Journal of Geochemical Exploration最新文献

{"title":"Relationships between hydrogeochemistry and diatoms in acid mine drainage affected media: The case of Iberian pyrite belt; functioning models for an all metallogenetic province","authors":"Ana Teresa Luís ,&nbsp;Juan Carlos Fortes ,&nbsp;María Santisteban ,&nbsp;José Miguel Dávila ,&nbsp;Manuel A. Caraballo ,&nbsp;Juan María Terrones-Saeta ,&nbsp;Jesus Diaz-Curiel ,&nbsp;José Antonio Grande","doi":"10.1016/j.gexplo.2024.107537","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107537","url":null,"abstract":"<div><p>The Iberian Pyritic Belt (IPB) is one of the most important metallogenic provinces, which hosts massive sulfides and extends over 230 km from Canal Caveira-Lousal in Portugal to Gerena (near Seville) in Spain. It has 88 active and inactive mines only in the Spanish part and near 30 in Portugal that generate Acid Mine Drainage (AMD) pollution to the main river basins, Corona, Roxo (Portugal), Odiel, Tinto, Guadiamar (Spain) and Chanza-Guadiana (Portugal/Spain) and consequenty to the 35 acidic sampling sites, 14 in Portugal and 21 in Spain, selected for this unique study. The physico-chemical parameters of waters (EC, Eh, pH, Al, As, Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn, SO₄²⁻), acidic diatoms (%Pinacid) and diatom diversity (N°sps) were determined in the laboratory. Then, the results were integrated in a database with 16 variables and 35 sampling points to be statistically analyzed by factor and cluster analysis. In the first, for the 35 sampling sites, it showed a clear inexistence of ecological barriers, exposing how could distantly sampling points be paired together. The last, allowed the pollution–biota interaction models formulation governed by 2 factors: 1-Unrestored Mining Surfaces and 2-WFD (Water Framework Directive) exceeding limits. Dispersion diagram showed that although the unrestored mining surface increases, starting from a certain concentration of contaminants, salts begin to precipitate: the AMD process increases but the WFD does not. There are numerous works in the scientific literature aimed to define diatom-hydro-geo-chemistry interrelationships, but none that covers an entire metallogenetic province where ecological barriers could exist, conditioning the diatom species and groups evolution and distribution in an acidic (pH: 1.90–4.43) environment.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141479080","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 of uranium-rich dispersed organic matter and their geological significance for uranium mineralization: A case study from the Ordos Basin","authors":"Fan Zhang ,&nbsp;Yangquan Jiao ,&nbsp;Liqun Wu ,&nbsp;Hui Rong ,&nbsp;Jianying Wang ,&nbsp;Chengcheng Zhang","doi":"10.1016/j.gexplo.2024.107528","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107528","url":null,"abstract":"<div><p>Geochemical characteristics of uranium minerals is an important content for uranium deposits, and is conducive to understand the formation mechanism, environment and genesis of sandstone-type uranium deposits. In the Diantou-Shuanglong uranium deposit from southern Ordos basin, carbonaceous debris (CD), dispersed organic matter, is widely distributed in sandstones from uranium-bearing strata, and is the dominant enrichment agent for uranium precipitation. The geochemical compositions of uranium-rich CD were investigated by using inductively coupled plasma mass spectrometry (i.e., ICP-MS) and scanning electron microscope-energy dispersive X-ray spectroscopy (i.e., SEM-EDS). The results show that element U bears a close relationship with elements W, Ta, Mo, Pb, Th, Bi, Mn, V, Ti, Co, Be, especially Mo, and Pb, indicating that these elements are rich in uranium-bearing minerals. The contents of rare-earth element (i.e., REE) and light rare-earth element (i.e., LREE) increase with the increasing uranium abundance, implying that REE primarily enrich in uranium minerals, especial for LREE. Moreover, LTEE (e.g., Nd) and Y are detected in uranium-bearing minerals. Besides, uranium-bearing CD exhibits similar REE geochemical characteristics and distribution patterns with the surrounding sandstones, indicating that they are homologous in sedimentary source, sedimentary environment, and tectonic background, and the CD is deposited during synsedimentary period. Given the distribution characteristics of trace element and REE, it is comprehensively inferred that the formation of uranium mineralization is not related to deep hydrothermal fluid below the lower crust, but is altered by the low-temperature hydrothermal fluid. Synsedimentary CD at the stage of low to medium thermal maturity is of certain adsorption and reduction, and is favorable for the precipitation and enrichment of uranium-bearing phase and the other trace element (e.g., Mo, V) similar in geophysical-chemical properties with U element, and the sedimentary environment is beneficial for preservation of uranium. It will be contributed to clarify the genesis of sandstone-type uranium deposit and to provide some guidance for the exploration of the uranium deposit in the studied area.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141479083","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":"Uranium mineralization in the Thrace Basin, NW Türkiye: Evidence from radiation-induced defects in detrital quartz and synchrotron XRF/XANES analysis","authors":"Ayetullah Tunc ,&nbsp;Yakup Çelik ,&nbsp;Renfei Feng ,&nbsp;Olcay İnanç ,&nbsp;Yuanming Pan","doi":"10.1016/j.gexplo.2024.107533","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107533","url":null,"abstract":"<div><p>The Paleogene-Neogene Thrace Basin in northwestern Türkiye has long been known to host economic gas and oil resources and has recently been reported to potentially host sandstone-type uranium deposits in the Oligocene Süloğlu Formation. The latter discovery raises questions about the source and deposition mechanism of uranium mineralization in the basin. This contribution reports on the results of a detailed electron paramagnetic resonance (EPR) spectroscopic study of detrital quartz from four sandstone and one mudstone samples in the Süloğlu Formation and documents the distribution and speciation of uranium using combined microbeam synchrotron X-ray fluorescence maps (μsXRF) and microbeam X-ray near edge structure spectroscopy (μsXANES). The EPR spectra of quartz separates are characterized by the presence of diagnostic radiation-induced defects (i.e., silicon-vacancy hole centers <em>H</em>′₃, <em>H</em>′₄, and <em>H</em>′₇ with <em>g</em>_<em>max</em> = 2.049, 2.034, and 2.018, respectively, and the oxygen-vacancy electron center <em>E</em>′₁), formed by the bombardment of alpha particles emitted from uranium, thorium, and their unstable progenies. Moreover, notable decreases in the intensity of silicon-vacancy hole centers in the EPR spectra of quartz separates after partial dissolution with hydrofluoric acid, provide compelling evidence for the circulation of uranium-bearing fluids in the Thrace Basin. The μsXRF and μsXANES data reveal the occurrences of mixed U⁶⁺ and U⁴⁺ species in hematite partially replacing pyrite aggregates but dominantly U⁴⁺ in disseminated pyrite and illite in sandstones of the Süloğlu Formation. These results provide new insights into uranium transport, reduction, and deposition mechanisms, with important implications for better understanding sandstone-type uranium deposits in general and further exploration in the Thrace Basin.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0375674224001493/pdfft?md5=92eb5469f6464e4fc939142a31f7ff94&pid=1-s2.0-S0375674224001493-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141478912","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":"Fractional precipitation of copiapite-halotrichite efflorescent salts on AuCu mine tailings under semi-arid climates in northern Chile","authors":"Javiera Gerding ,&nbsp;Juan Morales ,&nbsp;Alexey A. Novoselov ,&nbsp;Santos Barrios Sánchez","doi":"10.1016/j.gexplo.2024.107536","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107536","url":null,"abstract":"<div><p>The oxidation of pyrite involves a series of chemical reactions that, depending on climatic conditions, can give rise to different mineral phases and morphologies. When oxidation takes place in semi-arid climate, the development of efflorescent salts on the surface of mine tailings is characteristic. These salts are mainly composed of Fe, Al and Mg sulfates and may accumulate valuable metals liberated through the dissolution of tailing minerals.</p><p>This research aims to describe the evolution of salt precipitation from the economic and environmental perspective. For this purpose, we sampled efflorescent salts formed during the summer season on the surface of a tailing impoundment located in the north of Chile. The materials underwent comprehensive characterization utilizing X-ray techniques and scanning electron microscopy.</p><p>The findings reveal a fractional precipitation in the crystallized salts. In an advanced oxidation system, characterized by multiple seasons of crystallization, dissolution and oxidation, the dry season begins with the precipitation of sulfates from a highly acidic solution dominated by Fe³⁺. This solution results from the dissolution and oxidation of the previous season sulfates. This initial stage is characterized by the presence of jarosite and gypsum, which are subsequently replaced by ferricopiapite. Towards the progress of the dry season, copiapite becomes more magnesian and precipitates alongside coquimbite and alunogen. Finally, halotrichite and pickeringite begin to crystallize. Base metal cations such as Co, Cu, Mn, Ni and Zn are preferentially incorporated into halotrichite-pickeringite sulfates during the most advanced evaporation phase.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141479075","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":"Nickel, chromium, and cobalt in soils developed on nickel laterites near an abandoned mining area in southern Czech Republic","authors":"Vojtěch Ettler ,&nbsp;Zuzana Pipková ,&nbsp;Jindřich Kvapil ,&nbsp;Martin Mihaljevič ,&nbsp;Petr Drahota ,&nbsp;Aleš Vaněk ,&nbsp;Vít Penížek","doi":"10.1016/j.gexplo.2024.107529","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107529","url":null,"abstract":"<div><p>Geochemical anomalies are gaining importance due to the Europe's renewed prospecting activities for technologically critical metals, such as nickel (Ni) and cobalt (Co). In this context, soils developed on Ni laterites near old open pit mining and exploration works near Křemže in southern Czech Republic were investigated using multi-method approach to assess the distribution, solid speciation, and (bio)availability of the trace metals, with a particular focus on Ni, chromium (Cr), and Co. The total concentrations of metals in the studied soils (Ni: 170–4950 mg/kg, Cr: 56–1190 mg/kg, Co: 14–424 mg/kg) exceeded the median world regulatory guideline values (Ni: 112 mg/kg; Cr: 250 mg/kg; Co: 50 mg/kg) as well as the Czech concentration limits for agricultural soils for most of the samples. The concentration of metals in the soil profiles generally increased as a function of depth with surface horizons in agricultural plots homogenized by ploughing. The effect of a former open pit mine (already closed for ca 80 years) on the vertical distribution of metallic elements has not been demonstrated. The extractable metals were relatively low (extraction efficiency order: water &lt; DTPA &lt; EDTA). The mean EDTA-extractable values corresponded to 4.2 % Ni_tot, 8.6 % Co_tot, and only 0.14 % Cr_tot. This contrasting metal availability is strictly related to the metal speciation in the solid phase. The primary minerals (olivine, clinopyroxene) are highly weathered to secondary phyllosilicates (lizardite, talc) and Fe oxyhydroxides and Mn oxides, all representing important carriers for Ni. Cobalt was exclusively hosted by Mn oxides, and the less mobile Cr was mainly bound in insoluble phases, likely spinel-family oxides. Despite the relatively low metal availability, elevated concentrations of Ni in the crop biomass (86 mg/kg) collected in the agricultural area suggest a metal uptake from the soil, which should be further investigated in detail.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141478915","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":"Stream sediment geochemical anomaly mapping based on the dynamic enhanced weighted drainage catchment basin method for mineral exploration","authors":"Chang Liu ,&nbsp;Renwei Zhu ,&nbsp;Shi Li ,&nbsp;Zijia Cui ,&nbsp;Jianping Chen ,&nbsp;Jie Zhao","doi":"10.1016/j.gexplo.2024.107535","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107535","url":null,"abstract":"<div><p>Accurately determining the presence of subterranean deposits is challenging due to the intricate geological processes that give rise to these deposits. The use of stream sediment geochemical data to identify and map geochemical anomalies is a widely employed technique in mineral exploration and offers a robust indicator of the possible presence of mineral deposits. This research presents a comparison between the weighted drainage catchment basin (WDCB) technique and its improved version, the dynamic enhanced weighted drainage catchment basin (DE-WDCB) approach, in the context of mineral exploration. We constructed a model of the catchment basin for the study area, clarified the upstream and downstream relationships between the basins, determined the background value in each basin via the trend surface method, and carried out geochemical anomaly mapping based on the DE-WDCB method. Then we conducted two comparative experiments using the WDCB method, employing both dynamic and nondynamic classification methods for anomaly classification. Finally, we compared the mineralization of the three methods and find that the DE-WDCB method exhibited superior performance in identifying sedimentary manganese ore anomalies, followed by the dynamic grading WDCB method and the nondynamic grading WDCB method. These results indicated that the DE-WDCB method revealed excellent performance when applied to stream sediment geochemistry in prospecting, hence enhancing its utility in mineral resource exploration.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141478903","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":"Understanding arsenic and manganese enrichment in the aquifers of the Ghaghara river basin, Middle Gangetic Plain (MGP), India: A multivariate statistical, compositional data analysis (CoDA), and receptor model approach","authors":"Mohd Usman Khan ,&nbsp;Nachiketa Rai ,&nbsp;Mohd Shahwaar ,&nbsp;Mohd Musahib ,&nbsp;Abdur Rahman","doi":"10.1016/j.gexplo.2024.107532","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107532","url":null,"abstract":"<div><p>The focus of this study was to comprehend the spatial distribution, source apportionment, evaluation of natural background level (NBL), and mobilization mechanisms of arsenic (As) and manganese (Mn) in the Ghaghara river basin, located in the middle Gangetic plain (MGP) of India. A combination of analytical tools was employed, including multivariate statistical analysis (MSA), correlation analysis, and receptor models such as positive matrix factorization (PMF) and principal component analysis-multi linear regression (PCA-MLR). Taking into consideration the compositional constraints of the geochemical data, compositional data analysis (CoDA) methods were applied on the raw data prior to the correlation analysis and MSA. The results of MSA, correlation analysis and receptor models showed that major ion chemistry and As, Mn enrichment in groundwater were largely controlled by carbonate weathering, Fe and Mn oxyhydroxides dissolution. Anthropogenic activities, such as the infiltration of dissolved organic matter-rich water from local surface water bodies used as dumping sites and the infiltration of fertilizer-rich water from agricultural lands, were found to notably impact the groundwater geochemistry and release of As in the research area. The lower NBL of As (5.92 μg/L) compared to its mean concentrations (17.9 μg/L) in the study area also indicated that the rate of As release in groundwater through natural processes was comparatively low but various anthropogenic activities operating in the study region possibly acted as a trigger for the mobility of As from the mineral phases of the subsurface sediments. This study also highlighted the significance of applying CoDA techniques on geochemical data prior to statistical analysis, and the importance of receptor models, to better understand the nature and contribution of various natural and anthropogenic processes governing the hydrochemistry of groundwater in the alluvial aquifers.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141539546","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 supergene-hydrothermal origin of the itabirite-hosted high-grade iron ores in the Mbarga prospect, Mbalam iron ore district, southern Cameroon, Congo Craton","authors":"George Lemewihbwen Ngiamte ,&nbsp;Eleanor C.R. Green ,&nbsp;Olugbenga Akindeji Okunlola ,&nbsp;Roland Maas ,&nbsp;Alan Greig ,&nbsp;Cheo Emmanuel Suh","doi":"10.1016/j.gexplo.2024.107517","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107517","url":null,"abstract":"<div><p>The Mbarga itabirite deposit in the Mbalam iron district on the northwest edge of the Congo Craton (CC) hosts two main types of iron ore enrichments: supergene and specularite ores. This study presents mineralogical, geochemical, and isotopic datasets on these ores to determine their genesis.</p><p>Ore microscopic studies indicate that the itabirites are of the oxide facies type, with magnetite showing partial to extensive alteration to hematite-martite. The supergene ores consist of hematite + martite + goethite ± gibbsite ± magnetite ± quartz, while the specularite ores are mainly composed of hematite + martite ± quartz. Magnetite microchemistry suggests formation under low-<em>T</em> hydrothermal conditions (~200–300 °C) with high <em>f</em>O₂. Geochemical analyses show that the supergene and specularite ores have higher Fe₂O₃ (88.27 to ~100 wt%) and lower SiO₂ (&lt;0.01 to 0.18 wt%) contents than the itabirites (31.95 wt% Fe₂O₃, 67.16 wt% SiO₂). The enrichment of Fe in the supergene ores is attributed to the depletion of major oxides and trace elements due to weathering and supergene enrichment, while the high Fe content in the specularite ores stems from the precipitation of iron-rich, but trace- and rare earth elements (REE)-deficient hydrothermal fluids. The slightly higher Al₂O₃ content and positive Ce anomalies in the supergene ores suggest the retention of Al-bearing minerals (gibbsite) and reveal highly oxidative conditions during martitization. Stable isotope analyses reveal that the supergene and specularite ores have δ¹⁸O values of −2.5 to −0.3 ‰ and − 2.0 to −3.4 ‰, and δ²H values of −75 to −123 ‰ and − 70 to −119 ‰, respectively, suggesting the involvement of isotopically light-evolved meteoric water in their formation. In contrast, the itabirites exhibit heavier δ¹⁸O (8.5 to 10.2 ‰) and δ²H (−85 to −91 ‰) values, suggesting formation from mixed magmatic and metamorphic fluid sources. A “polygenic-supergene-hydrothermal” model is suggested for the formation of the Mbarga itabirite-hosted iron ores.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141328326","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":"Organochlorine pesticides in water and sediment at a typical karst wetland in Southwest China","authors":"Qianqian Hu ,&nbsp;Yanpeng Liang ,&nbsp;Honghu Zeng ,&nbsp;Huanfang Huang ,&nbsp;Wenwen Chen ,&nbsp;Litang Qin ,&nbsp;Xiaohong Song ,&nbsp;Xiaoyu Yan","doi":"10.1016/j.gexplo.2024.107519","DOIUrl":"10.1016/j.gexplo.2024.107519","url":null,"abstract":"<div><p>The Huixian karst wetland, situated in southwest China, is the largest karst wetland. Historically, organochlorine pesticides (OCPs) have negatively affected the aquatic environment and the health of surrounding residents. In this study, the pollution status and environmental fate of OCPs in multiple environmental media in the Huixian wetland were investigated. The 15 OCPs' total concentration ranges in lake water, ditch water, groundwater, and lake sediment were 46.8–306 ng·L⁻¹, 77.8–251 ng·L⁻¹, 26.0–233 ng·L⁻¹, and 44.8–345 ng·g⁻¹, respectively. The concentrations and proportions of the different OCPs demonstrated significant seasonality. Historical residues are the main source of OCPs in the region, as evidenced by the typical ratios of DDTs and HCHs. Karst regions are extremely vulnerable to environmental changes, as evidenced by the highly dynamic character of the karst wetland system and the rapid migration of multimodal OCPs in different media without considerable damage. According to the risk assessment, both the possible carcinogenic risk to sediments in the Huixian wetland and the ecological risk to water bodies were acceptable. In contrast, the consumption of lake water may put the local population at health risk, which is a cause of concern.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141279801","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":"Soil-forming accumulation of heavy metals in geological high background areas: Constraints of structure, lithology, and overlying soil geochemistry","authors":"Manzhi Chen ,&nbsp;Xuexian Li ,&nbsp;Xingxing Cao ,&nbsp;Wentao Yang ,&nbsp;Pan Wu ,&nbsp;Haiyang Hao ,&nbsp;Zhijun Fei ,&nbsp;Yining Gao","doi":"10.1016/j.gexplo.2024.107518","DOIUrl":"https://doi.org/10.1016/j.gexplo.2024.107518","url":null,"abstract":"<div><p>Heavy metals (HMs) are often abnormally enriched in soils in geologically high background areas, posing a serious threat to the ecosystem and human health. However, the material origin of HMs in overlying soils is unclear. In this paper, we studied the accumulation control and formation process of HMs (Cd, Hg, As, Pb, Cr, Cu, Ni, and Zn) in soils overlying bedrock from different geological periods in a typical anticline structure area in southwest of Guizhou province. The results revealed that the content of HMs in the bedrock were ranked as Carboniferous carbonate rocks &lt; Permian carbonate rocks &lt; Triassic clastic rocks, while the opposite trend was observed for the HMs content in the overlying soil. The slopes of the EF-Q values of HMs in the soils overlying the Carboniferous, Permian, and Triassic rocks were 0.003, 0.007, and 0.83, respectively, which suggests that HMs enrichment or leaching was more complicated in the process of carbonate weathering soil-forming, whereas it was mainly in situ weathering during the process of clastic weathering soil-forming. The soils overlying the bedrock of the three geological periods experienced similar weathering processes and had the same source of soil-forming matrices, as it was observed that their Fe₂O₃-Al₂O₃, Hf-Zr, Nb-Ta, Th/Sc-Zr/Sc and Y/Ho-Y contents were significantly correlated (with R² values of 0.80, 0.94, 0.72, 0.60, and 0.76, respectively) with very similar REE assignment patterns. The results corroborated the causes of the high background geological heterogeneity of HMs in the overlying soils in karst areas and supported the theory of the source of weathering soil-forming materials from carbonate rocks in karst areas.</p></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141242338","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}