Journal of Geochemical Exploration最新文献

{"title":"High-resolution mapping and multivariate technique (factor analysis) to support hydrogeochemical analysis and identification of surface water contamination","authors":"Daniela Vasconcelos Machado ,&nbsp;Eduardo Duarte Marques ,&nbsp;Eduardo Paim Viglio ,&nbsp;Everton Assunção Martins dos Santos ,&nbsp;Rafael Tarantino Amarante ,&nbsp;Gerson Cardoso da Silva Júnior ,&nbsp;Emmanoel Vieira Silva-Filho","doi":"10.1016/j.gexplo.2024.107495","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107495","url":null,"abstract":"<div><p>The study presented a high-resolution regional mapping of a significant Brazilian watershed, which is heavily influenced by mining, agriculture, and domestic/industrial effluents. Upper São Francisco Basin encompasses the largest karst area in the country and includes three important Brazilian biomes: Cerrado, Atlantic Forest, and Caatinga. Surface water (1418 samples) was collected during the dry season and was analyzed for physical-chemical parameters, cations, anions, and some metals. The spatial distribution and abundance of variables were assessed, and the processes controlling the sources of dissolved loads in surface waters were discussed. The results indicate that rock weathering is the primary factor controlling water chemistry, with a strong influence of carbonate and silicate minerals. Anthropogenic activities, particularly agriculture, play a key role in the chemical composition of the microbasins. Soil erosion and leaching processes also contribute significantly to the region, driven by land use practices and mineral extraction, which intensify erosion processes. The northern sector of the Upper São Francisco Basin, characterized by an arid climate and Caatinga vegetation, experiences low precipitation and high evapotranspiration rates. The VG stands out due to the presence of the karst zone and for the mixture of natural to anthropogenic sources.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140950517","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 alteration and geochemical proximity indicators to ore at the Metsämonttu Zn–Pb–Cu–Au–Ag deposit, Uusimaa belt, southern Finland","authors":"Janne Hokka ,&nbsp;Hanna Leväniemi ,&nbsp;Tuomas Leskelä","doi":"10.1016/j.gexplo.2024.107491","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107491","url":null,"abstract":"<div><p>The Paleoproterozoic Metsämonttu Zn–Pb–Cu–Ag–Au deposit (1.5 Mt at 3.5 wt% Zn, 0.8 wt% Pb, 0.3 wt% Cu, 13.2 wt% S, 25 g/t Ag, and 1.4 g/t Au, production 1952–1974) is the largest past-producing mine in the Aijala–Orijärvi area (Orijärvi formation, Aijala member) within the Uusimaa belt, southern Finland. The Aijala member is characterized by 1.9–1.88 Ga felsic-dominated volcanic-sedimentary supracrustal rocks with intercalated sedimentary carbonates and iron formations. The area is underexplored, and little deposit-scale research has been carried out, despite the lateral continuum to the world-class ore district of Bergslagen in south-central Sweden. To better understand the Metsämonttu VMS-related alteration system, we reassessed the previously described metamorphic mineral assemblages and their protolith rock compositions by using mobile and immobile element geochemistry. This resulted in the definition of four metamorphosed alteration mineral assemblages and eight chemostratigraphic rock units. The chemostratigraphic results suggest that the lithological and/or structural setting of the Metsämonttu succession is more complex than previously considered. The stratigraphic footwall is mainly characterized by an extensive cordierite + anthophyllite ± biotite ± phlogopite + pyrite ± pyrrhotite (Mg–Fe–S) assemblage dominated by mafic rocks, designated Mafic B1 and Mafic B2, and Andesite A1. The main sulfide mineralization is hosted by tremolite + diopside ± biotite ± phlogopite ± chlorite skarn (Ca–Mg–K). A sericite-bearing muscovite + quartz ± biotite ± phlogopite + pyrite (K–Si–S) assemblage is composed of felsic to mafic protoliths (Mafic B1–B2, Andesite A1, Dacite A1, Dacite B1, Dacite C1) and extends several tens of meters into the stratigraphic hanging-wall. A quartz + pyrite ± muscovite (Si–S) assemblage represents the immediate ore-proximal alteration and is derived from rocks with a rhyolitic composition (Rhyolite A1).</p><p>Limited drill core samples near Metsämonttu mineralization, along with restricted surface alteration, pose challenges in studying geochemical variations from distal to ore proximal areas and limits the ability to model the shape and size of the alteration zone. Large mass changes suggest that the alteration was hydrothermal, and due to several protolith compositions, the alteration is interpreted to be predominantly discordant to stratigraphy. A 60-m-wide alteration halo surrounds the Metsämonttu deposit. Major and trace elements, namely MgO, Na₂O, K₂O, SiO₂, Fe₂O₃, Cu, Zn, Pb, S, Ag, Tl, Hg, Se, Te, Sn, Sb, Rb, and Sr, and the indices modified alteration index (MAI), Ishikawa alteration index (AI), chlorite‑carbonate-pyrite index (CCPI), S/Na₂O can be used for chemical vectoring, which can assist regional or near-mine exploration. Elements MnO, Ba, Cd, Bi, As, Ni, Co, W, Ga, Mo, and indices Hashigushi index and advance argillic alteration index (","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0375674224001079/pdfft?md5=f083ca07038338944e239cc134f06160&pid=1-s2.0-S0375674224001079-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140906051","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":"Heavy metals in surface sediments of Lake Patria wetland, southern Italy, and environmental risk","authors":"Michele Arienzo ,&nbsp;Sergio Bravi ,&nbsp;Maria Toscanesi ,&nbsp;Carlo Donadio ,&nbsp;Giuseppe De Simone ,&nbsp;Corrado Stanislao ,&nbsp;Luciano Ferrara ,&nbsp;Vincenzo Allocca ,&nbsp;Antonella Giarra ,&nbsp;Marco Trifuoggi","doi":"10.1016/j.gexplo.2024.107490","DOIUrl":"10.1016/j.gexplo.2024.107490","url":null,"abstract":"<div><p>The study investigated the presence of heavy metals in the surface sediments of one of the most important wetlands in south Italy, Lake Patria, and the related environmental risk. Surface sediments were analyzed for particle size and shape, total organic carbon and As, Cd, Cr, Cu, Fe, Hg, Ni, Pb and Zn levels. Mean total organic carbon was high, 3.1 %, with a peak of 5.9 % near the input of freshwater channel whereas sediments appeared to be mainly composed of sand and/or gravel and significantly polluted by metals especially Cr, Cu and Zn. Data from heavy metals spatial distribution, Pearson correlation, principal component analysis and geochemical indices suggested dominant anthropogenic source for most metals. Mean I_geo values of Cr, Cu and Ni were in the range of 4.6–7.3 of strongly polluted class while their relative mean enrichment factors were largely exceeding the threshold of the anthropic pollution, 1.5. A very high pollution situation was also outlined when considering the Cf indices, with Cr, Cu and Ni possessing mean values from an order of magnitude of ten to hundred times higher the very high polluted class, 6 ≤ Cf. On the overall, the integrated indices of modified contamination degree, pollution load and ecological risk revealed a serious pollution scenario. The mean comprehensive ecological hazard index was fivefold the most critical limit, ≥600, in almost all the lagoon and especially in the locations close to channel.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141038446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemistry and sources of boron and strontium of geothermal waters from the Pearl River Delta region, South China: Implications for water-rock interactions","authors":"Zhengan Wei ,&nbsp;Shaopeng Huang ,&nbsp;Chengshan Wang","doi":"10.1016/j.gexplo.2024.107492","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107492","url":null,"abstract":"<div><p>Pearl River Delta (PRD) region of South China is abundant of geothermal water resources. However, the development and utilization level of geothermal resources in this region is relatively low, due in part to the lack of fundamental geochemical research. To access water-rock interaction processes of the PRD geothermal system, we analyzed the geochemistry of geothermal waters by combining trace elements (B, Sr, and Br) and isotopes (δ¹¹B and ⁸⁷Sr/⁸⁶Sr) with conventional tracers (major elements) that had been reported. The Cl/Br ratios (from 31 to 639) confirm the multi-source salinity of marine origin, precipitation, and a minor dissolution of halite. Major ions chemistry highlights the influence of ions exchange, the dissolution of carbonate, silicate, and sulphate minerals as well as the contribution of seawater. The Cl/B ratios (61 to 22,583) suggest interactions with carbonate rock and felsic rock, input of seawater, and groundwater mixing. Boron isotopic compositions (δ¹¹B) range between −9.22 and +39.78 ‰. Sr contents and ⁸⁷Sr/⁸⁶Sr ratios are more homogeneous, falling between 0.06 and 32.26 mg/L and between 0.71239 and 0.72121, respectively. The B and Sr isotopic signatures show that three processes contribute to geochemistry of geothermal waters: 1) water/rock interaction involving marine carbonate rock, evaporite, and granitoid or/and gneiss, 2) seawater intrusion, and 3) shallow groundwater mixing. Major-trace element chemistry and these isotope systematics on their own indicates essential information on the aspects of fluid origin or water-rock interaction processes, and however provide a more comprehensive understanding of the geothermal system in the PRD region, South China.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140820164","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":"Syenite mapping and prediction of geochemical Na versus K signatures: A novel remote sensing approach and implications for mineral resources","authors":"Youssef Ahechach ,&nbsp;Otmane Raji ,&nbsp;Muhammad Ouabid ,&nbsp;Cheikh-Elwali Malainine ,&nbsp;Jean-Louis Bodinier ,&nbsp;Fleurice Parat ,&nbsp;Hicham El Messbahi ,&nbsp;Oussama Khadiri-Yazami ,&nbsp;Essaid Jourani ,&nbsp;Jean-Marie Dautria","doi":"10.1016/j.gexplo.2024.107489","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107489","url":null,"abstract":"<div><p>Syenites are highly valued for economic and strategic exploration programs worldwide, along with associated rocks (e.g., carbonatites), as a primary source for several industrial minerals and strategic elements, such as phosphate, potash, rare earth elements (REE), and Nb. Rapid identification and mapping of syenite outcrops and their major geochemical signatures (i.e. potassic and sodic) over vast areas are crucial for exploration programs aimed at identifying new economic deposits. For this, remote sensing provides an interesting way to delineate these alkaline igneous rocks and predicts their mineralogical and geochemical characteristics. In the literature, few remote sensing studies have been devoted to syenite outcrops, and an effective predictive tool for their mapping and mineralogical-geochemical classification remains to be done. Accordingly, we explore in the present study the potential of using ASTER thermal emissivity data for prospectivity mapping and predicting the main alkaline mineralogical and geochemical affinities of syenite rocks. This approach was applied to the Moroccan High-Atlas Mountains (area ∼ 42,000 km²), known for the presence of several alkaline intrusions hosting different alkali-syenites. Hence, a spectral syenite index [SyI = (B10/B11 * B10/B13 * B14/B13)] without the use of in-situ field data, was suggested in the first stage to quickly highlight potential areas, reducing the initial exploration zone to only ∼1000 km²/42000 km² that include all well-known syenites in the studied area. Subsequently, several in-situ field missions were conducted in the identified zones to sample and obtain precise GPS points of well-exposed syenitic outcrops. For discrimination of mineralogical and geochemical endmembers (Na vs. K) of syenites, two new spectral indices were proposed [SpI-A = (B14-B12)/(B14 + B12) for K syenite signature and SpI-B = (B10-B11)/(B10 + B11) for Na syenite signature]. These indices highlight the two major geochemical affinities in the High-Atlas Mountains: the potassic syenite character (K-feldspar- and nepheline-rich) in the Midelt-Tamazeght Cenozoic complex and the sodic syenite character (albite-rich) in the Imilchil Mesozoic massifs. The results have significant implications for early exploration programs, aiming to cost-effectively discover favorable areas of alkali syenites, potassic against sodic affinities, and optimize fieldwork as well as preliminarily mineralogical and geochemical characterization.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140879090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of metal-bearing nanoparticles observed in loess-covered terrain: Implications for prospecting","authors":"Yuexin Lu,&nbsp;Bimin Zhang,&nbsp;Xueqiu Wang,&nbsp;Hanliang Liu,&nbsp;Jian Zhou","doi":"10.1016/j.gexplo.2024.107488","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107488","url":null,"abstract":"<div><p>The recent depletion of mineral resources near the Earth's surface has led to a shift in mineral exploration toward concealed deposits in covered terrain. Consequently, significant attention has been directed toward metal-bearing nanoparticles in the soil above such deposits to gain insights into the composition of concealed ore bodies.</p><p>In this study, the characteristics (type, size, shape, chemical composition, and aggregation) of metal-bearing nanoparticles in ore samples of the Zhonghedi Ag-Pb-Zn polymetallic deposit and their overlying loess were systematically analyzed using transmission electron microscopy. Numerous nanoparticles containing Ag, Au, Cu, Pb, Zn, Fe, Mo, and other metallic elements were observed in the loess overlying the deposits as well as the ore samples. These nanoparticles exhibit a well-defined crystal shape, suggesting their primary particle nature. Moreover, the nanoparticles in the loess and ore samples share similarities in element distribution, size, and type, demonstrating their homologous nature. However, ore-related metal-bearing nanoparticles were not detected in samples collected from the background areas. Most metal-bearing nanoparticles in loess, excluding native particles, were oxides and sulfates, which may be attributed to oxidation of the native metal particles near the surface where oxygen fugacity increases. The elemental mapping of the nanoparticles showed that the ore-forming elements had the same distribution patterns and element assemblages to the ore material. These results indicate that metal-bearing nanoparticles in the loess have likely relationships with concealed ore bodies. Accordingly, the metal-bearing nanoparticles in the loess can provide information about concealed ore deposits, explain surface geochemical anomalies, and improve prospecting accuracy as a vector to mineralization.</p><p>Routinely finding nanoparticles in transported cover remains a challenge. However, this study shows it is viable and marks substantial progress in our knowledge and comprehension of metal-bearing nanoparticles in loess-covered terrain. Evidence of their presence and association with concealed ore bodies contributes significantly to our understanding of mineral exploration processes and offers new avenues for future research and practical applications.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140824166","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 associations between the lateritic crusts and carbonatitic rocks of the Carbonatitic Complex at Morro dos Seis Lagos, AM, Brazil","authors":"Ana Carolina de Faria Duarte ,&nbsp;Claudio Gerheim Porto ,&nbsp;Artur Cezar Bastos Neto ,&nbsp;Reiner Neumann ,&nbsp;Lucy Takehara ,&nbsp;João Pedro Proença Bento","doi":"10.1016/j.gexplo.2024.107494","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107494","url":null,"abstract":"<div><p>The carbonatite rocks present at the Seis Lagos Carbonatite Complex (SLCC) are siderite carbonatites, and constitute the source of the titano-niobian mineralization hosted in the lateritic crusts that cover the complex. This study is based on the geochemical data from 6 drill holes conducted by the Geological Survey of Brazil (CPRM) in the 1980s plus the mineralogical descriptions and analyzes performed on these cores. The quality of the geochemical data was evaluated in order to select the most reliable elements for statistical treatment. Given the compositional character of the geochemical data, these were transformed into Centered Log Ratio (CLR) and submitted to principal component analysis. These data enabled definition of geochemical association of 4 types of carbonatite rock: (i) C1, siderite carbonatite; (ii) C2, friable siderite carbonatite; (iii) C3, light siderite carbonatite; and (iv) B1, carbonatite breccia. B1 is more phosphatic and enriched in Al, P, La, Ce, Ba, Sr, Zr, S, Be, U and REE minerals like bastnaesite-(Ce), monazite-(Ce), as well as those belonging to the plumbogummite group (such as florencite-(Ce)) — which were formed during a later carbohydrothermal stage. C3 is also enriched in the same suite of metals as a result of hydrothermal alteration after C1. The transition from C1 to its friable equivalent, C2, is more abrupt, suggesting that the weathering took place with well-defined limits in depth and was possibly delimited by structures. C2 is characterized by its enrichment in Th, Zn, Sn, Co, and Sb, with some influence from both Mn and Fe, and the leaching of Ce, Ba, La, and Sr. C2 contains goethite, rutile, brookite and gibbsite, evidencing the impact of weathering. Lateritic crusts are distinguished into 5 types: (i) L1, a fragmented cavernous crust; (ii) L2, a reddish-brown crust; (iii) L3, a manganese crust; (iv) L4, a gray crust; and (v) L5, a compact, grayish crust. The L1 crusts are richer in Al, P, Zr, La and U due to the residual enrichment of their immobile elements and to the formation of secondary aluminum phosphates, mainly florencite-(Ce). The L3 manganese crusts are characterized by a suite of metals, composed of Mn, Ba, Mo, Co and Ce. The contrasting compositions between segments of the upper and lower crusts it is more likely due to compositional differences in the siderite carbonatite, rather than reflecting the depth and hence intensity of weathering. A specific type of crust to which the Nb<img>Ti mineralization might be associated with was not identified. No specific geochemical association was identified for the deeper crusts, such as L4 and L5; however, the occurrence of Ce-rich pyrochlore, cerianite and carbonates in them, coupled with their absence in the upper crusts, suggests that the aforementioned ones are less evolved and therefore, closer to the carbonatite protolith. Our results indicate that despite intense weathering the composition of the primary siderite carbonatite exerts a","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140843232","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 behavior of the rare earth elements and yttrium in groundwaters of the Holy Cross Mountains, SE Poland","authors":"Dorota Kaczor-Kurzawa ,&nbsp;Irena Wysocka ,&nbsp;Monika Chuchro","doi":"10.1016/j.gexplo.2024.107493","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107493","url":null,"abstract":"<div><p>In areas of contrasting geology, local but significant spatial changes in environmental conditions can occur suddenly and unexpectedly within aquifers, hampering accurate assessment of groundwater chemistry. Recently, the rare earth elements (REEs) have become extensively used in identifying geochemical processes in aqueous systems, due to their unique sensitivity to environmental changes. In this study, the REEs and Y (yttrium), combined with the chemical parameters of the main, minor and trace water components, and with the isotopic signatures of δ¹⁸O-H₂O, δ²H-H₂O, ³H-H₂O, δ³⁴S-SO₄, δ¹⁸O-SO₄, were investigated in order to gain a better understanding of the geochemistry of the groundwaters in the Holy Cross Mountains, which possesses a diverse hydrogeological system. The waters studied are ‘young’, meteoric-derived, of acidic to slightly alkaline pH (4.95–7.75) and TDS values of 38.97–2713.91 mg/L. They represent predominantly the HCO₃-Ca-Mg and less often the HCO₃-Ca-SO₄-(Mg) or SO₄-Ca-(Mg) types. The dissolved (&lt;0.45 μm) concentrations of the REEs (5.55 to 13,857.35 ng/L) and Y (4.43 to 2450.22 ng/L) in the waters studied are the result of host rock dissolution, and tend to increase significantly, by up to several orders of magnitude, via interactions between the rocks and acidic waters. Speciation calculation reveals that dissolved REE + Y in neutral and alkaline waters are transported mainly as bicarbonate (CO₃)₂⁻ and carbonate CO₃⁺ complexes, while in a more acidic environment these elements occur preferably as free ions (REE³⁺+Y³⁺), and their abundance gradually increases along with decreasing pH value. The EUS (European Shale) normalized REE patterns of the waters studied show two distinct dominant types: (i) upwards-sloping with HREE-enrichment (LREEs&lt;MREEs&lt;HREEs), (ii) convex with MREE-enrichment (LREEs&lt;MREEs&gt;HREEs). The first pattern type reflects REE fractionation in alkaline and oxygenated waters, leading to preferential LREE adsorption onto mineral particles, accompanied by complexation of HREEs with carbonate and bicarbonate ions, while the second pattern type results from dissolution of the host rocks in more acidic conditions. The REE patterns in the waters studied are mostly different from the REE patterns characteristic of the host rocks, except for some water samples from carbonate aquifers. Ce and Eu anomalies were recorded in the waters studied. Some of the negative Ce and positive Eu anomalies were inherited from host rock dissolution, while other negative or positive Ce anomalies reflect oxygenic or more reducing conditions, respectively.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140924410","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":"Co-enrichment of selenium and cadmium in soils of southern China and its implication for the safe utilisation of selenium-rich lands","authors":"Zhixuan Han ,&nbsp;Yang Li ,&nbsp;Ruiwei Zhao ,&nbsp;Yuzhen Yang ,&nbsp;Yuqun Cai ,&nbsp;Haotian Lu","doi":"10.1016/j.gexplo.2024.107487","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107487","url":null,"abstract":"<div><p>Dietary deficiency of selenium (Se) is a global health threat related to low Se concentrations in crops. Southern China has abundant Se-rich land resources, but the cadmium (Cd) pollution problem is prominent, which may lead to Cd exceeding the safety standard in Se-rich crops. Therefore, it is important to delineate Se-rich land without Cd pollution in order to develop green Se-rich agriculture. Based on soil/sediment geochemical survey data covering 2.3 million km² of southern China, this study analysed the concentration and spatial distribution of Se and Cd, discussed their enrichment mechanisms and proposed suggestions for the safe use of Se-rich land. The results showed that the soil/sediments in southern China were significantly enriched in Se and Cd, and the median values were 0.31 mg·kg⁻¹ and 221 μg·kg⁻¹, which were 1.8 times and 2.5 times the national soil background values, respectively. In addition, a significant positive correlation was observed between Se and Cd, indicating that Cd contamination in Se-rich soils frequently exceeded the pollution limit. According to statistics, Se-rich land accounted for 32.13 % of southern China. However, due to the co-enrichment of Se and Cd, areas without Cd pollution accounted for only one-third of the total Se-rich area. In particular, the areas with co-enrichment of Se<img>Cd are primarily distributed in Yunnan, Guizhou, Guangxi, western Hubei, northwestern Zhejiang, western Hunan, southern Hunan and northern Guangdong. The enrichment of Se is predominantly associated with parent rocks (black and carbonate rocks). At the same time, the enrichment of Cd is influenced by the parent rocks and Pb<img>Zn mineralisation and mining activities. Three recommendations for managing Se-rich land were proposed: imposing restrictions on the utilisation of heavily contaminated Se-rich land for agricultural production, adopting a rational approach towards utilising lightly polluted Se-rich land and actively promoting the development of Se-rich agriculture in uncontaminated Se-rich areas. In the future, it is necessary to develop technologies that simultaneously enhance Se absorption while inhibiting Cd absorption in order to safely exploit Se-rich lands affected by Cd pollution.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140820195","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 Danping bauxite (Northern Guizhou, China) and associated lithium: Evidence from LA-ICP-MS analysis of Al-bearing minerals","authors":"Bing Liu ,&nbsp;Peiwen Chen ,&nbsp;Tianshun Wang ,&nbsp;Guotao Sun ,&nbsp;Mingfei Duan ,&nbsp;Kejun Hou ,&nbsp;Qingdong Zeng ,&nbsp;Yong Fu","doi":"10.1016/j.gexplo.2024.107464","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107464","url":null,"abstract":"<div><p>Lithium (Li), as an essential element of green new energy technology, is a global strategic resource. Sedimentary Li is primarily associated with bauxite, with a local grade of &gt;1000 ppm, and has a huge utilization prospect. However, fine particles limit the study of the occurrence of Li. The Danping bauxite deposit, located in northern Guizhou, China, which accompanying considerable Li resources. In this study, in situ elemental concentration analyses were conducted by laser ablation-inductively coupled plasma-mass spectrometry. The analysis results show that Li is mainly enriched at the bottom and top of the aluminiferous rock series, and the Li content at the top is higher (615.98–3289.98 ppm). Li content is positively correlated with Mg and Fe content, indicating that chlorite is a potential Li-bearing mineral. K content of &lt;10,000 ppm, K content is positively correlated with Li content, indicating that illite may also be a Li-bearing mineral. Kaolinite, transformed from montmorillonite, may also have a high Li content. Ga content is always positively correlated with Al content, indicating that Ga mainly occurs in diaspores. Bauxite has similar Nb/Ta and Zr/Hf ratios to the underlying Hanjiadian Formation shale, as well as the same positive Ce anomalies (negative anomalies in Huanglong Formation), indicating that the ore-forming material of Danping is primarily derived from the underlying Hanjiadian Formation.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140607247","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}