Journal of Geochemical Exploration最新文献

{"title":"Multistage ore-forming processes in the genesis of the fluorite-baryte Merguechoum ore deposit (Moroccan eastern Meseta) in relation to Pangea rifting","authors":"Larbi Rddad ,&nbsp;Mohammed Cherai ,&nbsp;Benjamin F. Walter ,&nbsp;Fouad Talbi","doi":"10.1016/j.gexplo.2025.107766","DOIUrl":"10.1016/j.gexplo.2025.107766","url":null,"abstract":"<div><div>This study investigates the origin of the hydrothermal fluorite-baryte veins at Merguechoum, hosted in Late Hercynian granite beneath the Paleozoic-Triassic unconformity in the Moroccan eastern Meseta. The ore comprises two stages: fluorite 1and baryte 1 precipitated from a hot (156 C°–180 °C), moderate- to- high salinity fluid (13.5 to 39.4 wt% NaCl+CaCl₂), followed by the deposition of fluorite 2 and baryte 2 from a cooler (100 °C–135 °C), lower salinity fluid (22.2–25.4 wt% NaCl). Crush-leach data and rare earth element signatures indicates that the ore-forming fluids were initially evaporated seawater, which infiltrated the Paleozoic basement via NNE-NE trending faults and fractures during the Permian-Triassic rifting and evolved into F- and Ba-rich brines through fluid-rock interactions.</div><div>During the Triassic-Jurassic extension, a high geothermal gradient triggered localized convection, circulating basement-derived metalliferous fluids toward shallower zones along reactivated faults and fractures. The mixing of these basement-derived fluids with less saline, calcium- and sulfate-rich fluids stored in open spaces causing the deposition of fluorite and baryte. This study highlights the role of rift-related convection and fault-controlled fluid pathways in ore genesis, offering insights for exploring similar unconformity-related ore deposits in extensional settings.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"275 ","pages":"Article 107766"},"PeriodicalIF":3.4,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143791735","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":"Zircon UPb geochronology and geochemistry of ore-bearing rhyolites in the Fuxingtun Ag–Pb–Zn deposit, Great Xing'an Range, NE China: Constraints on petrogenesis and tectonic setting","authors":"Shanming Zhang ,&nbsp;Xiangguo Guo ,&nbsp;Haijun Li ,&nbsp;Genhou Wang ,&nbsp;Lixin Fan ,&nbsp;Erhong Hu ,&nbsp;Fukang Fang ,&nbsp;Junyi Zi ,&nbsp;Minghao Wang","doi":"10.1016/j.gexplo.2025.107765","DOIUrl":"10.1016/j.gexplo.2025.107765","url":null,"abstract":"<div><div>The Fuxingtun Ag–Pb–Zn deposit, located in the Right Front Banner of Horqin, Inner Mongolia, is a superlarge Ag–Pb–Zn deposit discovered in 2019 in the southern-central Great Xing'an Range. In this work, LA–ICP–MS zircon U<img>Pb, petrogeochemical and zircon Hf isotope data were obtained from ore-bearing rhyolites in the Manketouebo Formation in the Fuxingtun mining area. The zircon U<img>Pb ages of the eight rhyolite samples range from 140.1 Ma to 133 Ma, corresponding to the Early Cretaceous. The geochemical characteristics reveal that the rhyolites belong to the high-k calc-alkaline peraluminous series and are characterized by high silicon, alkali and aluminum contents and low iron, magnesium and calcium contents. The total amount of rare earth elements (REEs) is low, and the light and heavy REEs exhibit a certain degree of fractionation, with a moderate negative Eu anomaly. The enrichment of Rb, Th, U, K, Zr, and Hf and the depletion of Ba, Sr, P, Ti, Nb, and Ta correspond to the geochemical characteristics of I-type rhyolites. The source of the rhyolitic magma may have been the remelting of Paleozoic juvenile crust in a postcollisional extensional geotectonic environment.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"275 ","pages":"Article 107765"},"PeriodicalIF":3.4,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143768260","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":"Isotopic study (UPb, SmNd, and PbPb) of rocks and auriferous mineralizations from the Volta Grande do Xingu deposits, Bacajá Domain, Amazonian craton","authors":"Moacir José Buenano Macambira ,&nbsp;Stephane Amireault","doi":"10.1016/j.gexplo.2025.107767","DOIUrl":"10.1016/j.gexplo.2025.107767","url":null,"abstract":"<div><div>The Três Palmeiras volcano-sedimentary sequence in the northern Bacajá Domain, southeastern of the Amazonian craton, hosts gold occurrences and deposits, classified as orogenic type. In the Volta Grande do Xingu area, samples of outcrops and drill holes allowed us to identify three main lithological units: (1) a sequence of mafic metavolcanic rocks, represented by metabasalt, mafic schist and restricted metagabbro bodies; (2) a sequence of intermediate metavolcanic rocks, represented by porphyritic meta-andesite and metavolcanoclastic rocks; both sequences are cut by (3) quartz-diorite and granodiorite bodies, correlated with the Oca Granodiorite, previously dated at 2160 ± 3 Ma. Gold mineralization occurs as microinclusions in pyrite, chalcopyrite and/or quartz. Dating results indicate that meta-andesite and metavolcanoclastic rocks are, respectively, 2417 ± 4 Ma and 2410 ± 7 Ma by Pb-evaporation in zircon method, whereas the metavolcanoclastic rock was dated at 2415 ± 50 Ma by the U<img>Pb (LA-ICP-MS) zircon method, age corroborated by a Sm<img>Nd whole-rock isochron of metabasalt and meta-andesite samples at 2465 ± 17 Ma. These ages denote the presence of Siderian volcanic rocks, predating those previously recorded in the Bacajá Domain (2359 ± 2 Ma). Pyrite (leachates) hosted in meta-andesite and quartz-diorite was dated at 2353 ± 43 Ma and 2146 ± 19 Ma, respectively, according to Pb-isotopic data, whereas gold particles yielded ages between 2.40 and 2.18 Ga by Pb-evaporation. The ages for pyrite and gold particles contained in dioritic suite samples imply at least two generations of pyrite, suggesting the mineralization likely relates to the Rhyacian granitogenesis recorded in the Bacajá Domain. Pb whole-rock isotopic analyses of meta-andesite and metabasalt samples indicate an age of 2403 ± 92 Ma, with high MSWD and error, but consistent with ages obtained by other methods for this sequence. The Nd-T_DM of 2.49 to 2.39 Ga and εNd_(t) (+2.03 to +3.63) indicate essentially a juvenile mantle origin for the metavolcanic rocks. The integration of field, mineralogical, isotopic, and geochronological data suggest that the mineralization event was most likely connected to metamorphic-deformational processes and granitoid intrusion associated with the Transamazonian cycle, complemented by inherited components from the Três Palmeiras sequence.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"274 ","pages":"Article 107767"},"PeriodicalIF":3.4,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747792","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":"Vanadium and other critical elements in North Gondwana Silurian black shales: The SE Sardinia (Italy) case","authors":"Maria Boni ,&nbsp;Nicola Mondillo ,&nbsp;Licia Santoro ,&nbsp;Giuseppina Balassone","doi":"10.1016/j.gexplo.2025.107760","DOIUrl":"10.1016/j.gexplo.2025.107760","url":null,"abstract":"<div><div>Vanadium currently represents a critical metal for the global economy, due to its increasing application in low CO₂-emission technologies such as vanadium redox flow batteries. Black shale-hosted deposits cover about 80 % of the potential global V resources, although only &lt;2 % of them is economic. During Silurian, significant black shale successions were deposited under strong anoxic conditions in the North Gondwana. This study aims at investigating the deportment of V in association with other trace elements in Silurian black shales of SE Sardinia (Italy), for understanding the nature of the depositional environment and the metallogenetic potential of these rocks at regional scale. Sardinian black shales have variable V amounts, ranging from hundreds to thousands ppm and organic carbon contents from 0.7 to 10.1 wt%. These values, together with observed Th/U, Ni/Co, V/Cr ratios indicate that the initial sedimentary environment was clearly anoxic. The positive correlation between V and total organic carbon indicates that organic matter retains most of V. Local V concentrations in rutile and illite may derive from metal remobilization during diagenesis and low-grade metamorphism. Compared to other coeval Silurian successions of North Gondwana, Sardinian black shales have anomalous values of Sb, Ba, Se, Mo, As, V, and Ag, this suggesting that, in the frame of a peculiar sedimentary process occurred in a similar way at the global scale, distinct controls existed in the various basins.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"275 ","pages":"Article 107760"},"PeriodicalIF":3.4,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916843","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 genesis of the largest Phanerozoic Mn deposits in the Paratethys: Inferences from 40Ar/39Ar and U/Pb ages in NE Bulgaria and NW Turkey","authors":"Peter Marchev ,&nbsp;Raya Raicheva ,&nbsp;Rositsa Ivanova ,&nbsp;Brian Jicha ,&nbsp;Irena Peytcheva","doi":"10.1016/j.gexplo.2025.107764","DOIUrl":"10.1016/j.gexplo.2025.107764","url":null,"abstract":"<div><div>The early Oligocene manganese (Mn) deposits around the Black Sea represent the second largest accumulation of Mn in the world (600 × 10⁶ tons). Various hypotheses have been offered to explain the genesis of these deposits. However, very few can explain all the major characteristics of the Mn deposits, in particular: 1) their contemporaneity and short depositional time; 2) vast covered territory; 3) the source of the great volume of metals (Mn, Fe, P and Si) and 4) the mechanisms of metal precipitation and concentration. Most of the former hypotheses assume the source for the Mn is the local crystalline rocks, ignoring or misinterpreting the involvement of volcanic material. Here, we propose a volcanic-derived model sourced from a 33.2 ± 0.1 Ma supereruption from the Rhodope Massif, Bulgaria, which covers large areas of the Central, Southern and Eastern Europe with ash. The model is based on radioisotopic age data of the volcanic material from two of the Mn deposits, located on the western shore of the Black Sea. Our model implies that the Mn (along with other metals, Fe, P, Si) have been transported by the large amount of erupted dust and aerosols with absorbed soluble fluoride, chloride, and sulfate metals. The fast dissolution of gases and aerosols into restricted or shallow Paratethys sea basins produced anoxic-euxinic conditions, which in turn promoted high concentration and deposition of the Mn. Final structuring of the zonation of the deposits was the result of the restoration of the normal sea redox-stratification after the end of the volcanic influence.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"274 ","pages":"Article 107764"},"PeriodicalIF":3.4,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724928","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":"Geostatistical modelling of mine tailings and comparative analysis of sampling methodologies: A case study of the Otanmäki ilmenite tailings storage facility project","authors":"Tuomas Leskelä ,&nbsp;Janne Hokka ,&nbsp;Teemu Karlsson","doi":"10.1016/j.gexplo.2025.107759","DOIUrl":"10.1016/j.gexplo.2025.107759","url":null,"abstract":"<div><div>Increasing concerns about the availability of Critical Raw Materials (CRMs) have shifted focus to extractive waste sites as potential sources for secondary resources. Resource assessment requires robust investigation and resource definition, necessitating representative sampling and use of an appropriate modelling method. In this study, spatial sampling sensitivity was tested at the Otanmäki tailings storage facility (TSF) by conducting multiple models at different scales, utilizing both previously collected and new data. Additionally, three tailings sampling methodologies were evaluated to ensure sample representativity and minimize contamination: a tube sampler with a valve, a flow-through blade, and an auger drill.</div><div>Results indicated that both the auger drill and the tube sampler perform well and provide similar results under low moisture conditions. However, the tube sampler was estimated to be more accurate in varying conditions, despite it having a smaller sample volume and being more time-consuming to use. According to the modelling results, there were minimal changes in grade and tonnage when increasing sampling density or changes in model scale. Thus, the existing resource estimation from the Otanmäki TSF that was based on a 100 × 100 m grid could be considered as having a high-confidence in relation to the G-category in the United Nations Framework Classification for Resources (UNFC) system with effective investigation of tailings sites requires a tailored approach considering factors such as ore deposit type, mineralization style, and information on ore processing and tailings disposal practices. This work provides insights into tailings resource modelling, estimation confidence, sample representativity, and optimal sampling strategies, aiding in the resource classification of tailings sites.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"274 ","pages":"Article 107759"},"PeriodicalIF":3.4,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of uranium exposure in drinking water sources across Ganderbal, Jammu and Kashmir: A biokinetic modelling approach","authors":"Mehak Mohi u Din ,&nbsp;Salik Nazir ,&nbsp;Shakeel Simnani ,&nbsp;Mohammad Rafiq Chakan ,&nbsp;Sajad Masood ,&nbsp;Supriya Rani ,&nbsp;Amit Kumar Singla","doi":"10.1016/j.gexplo.2025.107763","DOIUrl":"10.1016/j.gexplo.2025.107763","url":null,"abstract":"<div><div>In response to concerns regarding potential health risks like nephritis, potential alterations to bone structure, and carcinogenic effects associated with uranium contamination in drinking water, a comprehensive study was conducted across Ganderbal, Jammu &amp; Kashmir to address concerns about potential health hazards associated with uranium contamination in drinking water. The study quantified uranium concentrations in 153 water samples collected from various sources. The uranium concentrations ranged from 0.51 to 6.83 μg L⁻¹, with an average concentration of 1.15 μg L⁻¹. The age and gender-specific annual effective ingestion doses were calculated along with carcinogenic and non-carcinogenic health risks. The study used Li's hair compartment model to analyze the biokinetics and toxic effects of uranium within the adult human body, particularly focusing on distribution, target organs for retention, and uranium excretion over a 60-year exposure period.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"274 ","pages":"Article 107763"},"PeriodicalIF":3.4,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704617","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":"Health risks due to geogenic and anthropogenic influences on groundwater quality in Southern India's hard rock terrain","authors":"B. Preethi ,&nbsp;T. Subramani ,&nbsp;R. Saravanan ,&nbsp;P. Gopinathan ,&nbsp;Zaixing Huang ,&nbsp;Brajesh Kumar","doi":"10.1016/j.gexplo.2025.107762","DOIUrl":"10.1016/j.gexplo.2025.107762","url":null,"abstract":"<div><div>Groundwater contamination poses a critical public health risk in Raichur district, Karnataka, India where groundwater is a vital resource for drinking and agriculture. A total of 54 groundwater samples were analyzed, revealing that 68.5 % exceeded the WHO's nitrate limit of 45 mg/L, with concentrations ranging from 2.2 mg/L to 830 mg/L, and 44.4 % surpassed the fluoride threshold of 1.5 mg/L, with levels ranging from 0.06 mg/L to 7.18 mg/L. A comprehensive Health Risk Assessment (HRA) identified infants, children, pregnant women, and lactating mothers as vulnerable populations, with Hazard Quotient (HQ) values reaching 67.25 for nitrate and 23.33 for fluoride. These elevated levels indicate significant risks, including methemoglobinemia and skeletal fluorosis. Geospatial analysis mapped contamination hotspots in the northern and central regions, highlighting the interplay of anthropogenic activities like excessive fertilizer use, inadequate waste management, and natural geological factors. Recommendations include precision farming, improved waste management, and community-level remediation systems, such as defluoridation and denitrification technologies. Artificial groundwater recharge and regulatory interventions are critical to maintaining water quality. By integrating geospatial tools and HRA, this study provides a replicable framework for addressing groundwater contamination and ensuring sustainable water resource management, particularly in regions with similar hydrogeological challenges.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"274 ","pages":"Article 107762"},"PeriodicalIF":3.4,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724927","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":"Gallium isotope variation in the Anning carbonate-hosted clay-type lithium deposit, Central Yunnan Province, China: Implications for the Li enrichment mechanism","authors":"Yuxu Zhang ,&nbsp;Hanjie Wen ,&nbsp;Pan Qiao ,&nbsp;Chuanwei Zhu ,&nbsp;Haifeng Fan ,&nbsp;Shengjiang Du","doi":"10.1016/j.gexplo.2025.107761","DOIUrl":"10.1016/j.gexplo.2025.107761","url":null,"abstract":"<div><div>Lithium deposits are mainly divided into three types: pegmatite-type, brine-type, and clay-type. Compared with traditional pegmatite-type and brine-type lithium deposits, clay-type lithium deposits have attracted increasing attention due to their large scale and stable distribution. We investigated the Ga isotope composition of three drill cores (ZK401, ZK406, and ZK408) in the Anning carbonate-hosted clay-type lithium deposit in central Yunnan Province, China. The δ⁷¹Ga_NIST994 values and Ga contents of the claystone sample from drill core ZK401 are 0.97–1.33 ‰ and 1840–4070 ppm, respectively, with a negative correlation between the Ga content and δ⁷¹Ga_NIST994 value. For drill core ZK406, the δ⁷¹Ga_NIST994 values and Ga contents of the claystone sample are 1.26–1.48 ‰ and 29.8–5950 ppm, respectively, with a positive correlation between the Ga content and δ⁷¹Ga_NIST994 values. For drill core ZK408, the δ⁷¹Ga_NIST994 values and Ga contents of the claystone sample are 1.04–1.22 ‰ and 2.70–4990 ppm, respectively, with no significant correlation observed. Previous studies have suggested that smectite is the precursor of Li-bearing minerals. However, the X-ray diffraction analysis showed that the clay minerals in the three drill cores were primarily illite, clinochlore, kaolinite, and diaspore/boehmite, indicating that these clay minerals underwent mutual transformation during the diagenesis process. The Ga isotope data suggested that during the mineral conversion process, solid-state transformation was the dominant reaction mechanism of the strata in drill core ZK401, while dissolution-crystallization was the dominant reaction mechanism of the strata in drill core ZK406. The cancellation of both mechanisms' effects may explain the lack of a clear correlation between the Ga contents and δ⁷¹Ga_NIST994 values in drill core ZK408. Lithium is more likely to be preserved via the solid-state transformation mechanism during the conversion of the parent mineral (such as smectite) into daughter minerals (such as illite and clinochlore), while the dissolution-crystallization mechanism is more likely to lead to the redistribution of Li.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"274 ","pages":"Article 107761"},"PeriodicalIF":3.4,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143703917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magmatic fertility of porphyry Ag-Pb-Zn deposits revealed by zircon and apatite chemistry: An example of the Lengshuikeng Ag-Pb-Zn deposit in South China","authors":"Xinlu Hu ,&nbsp;Yongpeng Ouyang ,&nbsp;Runling Zeng ,&nbsp;Jinwei Li ,&nbsp;Libo Li ,&nbsp;Yi Shang","doi":"10.1016/j.gexplo.2025.107757","DOIUrl":"10.1016/j.gexplo.2025.107757","url":null,"abstract":"<div><div>Porphyry Ag-Pb-Zn deposits are globally rare, with limited understanding of their magma origins, compositions, and physical-chemical conditions. To address this, we conducted a comprehensive investigation of the chemical and Sr<img>Nd isotopic composition of apatites, along with the U<img>Pb dating, trace element analysis, and Lu<img>Hf isotopic analysis of zircons from the igneous rocks at the giant Lengshuikeng Ag-Pb-Zn deposit in South China. The igneous rocks at Lengshuikeng are primarily composed of granite porphyry, K-feldspar granite porphyry, and volcanic rocks of the Daguding and Ehuling Formations. LA-ICP-MS zircon U<img>Pb dating yielded ages 159.7 ± 2.0 Ma for the rhyolitic tuff of the Ehuling Formation, 159.0 ± 2.3 Ma for the granite porphyry, and 152.5 ± 1.9 Ma for the K-feldspar granite porphyry. Combined with previously published age data, we propose that the Ehuling Formation experienced at least two eruption stages: the first at ca. 160 Ma (S1), and the second at 147–138 Ma (S2). The K-feldspar granite porphyry intruded in two stages, dated at 152.5 Ma (S1) and 138–136.6 Ma (S2). The evolutionary sequence of igneous rocks is inferred as: Daguding Formation → Ehuling Formation (S1) → granite porphyry → K-feldspar granite porphyry (S1) → Ehuling Formation (S2) → K-feldspar granite porphyry (S2).</div><div>Zircons from these rocks show ε_Hf(t) values of −13 to −8.5. The (⁸⁷Sr/⁸⁶Sr)_i ratios and ε_Nd(t) values of apatite vary from 0.7075 to 0.7171 and from −12.7 to −4.5, respectively. Similar Sr-Nd-Hf isotopic compositions indicate a common source for these igneous rocks, all derived from partial melting of Paleo- to Mesoproterozoic continental crust. Comparable zircon Ce⁴⁺/Ce³⁺ and Ce/Ce^⁎ ratios and apatite Mn-Ce-Eu-Ga contents indicate similar oxidation states and water contents in the parental magmas. Compared to regional porphyry Cu deposits, the parental magma of the Lengshuikeng Ag-Pb-Zn deposit has lower oxygen fugacity and S concentration. Apatites from the ore-forming granite porphyry have significantly higher concentrations of Cu, Zn and Cl than those from other igneous rocks. Our study suggests that the metal and Cl⁻ contents within parental magma, rather than the oxidation state and water content, are key factors controlling porphyry Ag-Pb-Zn mineralization. Apatite Cu, Zn and Cl contents can serve as valuable indicators of magma fertility in porphyry Ag-Pb-Zn deposits.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"274 ","pages":"Article 107757"},"PeriodicalIF":3.4,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143696759","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}