Pub Date : 2025-02-25DOI: 10.1016/j.gexplo.2025.107742
Mi Tian , Chao Wu , Xueqiu Wang , Binbin Sun , Jian Zhou , Qinghai Hu , Wei Wang , Hanliang Liu , Baoyun Zhang , Yu Qiao
Temperature sensitivity of soil respiration (Q10) plays an important role in terrestrial soil carbon-climate feedback. However, Q10 exhibits significant spatial heterogeneity on a large scale, and the factors influencing its spatial variability are not yet fully understood. In this research, we collected Q10 values from 236 field studies in China to explore the spatial heterogeneity and controlling factors of Q10 values at national scale. The relative importance of different climate factors such as annual average temperature (MAT), annual average temperature (MAP) and evapotranspiration (ET), soil geochemical factors including pH, soil organic carbon, soil total nitrogen, C/N, metal oxides, vegetation types and geological backgrounds in predicting Q10 values were explored using a random forest model. The study found that the range of Q10 values in China is 1.17–5.51, with a median of 2.3 and a mean of 2.47. The main influencing factors of the spatial variation of temperature sensitivity of soil respiration Q10 at the national scale are the supply and quality of soil respiration substrates. The more soil organic carbon content, the bigger the Q10. The more difficult it is to decompose (the more complex the molecular structure presented by correlations between Q10 and C/N, and the more mineral-bounded organic carbon presented by correlations between Q10 and FeO), the stronger the temperature sensitivity of soil respiration. In comparison, the influence of climate factors on Q10 is less important and complex, Q10 increases nonlinearly with the increase of ET and decreases with the increase of temperature. The Q10 value is higher when the precipitation is moderate (800-1200 mm), and decreases when there is excessive or insufficient rainfall. In summary, the interaction between soil geochemical factors and climate controls the storage and turnover of soil organic carbon, and soil geochemistry plays the most important role. The results of this study are helpful for accurately assessing the global soil organic carbon storage and spatiotemporal changes, and are of great significance for studying the feedback mechanism of organic carbon under the background of global carbon cycle and global warming.
{"title":"Spatial heterogeneity and driving factors of temperature sensitivity of soil respiration (Q10) at national scale","authors":"Mi Tian , Chao Wu , Xueqiu Wang , Binbin Sun , Jian Zhou , Qinghai Hu , Wei Wang , Hanliang Liu , Baoyun Zhang , Yu Qiao","doi":"10.1016/j.gexplo.2025.107742","DOIUrl":"10.1016/j.gexplo.2025.107742","url":null,"abstract":"<div><div>Temperature sensitivity of soil respiration (Q10) plays an important role in terrestrial soil carbon-climate feedback. However, Q10 exhibits significant spatial heterogeneity on a large scale, and the factors influencing its spatial variability are not yet fully understood. In this research, we collected Q10 values from 236 field studies in China to explore the spatial heterogeneity and controlling factors of Q10 values at national scale. The relative importance of different climate factors such as annual average temperature (MAT), annual average temperature (MAP) and evapotranspiration (ET), soil geochemical factors including pH, soil organic carbon, soil total nitrogen, C/N, metal oxides, vegetation types and geological backgrounds in predicting Q10 values were explored using a random forest model. The study found that the range of Q10 values in China is 1.17–5.51, with a median of 2.3 and a mean of 2.47. The main influencing factors of the spatial variation of temperature sensitivity of soil respiration Q10 at the national scale are the supply and quality of soil respiration substrates. The more soil organic carbon content, the bigger the Q10. The more difficult it is to decompose (the more complex the molecular structure presented by correlations between Q10 and C/N, and the more mineral-bounded organic carbon presented by correlations between Q10 and FeO), the stronger the temperature sensitivity of soil respiration. In comparison, the influence of climate factors on Q10 is less important and complex, Q10 increases nonlinearly with the increase of ET and decreases with the increase of temperature. The Q10 value is higher when the precipitation is moderate (800-1200 mm), and decreases when there is excessive or insufficient rainfall. In summary, the interaction between soil geochemical factors and climate controls the storage and turnover of soil organic carbon, and soil geochemistry plays the most important role. The results of this study are helpful for accurately assessing the global soil organic carbon storage and spatiotemporal changes, and are of great significance for studying the feedback mechanism of organic carbon under the background of global carbon cycle and global warming.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"273 ","pages":"Article 107742"},"PeriodicalIF":3.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562392","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}
Pub Date : 2025-02-25DOI: 10.1016/j.gexplo.2025.107731
Diego Arán , Adelaida Patrasc-Lungu , Amaia Nogales , Maria Manuela Abreu , Erika S. Santos
Soil degradation caused by the mining activities is one of the major impacts and challenges for society. Nature-based solutions, such as Technosols, are an alternative for their recovery, which can be accelerated by the use of microorganisms. The objective of this study was to evaluate the viability of implementing risk-free grazing land on sulfide-rich tailings recovered with a Tecnosol with/without a fungal inoculum (Rhizoglomus irregulare and Trichoderma sp.). A mesocosm assay was carried out, under greenhouse and controlled conditions, with sulfide-rich tailings from the Aznalcóllar mine and a Technosol designed with alkaline and eutrophic properties for eight months. Three treatments were established (Tailing + Technosol with fungal inoculation (YM), Tailing + Technosol without fungal inoculation (NM), and Tailing with fungal inoculation (Control)) and a commercial pasture was sown. Several parameters related to the materials collected in each treatment, plant development and multielemental composition of the shoots in two growth cycles were determined. The single application of the fungal inoculum was not sufficient to improve the sulfide-rich tailings and to allow plant germination. Independently of the inoculum application, the Technosol improved the physico-chemical characteristics of the tailings (e.g., increased pH, fertility and decreased the availability of potentially toxic elements). Shoots from the YM and NM treatments showed no significant differences in yield and development and no any risk to animal consumption. The results confirmed that sulfide-rich tailings can be environmentally recovered and socio-economically valorized through the application of a Technosol and pasture land.
{"title":"Valorization of sulfide rich tailings with nature-based solutions for pasture lands","authors":"Diego Arán , Adelaida Patrasc-Lungu , Amaia Nogales , Maria Manuela Abreu , Erika S. Santos","doi":"10.1016/j.gexplo.2025.107731","DOIUrl":"10.1016/j.gexplo.2025.107731","url":null,"abstract":"<div><div>Soil degradation caused by the mining activities is one of the major impacts and challenges for society. Nature-based solutions, such as Technosols, are an alternative for their recovery, which can be accelerated by the use of microorganisms. The objective of this study was to evaluate the viability of implementing risk-free grazing land on sulfide-rich tailings recovered with a Tecnosol with/without a fungal inoculum (<em>Rhizoglomus irregulare</em> and <em>Trichoderma</em> sp.). A mesocosm assay was carried out, under greenhouse and controlled conditions, with sulfide-rich tailings from the Aznalcóllar mine and a Technosol designed with alkaline and eutrophic properties for eight months. Three treatments were established (Tailing + Technosol with fungal inoculation (YM), Tailing + Technosol without fungal inoculation (NM), and Tailing with fungal inoculation (Control)) and a commercial pasture was sown. Several parameters related to the materials collected in each treatment, plant development and multielemental composition of the shoots in two growth cycles were determined. The single application of the fungal inoculum was not sufficient to improve the sulfide-rich tailings and to allow plant germination. Independently of the inoculum application, the Technosol improved the physico-chemical characteristics of the tailings (e.g., increased pH, fertility and decreased the availability of potentially toxic elements). Shoots from the YM and NM treatments showed no significant differences in yield and development and no any risk to animal consumption. The results confirmed that sulfide-rich tailings can be environmentally recovered and socio-economically valorized through the application of a Technosol and pasture land.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"273 ","pages":"Article 107731"},"PeriodicalIF":3.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508830","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}
Pub Date : 2025-02-25DOI: 10.1016/j.gexplo.2025.107740
Shaofeng Xie , Zhankun Liu , Xiancheng Mao , Cheng Wang , Longbo Li
Improving the understanding of fluid migration and mineralization localization within epithermal gold systems is of utmost significance for mineral exploration. In this study, a series of numerical simulation experiments were carried out at the Axi low-sulfidation epithermal gold deposit in western China under variable stress conditions by employing the FLAC3D software. The objective was to explore the fluid migration process during the ore-forming period. The results demonstrate that the extensional deformation and fluid migration patterns of simple compressive or tensional model cannot yield the known mineralization distribution, while the corrected 30° tension model leads to sinistral strike-slip, resulting in the current gold mineralization pattern. The NE-trending fault extension zone associated with the deformation setting is inferred as the migration pathway of the deep-seated ore-forming fluids. Several deep fluid migration pathways beneath the known mineralization are determined. Numerical simulation of the metallogenic process reveals that the fault structure controls the scale and extent of fluid migration. The gold distribution in the Axi deposit can be ascribed to shear strain localization, the development of dilation, and the focusing of fluids into the dilatant fault. By means of thermo-fluid-mechanical coupling, the models have generated several potential gold mineralization targets in the southern and northern segments. This case study emphasizes that the mineralization of the Axi gold deposit is predominantly controlled by fault geometry associated with specific stress directions and demonstrates that numerical modeling is a robust tool for identifying potential mineralization.
{"title":"Ore-forming simulation of the Axi low-sulfidation epithermal gold deposit, Western China: Genetic implications on mineralization pattern","authors":"Shaofeng Xie , Zhankun Liu , Xiancheng Mao , Cheng Wang , Longbo Li","doi":"10.1016/j.gexplo.2025.107740","DOIUrl":"10.1016/j.gexplo.2025.107740","url":null,"abstract":"<div><div>Improving the understanding of fluid migration and mineralization localization within epithermal gold systems is of utmost significance for mineral exploration. In this study, a series of numerical simulation experiments were carried out at the Axi low-sulfidation epithermal gold deposit in western China under variable stress conditions by employing the FLAC<sup>3D</sup> software. The objective was to explore the fluid migration process during the ore-forming period. The results demonstrate that the extensional deformation and fluid migration patterns of simple compressive or tensional model cannot yield the known mineralization distribution, while the corrected 30° tension model leads to sinistral strike-slip, resulting in the current gold mineralization pattern. The NE-trending fault extension zone associated with the deformation setting is inferred as the migration pathway of the deep-seated ore-forming fluids. Several deep fluid migration pathways beneath the known mineralization are determined. Numerical simulation of the metallogenic process reveals that the fault structure controls the scale and extent of fluid migration. The gold distribution in the Axi deposit can be ascribed to shear strain localization, the development of dilation, and the focusing of fluids into the dilatant fault. By means of thermo-fluid-mechanical coupling, the models have generated several potential gold mineralization targets in the southern and northern segments. This case study emphasizes that the mineralization of the Axi gold deposit is predominantly controlled by fault geometry associated with specific stress directions and demonstrates that numerical modeling is a robust tool for identifying potential mineralization.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"273 ","pages":"Article 107740"},"PeriodicalIF":3.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143549609","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}
Pub Date : 2025-02-25DOI: 10.1016/j.gexplo.2025.107732
Anicia Henne , Ellishia Schmidtke , Ryan R.P. Noble , Dave Craw , Michael Verrall , Mario Iglesias-Martinez , Robert Thorne
With the rising interest in rare earth element (REE) exploration in Australia and beyond, the focus of many greenfields exploration campaigns is on identifying the best methods for recovery of REE from soils to better define exploration targets. In this study, we compared analyses of the ultrafine (<2 μm) fraction of soils with more traditional soil alkaline fusion analysis of the bulk soil fraction at two regolith-hosted REE prospects near Esperance, Western Australia. We complement this data with sequential leaching and scanning electron microscopy on soils to establish where REE are hosted within the samples and to investigate the potential causes for differences in REE abundancies recovered via the two soil analytical methods. At both sites, the majority of REE in mineralised downhole samples were hosted in REE-bearing phosphates. The primary REE sources have been altered within the regolith via oxidation and re-precipitation. Altered and disaggregated primary and secondary REE-minerals are now hosted in clays and altered micas, and <1 % of REE are ionically bound to the clays in soils. Recovery of REE from the ultrafine fraction of soils was generally higher than via alkaline fusion. Correlation between the two methods was only moderate because of the “nugget effect” of particles >5 μm. Soils have been physically transported downslope and REE occur as detrital mineral particles, some of which are encapsulated in other detrital minerals. By excluding the larger REE ‘nuggets’ the ultrafine fraction results return more consistent results of the detrital fraction in transported soils. Our study highlights the importance of understanding landscape context for analysis and interpretation of exploration soil samples.
{"title":"Implications of mineralogy, textures and landscape context on surface exploration of rare earth elements: A comparison of soil analytical methods near Esperance, Western Australia","authors":"Anicia Henne , Ellishia Schmidtke , Ryan R.P. Noble , Dave Craw , Michael Verrall , Mario Iglesias-Martinez , Robert Thorne","doi":"10.1016/j.gexplo.2025.107732","DOIUrl":"10.1016/j.gexplo.2025.107732","url":null,"abstract":"<div><div>With the rising interest in rare earth element (REE) exploration in Australia and beyond, the focus of many greenfields exploration campaigns is on identifying the best methods for recovery of REE from soils to better define exploration targets. In this study, we compared analyses of the ultrafine (<2 μm) fraction of soils with more traditional soil alkaline fusion analysis of the bulk soil fraction at two regolith-hosted REE prospects near Esperance, Western Australia. We complement this data with sequential leaching and scanning electron microscopy on soils to establish where REE are hosted within the samples and to investigate the potential causes for differences in REE abundancies recovered via the two soil analytical methods. At both sites, the majority of REE in mineralised downhole samples were hosted in REE-bearing phosphates. The primary REE sources have been altered within the regolith via oxidation and re-precipitation. Altered and disaggregated primary and secondary REE-minerals are now hosted in clays and altered micas, and <1 % of REE are ionically bound to the clays in soils. Recovery of REE from the ultrafine fraction of soils was generally higher than via alkaline fusion. Correlation between the two methods was only moderate because of the “nugget effect” of particles >5 μm. Soils have been physically transported downslope and REE occur as detrital mineral particles, some of which are encapsulated in other detrital minerals. By excluding the larger REE ‘nuggets’ the ultrafine fraction results return more consistent results of the detrital fraction in transported soils. Our study highlights the importance of understanding landscape context for analysis and interpretation of exploration soil samples.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"274 ","pages":"Article 107732"},"PeriodicalIF":3.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580757","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}
Pub Date : 2025-02-25DOI: 10.1016/j.gexplo.2025.107739
Jun Liu , Wenchang Li , Qing Zhou , Tongzhu Li , Huihua Zhang , Yanpei Dai , Zhihui Dai , Zhanwu Shen , Dan Chen
Metasedimentary rock-hosted stratiform Cu-Co (MSC) deposits are one of the important types of Co deposits. Previous research has primarily concentrated on Cu mineralization, while the occurrence, source, and enrichment process of Co remain poorly understood. In this study, we conducted LA-ICP-MS elemental analysis of the primary sulfides (pyrrhotite, chalcopyrite, and sphalerite) from the Heiniudong MSC deposit, the largest of its kind in western Sichuan, China. The results indicate that Co in Heiniudong primarily exists as isomorphic substitutions within pyrrhotite (393–1222 ppm) and sphalerite (162–393 ppm), with a possible substitution mechanism of Co2+ ↔ (Fe, Zn)2+. Additionally, Co is occasionally present as costibite and micro- to nano-inclusions within chalcopyrite. The Cu and Co elements in the Heiniudong deposit exhibit homologous relationships, primarily originating from the Liwu Group during the early stages of mineralization. Furthermore, contributions from other geological end-members may also be present during this main mineralization stage. The Co enrichment observed in the Heiniudong deposit can be attributed to complex multi-stage geological processes, mainly including (1) initial Co enrichment during the sedimentary-diagenetic stage, (2) early activation induced by tectonic and metamorphic events, and (3) re-enrichment following hydrothermal superposition and transformation events. Owing to its unique properties, Co exhibits a remarkable tendency to progressively accumulate in recrystallized sulfides of the Heiniudong deposit over geological time.
{"title":"Occurrence, source, and enrichment process of cobalt from the Heiniudong metasedimentary rock-hosted stratiform Cu-Co polymetallic deposit, western Sichuan, China","authors":"Jun Liu , Wenchang Li , Qing Zhou , Tongzhu Li , Huihua Zhang , Yanpei Dai , Zhihui Dai , Zhanwu Shen , Dan Chen","doi":"10.1016/j.gexplo.2025.107739","DOIUrl":"10.1016/j.gexplo.2025.107739","url":null,"abstract":"<div><div>Metasedimentary rock-hosted stratiform Cu-Co (MSC) deposits are one of the important types of Co deposits. Previous research has primarily concentrated on Cu mineralization, while the occurrence, source, and enrichment process of Co remain poorly understood. In this study, we conducted LA-ICP-MS elemental analysis of the primary sulfides (pyrrhotite, chalcopyrite, and sphalerite) from the Heiniudong MSC deposit, the largest of its kind in western Sichuan, China. The results indicate that Co in Heiniudong primarily exists as isomorphic substitutions within pyrrhotite (393–1222 ppm) and sphalerite (162–393 ppm), with a possible substitution mechanism of Co<sup>2+</sup> ↔ (Fe, Zn)<sup>2+</sup>. Additionally, Co is occasionally present as costibite and micro- to nano-inclusions within chalcopyrite. The Cu and Co elements in the Heiniudong deposit exhibit homologous relationships, primarily originating from the Liwu Group during the early stages of mineralization. Furthermore, contributions from other geological end-members may also be present during this main mineralization stage. The Co enrichment observed in the Heiniudong deposit can be attributed to complex multi-stage geological processes, mainly including (1) initial Co enrichment during the sedimentary-diagenetic stage, (2) early activation induced by tectonic and metamorphic events, and (3) re-enrichment following hydrothermal superposition and transformation events. Owing to its unique properties, Co exhibits a remarkable tendency to progressively accumulate in recrystallized sulfides of the Heiniudong deposit over geological time.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"273 ","pages":"Article 107739"},"PeriodicalIF":3.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508829","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}
Pub Date : 2025-02-25DOI: 10.1016/j.gexplo.2025.107736
Zaizhi Yang , Tao Jiang , Zuobin Liang , Xinfeng Zhao , Kun Ren , Di Tian , Lei Gao , Qirui Wu , Shaoheng Li , Rui Li , Lichun Xie , Jianyao Chen
This study investigated long-term hydrochemical data from the main channel (Beijiang) and three tributaries (Lianjiang, Wujiang, and Zhenjiang) in the middle and upper Beijiang River, the second-largest tributary of the Pearl River, from 1985 to 2023. The results showed that Ca2+ (>44.1 %) and HCO₃− (>76.17 %) are the dominant cation and anion, respectively. These results indicate that weathering of carbonates and silicates was the primary natural factor influencing riverine chemistry in the basin. Total dissolved solids (TDS) fluctuated between 33.3 and 399 mg/L and pH between 6.5 and 9.2, with the highest TDS levels in Wujiang (191 mg/L), followed by Lianjiang (175 mg/L), Beijiang (149 mg/L), and Zhenjiang (84.7 mg/L). The TDS trend in Beijiang exhibited a significant decline before 2001, followed by a subsequent increase, while the average concentrations of acidic substances (Cl−, NO₃−, and SO₄2−) increased by >38 %, while pH value does not decrease in response to the elevated SO₄2− due to dissolution of carbonate. Ion concentrations mostly decline with discharge rate, except for NO₃−, which showed transport limitation and enrichment with increasing discharge rate. The ion flux patterns were classified as discharge-dominated or concentration-dominated. The annual TDS flux of Beijiang was approximately 5.0 × 106 tons and the ionic runoff modulus was 148.4 t·km−2·yr−1, which was relatively high compared to that of other rivers in the world. The correlation between ions concentrations and socioeconomic factors suggests that socio-economic activities significantly influence water chemistry. Industrial relocation and large hydraulics project may lead to abrupt fluctuations and sustained increases in water chemistry parameters. The generalized additive models showed that natural factors explained 40.8–50.7 % of the deviance, while socioeconomic factors related to anthropogenic activities explained >79.5 % due to increasing SO₄2−, NO₃− and Cl− trends. Given the importance of the river to the Guangdong–Hong Kong–Macao Greater Bay Area, enhanced management and monitoring are needed to protect the regional water supply.
{"title":"Evolution of and mechanisms controlling water chemistry in the Beijiang River Basin over the past four decades","authors":"Zaizhi Yang , Tao Jiang , Zuobin Liang , Xinfeng Zhao , Kun Ren , Di Tian , Lei Gao , Qirui Wu , Shaoheng Li , Rui Li , Lichun Xie , Jianyao Chen","doi":"10.1016/j.gexplo.2025.107736","DOIUrl":"10.1016/j.gexplo.2025.107736","url":null,"abstract":"<div><div>This study investigated long-term hydrochemical data from the main channel (Beijiang) and three tributaries (Lianjiang, Wujiang, and Zhenjiang) in the middle and upper Beijiang River, the second-largest tributary of the Pearl River, from 1985 to 2023. The results showed that Ca<sup>2+</sup> (>44.1 %) and HCO₃<sup>−</sup> (>76.17 %) are the dominant cation and anion, respectively. These results indicate that weathering of carbonates and silicates was the primary natural factor influencing riverine chemistry in the basin. Total dissolved solids (TDS) fluctuated between 33.3 and 399 mg/L and pH between 6.5 and 9.2, with the highest TDS levels in Wujiang (191 mg/L), followed by Lianjiang (175 mg/L), Beijiang (149 mg/L), and Zhenjiang (84.7 mg/L). The TDS trend in Beijiang exhibited a significant decline before 2001, followed by a subsequent increase, while the average concentrations of acidic substances (Cl<sup>−</sup>, NO₃<sup>−</sup>, and SO₄<sup>2−</sup>) increased by >38 %, while pH value does not decrease in response to the elevated SO₄<sup>2−</sup> due to dissolution of carbonate. Ion concentrations mostly decline with discharge rate, except for NO₃<sup>−</sup>, which showed transport limitation and enrichment with increasing discharge rate. The ion flux patterns were classified as discharge-dominated or concentration-dominated. The annual TDS flux of Beijiang was approximately 5.0 × 10<sup>6</sup> tons and the ionic runoff modulus was 148.4 t·km<sup>−2</sup>·yr<sup>−1</sup>, which was relatively high compared to that of other rivers in the world. The correlation between ions concentrations and socioeconomic factors suggests that socio-economic activities significantly influence water chemistry. Industrial relocation and large hydraulics project may lead to abrupt fluctuations and sustained increases in water chemistry parameters. The generalized additive models showed that natural factors explained 40.8–50.7 % of the deviance, while socioeconomic factors related to anthropogenic activities explained >79.5 % due to increasing SO₄<sup>2−</sup>, NO₃<sup>−</sup> and Cl<sup>−</sup> trends. Given the importance of the river to the Guangdong–Hong Kong–Macao Greater Bay Area, enhanced management and monitoring are needed to protect the regional water supply.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"273 ","pages":"Article 107736"},"PeriodicalIF":3.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511215","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}
Pub Date : 2025-02-21DOI: 10.1016/j.gexplo.2025.107710
J. Fernández-Suárez , Vera Pawlowsky-Glahn , J.J. Egozcue
A growing number of researchers in the Earth Science community use the information provided by the UPb ages of detrital zircon in sedimentary environments, be these modern (sediments) or ancient (sedimentary or metasedimentary rocks). This information is key to understanding detritus's past and present flow on Earth and its attendant geological implications. An essential component of the investigation concerning detrital zircon age distributions (DZD) and their bearing on several sedimentological, tectonic, geodynamic, paleogeographic, or climatic issues is to compare DZD from different samples. Much theoretical and empirical research has been devoted to ascertaining how to best compare and measure the dissimilarity/distance between DZDs. This ongoing endeavour has generated a variety of metrics and statistical procedures to perform such tasks. In this contribution, a metric based on the Aitchison distance to measure the dissimilarity of any given set of DZD (samples represented by density functions) is presented. The Aitchison distance is used in the reference framework of the Bayes-Hilbert spaces, whose properties help to avoid some of the limitations of previously used metrics. The mathematical and methodological foundations are presented and illustrated with three geological examples taken from the recent literature, using both sedimentary rocks and recent sediments in different geological and geographical settings. The proposed approach results in a consistent statistical tool to determine whether a set of samples is likely to be derived from a common source or, at least, from indistinguishable sources based on DZD data alone.
{"title":"Detrital zircon age distributions in Bayes-Hilbert spaces","authors":"J. Fernández-Suárez , Vera Pawlowsky-Glahn , J.J. Egozcue","doi":"10.1016/j.gexplo.2025.107710","DOIUrl":"10.1016/j.gexplo.2025.107710","url":null,"abstract":"<div><div>A growing number of researchers in the Earth Science community use the information provided by the U<img>Pb ages of detrital zircon in sedimentary environments, be these modern (sediments) or ancient (sedimentary or metasedimentary rocks). This information is key to understanding detritus's past and present flow on Earth and its attendant geological implications. An essential component of the investigation concerning detrital zircon age distributions (DZD) and their bearing on several sedimentological, tectonic, geodynamic, paleogeographic, or climatic issues is to compare DZD from different samples. Much theoretical and empirical research has been devoted to ascertaining how to best compare and measure the dissimilarity/distance between DZDs. This ongoing endeavour has generated a variety of metrics and statistical procedures to perform such tasks. In this contribution, a metric based on the Aitchison distance to measure the dissimilarity of any given set of DZD (samples represented by density functions) is presented. The Aitchison distance is used in the reference framework of the Bayes-Hilbert spaces, whose properties help to avoid some of the limitations of previously used metrics. The mathematical and methodological foundations are presented and illustrated with three geological examples taken from the recent literature, using both sedimentary rocks and recent sediments in different geological and geographical settings. The proposed approach results in a consistent statistical tool to determine whether a set of samples is likely to be derived from a common source or, at least, from indistinguishable sources based on DZD data alone.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"273 ","pages":"Article 107710"},"PeriodicalIF":3.4,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471203","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}
<div><div>Within the Bou Azzer El Graara inlier, Morocco, the analysis of hydrothermal alteration along the N120 and N040 composite faults hosting Co<img>Ni mineralization is of major importance in evaluation of petrogenesis and exploration potential. This research aims to address this through the use remote sensing data followed up with fieldwork linked with detailed sampling with follow-up petrographic and geochemical analyses. The combination of these approaches reveals a strong relationship between brittle deformation and hydrothermal alteration and mineralization, with zonation from core to fault margin; these variably mineralized faults cross-cut the <em>syn</em>- to late-collisional Cryogenian Aït Ahmane and Ousdrat plutons. The mineralization and alteration is also visible at the nodes between the N120 and N040 faults. The Chlorite-Carbonate-Pyrite Index (CCPI) is used to generally geochemically characterize the alteration associated with the Co<img>Ni mineralization in Bou Azzer. The moderately low CCPI and high Alteration Index (AI) support the observations that sericite, propylitic, and chlorite alteration types are spatially associated with these mineralized veins. As a mineral exploration tool, we have adopted appropriate methods by calculating the Molar Element Ratios (MER) (precisely: PER and GER diagrams) and mass changes. These MER diagrams show that the samples from faulted zones in two quartz diorite plutons are the traps of K-Mg-Ca-Si metasomatism linked to gains of these elements with the probable release of others elements, such as Fe and Mg. Closer to the vein core, this metasomatism intensifies and can be correlated with some base and strategic metals (Co-Ni-As-Cu-Pb-Zn-Ag) forming an ore assemblage with rammelsbergite, skutterudite, nickeline, cobaltite, loellingite, and other sulfide species, etc. This ore assemblage is probably formed during the cycling of the ductile-brittle transition during epidodic faulting and fluid flow. The examination of the distribution and abundance of propylitic, chloritic, sericitic, and carbonate alteration and the analysis of mass change exhibit a gain of K, Ca, and Mg and significant loss of Si and Fe linked to those alteration types; these alteration features are regionally extensive, possibly considered as a geochemical 6. In addition, the intermediate plutons that host alteration-mineralization have changed from Mg-Ca-Fe to K-Mg-Si alteration assemblages; these are linked to the cogenetic mineralization episode (along the NE-veins), and triggered by the reactivation of NW-SE contact zones, with remobilization, and the generation of NE-SW faults. Following these findings, we propose that these faults, which were generated during the late Pan-African and the early Cadomian orogenies, respectively, are a good structural and geochemical metallotect. As such, they deserve in-depth study within a framework of regional exploration in the Bou-Azzer El Graara inlier and throughout the Anti Atla
{"title":"Quantification of hydrothermal alteration in Co-Ni-rich mineralized structures along fault segments crossing the Aït Ahmane and Ousdrat plutons, Bou Azzer El-Graara inlier, Central Anti-Atlas: Implications for genesis and mineral exploration","authors":"Saber Salmi , Ezzoura Errami , Abdellatif Jouhari , David R. Lentz , Mourad Essalhi , Omar Outaaoui , Nacer Ennih , Lhoussayn Ouhoussa , Abdelhaq Karfal","doi":"10.1016/j.gexplo.2025.107712","DOIUrl":"10.1016/j.gexplo.2025.107712","url":null,"abstract":"<div><div>Within the Bou Azzer El Graara inlier, Morocco, the analysis of hydrothermal alteration along the N120 and N040 composite faults hosting Co<img>Ni mineralization is of major importance in evaluation of petrogenesis and exploration potential. This research aims to address this through the use remote sensing data followed up with fieldwork linked with detailed sampling with follow-up petrographic and geochemical analyses. The combination of these approaches reveals a strong relationship between brittle deformation and hydrothermal alteration and mineralization, with zonation from core to fault margin; these variably mineralized faults cross-cut the <em>syn</em>- to late-collisional Cryogenian Aït Ahmane and Ousdrat plutons. The mineralization and alteration is also visible at the nodes between the N120 and N040 faults. The Chlorite-Carbonate-Pyrite Index (CCPI) is used to generally geochemically characterize the alteration associated with the Co<img>Ni mineralization in Bou Azzer. The moderately low CCPI and high Alteration Index (AI) support the observations that sericite, propylitic, and chlorite alteration types are spatially associated with these mineralized veins. As a mineral exploration tool, we have adopted appropriate methods by calculating the Molar Element Ratios (MER) (precisely: PER and GER diagrams) and mass changes. These MER diagrams show that the samples from faulted zones in two quartz diorite plutons are the traps of K-Mg-Ca-Si metasomatism linked to gains of these elements with the probable release of others elements, such as Fe and Mg. Closer to the vein core, this metasomatism intensifies and can be correlated with some base and strategic metals (Co-Ni-As-Cu-Pb-Zn-Ag) forming an ore assemblage with rammelsbergite, skutterudite, nickeline, cobaltite, loellingite, and other sulfide species, etc. This ore assemblage is probably formed during the cycling of the ductile-brittle transition during epidodic faulting and fluid flow. The examination of the distribution and abundance of propylitic, chloritic, sericitic, and carbonate alteration and the analysis of mass change exhibit a gain of K, Ca, and Mg and significant loss of Si and Fe linked to those alteration types; these alteration features are regionally extensive, possibly considered as a geochemical 6. In addition, the intermediate plutons that host alteration-mineralization have changed from Mg-Ca-Fe to K-Mg-Si alteration assemblages; these are linked to the cogenetic mineralization episode (along the NE-veins), and triggered by the reactivation of NW-SE contact zones, with remobilization, and the generation of NE-SW faults. Following these findings, we propose that these faults, which were generated during the late Pan-African and the early Cadomian orogenies, respectively, are a good structural and geochemical metallotect. As such, they deserve in-depth study within a framework of regional exploration in the Bou-Azzer El Graara inlier and throughout the Anti Atla","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"273 ","pages":"Article 107712"},"PeriodicalIF":3.4,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453530","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}
Pub Date : 2025-02-14DOI: 10.1016/j.gexplo.2025.107705
Sidy Morin-Ka , Ignacio González-Álvarez , Paul Duuring , Christopher M. Gonzalez
Heavy mineral sands (HMS) represent an alternative major resource of Rare Earth Elements (REE) deposits with over 90 % of these formed within the past 66 Myr. These deposits exhibit a diverse range of mineral compositions (i.e. ilmenite, rutile, zircon, monazite, xenotime, and garnet) and can be formed from a wide range of geological and surficial processes. However, few studies examined the in-depth geological characteristics and exploration strategies to specifically target HMS mineralisation, and particularly none have specifically focussed on the REE component of these deposits. Here we show a total of 1173 REE-HMS deposits that exhibit diverse heavy mineral compositions. The largest REE-HMS deposits show an average heavy mineral grade of 7 % (SD = 12) and an average resource size of 1337 Mt. (SD = 1932). REE-HMS deposits commonly concentrate along Quaternary coastlines that cluster within a 100 km radius and predominate in tropical humid areas within 25 degrees north and south of the Equator. Yet, 40 % of large REE-HMS deposits formed during the Neogene, Paleogene, and Cretaceous situated inland from modern coastlines. Another feature of REE-HMS clusters shows that coastal areas that are protected from major global oceanic currents show a higher prevalence than regions that remain unprotected. REE-HMS deposits originate from rocks found in high-grade metamorphic belts, orogenic belts, and cratons, transported by wind and well-developed river systems, particularly in tropical and humid climates. This study highlights the importance of geological, climatic, and surface process factors in shaping the distribution of REE-HMS deposits. Furthermore, we also consider socioeconomic factors, such as land accessibility, politics, exploration maturity, and market demand playing crucial roles. A mineral exploration approach is proposed that emphasises the use of specific datasets and exploration methodologies tailored to the footprints of REE-HMS deposits. Overall, this study's findings contribute to a better understanding of REE-HMS deposits, providing insights for future exploration and resource management.
{"title":"Understanding rare earth elements in heavy mineral sand systems","authors":"Sidy Morin-Ka , Ignacio González-Álvarez , Paul Duuring , Christopher M. Gonzalez","doi":"10.1016/j.gexplo.2025.107705","DOIUrl":"10.1016/j.gexplo.2025.107705","url":null,"abstract":"<div><div>Heavy mineral sands (HMS) represent an alternative major resource of Rare Earth Elements (REE) deposits with over 90 % of these formed within the past 66 Myr. These deposits exhibit a diverse range of mineral compositions (i.e. ilmenite, rutile, zircon, monazite, xenotime, and garnet) and can be formed from a wide range of geological and surficial processes. However, few studies examined the in-depth geological characteristics and exploration strategies to specifically target HMS mineralisation, and particularly none have specifically focussed on the REE component of these deposits. Here we show a total of 1173 REE-HMS deposits that exhibit diverse heavy mineral compositions. The largest REE-HMS deposits show an average heavy mineral grade of 7 % (SD = 12) and an average resource size of 1337 Mt. (SD = 1932). REE-HMS deposits commonly concentrate along Quaternary coastlines that cluster within a 100 km radius and predominate in tropical humid areas within 25 degrees north and south of the Equator. Yet, 40 % of large REE-HMS deposits formed during the Neogene, Paleogene, and Cretaceous situated inland from modern coastlines. Another feature of REE-HMS clusters shows that coastal areas that are protected from major global oceanic currents show a higher prevalence than regions that remain unprotected. REE-HMS deposits originate from rocks found in high-grade metamorphic belts, orogenic belts, and cratons, transported by wind and well-developed river systems, particularly in tropical and humid climates. This study highlights the importance of geological, climatic, and surface process factors in shaping the distribution of REE-HMS deposits. Furthermore, we also consider socioeconomic factors, such as land accessibility, politics, exploration maturity, and market demand playing crucial roles. A mineral exploration approach is proposed that emphasises the use of specific datasets and exploration methodologies tailored to the footprints of REE-HMS deposits. Overall, this study's findings contribute to a better understanding of REE-HMS deposits, providing insights for future exploration and resource management.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"274 ","pages":"Article 107705"},"PeriodicalIF":3.4,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610333","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}
Pub Date : 2025-02-11DOI: 10.1016/j.gexplo.2025.107703
Hu Peng , Yangquan Jiao , Xiaofei Fu , Liqun Wu , Xiaodan Guo , Qingshuang Wang , Chao Liu
The study of uranium sources in sandstone-type uranium deposits has been significantly hindered by the absence of effective methodologies, thereby impeding uranium resource exploration efforts. This paper delves into the origin and evolution of sandstone-type uranium deposits, particularly in two newly discovered mineral localities in the southeastern Songliao Basin, employing zircon UPb geochronology and petrogeochemistry. Additionally, it examines the evolutionary history of these deposits within the Paleo-Asian Ocean tectonic domain. The research reveals that the uranium-bearing series in the study area primarily originate from intermediate-acid magmatic rocks located in the active belt of the northern margin of the North China Craton and the continental island arc tectonic environment. The detrital zircon in the uranium reservoir sandstone, with a peak age range of 270–236 Ma, bears witness to the orogenic events involving the subduction, closure, and collision of the Paleo-Asian Ocean and the back-arc ocean basin. Meanwhile, the peak age range of 181–154 Ma signifies the Paleo-Pacific Ocean subduction impact in the study area. A comprehensive comparative analysis of zircon UPb chronology and lithogeochemistry indicates that the highly differentiated granite (Baijiagou Pluton), which mixed with the crust in the Early Triassic syn-collisional orogenic environment, serves as a promising source of uranium in the study area. By utilizing the differences in weathering resistance between zircon and rock, specifically the stable Th/U ratio in zircon and the unstable Th/U ratio in rocks, this relationship can be used to trace favorable uranium sources. This method provides an effective approach for identifying uranium sources in the exploration of sedimentary uranium deposits. The ocean-arc system present on the active continental margins of the Paleo-Asian Ocean's northern and southern sides continuously facilitates the material cycle of uranium rich sediments and magmatic uranium elements. This process, coupled with multi-stage and multi-material magmatism, ultimately leads to the formation of a favorable uranium rich geological body. This serves as the material and uranium source basis for the formation of sedimentary uranium deposits in northern China.
{"title":"Provenance and uranium source tracing for uranium-bearing series in the south of Songliao Basin: Evidence from zircon UPb chronology and lithogeochemistry","authors":"Hu Peng , Yangquan Jiao , Xiaofei Fu , Liqun Wu , Xiaodan Guo , Qingshuang Wang , Chao Liu","doi":"10.1016/j.gexplo.2025.107703","DOIUrl":"10.1016/j.gexplo.2025.107703","url":null,"abstract":"<div><div>The study of uranium sources in sandstone-type uranium deposits has been significantly hindered by the absence of effective methodologies, thereby impeding uranium resource exploration efforts. This paper delves into the origin and evolution of sandstone-type uranium deposits, particularly in two newly discovered mineral localities in the southeastern Songliao Basin, employing zircon U<img>Pb geochronology and petrogeochemistry. Additionally, it examines the evolutionary history of these deposits within the Paleo-Asian Ocean tectonic domain. The research reveals that the uranium-bearing series in the study area primarily originate from intermediate-acid magmatic rocks located in the active belt of the northern margin of the North China Craton and the continental island arc tectonic environment. The detrital zircon in the uranium reservoir sandstone, with a peak age range of 270–236 Ma, bears witness to the orogenic events involving the subduction, closure, and collision of the Paleo-Asian Ocean and the back-arc ocean basin. Meanwhile, the peak age range of 181–154 Ma signifies the Paleo-Pacific Ocean subduction impact in the study area. A comprehensive comparative analysis of zircon U<img>Pb chronology and lithogeochemistry indicates that the highly differentiated granite (Baijiagou Pluton), which mixed with the crust in the Early Triassic <em>syn</em>-collisional orogenic environment, serves as a promising source of uranium in the study area. By utilizing the differences in weathering resistance between zircon and rock, specifically the stable Th/U ratio in zircon and the unstable Th/U ratio in rocks, this relationship can be used to trace favorable uranium sources. This method provides an effective approach for identifying uranium sources in the exploration of sedimentary uranium deposits. The ocean-arc system present on the active continental margins of the Paleo-Asian Ocean's northern and southern sides continuously facilitates the material cycle of uranium rich sediments and magmatic uranium elements. This process, coupled with multi-stage and multi-material magmatism, ultimately leads to the formation of a favorable uranium rich geological body. This serves as the material and uranium source basis for the formation of sedimentary uranium deposits in northern China.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"272 ","pages":"Article 107703"},"PeriodicalIF":3.4,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395509","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}
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