposit. In barren tourmalinites, the compositions are mainly controlled by the chemical composition of the host metasedimentary units. The VMS tourmaline shows higher Al, Mg, and V, whereas CD has higher Ca, Co, K, Mn, Li, La, Ce, Eu, Zn, and Pb; tourmalinites show higher Fe, Na, Ti, Sr, Cr, Sc, Sn, Ga, and Cu. A partial least-squares discriminant analysis (PLS-DA) model is used to classify VMS deposits, CD Zn-Pb deposits, and barren tourmalinites. The results show that VMS tourmaline correlates with Mg, Sn, Ga, and V; CD Zn-Pb tourmaline correlates with Pb, Zn, K, Mn, and Eu; and tourmaline from barren tourmalinites correlates with Fe, Ti, and Sr. These elements were used to build bivariate classification plots using element ratios that enhance the geochemical distinction of VMS and CD Zn-Pb tourmaline from tourmaline in granite-related Sn-W, orogenic gold, porphyry Cu-Mo-Au, iron oxide‑copper‑gold, and barren geological environments.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107913"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362312","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":"Metamorphogenic compositional changes in sulfides and their role in metal enrichment in SEDEX deposits: Insights from machine learning algorithms","authors":"Niraj Bhuyan ,&nbsp;Pranjit Hazarika ,&nbsp;Rissnalin Syiemlieh ,&nbsp;Eeshankur Saikia","doi":"10.1016/j.gexplo.2025.107915","DOIUrl":"10.1016/j.gexplo.2025.107915","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Metamorphosed sedimentary exhalative (SEDEX) deposits contain higher concentrations of sulfosalts and rare metals within their remobilized zones. As sulfides (e.g., pyrite and sphalerite) incorporate a wide range of trace elements during &lt;em&gt;syn&lt;/em&gt;-sedimentary Pb&lt;img&gt;Zn mineralization, their recrystallization during metamorphism may play a crucial role in metal enrichments in the remobilized zones of SEDEX deposits. To explore this, we analyzed pyrite and sphalerite from different ore stages (syngenetic, &lt;em&gt;syn&lt;/em&gt;-metamorphic, and post-metamorphic) of two major SEDEX deposits (Rajpura-Dariba and Rampura-Agucha) of Aravalli-Delhi Fold Belt (ADFB), northwestern India. We further applied supervised machine learning (ML) algorithms (XGBoost, LightGBM, Random Forest and Extra Tree) on sulfide compositions from the ADFB and global “world class” SEDEX deposits to assess if ML models could efficiently classify sulfides formed at distinct stages of ore genesis and thus constrain trace element re-distribution. This exercise allowed us to investigate the role of sulfide recrystallization in trace element enrichments within SEDEX deposits.&lt;/div&gt;&lt;div&gt;Ore textures suggest that sulfides in the SEDEX deposits of ADFB have broadly formed in three distinct episodes; during, 1) syngenetic (&lt;em&gt;syn&lt;/em&gt;-sedimentary to diagenetic) ore mineralization, 2) metamorphic recrystallization, and 3) retrograde cooling of sulfide melts produced at peak metamorphism. The syngenetic to diagenetic pyrite and sphalerite can be distinguished by their higher Pb, Ag, Sb and Tl contents. Pyrite and sphalerite formed during metamorphic recrystallization of early formed sulfides are characterized by higher concentrations of structure bound elements (As, Co and Ni in pyrite and Hg, Cd, Mn and Ga in sphalerite). Our study reveals that the tested ML algorithms (XGBoost, LightGBM, Random Forest and Extra Tree) can effectively identify sulfides (pyrite and sphalerite) of distinct origin, with significant accuracy (93–96 %), thus, providing new insights on the applicability of ML methods to study ore genesis. Similarly, syngenetic sulfides (Py-S and Sph&lt;img&gt;S) from global SEDEX deposits are also characterized by higher concentrations of low melting point chalcophile elements (LMCEs: Pb, Ag, Sb and Tl) and lower concentrations of structure bound trace elements (As, and Ni in pyrite; Mn, Ga and Ge in sphalerite) compared to metamorphic recrystallized sulfides (Py-M and Sph-M). The expulsion of metals (Pb, Ag, Sb and Tl) during metamorphic sulfide recrystallization, as observed in the ADFB and global SEDEX deposits, suggests that the redistribution of trace elements from sulfides during metamorphism plays a critical role in the enrichment of rare metals (Ag, Sb and Tl) in remobilized zones of SEDEX deposits. This is consistent with the textural observation that remobilized zones contain abundant sulfosalts of Ag, Sb and Tl in these deposits.&lt;/div&gt;&lt;div&gt;Our study further highlights ","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107915"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145324552","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":"Bauxite exploration in Odisha using advanced hyperspectral remote sensing and analytical techniques","authors":"Susovan Layek ,&nbsp;Ashim Sattar ,&nbsp;Deep Raj Das ,&nbsp;A. Abhinav ,&nbsp;Richa Upadhyay Sharma ,&nbsp;T.K. Biswal","doi":"10.1016/j.gexplo.2025.107930","DOIUrl":"10.1016/j.gexplo.2025.107930","url":null,"abstract":"<div><div>Bauxite, being the primary source of aluminium, is essential for industries such as aerospace, construction, and packaging. The study reports the first regional-scale potential bauxite exploration zones in Odisha, India covering two entire districts-Koraput and Rayagada. PRISMA hyperspectral data of SWIR wavelength range between 1.55 μm and 2.3 μm is exploited, due to its sensitivity to Al-OH absorption in bauxite. Spectral response curves are compared to lab spectroscopy of field samples from the bauxite zones of Marwaiguda village in Koraput district. The study is supplemented by petrographic, geochemical (XRD and XRF), and geomorphological assessments showing its distribution on flat-topped hills with ooides and pisoides microstructures, and Al₂O₃ wt% ranging between 43 % and 50 %. The average RMSE in reflectance between lab spectra vs. USGS and lab spectra vs. PRISMA is 0.16 and 0.18, respectively, whereas the cosine similarity is 0.99 and 0.90, respectively, which defines a well correlation between the spectra. The results show that the bauxite is distributed linearly along the NE-SW direction traversing the Koraput and Rayagada districts. The hyperspectral-based potential zones is validated by creating an inventory of existing bauxite mines and zones in advanced stages of initial exploration. The results show a strong correspondence between the identified zones and existing bauxite mines. The new potential bauxite exploration zones in the study can support future bauxite exploration in Odisha. The results will aid stakeholders such as the Odisha Mining Corporation, NALCO, Vedanta, Hindalco, and other government agencies in cost-effective bauxite exploration.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107930"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145516469","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":"Mineralogical analysis: The light-induced oxidation driving mechanism of heavy metals in lead-zinc smelting slag","authors":"Hanjing Yu,&nbsp;Chenchen Li,&nbsp;Jin Yan,&nbsp;Yaoqiang Ma,&nbsp;Xinyu Zhou,&nbsp;Wanquan Yu,&nbsp;Huiying Kan,&nbsp;Qi Meng,&nbsp;Ruosong Xie,&nbsp;Peng Dong","doi":"10.1016/j.gexplo.2025.107912","DOIUrl":"10.1016/j.gexplo.2025.107912","url":null,"abstract":"<div><div>Heavy metals (HMs) pollution in lead‑zinc (Pb<img>Zn) smelting slag is a widespread environmental issue. However, the weathering and toxic leaching behavior of Pb<img>Zn smelting slag under strong ultraviolet (UV) radiation, particularly in plateau areas, has rarely been studied. The interaction between HMs and minerals in Pb<img>Zn smelting slag under intense sunlight remains unclear. In this study, we simulate and analyze for the first time the oxidative stress process of HMs, melilite, and pyrite in Pb<img>Zn smelting slag under natural environmental conditions, considering the unique mineralogical and climatic characteristics. Notably, UV radiation acts as an energy source, exciting pyrite and promoting the migration of electrons (e⁻) and holes (h⁺), which triggers redox reactions. Reactive oxygen species (ROS) act as intermediates, converting As(III) to the more stable As(V). Due to the differing symbiotic relationships, the Pb-containing mineral (galena) is directly oxidized to PbSO₄ by ROS (H₂O₂), increasing the leaching rate of Pb by 12.4 % and 29.3 %. This also accelerates Zn release by 3.5 % and 21.1 %. This study offers new insights into the migration and transformation behavior of heavy metals in Pb<img>Zn smelting slag.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107912"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145267207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trends of Cu and Co contaminated sediment dispersal along the Kafue River, the Zambian Copperbelt","authors":"Ondřej Bábek ,&nbsp;Ondra Sracek ,&nbsp;Vojtěch Ettler ,&nbsp;Jaroslav Kapusta ,&nbsp;Bohdan Kříbek ,&nbsp;Martin Mihaljevič ,&nbsp;Imasiku Nyambe ,&nbsp;Vít Penížek ,&nbsp;Aleš Vaněk ,&nbsp;Gabriel Ziwa","doi":"10.1016/j.gexplo.2025.107900","DOIUrl":"10.1016/j.gexplo.2025.107900","url":null,"abstract":"<div><div>Rivers are important pathways for metal(loid) contamination in mining areas. The Kafue River flows through the Zambian Copperbelt with nearly a hundred-year history of Cu and Co mining. Nine cores down to 2.5 m deep were drilled in fluvial sediments along a 750-km long river section and analysed for grain size, elemental composition, and mineralogy using extraction tests and scanning electron microscopy with an aim to investigate the spatial and temporal contamination patterns. The silty and fine- to coarse grained sandy sediments were deposited in natural levees, semi-abandoned meanders, and channel bars. They are heavily polluted by Cu reaching ore grade (up to 1.9 %) and Co, with UCC-based enrichment factors (EF) as high as 704 and 60, respectively, which is more than an order of magnitude higher than the most severely impacted large European rivers, and slightly polluted by Pb, As, U and other elements. The main carriers of Cu are malachite, pseudomalachite, secondary Fe oxyhydroxides (ferrihydrite, goethite), sulphides, and Cu-bearing grains of kaolinite, chlorite, and mica. This Cu contamination is traceable (EF up to 13) in sediments 750 km downstream of the Kafue River inflow to the Copperbelt. The contaminated sediments are ~100 cm to ~220 cm thick and their average sediment accumulation rates ~12 to ~27 mm/yr indicating that the contaminated suspended particulate matter can be rapidly deposited along the river, representing a potential environmental hazard. Arsenic and Pb can be scavenged to Fe oxyhydroxides and accumulate in capillary fringe above groundwater level during early diagenesis.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107900"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}