Journal of Geochemical Exploration最新文献

{"title":"Mississippi Valley-type mineralization in the Jurassic Smackover Formation, Gulf Coast Basin, USA: Controls on the origin of Zn-Pb-Ag systems in deep sedimentary basins","authors":"J. Richard Kyle, András Fall, Jean-Philippe Nicot","doi":"10.1016/j.gexplo.2025.107807","DOIUrl":"10.1016/j.gexplo.2025.107807","url":null,"abstract":"<div><div>The northern margin of the central Gulf Coast Basin provides an opportunity to examine Mississippi Valley-type (MVT) Zn-Pb-Ag sulfide mineralization at depths of 2.5+ km and under interpreted formative conditions. This geologically young province is a significant petroleum producer, including from the Upper Jurassic Smackover Formation. The Smackover in this area contains circa 100 °C Na-Ca-Cl brines with elevated H<sub>2</sub>S, Br, and Li concentrations. The Smackover intercepted in the No. 1 Teague well contains Zn-Pb-Ag sulfides throughout the entire cored interval from 2549 to 2586 m with the highest concentrations in ooid grainstones in the upper 10 m. Stylolites are locally dilated and contain euhedral sulfide crystals, indicating that at least some sulfide mineralization post-dates maximum burial and compaction. Ag content of the high Zn-Pb zones generally is low (<1 to 10 ppm), but a 1.5-m acanthite-bearing interval averages 545 ppm.</div><div>Fluid inclusions (FI) were studied in late-stage calcite and sphalerite in the No. 1 Teague core. Homogenization temperatures (T<sub>h</sub>) for aqueous fluid inclusions in sphalerite range between 93 and 113 °C, whereas T<sub>h</sub> for FI in calcite are between 72 and 126 °C. Oil inclusions in late-stage calcite homogenize between 82° and 105 °C. Final ice melting temperatures of FI in sphalerite range from -24.9° and -26.5 °C, corresponding to salinities of 25.5 to 26.5 wt% NaCl equivalent. Final melting temperature of FI in calcite range from -26.0 to -23.2 °C for water ice and -5.8 to -7.8 °C for hydrohalite, corresponding to NaCl and CaCl<sub>2</sub> of concentrations ranging from 15.2 to 20.3 wt% NaCl and 5.6 to 11.7 wt% CaCl<sub>2</sub>, respectively. The first melting temperatures for FI ranging ∼ -50 to -60 °C are comparable to the eutectic (-52 °C) for the NaCl-CaCl<sub>2</sub>-H<sub>2</sub>O system, and fluid salinities ∼26 wt% TDS are compatible with current Smackover formation waters. δ<sup>34</sup>S<sub>CDT</sub> of Smackover sulfides ranges from 8.9 to 16.6 ‰, and Smackover H<sub>2</sub>S has a similar δ<sup>34</sup>S<sub>CDT</sub> range (18 ± 2 ‰) as Late Jurassic seawater sulfate, suggesting that thermochemical reduction of reservoir sulfate was the source of H<sub>2</sub>S for sulfide precipitation. A complex history of local crustal Pb evolution is indicated by the radiogenic Pb isotope characteristics of galena. These relationships support the introduction of a metal-bearing brine into a H<sub>2</sub>S-rich Smackover reservoir resulted in local Zn-Pb-Ag sulfide precipitation. Burial history plots for the Smackover in southern Arkansas indicate that maximum burial occurred during the early Paleogene. Smackover MVT sulfides not only occur at depths >2.5 km, but sulfide minerals within dilated stylolites indicate that mineralization also took place at these depths. Smackover Zn-Pb-Ag sulfide concentrations represent one of the youngest and deepest known examples ","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"277 ","pages":"Article 107807"},"PeriodicalIF":3.4,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144166587","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":"Multivariate analysis and stochastic risk assessment of metal(oid) contamination in playground soils: A case study from Recife, Brazil","authors":"Fernando Bruno Vieira da Silva ,&nbsp;Luiz Henrique Vieira Lima ,&nbsp;Alfredo Montero Álvarez ,&nbsp;Paula Renata Muniz Araújo ,&nbsp;Lucas José Souza de Mello ,&nbsp;Taciana da Silva Paraizo ,&nbsp;Clístenes Williams Araújo do Nascimento","doi":"10.1016/j.gexplo.2025.107799","DOIUrl":"10.1016/j.gexplo.2025.107799","url":null,"abstract":"<div><div>This study examined concentrations, sources, and risks of eighteen metal(<em>oid</em>)s (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Se, Sr, Ti, V, and Zn) in playground topsoil within the second-largest urban–industrial center of northeastern Brazil. Source apportionment was conducted using absolute principal component scores combined with multiple linear regression, and probabilistic risks for children were estimated via Monte Carlo simulations. Metal(oid) concentrations exceeded background values, with 90 % of soils showing moderate to very high contamination. Five major sources were identified—geogenic, building-related, industrial, vehicle exhaust, and non-vehicle exhaust—each contributing to metal(oid) accumulation at varying degrees. Chromium, arsenic, lead, barium, and vanadium posed the greatest health concerns, with industries and construction sites being the primary anthropogenic contributors. Risk assessment revealed elevated non-cancer risks for 68 % of scenarios and cancer risks exceeding safety thresholds in 98.4 % of cases, underscoring the urgent need for pollution control measures to reduce children's exposure. The integration of APCS-MLR for source apportionment and Monte Carlo simulations for probabilistic risk assessment provides a transferable framework for assessing metal(oid) contamination and health risks in playground soils with different environments. While specific contamination sources may vary across cities, the study's methodological approach allows for tailored risk assessments in diverse urban contexts. Policymakers can use these insights to establish targeted mitigation strategies, stricter industrial regulations, and soil quality monitoring programs to reduce children's exposure to metal(<em>oid</em>)s.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"277 ","pages":"Article 107799"},"PeriodicalIF":3.4,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144116173","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":"LA-ICP-MS element analysis of Cu–Co sulfides from the Central African Copperbelt: implications for the mobility and redistribution of metals","authors":"Qiuping Liu ,&nbsp;Pascal Mambwe ,&nbsp;Philippe Muchez","doi":"10.1016/j.gexplo.2025.107800","DOIUrl":"10.1016/j.gexplo.2025.107800","url":null,"abstract":"<div><div>This study involves the geochemical analysis of sulfides from the Tenke Fungurume mining district (TFMD), Kamoto and Luiswishi deposits in the Congolese Copperbelt and the Nkana deposit in the Zambian Copperbelt. The objective is to better understand the ore-forming processes and the distribution of metals within these deposits. The trace element contents of carrollite and chalcopyrite suggest that ore fluids varied in metal contents across different locations within the Central African Copperbelt (CACB). This variability likely reflects localized ore fluid sources and separated mineralizing systems for each deposit, rather than a single, homogenized basin-wide fluid reservoir. Carrollite displays a trend of decreasing Co/Cu ratios from the central part of the Congolese Copperbelt, i.e. from Luiswishi through TFMD to Kamoto in the western part. Within each deposit, the trace element content of carrollite exhibits minimal variations across different paragenetic phases, indicating the re-equilibration of the diagenetic sulfides during the subsequent mineralization phases. This is further corroborated by the trace element composition of chalcopyrite, which exhibits consistent patterns across the main mineralization phases. However, at TFMD, chalcopyrite from the <em>syn</em>-folding vein differs notably from that in the pre-folding and post-folding veins, suggesting the presence of separate mineralizing phases within a single deposit. The exceptionally high germanium (Ge) content (av. = 273 ppm, up to 772 ppm) in chalcopyrite from the post-folding stage at TFMD may be linked to a significant post-orogenic mineralization event that led to the formation of the Cu-Zn-Pb (Ge, Ag) Kipushi deposit in the Congolese Copperbelt.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"277 ","pages":"Article 107800"},"PeriodicalIF":3.4,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144083610","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":"Early Permian granitic magmatism and mineralization in the Zhongbao W deposit, East Tianshan, NW China: Constraints from geochronology and whole-rock geochemistry","authors":"Kai Weng ,&nbsp;Bo Chen ,&nbsp;Zhongping Ma ,&nbsp;Yongwei Gao ,&nbsp;Xiaojian Zhao ,&nbsp;Wenbin Kang ,&nbsp;Kai Cao","doi":"10.1016/j.gexplo.2025.107798","DOIUrl":"10.1016/j.gexplo.2025.107798","url":null,"abstract":"<div><div>Numerous Early Permian tungsten (W) deposits, associated with granitic formations, have been identified in the southwest of the Central Tianshan terrane, East Tianshan, NW China. However, the relationship between granitic magma, mineralization, and tectonic setting remains debated. The Zhongbao W deposit is spatially associated with mica monzogranite in the Kumish area. Zircon and monazite U<img>Pb dating of the granite yielded ages of 304–298 Ma, consistent with the ⁴⁰Ar/³⁹Ar age of 296 Ma from muscovite within the greisen orebodies, indicating a genetic link between the Zhongbao pluton and W mineralization. Geochemically, the granite is highly fractionated I-type, with high SiO₂ and K₂O, low Na₂O/K₂O, and distinct trace element characteristics (e.g., wide 10,000*Ga/Al = 2.24–2.99, Zr + Nb + Ce + Y &lt; 350 ppm), with a negative correlation exists between P₂O₅ and SiO₂. Isotopic data (ε_Nd(t) = −6.77 to −3.15; ε_Hf(t) = −0.9 to +3.3; (²⁰⁷Pb/²⁰⁴Pb)_<em>i</em> = 15.581 to 15.714; δ¹⁸O_V-SMOW = 7.61 to 14.17 ‰) suggest an ancient crustal source. Low zircon Ce⁴⁺/Ce³⁺ (9.8–164) and δEu (0.10–0.57) ratios imply low oxygen fugacity, while low K/Rb and high Rb/Sr ratios indicate significant fractional crystallization, crucial for transportation and concentration of ore-forming elements. The I-type granite characteristics of the Zhongbao pluton suggest its formation during a post-collisional tectonic setting. Furthermore, the Early Permian W deposits, including Zhongbao W deposit, constitute a NW-trending mineralization belt situated between the Central Tianshan terrane and the Tarim Craton. Additionally, the post-collisional extension setting has been identified along the southwestern margin of the Central Tianshan terrane during the Early Permian. We propose that the formation of Zhongbao W deposit be attributed to the local closure of the southern Tianshan ocean in the Early Permian.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"276 ","pages":"Article 107798"},"PeriodicalIF":3.4,"publicationDate":"2025-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068800","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":"Geochronology, petrology and Sr-Nd-Hf isotope geochemistry of the newly discovered Narenguole magmatic Ni-Cu sulfide prospect, Eastern Kunlun Orogenic Belt, Qinghai Province, NW China","authors":"XingSen Chen ,&nbsp;FengYue Sun ,&nbsp;Jianfeng Qiao ,&nbsp;Yun Chai ,&nbsp;Yajing Zhang ,&nbsp;Li Wang ,&nbsp;Chao Hui ,&nbsp;Shahzad Bakht ,&nbsp;Tao Wang","doi":"10.1016/j.gexplo.2025.107794","DOIUrl":"10.1016/j.gexplo.2025.107794","url":null,"abstract":"<div><div>Since the discovery of the giant Xiarihamu magmatic Ni-Cu-Co sulfide deposit in the Eastern Kunlun orogenic belt (EKOB) in 2011, more and more mafic-ultramafic intrusions containing sulfide mineralization has been found in this area, indicating that the magmatic sulfide deposit has great exploration potential. Recently, magmatic sulfide mineralization of economic significance has been found in the I intrusion of the Narenguole (NRGL) magmatic sulfide prospect in the eastern segment of EKOB, with Cu grade of 0.59 wt% and Ni grade of 2.07 wt%, showing great prospecting potential.</div><div>However, the age, the nature of source area and the geodynamic background of its formation have not been studied. In this paper, the petrography, geochemistry, chronology and Sr-Nd-Hf isotopic composition of NRGL I intrusion are reported for the first time. The petrographic observations show that the lithology of the NRGL I intrusion is olivine pyroxenite, which is mainly composed of olivine and orthopyroxene, with a small amount of hornblende and phlogopite. The ore minerals are mainly composed of disseminated to net-textured pyrrhotite, pentlandite and chalcopyrite. Zircon laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb dating is 258.7 ± 1.4 Ma, suggesting that the intrusion was formed in the Late Permian. The ultramafic rocks are enriched in light rare earth elements (LREE) and large-ion lithophile elements (LILE), depleted in high-field strength elements (HFSE), indicative of arc geochemical affinities. They have low Ce/Pb (10.18–17.30) and Nb/Th (2.02–3.27) ratios, indicating a certain degree of crustal contamination. The ε_Hf(t) values of zircon range from −1.38 to +1.20, with an average value of −0.17. The initial ⁸⁷Sr/⁸⁶Sr ratios and ε_Nd(t) values of the whole rocks range from 0.707633 to 0.708737 and from −3.9 to −4.3, respectively, which are close to the isotopic composition of the enriched mantle (EMII). It is also similar to the contemporary mafic dikes and mafic microgranular enclaves (MMEs) in EKOB. These data suggest that the parental magmas of the NRGL I intrusion has undergone a certain degree of crustal contamination and originated from an enriched mantle source that had been metasomatized by slab-derived fluids. Our results, combined with regional geological constraints, indicate that NRGL I intrusion formed in an Andean-type active continental margin environment. More importantly, a Late Permian magmatic sulfide mineralization event occurred in the EKOB.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"276 ","pages":"Article 107794"},"PeriodicalIF":3.4,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143927763","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 UPb chronology of detrital zircon in the Neogene Shizigou Formation, Qigequan area, western Qaidam Basin: Implications for tectonics, paleoclimate, and uranium sources","authors":"Chao Zhang ,&nbsp;Shanbo Wang ,&nbsp;Yinhang Cheng ,&nbsp;Jiarun Tu ,&nbsp;Reng’’an Yu ,&nbsp;Ping Feng ,&nbsp;Zhifeng Zuo ,&nbsp;Yongliang Zang","doi":"10.1016/j.gexplo.2025.107797","DOIUrl":"10.1016/j.gexplo.2025.107797","url":null,"abstract":"<div><div>Uranium deposits have been recently discovered in the Qigequan mining area, located at the transition zone between the Cenozoic strata of the Qaidam Basin and Altyn Tagh orogenic belt. This study presents detailed petrogeochemical and U<img>Pb detrital zircon geochronological analyses of sandstones from the Cenozoic Shizigou Formation within this region. This study aims to clarify the provenance and explore the interrelations among stratigraphy, tectonics, paleoclimate, hydrocarbons, and the genesis of sandstone-type uranium deposits. Detrital zircon ages are clustered in two periods: 343–542 and 200–285 Ma, corresponding with rock units in the Altyn Tagh and East Kunlun orogenic belts. Comparative analysis of zircon age spectra reveals the Altyn Tagh and Qimantag mountains as the primary source areas, with the Altyn Tagh being the most significant. Major, trace, and rare earth element analyses suggest relatively stable tectonic conditions and an oxidizing sedimentary environment during the deposition of the Lower Shizigou Formation, with a high concentration of reducing media. Low chemical weathering in the source region, coupled with the angularity of detrital zircon grains, indicates rapid uplift under arid climatic conditions, leading to the swift transport and deposition of unweathered clastic material. Oxygenated surface waters transported uranium from erosion areas into the structural cavities of the Lower Shizigou Formation, depositing it in oxygen-rich sedimentary layers. Subsequently, ascending hydrocarbon and brine-rich fluids intruded along structural fractures, leaching uranium from the strata and creating a favorable reducing environment for uranium mineralization. The Cenozoic subduction and collision of the Indian and Eurasian plates triggered the rapid uplift of the Altyn Tagh, driving climatic changes that generated the necessary redox conditions for uranium ore formation. These findings provide valuable insights into the sedimentary processes, tectonic evolution, and exploration of sandstone-type uranium deposits.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"277 ","pages":"Article 107797"},"PeriodicalIF":3.4,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144088995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genesis of Zhutian ion-adsorption-type rare earth deposit in South China: Constraints from whole-rock and zircon, apatite, monazite geochemistry, and geochronology","authors":"Ruilin Wang ,&nbsp;Huan Li ,&nbsp;Jianjun Liu ,&nbsp;Yasin Rahim ,&nbsp;Yue Hou","doi":"10.1016/j.gexplo.2025.107795","DOIUrl":"10.1016/j.gexplo.2025.107795","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Ion-adsorption rare earth deposits are special resources that are widely distributed in South China and have become one of the most important sources of rare earth elements (REEs). To illustrate how the host rock affects the formation of these deposits, this study perpetually sampled the weathered crust profile of a typical granite from top to bottom in the Luoyang-Nanmu mining area of Guangdong Province. We collected 7 representative samples to analyze whole-rock major and trace elements and to carry out U&lt;img&gt;Pb dating of zircon, apatite, and monazite. Additionally, the relationship between the characteristics of the parent rock and the weathered crust was further studied. (1) The U&lt;img&gt;Pb isotope results of zircon, apatite, and monazite show that the parent rocks were formed at 229.1 ± 2.0 Ma, 226.0 ± 1.1 Ma, and 277.4 ± 0.8 Ma, respectively. This indicates, that the weathered crust parent rock is Indosinian biotite monzogranite, which can provide favorable metallogenic conditions for the formation of weathered crust. The major and trace elements data from the whole-rock analysis show that the Chemical Index of Alteration (CIA) values of the weathered crust range from 0.61 to 0.92 gradually decreasing from shallow to deep. As the weathering degree increases, changes in the content and ratios of LREEs to HREEs, (LREEs/HREEs = 12.68–22.97), Ce anomaly (Ce/Ce* = 0.33–1.89) and Eu anomaly (Eu/Eu* =0.56–0.67) in the profile are observed. Combined with the mineral characteristics and REE composition patterns of the minerals, it is evident that the parent rock materials in the weathered crust are controlled by monazite. Monazite and plagioclase are the main minerals responsible for REE enrichment in the weathered crust. Monazite, together with apatite, influences the rare earth distribution mode of the weathered crust (especially the LREEs). Zircon is resistant to weathering, limiting the enrichment of HREEs, and thus, LREEs are more easily enriched in the weathered crust of the parent rock. Furthermore, plagioclase feldspar provides an adsorption medium for ion-REEs as it weathers to form kaolin. (3) The trace elements data characteristics of zircon and apatite in the profile samples &lt;del&gt;can&lt;/del&gt; reflect the degree of magma evolution, among which the content of U, Th, and Y in zircon is low while the Th/U ratio is approximately 1, and the ratios of Zr/Hf = 36.3–62.7, indicating that zircon is primarily of magmatic origin and the magma evolution is of moderate degree. The ratios of (La/Yb)&lt;sub&gt;N&lt;/sub&gt;, (La/Sm)&lt;sub&gt;N&lt;/sub&gt;, and (Sm/Yb)&lt;sub&gt;N&lt;/sub&gt; in apatite reflect magma differentiation characteristics: (La/Yb)&lt;sub&gt;&lt;em&gt;N&lt;/em&gt;&lt;/sub&gt; = 1.81–5.29, (La/Sm)&lt;sub&gt;&lt;em&gt;N&lt;/em&gt;&lt;/sub&gt; = 0.48–0.91, and (Sm/Yb)&lt;sub&gt;&lt;em&gt;N&lt;/em&gt;&lt;/sub&gt; = 3.79–6.41, showing a positive correlation with Sr. Additionally, apatite exhibits a strong negative Eu anomaly, indicating plagioclase separation and crystallization during magma differentiation. The evidence presented sug","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"276 ","pages":"Article 107795"},"PeriodicalIF":3.4,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143927595","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":"In situ pyrite thermoelectricity and geochemistry: Implications for exploration in the Longhua Ni-Co vein deposit, Dayaoshan area, South China","authors":"Xinmin Yang ,&nbsp;Xiao Nie ,&nbsp;Zhen Deng ,&nbsp;Kuifeng Mi ,&nbsp;Xuepeng Duan ,&nbsp;Xiaofeng Qin ,&nbsp;Zongqi Wang","doi":"10.1016/j.gexplo.2025.107796","DOIUrl":"10.1016/j.gexplo.2025.107796","url":null,"abstract":"<div><div>Pyrite thermoelectricity has been widely utilized in predicting deep/concealed quartz-vein-related gold orebodies. However, whether this methodology can be utilized as vector for Ni-Co mineral exploration remains to be explored. This study investigates the major element composition, trace element composition, and thermoelectric characteristics of pyrite across a vertical profile (531 m, 492 m, and 446 m above sea level, a.s.l.) along the No. 3 orebody of the Longhua Ni-Co deposit to evaluate their potential for Ni-Co exploration. In this deposit, Ni-Co mineralization is dominated by arsenides (e.g., niccolite), sulfarsenides (e.g., gersdorffite and cobaltite), and sulfides (e.g., pentlandite and bravoite), which are primarily hosted in quartz veins. Field observations indicate that pyrite from different elevations is closely associated with Ni-Co ore minerals. Time-resolved LA-ICP-MS depth profiles of Co, Ni, and As in pyrite from different elevations exhibit gentle curves, suggesting that these elements primarily incorporate into the pyrite lattice in an isomorphic form. Despite a relatively low Co/Ni ratio (mostly &lt;1), the quartz-vein-controlled occurrence of pyrite points to a hydrothermal origin. The trace elements exhibit a cyclic variation along the vertical profile: from 531 m to 492 m and then to 446 m a.s.l., the (Co + Ni) content initially decreases then increases, while As content shows an inverse trend. Correspondingly, pyrite thermoelectricity changes from N-type conductivity at 531 m a.s.l. to P-type at 492 m a.s.l., and reverting to N-type at 446 m a.s.l. This variation is attributed to a direct link between (Co + Ni) content and N-type conductivity, and between As content and P-type conductivity. The observed association of arsenide ores with P-type pyrite and sulfide ores with N-type pyrite establishes these conductivity types as indicators for distinct mineralization characteristics. Furthermore, the increase in sulfur fugacity below 446 m a.s.l., combined with the presence of N-type pyrite at 430 m a.s.l. (from drill-hole along the inferred extension of the No. 3 orebody), indicates the potential for deeper sulfide-rich mineralization below currently investigated 446 m a.s.l. drift. This study highlights the feasibility of using the pyrite thermoelectricity and geochemistry to guide the Ni-Co mineral exploration.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"276 ","pages":"Article 107796"},"PeriodicalIF":3.4,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068799","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":"Sources and occurrence of trace elements in water and sediments of Darbandikhan reservoir in Iraqi Kurdistan: A human health and ecological risk assessment","authors":"Karzan Hawrami ,&nbsp;Abdolbaset Baset ,&nbsp;Kocher Ibrahim ,&nbsp;Hardi Baqi ,&nbsp;Farhan Abdulrahman ,&nbsp;Ari Ali ,&nbsp;Fadhil Lawa ,&nbsp;Abdul-Wahab Mossa ,&nbsp;Maria Izquierdo","doi":"10.1016/j.gexplo.2025.107793","DOIUrl":"10.1016/j.gexplo.2025.107793","url":null,"abstract":"<div><div>Freshwater pollution is a global threat, contributing to the decline in biodiversity whilst making water unsafe for human consumption. Climate change may further aggravate water scarcity and quality. Iraq is ranked as highly vulnerable to climate change and predicted to be extremely water stressed by 2040. Iraqi population relies on surface water, yet its availability and quality face several challenges. This study reports on Darbandikhan, a major water reservoir in Iraqi Kurdistan. The occurrence, spatial/vertical distribution and associations of 50+ elements in sediments, surface and deep water in 48 sites shed light on contamination patterns and enabled identification of several geogenic and anthropogenic sources, and locally enriched areas where mitigation actions are recommended. Darbandikhan sediments revealed a distinctive geogenic signature reflecting the Zagros geological setting. The presence of mafic/ultramafic rocks and mineralisations in the catchment resulted in high levels of As, Cr and Ni in sediments, whilst no anthropogenic sources could be unequivocally discriminated. Elemental associations with a geogenic signature and higher concentrations in deep water suggested that bottom sediments act as a secondary source of potentially toxic elements into the overlying water column. By contrast, surface water composition was primarily controlled by fresh inputs from several streams draining into the reservoir. Local enrichments in As, Ba, Mo, Ni, Sb, V and Zn were traced back to specific anthropogenic discharges. Assessment of the contamination status with several indices suggested mild to moderate environmental risk and low health risk in the majority of sites, although caution in water consumption is advised.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"276 ","pages":"Article 107793"},"PeriodicalIF":3.4,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143931470","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":"Comment on “Spatial distributions, potential sources, and ecological risks of heavy metals in stream sediments of Zambia” by Sun et al. (2025)","authors":"Ondra Sracek ,&nbsp;Bohdan Kříbek ,&nbsp;Vojtěch Ettler ,&nbsp;Martin Mihaljevič ,&nbsp;Aleš Vaněk ,&nbsp;Imasiku Nyambe","doi":"10.1016/j.gexplo.2025.107791","DOIUrl":"10.1016/j.gexplo.2025.107791","url":null,"abstract":"","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"275 ","pages":"Article 107791"},"PeriodicalIF":3.4,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883231","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}