Journal of Geochemical Exploration最新文献

{"title":"Material source and genesis analysis of lithium-rich claystone in Balun Mahai Salt Lake, Qaidam Basin","authors":"Fan Zhang ,&nbsp;Xiwei Qin ,&nbsp;Yuliang Ma ,&nbsp;Sha Yang ,&nbsp;Tong Pan ,&nbsp;Jianzhou Chen ,&nbsp;Chenglin Liu ,&nbsp;Chengwang Ding ,&nbsp;Ziwen Jiang ,&nbsp;Dong Zhang ,&nbsp;Qingkuan Li ,&nbsp;Genhou Wang ,&nbsp;Ning Feng ,&nbsp;Ruibo Liu ,&nbsp;Zhaopeng Ding ,&nbsp;Erfeng Ren","doi":"10.1016/j.gexplo.2025.107935","DOIUrl":"10.1016/j.gexplo.2025.107935","url":null,"abstract":"<div><div>The potential resources of the clay-type lithium ore in the Balun Mahai Salt Lake of the Qaidam Basin are considerable. However, systematic theoretical research on the metallogenic enrichment regularity of the clay-type lithium ore is still lacking. In this paper, the Quaternary clay layer in the Balun Mahai Basin is taken as the research object. By adopting the methods of rock geochemistry and isotope geochemistry, the sedimentary environment, material source, evolution process and lithium source of the lithium-rich clay layer are explored. The distribution pattern diagrams of rare earth elements indicate that the lithium - rich clay rocks in the Mahai Basin are enriched in light rare earth elements and depleted in heavy rare earth elements, presenting distinct fractionation within the rare earth element assemblage, and the materials of the source rock and the weathering conditions remain stable. The elemental indicators of the sedimentary environment and the isotope indicators of B, C, and O suggest that the sedimentary water body was in a non - marine brackish water environment with weak oxidation - weak reduction conditions, which was affected by a climate characterized by aridity and scarce precipitation. The sediment provenance discrimination diagrams and rare earth element distribution pattern diagrams suggest that the clay source rocks are primarily derived from the biotite adamellite, quartz diorite, gneissic granite of Little Seshten Mountain, adamellite of Qaidam Mountain in the South Qilian Mountains and the granitic gneisses in the Yuqia River region. Weathering indices such as Chemical Index of Alteration (CIA) and Index of Compositional Variability (ICV) indicate that the source rocks generated detrital materials under the influence of weak weathering processes. These detrital materials were then transported to the basin via rivers and, through sedimentation and diagenesis, gave rise to clay minerals. Subsequently, in an alkaline fluid environment, the potassium feldspar was transformed into illite. The isotopic characteristics of Li and B suggest that the lithium in the clay has two sources: lithium in the enriched brine and lithium in the detrital materials of the retained source rocks. Moreover, the amount of lithium adsorbed from the brine is higher than that of the structural lithium in the source rock detritus. Through a comprehensive analysis of the sedimentary environment, material sources, evolution process, and lithium sources of the lithium - rich clay, its genesis can be divided into multiple stages, including the weathering of parent rocks, material transportation, sedimentation, and diagenesis.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"281 ","pages":"Article 107935"},"PeriodicalIF":3.3,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682164","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":"Hydrothermal geochemical signatures in zircon as a pathfinder for IOCG mineralization: An example from the Carajás Mineral Province (Brazil)","authors":"Maurício L. Borba ,&nbsp;Colombo C. Tassinari ,&nbsp;Fernando M. Matos ,&nbsp;John M. Hanchar ,&nbsp;Fernando Tornos ,&nbsp;Sergio Huhn ,&nbsp;Kei Sato","doi":"10.1016/j.gexplo.2025.107934","DOIUrl":"10.1016/j.gexplo.2025.107934","url":null,"abstract":"<div><div>Zircon from hydrothermally altered host rocks of Archean iron oxide‑copper‑gold (IOCG) deposits in the Carajás Mineral Province (CMP), Brazil, display distinct U, Th, and rare earth element (REE) compositions when compared to zircon from typical unaltered igneous rocks. Uranium-Pb geochronology of zircon from the Furnas and Paulo Afonso deposits reveals a complex, multi-episodic, evolution of deposit formation, characterized by: (1) ∼2.75 Ga zircon grains from wall rocks that exhibit typical magmatic features and lack evidence of metasomatic alteration (e.g., sieve texture, elevated U, and LREE enrichment); (2) ∼2.55 Ga zircon from the same rocks showing metasomatic textures and compositions; and (3) ∼1.9 Ga zircon crystals from host rocks displaying magmatic Chondrite-normalized REE patterns but with significant U enrichment. Both the Furnas and Paulo Afonso deposits contain at least three zircon populations; recording Archean and Proterozoic magmatic-tectonic and metasomatic events. Hydrothermal zircon of ∼2.55 Ga occurs regionally in CMP rocks; commonly associated with major IOCG deposits and aligned with the regional-scale Cinzento Shear Zone (CSZ). These zircon crystals are interpreted as having crystallized from, or altered by, chemically similar hydrothermal fluids during <em>syn</em>-tectonic hydrothermal activity, rather than through direct magmatic crystallization. Their complex geochronological record, trace element compositions, and internal zoning and structures, reflect overprinting by hydrothermal fluids associated with IOCG mineralization. We propose that these hydrothermal zircon populations may serve as pathfinder indicators of <em>syn</em>-mineralization hydrothermal activity, and thus represent valuable exploration vectors for IOCG systems in similar polycyclic terranes elsewhere. In addition, the newly introduced Sm/Sm* parameter (derived from zircon REE systematics) emerges as a promising geochemical tool for mineral exploration. By quantifying subtle LREE flattening associated with hydrothermal modification, Sm/Sm* is a promising parameter for distinguishing ore-related from barren zircon populations and reinforces the potential of zircon geochemistry as a practical proxy in IOCG-style systems.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"281 ","pages":"Article 107934"},"PeriodicalIF":3.3,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617341","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":"Physicochemical controls on Mo mineralisation of the Caosiyao porphyry deposit, northern North China Block","authors":"Jialu Song ,&nbsp;Fan Yang ,&nbsp;Zhenyu Qin ,&nbsp;Leon Bagas ,&nbsp;Yingjie Li ,&nbsp;Xiaoyu Ge ,&nbsp;Likun Yang","doi":"10.1016/j.gexplo.2025.107931","DOIUrl":"10.1016/j.gexplo.2025.107931","url":null,"abstract":"<div><div>Physicochemical conditions play a key role in magmatic differentiation, fluid exsolution and migration, and the enrichment of ore-forming elements in porphyry deposits. Biotite is a critical indicator mineral that has been used to constrain physicochemical conditions and trace the hydrothermal evolution of mineralisation. The Caosiyao deposit, a super-large porphyry Mo deposit located at the northern margin of the North China Block, has been primarily studied in terms of its metallogenic age and genetic evolution. However, the physicochemical conditions during magmatic and hydrothermal evolution remain poorly understood. This study analysed major and trace elements of hydrothermal biotite from the mineralised granite porphyry to better constrain the physicochemical conditions, hydrothermal evolution, and Mo mineralisation at Caosiyao. Hydrothermal biotite geochemical data reveals crystallisation temperatures ranging from 174 to 462 °C, high oxygen fugacity, and elevated F fugacity (IV(F) = 0.87–1.33; IV(Cl) = −4.63 to −3.74; IV(F/Cl) = 4.83–5.77). During the formation of deposit, the mixing of late hydrothermal fluids with meteoric water promoted the generation and transport of stable Cl⁻ and Mo⁶⁺ complexes under favorable physicochemical conditions, resulting in significant Mo enrichment. The formation of the Caosiyao Mo deposit can be divided into three main stages: (1) The mineralisation process initiated with the generation of high-K, high-<em>f</em>O₂ granitic magmas derived from lower crustal melting, triggered by an enriched mantle source. Magmatic differentiation concentrated Mo in the residual melt, whereas fluid exsolution facilitated the migration of Mo-rich fluids along fractures, accompanied by widespread K-alteration. (2) Subsequent fluid–rock interaction led to the decomposition of Mo complexes and the precipitation of ore minerals in structurally weak zones. (3) In the late stage, the mixing of hydrothermal fluids with meteoric water and the release of sulfide altered the physicochemical conditions of the hydrothermal system, further enhancing Mo deposition. This study provides new insights into the common mineralisation processes observed in similar Mo deposits worldwide and offers significant implications for prospecting.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107931"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145568418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Formation mechanism of high arsenic geothermal water in Gonghe basin, Northwest China","authors":"Zhen Wang ,&nbsp;Yongge Li ,&nbsp;Chuanxia Ruan ,&nbsp;Fu Wang ,&nbsp;Wenjing Lin ,&nbsp;Yu Yang ,&nbsp;Narsimha Adimalla","doi":"10.1016/j.gexplo.2025.107890","DOIUrl":"10.1016/j.gexplo.2025.107890","url":null,"abstract":"<div><div>The occurrence of high arsenic (As) concentrations in groundwater within overlying aquifers, influenced by deep geothermal activities, has been reported globally. However, its genetic mechanisms remain inadequately understood. In this study, forty-one water samples were collected to analyze the major and trace chemical compositions of water, along with isotopic signatures (δ¹⁸O, δD, δ¹³C, δ¹⁴C, δ³²S_SO4). Results show that As concentrations in NGW (with an average 452 μg/L) are significantly higher than in QGW (with an average 36.0 μg/L). Additionally, hydrochemical type of QGW gradually evolves from Na-HCO₃ to Na-SO₄ and Na-Cl·SO₄ along the flow path. The δ¹⁸O and δD isotopic results suggest that local atmospheric precipitation is the primary source of QGW, while glacial meltwater or high altitude atmospheric precipitation serves as the main source of NGW. The high temperature environment contributes to an oxygen drift in the δ¹⁸O of NGW. Results of δ¹³C indicate that the main sources of inorganic carbon in geothermal water are likely from the dissolution of carbonates and decomposition of organic matter. According to δ¹⁴C data, the average apparent age of QGW is 18.8 ka, with relatively older ages found in the south and southeastern parts of the study area, whereas NGW has an average age of 29.1 ka. The continuous upwelling of deep geothermal energy raises the temperature of hot storage aquifer, promoting the release and migration of As. Additionally, silicate weathering and microbial sulfate reduction play significant roles in As enrichment in both QGW and NGW. Furthermore, As desorption from QGW and NGW is another factor contributing to the elevated As levels in the investigated region.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107890"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144989841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Age and mineralization mechanisms of the Babanqiao tin polymetallic deposit in the Dupangling area, Nanling region, South China","authors":"Chunlan Meng ,&nbsp;Lingan Bai ,&nbsp;Shouyu Zhou ,&nbsp;Yu Dai ,&nbsp;Chongjin Pang ,&nbsp;Zuohai Feng ,&nbsp;Xijun Liu ,&nbsp;Chunyan Zhou ,&nbsp;Jiao Yang","doi":"10.1016/j.gexplo.2025.107926","DOIUrl":"10.1016/j.gexplo.2025.107926","url":null,"abstract":"<div><div>The Nanling region in South China contains widespread granites of variable ages. Large-scale W and Sn mineralization were closely associated with Yanshan granites, but the mineralization related to granites of other ages has been little studied. Understanding the metallogenic significance of Indosinian granites is crucial for refining exploration models, as recent discoveries suggest they may have played a greater role than previously recognized. The weighted mean zircon U<img>Pb age of the biotite granite from the eastern part of the Dupangling pluton is 224.7 ± 4.8 Ma, while the cassiterite U<img>Pb age from the Babanqiao Sn-polymetallic deposit is 223.6 ± 4.0 Ma. These results indicate that the Babanqiao deposit formed contemporaneously with late Indosinian granitic magmatism, suggesting that the deposit was likely associated with granitic activity during the late Indosinian period. Fluid inclusion data reveal the initial ore-forming fluids were part of a NaCl–H₂O system with high to moderate temperatures and salinities, which contained CH₄ ± N₂. Homogenization temperatures ranged from 182.1 °C to 381.5 °C in the early mineralization stage and decreased to 145.4 °C to 279.8 °C in the main mineralization stage, with corresponding salinities of 13.62–25.15 wt% NaCl equiv. and 7.45–19.76 wt% NaCl equiv., respectively. These values indicate that ore deposition occurred under reducing conditions, with a progressive decrease in temperature and salinity as meteoric water mixed with the magmatic fluids. δ¹⁸O and δD values show that the ore-forming fluids were magmatic waters that gradually transitioned to meteoric waters. This progressive dilution likely influenced metal transport. Integrated analysis indicates that during the Indosinian period, Sn-bearing magmatic–hydrothermal fluids migrated into closely spaced microfractures and joints, where localized boiling may have occurred, producing limited precipitation. The fluids then ascended along these structures and mixed with infiltrating meteoric water, destabilizing Sn<img>Cl complexes and precipitating Sn in fault zones to form quartz-vein–type Sn ore. Thus, fluid mixing was the primary mineralization mechanism at Babanqiao. These findings also highlight the exploration potential of Indosinian granites in South China as hosts of previously unrecognized W<img>Sn systems.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107926"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145466345","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 uranium occurrence state of carbonaceous-siliceous slates and their geological significance for uranium mineralization: A case study from the Tichong black shale-type uranium deposit","authors":"Fan Zhang ,&nbsp;Jianying Wang ,&nbsp;Yangquan Jiao ,&nbsp;Shiping Yang ,&nbsp;Liqun Wu ,&nbsp;Hui Rong ,&nbsp;Qunzong Luobu","doi":"10.1016/j.gexplo.2025.107927","DOIUrl":"10.1016/j.gexplo.2025.107927","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Black shale-type uranium deposits make important contributions to uranium resources. However, there is controversy over the enrichment mechanism of uranium in black shale. In the Tichong black shale-type uranium deposit from Hubei province, carbonaceous-siliceous slates are the dominant enrichment agent for uranium enrichment. The geochemical compositions and uranium mineralogy of carbonaceous-siliceous slates were investigated by using rock pyrolysis analyzer, X-ray diffractometer (i.e., XRD), inductively coupled plasma mass spectrometry (i.e., ICP-MS), sequential chemical extraction (i.e., SCE) and scanning electron microscope-energy dispersive X-ray spectroscopy (i.e., SEM-EDS). The results show that total organic carbon (TOC) of carbonaceous-siliceous slates is about 4.00 %, and inorganic minerals are composed of quartz, clay mineral, albite and pyrite. Uranium contents of carbonaceous-siliceous slates are from 39 ppm to 174 ppm, element U bears positive relationships with elements V, Ni, Mo, Cu, Zn, and Pb, indicating that uranium enrichment might be related to hydrothermal fluid. Uranium occurrence states are composed of scattered adsorption state (accounting for 52.39 %) and uranium minerals, including that coffinite and (REE-bearing) pitchblende are the primary uranium minerals. Uranium minerals mostly occur around organic matter (OM), intergranular pores of pyrites, kaolinite, corrosion of quartz, monazite, sericite and limonite. Moreover, element U also closely coexists with elements Ni, Zn, REY, Cu, and V by using SEM-EDS. Pyrites coexisting with uranium minerals are unevenly altered by xenotime. Moreover, element U is closely associated with elements Rb and C, implying that uranium might originate from magmatism, and OM might play roles in uranium enrichment. It is also supported by the positive relations among U and TOC, S1 (liquid hydrocarbons), and S2 (thermally cracked hydrocarbons). OM is at the stage of overmaturity with vitrinite reflectance from 3.56 % to 4.27 %, and the maximum rock pyrolysis temperature S2 of about 480 °C. It could produce low molecular organic compounds, which is beneficial for uranium reduction. Besides, sphalerite, chrysocolla, chalcocite, and (Y-) monazite also display that hydrothermal fluid exists. The REY distributions of the carbonaceous-siliceous slates are similar to the Mufushan rock formation rather than the Dahushan rock formation, suggesting the uranium source might be from the Mufushan rock formation. Hence, it is referred that uranium enrichment is comprehensively affected by multiple factors. Under certain geological conditions, uranium from the marine sedimentary environment is pre-enriched in the Lower Cambrian Niutitang Formation (∈&lt;sub&gt;1&lt;/sub&gt;&lt;em&gt;n&lt;/em&gt;), and is adsorbed and precipitated by pyrite and organic matter (i.e., OM). Then, the fracture zones develop, especially the Taoshugang fault by the influences of Indosinian and Yanshanian tectonic movements. The uranium-bearing","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107927"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145466342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A GIS-based intelligent system for geochemical sampling: From fieldwork to data management","authors":"Zhou Yining ,&nbsp;Chang Chan ,&nbsp;Ma Jianguo ,&nbsp;Gao Yanfang ,&nbsp;Tian Mi ,&nbsp;Liu Qingqing ,&nbsp;Wang Xueqiu ,&nbsp;Sun Binbin ,&nbsp;Wang Jing","doi":"10.1016/j.gexplo.2025.107925","DOIUrl":"10.1016/j.gexplo.2025.107925","url":null,"abstract":"<div><div>In traditional geochemical field surveys, particularly in areas with large sample volumes and harsh environmental conditions, the cumbersome transportation of sampling tools and the labor-intensive process of data organization often compromise the quality and accuracy of the survey. The computerization and automation of geochemical field sampling are not only an essential response to contemporary demands but also an inevitable trend driven by advancements in methods and technologies. In this study, we integrate mobile GIS, database technologies, and other tools to streamline the geochemical field sampling. A geochemical field sampling software has been developed on the ArcGIS and Android platforms, incorporating functionalities such as task assignment, field work, and quality control. The system facilitates the computerization and automation of the entire geochemical survey process, simplifying field sampling, reducing the time required for fieldwork, enhancing the efficiency of data processing, improving the quality and accuracy of field data, and advancing the digitalization of geochemical field surveys.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107925"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145466343","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 effect of FeP coupling on arsenic species in sediments during the ice-bound period of lakes in cold regions","authors":"Wenjing Shi ,&nbsp;Xinya Zhao ,&nbsp;Yizhe Liu ,&nbsp;Haoran Xu ,&nbsp;Changwei Lü ,&nbsp;Weiping Li","doi":"10.1016/j.gexplo.2025.107903","DOIUrl":"10.1016/j.gexplo.2025.107903","url":null,"abstract":"<div><div>The redox behavior of iron (Fe) significantly impacts the biogeochemical cycle of arsenic (As), with iron minerals serving as major reservoirs for phosphate (P). The cycle of As inherently associates with its species. However, the effect of Fe<img>P coupling on As species in lake sediments remain largely unknown, especially during the ice-bound period. The novelty of this study is to explore the effect of Fe<img>P coupling on As speciation during an ice-bound period using PLS-SEM model based on As、Fe and P species as well as environmental factors monitoring in sediments. Our findings revealed that Fe<img>P coupling accounts for 95.7 % of As speciation variability, playing a pivotal role in As transformation and partitioning, particularly in labile As pool that contained adsorbed As, moderately labile As pool that closely related to iron species, and pyrite-coprecipitated As. The significant influence of Fe<img>P coupling on the reductive transformation and re-distribution of amorphous and crystalline iron oxides, which in turn affects As adsorption-desorption processes. This interaction subsequently influences the speciation of Fe and P, as well as the release and ecotoxicity of As. Notably, exchangeable phosphorus, iron-bound P fraction and organic P fraction (OP) were identified as the primary P species mediating the effects of Fe<img>P coupling on As speciation. Interesting, OP also play the major role in the effect of Fe<img>P coupling on As species, potentially releasing As adsorbed on crystalline Fe hydroxides during organic matter mineralization. Results emphasize the importance of Fe(hydro)oxides and P in controlling As partitioning, with iron (hydro)oxides being particularly critical in P behavior and its interaction with As. This work provides insights into the cycling of As and the enrichment of P and As in sediment-water systems, providing a reference for environmental monitoring and remediation in sedimentary environments facing dual risks of As pollution and eutrophication.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107903"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Native plant species screening for phytogeochemical exploration in the Zambian Copperbelt","authors":"Pumulo Mukube ,&nbsp;Stephen Syampungani ,&nbsp;Lerato Machogo-Phao ,&nbsp;Murray Hitzman","doi":"10.1016/j.gexplo.2025.107914","DOIUrl":"10.1016/j.gexplo.2025.107914","url":null,"abstract":"<div><div>Trace element analysis of plant tissues can aid mineral exploration for sediment hosted Cu-Co deposits in the Zambian Copperbelt (ZCB). This study was conducted at the Mitumba prospect, an area in the ZCB known to have copper minerals but no historical mining activities, to identify native plant species and their tissues that are most indicative of mineralized zones. Field inventory and ecological analysis identified 22 native plant species from 12 different families, of which Fabaceae (36.4%) was dominant. At species level and based on the coating index, we identified several predominant species, among them, <em>Haumaniastrum katangense</em> (Lamiaceae), <em>Aframomum angustifolium</em> (Zingiberaceae), <em>Brachystegia boehmii</em> (Fabaceae), and <em>Diplorynchus condilocarpon</em> (Apocynaceae). Sampling was undertaken of soils and plant organs above the known mineralized zone and at control points outside of the mineralized area. Most species translocated Cu from the roots to the aboveground biomass as indicated by translocation factors (TF) <span><math><mo>&gt;</mo></math></span> 1 but only three species, namely, <em>Haumaniastrum katangense</em>, <em>Aframomum angustifolium</em> and <em>Diplorynchus condilocarpon</em> can both translocate and bioconcentrate (BCF <span><math><mo>&gt;</mo></math></span> 1) bioavailable Cu from the rhizosphere, making them ideal candidates for phytogeochemical exploration. Only <em>Haumaniastrum katangense</em> and <em>Aframomum angustifolium</em> accumulated Co. Plant roots and leaves demonstrate significant Cu anomalism and show a wider population of anomalous values compared to the soils. Statistical and machine learning techniques both indicate significant relationships between soil Cu concentration and the content of Cu in plant roots and leaves highlighting soil pH, organic matter and clay content as the major physicochemical variables influencing metal bioavailability in soil-plant systems.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107914"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145267257","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":"Critical mineral potential of Indian phosphorites: Evidence of REE enrichment in Ediacaran sediments from the Cuddapah Basin","authors":"Gangula Harshitha ,&nbsp;Ignacio González-Álvarez ,&nbsp;Chakravadhanula Manikyamba ,&nbsp;Joëlle D'Andres ,&nbsp;Jayant Kumar Yadav ,&nbsp;Mrinal Kanti Mukherjee","doi":"10.1016/j.gexplo.2025.107918","DOIUrl":"10.1016/j.gexplo.2025.107918","url":null,"abstract":"<div><div>Phosphorites constitute a potential non-traditional source of rare earth elements (REE), although their resource viability is still being evaluated globally. This study presents the first documentation of REE-enriched sediment-hosted phosphorites from India, and evaluates the processes driving REE mobilization, enrichment and accumulation. The Ediacaran phosphatic beds from the Owk Shale Formation, Kurnool Group of the Cuddapah basin, interbedded with shales and tuffs, were analysed using optical and SEM imaging, whole rock geochemical, in-situ fluorapatite (EPMA, LA-ICP-MS) and Raman spectroscopic analyses. Two apatite phases were identified: primary authigenic (Ap-1), fluorine-poor variety and secondary/reprecipitated REE-enriched fluorapatite (Ap-2). Whole-rock REE + Y concentrations reach up to 1075 ppm, with characteristic middle REE (MREE) enriched patterns, also recorded in fluorapatite, interpreted as a result of diagenetic uptake from sediment porewaters. A strong correlation between REE + Y and redox tracer, Mn indicates initial MREE scavenging by Mn-(oxy)hydroxides and organic matter, followed by MREE release during Mn-reductive dissolution. While diagenesis enhanced REE enrichment, post-diagenetic hydrothermal reworking associated with igneous intrusions diluted REE concentrations through the formation of abundant Fe<img>Mg chlorite (chamosite) and REE and P redistribution within the interbedded shales. Sequence stratigraphic analysis suggests that these pristine phosphorites were deposited during marine regression, without subsequent reworking, preventing the formation of high grade phosphorite deposit, emphasizing the role of sea-level changes in controlling phosphogenesis, formation of a phosphorite giant and thus, REE enrichment. A temporal analysis of global phosphorites further reveals that progressive seawater influence, modulated by biogeochemical recycling and episodic weathering, together controlled the REE enrichment patterns in phosphorites through Earth's history.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107918"},"PeriodicalIF":3.3,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145267259","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}