Applied Geochemistry最新文献_第7页

Fluoride sources, hydrogeochemical dynamics, and probabilistic risk evaluation in deep groundwater of the Bozhou Plain, Eastern China 亳州平原深层地下水氟源、水文地球化学动力学及概率风险评价

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2025-10-28 DOI: 10.1016/j.apgeochem.2025.106607

Jinzhao Xu , Wen Si , Jun Wang , Bin Chen , Guijian Liu

Fluoride enrichment in deep groundwater systems poses critical environmental and public health challenges. In this study, 106 deep groundwater samples from the Bozhou Plain (BZP) were systematically analyzed using hydrogeochemical approaches and probabilistic risk modeling to identify fluoride sources, elucidate geochemical dynamics, and assess health risks. The results demonstrated that the groundwater exhibited weak alkalinity and moderate mineralization. Hydrochemical facies were dominated by Cl·HCO₃–Na and HCO₃–Na. Fluoride concentrations varied between 0.5 and 5.9 mg L⁻¹(mean: 1.9 mg L⁻¹), with 87.7 % of samples exceeding the Chinese National Drinking Water Standards. Geochemical evidence from Piper diagrams, Gibbs plots, and saturation indices indicated that fluorite dissolution was the principal source of F⁻, while calcite precipitation and cation exchange reduced Ca²⁺ activity, thereby enhancing fluoride accumulation. Health risk assessment using Monte Carlo simulations revealed that the mean hazard index for children was 1.57, significantly higher than 0.91 for adults. The probability of non-carcinogenic risk reached 75.71 % for children, compared to 36.22 % for adults. These findings quantitatively clarify the mechanisms of fluoride enrichment in confined aquifers and highlight the elevated vulnerability of children, providing essential insights for groundwater safety management in fluoride-affected regions.

深层地下水系统中的氟化物富集对环境和公共卫生构成了严峻的挑战。本研究采用水文地球化学方法和概率风险模型对亳州平原106份深层地下水样本进行了系统分析，以确定氟化物来源，阐明地球化学动力学，并评估健康风险。结果表明，地下水呈弱碱度、中度矿化特征。水化学相以Cl·HCO3-Na和HCO3-Na为主。氟化物浓度在0.5 ~ 5.9 mg L - 1之间（平均1.9 mg L - 1）， 87.7%的样品超过中国国家饮用水标准。来自Piper图、Gibbs图和饱和度指数的地球化学证据表明，萤石溶解是F -的主要来源，而方解石沉淀和阳离子交换降低了Ca2+活性，从而增强了氟化物的积累。利用蒙特卡罗模拟进行的健康风险评估显示，儿童的平均危害指数为1.57，显著高于成人的0.91。儿童非致癌风险的概率为75.71%，而成人为36.22%。这些发现定量地阐明了承压含水层中氟化物富集的机制，突出了儿童的脆弱性增加，为受氟化物影响地区的地下水安全管理提供了重要见解。

{"title":"Fluoride sources, hydrogeochemical dynamics, and probabilistic risk evaluation in deep groundwater of the Bozhou Plain, Eastern China","authors":"Jinzhao Xu , Wen Si , Jun Wang , Bin Chen , Guijian Liu","doi":"10.1016/j.apgeochem.2025.106607","DOIUrl":"10.1016/j.apgeochem.2025.106607","url":null,"abstract":"<div><div>Fluoride enrichment in deep groundwater systems poses critical environmental and public health challenges. In this study, 106 deep groundwater samples from the Bozhou Plain (BZP) were systematically analyzed using hydrogeochemical approaches and probabilistic risk modeling to identify fluoride sources, elucidate geochemical dynamics, and assess health risks. The results demonstrated that the groundwater exhibited weak alkalinity and moderate mineralization. Hydrochemical facies were dominated by Cl·HCO<sub>3</sub>–Na and HCO<sub>3</sub>–Na. Fluoride concentrations varied between 0.5 and 5.9 mg L<sup>−1</sup>(mean: 1.9 mg L<sup>−1</sup>), with 87.7 % of samples exceeding the Chinese National Drinking Water Standards. Geochemical evidence from Piper diagrams, Gibbs plots, and saturation indices indicated that fluorite dissolution was the principal source of F<sup>−</sup>, while calcite precipitation and cation exchange reduced Ca<sup>2+</sup> activity, thereby enhancing fluoride accumulation. Health risk assessment using Monte Carlo simulations revealed that the mean hazard index for children was 1.57, significantly higher than 0.91 for adults. The probability of non-carcinogenic risk reached 75.71 % for children, compared to 36.22 % for adults. These findings quantitatively clarify the mechanisms of fluoride enrichment in confined aquifers and highlight the elevated vulnerability of children, providing essential insights for groundwater safety management in fluoride-affected regions.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"194 ","pages":"Article 106607"},"PeriodicalIF":3.4,"publicationDate":"2025-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145413871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Behaviours of 210Pb and 137Cs in Yellow Sea sediments under the influence of waste dumping 垃圾倾倒影响下黄海沉积物中210Pb和137Cs的行为

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2025-10-27 DOI: 10.1016/j.apgeochem.2025.106606

Xiaoyu Chen , Jaeeun Lee , Junhyeong Seo , Hyunmi Lee , Intae Kim

This study presents and evaluates the distribution patterns and deposition fluxes of both natural and artificial radionuclides, ²¹⁰Pb and ¹³⁷Cs, in the sediments of the Yellow Sea region. Higher sediment deposition fluxes of ²¹⁰Pb were observed in the muddy sediment area compared to the sandy area. In addition, the deposition fluxes of excess ²¹⁰Pb at the dumping site and surrounding areas showed higher values (663.1 ± 588.6 Bq/m² yr⁻¹) than those at the non-dumping sites (359.7 ± 373.3 Bq/m² yr⁻¹) within the muddy area. Thus, although the sedimentation rates in the study area calculated using excess ²¹⁰Pb showed an average value of 0.35 ± 0.23 cm yr⁻¹, which is comparable with those reported in previous studies of the Yellow Sea, this study indicates the significant influence of anthropogenic waste dumping on the accumulation of ²¹⁰Pb in the bottom sediments. The ¹³⁷Cs activities in most stations exhibited an exponential decrease from the surface sediments, similar to the pattern of ²¹⁰Pb, although one site showed peak values at depths of 9–13 cm. However, unlike the typical ¹³⁷Cs peaks that correspond to major events, such as the 1963 nuclear tests, the age of the sediments at peak depths in this study ranged widely, from the 1950s to the 1970s. This imprecision in dating is likely attributable to the high sediment turbulence in the Yellow Sea and the weaker particle-reactive nature of ¹³⁷Cs, which facilitates the remobilization of particulate ¹³⁷Cs into the dissolved phase. Moreover, our results indicate a much lower deposition flux of ¹³⁷Cs compared to previous studies, further demonstrating the limitations of using ¹³⁷Cs as a tracer in high-sediment-surface areas. Overall, this study highlights the impact of waste dumping on the accumulation of ²¹⁰Pb in marginal seas, even in dynamic sedimentary environments such as the Yellow Sea.

本文介绍并评价了黄海地区天然和人工放射性核素（210Pb和137Cs）在沉积物中的分布规律和沉积通量。泥质沉积区210Pb的沉积通量高于沙质沉积区。此外，堆积场及周边地区过量210Pb的沉降通量（663.1±588.6 Bq/m2 yr−1）高于非堆积场（359.7±373.3 Bq/m2 yr−1）。因此，尽管利用过量210Pb计算的研究区沉积速率平均值为0.35±0.23 cm yr−1，与以往黄海研究结果相当，但本研究表明，人为倾倒废弃物对海底沉积物中210Pb的积累有显著影响。137Cs活度在表层沉积物中呈指数型下降，与210Pb相似，但有一个站点在9 ~ 13 cm深度处出现峰值。然而，与1963年核试验等重大事件对应的典型137Cs峰值不同，本研究中峰值深度沉积物的年龄范围很广，从1950年代到1970年代不等。这种测年的不精确可能是由于黄海沉积物湍流度高，137Cs的颗粒反应性较弱，这有利于137Cs颗粒再活化到溶解相。此外，我们的研究结果表明，与以往的研究相比，137Cs的沉积通量要低得多，这进一步证明了在高沉积表面积地区使用137Cs作为示踪剂的局限性。总体而言，本研究强调了倾倒废弃物对边缘海中210Pb积累的影响，甚至在黄海等动态沉积环境中也是如此。

{"title":"Behaviours of 210Pb and 137Cs in Yellow Sea sediments under the influence of waste dumping","authors":"Xiaoyu Chen , Jaeeun Lee , Junhyeong Seo , Hyunmi Lee , Intae Kim","doi":"10.1016/j.apgeochem.2025.106606","DOIUrl":"10.1016/j.apgeochem.2025.106606","url":null,"abstract":"<div><div>This study presents and evaluates the distribution patterns and deposition fluxes of both natural and artificial radionuclides, <sup>210</sup>Pb and <sup>137</sup>Cs, in the sediments of the Yellow Sea region. Higher sediment deposition fluxes of <sup>210</sup>Pb were observed in the muddy sediment area compared to the sandy area. In addition, the deposition fluxes of excess <sup>210</sup>Pb at the dumping site and surrounding areas showed higher values (663.1 ± 588.6 Bq/m<sup>2</sup> yr<sup>−1</sup>) than those at the non-dumping sites (359.7 ± 373.3 Bq/m<sup>2</sup> yr<sup>−1</sup>) within the muddy area. Thus, although the sedimentation rates in the study area calculated using excess <sup>210</sup>Pb showed an average value of 0.35 ± 0.23 cm yr<sup>−1</sup>, which is comparable with those reported in previous studies of the Yellow Sea, this study indicates the significant influence of anthropogenic waste dumping on the accumulation of <sup>210</sup>Pb in the bottom sediments. The <sup>137</sup>Cs activities in most stations exhibited an exponential decrease from the surface sediments, similar to the pattern of <sup>210</sup>Pb, although one site showed peak values at depths of 9–13 cm. However, unlike the typical <sup>137</sup>Cs peaks that correspond to major events, such as the 1963 nuclear tests, the age of the sediments at peak depths in this study ranged widely, from the 1950s to the 1970s. This imprecision in dating is likely attributable to the high sediment turbulence in the Yellow Sea and the weaker particle-reactive nature of <sup>137</sup>Cs, which facilitates the remobilization of particulate <sup>137</sup>Cs into the dissolved phase. Moreover, our results indicate a much lower deposition flux of <sup>137</sup>Cs compared to previous studies, further demonstrating the limitations of using <sup>137</sup>Cs as a tracer in high-sediment-surface areas. Overall, this study highlights the impact of waste dumping on the accumulation of <sup>210</sup>Pb in marginal seas, even in dynamic sedimentary environments such as the Yellow Sea.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"194 ","pages":"Article 106606"},"PeriodicalIF":3.4,"publicationDate":"2025-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145413870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Open versus closed system injection: A key critical geochemical control on in-situ CO2 mineralisation in basalts 开放与封闭系统注入：玄武岩原位CO2矿化的关键地球化学控制

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2025-10-22 DOI: 10.1016/j.apgeochem.2025.106603

Domenik Wolff-Boenisch, Stephanie Vialle

Over a decade ago, CarbFix1 in Iceland (Matter et al., 2016) and the Wallula Basalt Project in Washington state (McGrail et al., 2017) showed in short succession that carbon mineralisation in the field at shallow depth (≤1 km) and low T (c. 35 °C) can be achieved in less than two years, orders of magnitude faster than previously anticipated.

Since then, no other field site has yet reproduced this carbon storage success -other than CarbFix2, which has been injecting CO₂ since 2014, albeit into a superhot basaltic reservoir at more than 250 °C (Clark et al., 2020). This contribution looks again at the low TP precursor sites, especially CarbFix1, to identify the reasons that drove the mineralisation of CO₂. It seeks to disentangle the confounding factors that affected carbonatisation. Based on geochemical modelling, it is reasoned that CarbFix1 (and Wallula) benefited primarily from the fact that injection was not continuous over a long period of time, only five and three weeks, respectively. This finite time frame allowed the attainment of closed reaction-controlled conditions along the flow path, which aided in the formation of secondary phases, including carbonates. It is reasoned that future CO₂ storage efforts into basalts will run on a considerably longer and, crucially, continuous time frame. Under such open injection conditions, the geochemistry of the reservoir will change; our models indicate that the groundwater will be buffered at pH ≤∼6.5. This pH buffer coincides with the ‘sweet spot’ for mineralisation of CO₂ in basalts at low temperatures (20–50 °C) that Snæbjörnsdóttir et al. (2018) postulated would allow (Ca)-Mg-Fe carbonate formation whilst keeping zeolite and smectite formation at bay. Open conditions will thus not run counter to, or become detrimental to, the carbon mineralisation efforts in basaltic terrains; however, the secondary mineralogy will very likely differ from that observed at CarbFix1.

十多年前，冰岛的CarbFix1 （Matter et al., 2016）和华盛顿州的Wallula玄武岩项目（McGrail et al., 2017）相继表明，在不到两年的时间内，可以在浅深度（≤1 km）和低温度（c. 35°c）的领域实现碳矿化，比先前预期的要快几个数量级。自那以后，除了CarbFix2之外，没有其他油田能够复制这种碳储存的成功，CarbFix2自2014年以来一直在注入二氧化碳，尽管是在250°C以上的超高温玄武岩储层中（Clark et al, 2020）。这项贡献再次研究了低TP前体位点，特别是CarbFix1，以确定驱动二氧化碳矿化的原因。它试图理清影响碳化的混杂因素。根据地球化学模型，CarbFix1（和Wallula）的主要受益于注入时间不长，分别只有5周和3周。这种有限的时间框架允许沿着流动路径达到封闭的反应控制条件，这有助于形成二次相，包括碳酸盐。有理由认为，未来在玄武岩中储存二氧化碳的努力将持续相当长的时间，而且至关重要的是，这是一个连续的时间框架。在这种开放注入条件下，储层地球化学会发生变化；我们的模型表明，地下水在pH≤~ 6.5时将被缓冲。该pH缓冲液与低温（20-50°C）下玄武岩中二氧化碳矿化的“最佳点”相吻合，Snæbjörnsdóttir等人（2018）认为，低温下（20-50°C）可以形成(Ca)-Mg-Fe碳酸盐，同时抑制沸石和蒙脱石的形成。因此，开放条件不会与玄武岩地形中的碳矿化工作背道而驰，也不会对其有害；然而，次生矿物学很可能与在CarbFix1观测到的不同。

{"title":"Open versus closed system injection: A key critical geochemical control on in-situ CO2 mineralisation in basalts","authors":"Domenik Wolff-Boenisch, Stephanie Vialle","doi":"10.1016/j.apgeochem.2025.106603","DOIUrl":"10.1016/j.apgeochem.2025.106603","url":null,"abstract":"<div><div>Over a decade ago, CarbFix1 in Iceland (Matter et al., 2016) and the Wallula Basalt Project in Washington state (McGrail et al., 2017) showed in short succession that carbon mineralisation in the field at shallow depth (≤1 km) and low T (c. 35 °C) can be achieved in less than two years, orders of magnitude faster than previously anticipated.</div><div>Since then, no other field site has yet reproduced this carbon storage success -other than CarbFix2, which has been injecting CO<sub>2</sub> since 2014, albeit into a superhot basaltic reservoir at more than 250 °C (Clark et al., 2020). This contribution looks again at the low TP precursor sites, especially CarbFix1, to identify the reasons that drove the mineralisation of CO<sub>2</sub>. It seeks to disentangle the confounding factors that affected carbonatisation. Based on geochemical modelling, it is reasoned that CarbFix1 (and Wallula) benefited primarily from the fact that injection was not continuous over a long period of time, only five and three weeks, respectively. This finite time frame allowed the attainment of closed reaction-controlled conditions along the flow path, which aided in the formation of secondary phases, including carbonates. It is reasoned that future CO<sub>2</sub> storage efforts into basalts will run on a considerably longer and, crucially, continuous time frame. Under such open injection conditions, the geochemistry of the reservoir will change; our models indicate that the groundwater will be buffered at pH ≤∼6.5. This pH buffer coincides with the ‘sweet spot’ for mineralisation of CO<sub>2</sub> in basalts at low temperatures (20–50 °C) that Snæbjörnsdóttir et al. (2018) postulated would allow (Ca)-Mg-Fe carbonate formation whilst keeping zeolite and smectite formation at bay. Open conditions will thus not run counter to, or become detrimental to, the carbon mineralisation efforts in basaltic terrains; however, the secondary mineralogy will very likely differ from that observed at CarbFix1.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"194 ","pages":"Article 106603"},"PeriodicalIF":3.4,"publicationDate":"2025-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145413873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mineral-driven persulfate activation: the role of recycled concrete alkalinity in oxidative water treatment 矿物驱动过硫酸盐活化：再生混凝土碱度在氧化水处理中的作用

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2025-10-21 DOI: 10.1016/j.apgeochem.2025.106590

Chiara Cappelli , Albert Fernández-Lagunas , María Usieto , Mònica Rosell , Clara Torrentó , Cristina Domènech , Jordi Palau , Albert Soler

The dissolution of concrete—a prevalent anthropogenic material—generates hyperalkaline, Ca-rich leachates that may influence redox processes in subsurface environments. The knowledge of these geochemical processes serves as theoretical framework for the application of recycling concrete material to circular economy systems, providing sustainable alternatives to the concerning issue of the construction waste management while positively acting on specific environmental settings. This study investigates the potential of recycled concrete as a long-term alkaline activator for sodium persulfate in In Situ Chemical Oxidation groundwater treatments, with a focus on application in groundwater-recharge interception trenches in the vadose zone. A laboratory-scale study was conducted using flow-through columns filled with crushed recycled concrete, which was exposed to contaminated groundwater. The research assessed (i) the ability of concrete to generate and maintain alkaline conditions for persulfate activation, (ii) its mineralogical composition to determine reactivity and surface passivation, and (iii) chemical changes occurring upon persulfate addition at two different dosages. Results showed that recycled concrete effectively maintained high pH and buffered the system after persulfate injection, enabling efficient activation of the oxidant and substantial degradation of dissolved organic carbon. The system was controlled by the dissolution of concrete aggregates and cement phase together with the carbonation and (re)precipitation of new phases. The role of calcium and aluminium/magnesium silicate hydrates was proven to be crucial for the stability of the concrete microstructure and for maintaining the alkalinity. These findings demonstrate the dual role of recycled concrete for providing long-term alkaline activation of persulfate and mitigating clogging risks, supporting is practical use in groundwater remediation strategies promoting circular economy principles. Furthermore, these findings mirror processes observed in different hyperalkaline systems (e.g., radioactive waste repositories, CO₂ storage) where mineral-driven redox reactions control contaminant fate and/or carbon sequestration.

混凝土是一种普遍存在的人为物质，它的溶解会产生高碱性、富钙的渗滤液，这可能会影响地下环境中的氧化还原过程。这些地球化学过程的知识为循环经济系统中回收混凝土材料的应用提供了理论框架，为建筑垃圾管理的相关问题提供了可持续的替代方案，同时积极作用于特定的环境设置。本研究探讨了再生混凝土作为过硫酸钠在原位化学氧化地下水处理中的长期碱性活化剂的潜力，重点研究了其在渗流带地下水补给拦截沟中的应用。一项实验室规模的研究是使用流动柱填充破碎的再生混凝土，暴露在受污染的地下水中。该研究评估了(i)混凝土产生和维持碱性条件以使过硫酸盐活化的能力，（ii）其矿物学成分以确定反应性和表面钝化，以及（iii）添加两种不同剂量的过硫酸盐后发生的化学变化。结果表明，注入过硫酸盐后，再生混凝土有效地维持了高pH值，缓冲了体系，实现了氧化剂的有效活化和溶解有机碳的大量降解。该体系受混凝土集料和水泥相的溶解以及新相的碳化和（再）沉淀的控制。钙和铝/镁硅酸盐水合物的作用被证明对混凝土微观结构的稳定性和保持碱度至关重要。这些发现证明了再生混凝土在提供过硫酸盐长期碱性活化和减轻堵塞风险方面的双重作用，支持其在促进循环经济原则的地下水修复策略中的实际应用。此外，这些发现反映了在不同的高碱性系统中观察到的过程（例如，放射性废物储存库、二氧化碳储存库），其中矿物驱动的氧化还原反应控制污染物的归宿和/或碳固存。

{"title":"Mineral-driven persulfate activation: the role of recycled concrete alkalinity in oxidative water treatment","authors":"Chiara Cappelli , Albert Fernández-Lagunas , María Usieto , Mònica Rosell , Clara Torrentó , Cristina Domènech , Jordi Palau , Albert Soler","doi":"10.1016/j.apgeochem.2025.106590","DOIUrl":"10.1016/j.apgeochem.2025.106590","url":null,"abstract":"<div><div>The dissolution of concrete—a prevalent anthropogenic material—generates hyperalkaline, Ca-rich leachates that may influence redox processes in subsurface environments. The knowledge of these geochemical processes serves as theoretical framework for the application of recycling concrete material to circular economy systems, providing sustainable alternatives to the concerning issue of the construction waste management while positively acting on specific environmental settings. This study investigates the potential of recycled concrete as a long-term alkaline activator for sodium persulfate in In Situ Chemical Oxidation groundwater treatments, with a focus on application in groundwater-recharge interception trenches in the vadose zone. A laboratory-scale study was conducted using flow-through columns filled with crushed recycled concrete, which was exposed to contaminated groundwater. The research assessed (i) the ability of concrete to generate and maintain alkaline conditions for persulfate activation, (ii) its mineralogical composition to determine reactivity and surface passivation, and (iii) chemical changes occurring upon persulfate addition at two different dosages. Results showed that recycled concrete effectively maintained high pH and buffered the system after persulfate injection, enabling efficient activation of the oxidant and substantial degradation of dissolved organic carbon. The system was controlled by the dissolution of concrete aggregates and cement phase together with the carbonation and (re)precipitation of new phases. The role of calcium and aluminium/magnesium silicate hydrates was proven to be crucial for the stability of the concrete microstructure and for maintaining the alkalinity. These findings demonstrate the dual role of recycled concrete for providing long-term alkaline activation of persulfate and mitigating clogging risks, supporting is practical use in groundwater remediation strategies promoting circular economy principles. Furthermore, these findings mirror processes observed in different hyperalkaline systems (e.g., radioactive waste repositories, CO<sub>2</sub> storage) where mineral-driven redox reactions control contaminant fate and/or carbon sequestration.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"194 ","pages":"Article 106590"},"PeriodicalIF":3.4,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145360155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Comparative analysis of one-dimensional convolutional neural network and predictive raster averaging for MVT Pb–Zn mineralization using the weighted class distribution evaluation framework 基于加权类分布评价框架的一维卷积神经网络与预测栅格平均在MVT铅锌矿化中的对比分析

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2025-10-21 DOI: 10.1016/j.apgeochem.2025.106595

Soran Qaderi, Abbas Maghsoudi

This study explores the use of geochemical and remote sensing data to predict areas with high mineralization potential in Mississippi Valley-Type (MVT) Pb–Zn deposits in western Semnan, Iran. Two methods were applied: 1DCNN (1D Convolutional Neural Network) and PRA (Predictive Raster Averaging). The 1DCNN model, known for its capacity to learn complex spatial patterns from high-dimensional data, was trained on satellite imagery and geochemical data, producing a probability map indicating potential mineralized zones. The simpler PRA method combined multiple raster layers through averaging, providing a computationally efficient alternative for generating prospectivity maps. Evaluation metrics, including Weighted Class Distribution (WCD) Method, ROC-AUC, and Feature Importance, were used to assess the performance of both methods. The WCD method was applied to evaluate the distribution of known mineral deposits across different probability classes, while ROC-AUC was used to measure the 1DCNN model's ability to distinguish between mineralized and non-mineralized areas. Feature Importance analysis helped identify which geochemical and remote sensing features contributed most to the predictions made by the 1DCNN model. Results showed that the 1DCNN model had higher accuracy in identifying the most promising mineralization zones, with 68.75 % of known deposits falling into the highest probability class, occupying 8 % of the study area. The PRA model, though less refined, successfully highlighted regions with mineral potential, albeit with a broader spread across probability classes. This research contributes to understanding the trade-offs between artificial intelligence-based and traditional mapping methods for mineral exploration, providing valuable insights for future studies in resource prospectivity.

利用地球化学和遥感资料对伊朗西Semnan地区密西西比河谷型铅锌矿床进行了高成矿潜力区预测。采用了两种方法：1DCNN （1D卷积神经网络）和PRA（预测光栅平均）。1DCNN模型以其从高维数据中学习复杂空间模式的能力而闻名，该模型在卫星图像和地球化学数据上进行了训练，生成了指示潜在矿化带的概率图。更简单的PRA方法通过平均将多个栅格层组合在一起，为生成远景图提供了一种计算效率更高的替代方法。评估指标，包括加权类分布（WCD）方法、ROC-AUC和特征重要性，用于评估两种方法的性能。WCD方法用于评估已知矿床在不同概率类别中的分布，而ROC-AUC用于衡量1DCNN模型区分矿化区和非矿化区的能力。特征重要性分析有助于确定哪些地球化学和遥感特征对1DCNN模型的预测贡献最大。结果表明，1DCNN模型对最有希望成矿带的识别精度较高，68.75%的已知矿床属于最高概率类，占研究面积的8%。PRA模型虽然不太完善，但成功地突出了具有矿产潜力的区域，尽管在概率类别中有更广泛的分布。该研究有助于理解基于人工智能和传统测绘方法在矿产勘查中的权衡，为未来的资源远景研究提供有价值的见解。

{"title":"Comparative analysis of one-dimensional convolutional neural network and predictive raster averaging for MVT Pb–Zn mineralization using the weighted class distribution evaluation framework","authors":"Soran Qaderi, Abbas Maghsoudi","doi":"10.1016/j.apgeochem.2025.106595","DOIUrl":"10.1016/j.apgeochem.2025.106595","url":null,"abstract":"<div><div>This study explores the use of geochemical and remote sensing data to predict areas with high mineralization potential in Mississippi Valley-Type (MVT) Pb–Zn deposits in western Semnan, Iran. Two methods were applied: 1DCNN (1D Convolutional Neural Network) and PRA (Predictive Raster Averaging). The 1DCNN model, known for its capacity to learn complex spatial patterns from high-dimensional data, was trained on satellite imagery and geochemical data, producing a probability map indicating potential mineralized zones. The simpler PRA method combined multiple raster layers through averaging, providing a computationally efficient alternative for generating prospectivity maps. Evaluation metrics, including Weighted Class Distribution (WCD) Method, ROC-AUC, and Feature Importance, were used to assess the performance of both methods. The WCD method was applied to evaluate the distribution of known mineral deposits across different probability classes, while ROC-AUC was used to measure the 1DCNN model's ability to distinguish between mineralized and non-mineralized areas. Feature Importance analysis helped identify which geochemical and remote sensing features contributed most to the predictions made by the 1DCNN model. Results showed that the 1DCNN model had higher accuracy in identifying the most promising mineralization zones, with 68.75 % of known deposits falling into the highest probability class, occupying 8 % of the study area. The PRA model, though less refined, successfully highlighted regions with mineral potential, albeit with a broader spread across probability classes. This research contributes to understanding the trade-offs between artificial intelligence-based and traditional mapping methods for mineral exploration, providing valuable insights for future studies in resource prospectivity.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"194 ","pages":"Article 106595"},"PeriodicalIF":3.4,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145360153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Interactions between basalt and CO2-saturated water at varying temperatures (100°C–300 °C) in a duplex reactor 玄武岩与二氧化碳饱和水在不同温度（100°C - 300°C）下的相互作用

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2025-10-17 DOI: 10.1016/j.apgeochem.2025.106593

Heejun Yang , Akira Ueda , Hideki Kuramitz , Amane Terai

This study experimentally investigated basalt–CO₂–water interactions at temperatures between 100 °C and 300 °C through flow-through experiments, with a focus on changes in solution composition and the formation of secondary minerals under varying temperature conditions relevant to enhanced geothermal systems (EGSs). A duplex reactor system was developed for the first time to simulate temperature variations in the reservoir, particularly in the vicinity of caprock.

The Mg²⁺ and Fe²⁺ concentrations were higher at lower temperatures (100 °C and 150 °C), whereas the other major cations exhibited an increasing trend with temperature. In the duplex reactor test (reactor 1 = 100 °C; reactor 2 = 250 °C; Fr6), the Mg²⁺ and Fe²⁺ concentrations were lower, suggesting potential Mg²⁺ and Fe²⁺ precipitation in high-temperature conditions. The SEM-EDS results primarily identified aluminium oxyhydroxide and clay minerals at temperatures above 250 °C, which were mainly oversaturated in beidellite, montmorillonite, illite, kaolinite, and boehmite. Conversely, at temperatures below 150 °C, primarily aluminium oxyhydroxide minerals were identified, which were oversaturated in boehmite. However, among the clay minerals, kaolinite mainly exhibited oversaturation, while the other minerals remained undersaturated.

The results of the duplex reactor test suggest that Mg²⁺ and Fe²⁺, which dissolved under lower-temperature conditions, may lead to the precipitation of clay minerals upon migration to higher-temperature regions within the EGS reservoir. This behavior is attributed to the decreasing solubility constants of these minerals with increasing temperature.

本研究通过流动实验研究了玄武岩-二氧化碳-水在100°C至300°C之间的相互作用，重点研究了与增强型地热系统（EGSs）相关的不同温度条件下溶液成分的变化和次生矿物的形成。首次开发了双反应器系统，以模拟储层中的温度变化，特别是盖层附近的温度变化。Mg2+和Fe2+浓度在较低温度（100°C和150°C）下较高，而其他主要阳离子随温度升高呈上升趋势。在双反应器试验中（反应器1 = 100°C，反应器2 = 250°C, Fr6）， Mg2+和Fe2+浓度较低，表明高温条件下Mg2+和Fe2+可能析出。SEM-EDS结果主要鉴定了250℃以上温度下的氢氧化铝和粘土矿物，其主要过饱和存在于贝德石、蒙脱土、伊利石、高岭石和薄水铝石中。相反，在低于150°C的温度下，发现主要是氢氧化铝矿物，它们在薄铝石中过饱和。而粘土矿物中，高岭石主要表现为过饱和，其他矿物则表现为欠饱和。双反应器试验结果表明，低温条件下溶解的Mg2+和Fe2+可能导致黏土矿物向EGS储层高温区域迁移时析出。这是由于这些矿物的溶解度常数随着温度的升高而降低。

{"title":"Interactions between basalt and CO2-saturated water at varying temperatures (100°C–300 °C) in a duplex reactor","authors":"Heejun Yang , Akira Ueda , Hideki Kuramitz , Amane Terai","doi":"10.1016/j.apgeochem.2025.106593","DOIUrl":"10.1016/j.apgeochem.2025.106593","url":null,"abstract":"<div><div>This study experimentally investigated basalt–CO<sub>2</sub>–water interactions at temperatures between 100 °C and 300 °C through flow-through experiments, with a focus on changes in solution composition and the formation of secondary minerals under varying temperature conditions relevant to enhanced geothermal systems (EGSs). A duplex reactor system was developed for the first time to simulate temperature variations in the reservoir, particularly in the vicinity of caprock.</div><div>The Mg<sup>2+</sup> and Fe<sup>2+</sup> concentrations were higher at lower temperatures (100 °C and 150 °C), whereas the other major cations exhibited an increasing trend with temperature. In the duplex reactor test (reactor 1 = 100 °C; reactor 2 = 250 °C; Fr6), the Mg<sup>2+</sup> and Fe<sup>2+</sup> concentrations were lower, suggesting potential Mg<sup>2+</sup> and Fe<sup>2+</sup> precipitation in high-temperature conditions. The SEM-EDS results primarily identified aluminium oxyhydroxide and clay minerals at temperatures above 250 °C, which were mainly oversaturated in beidellite, montmorillonite, illite, kaolinite, and boehmite. Conversely, at temperatures below 150 °C, primarily aluminium oxyhydroxide minerals were identified, which were oversaturated in boehmite. However, among the clay minerals, kaolinite mainly exhibited oversaturation, while the other minerals remained undersaturated.</div><div>The results of the duplex reactor test suggest that Mg<sup>2+</sup> and Fe<sup>2+</sup>, which dissolved under lower-temperature conditions, may lead to the precipitation of clay minerals upon migration to higher-temperature regions within the EGS reservoir. This behavior is attributed to the decreasing solubility constants of these minerals with increasing temperature.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"194 ","pages":"Article 106593"},"PeriodicalIF":3.4,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145360235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Chemical and isotopic variations of geothermal water record the enhanced water-rock interactions after seismicity in the western capital region of China 地热水化学和同位素变化记录了中国西部首都地区地震活动后水岩相互作用的增强

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2025-10-17 DOI: 10.1016/j.apgeochem.2025.106592

Shujuan Su , Chang Lu , Ying Li , Xiaocheng Zhou , Mingbo Yang , Zhaofei Liu , Jia Ren

Earthquake-related hydrochemical and isotopic changes are widely reported in active seismic areas. To investigate the hydrochemical anomalies related to earthquake events in the Beijing region of China (capital area), 960 water samples were collected from the Houhaoyao and Songshan geothermal wells, and the Chicheng spring every three days between 2022 and 2024. Major ion concentrations and stable isotope compositions (δ²H and δ¹⁸O) in the geothermal water were determined. The results showed anomalies in Na⁺, SO₄²⁻ and Cl⁻ concentrations during seismic activity periods. The δ²H and δ¹⁸O values ranged from −95 ‰ to −84 ‰ and from −13.5 ‰ to −11.0 ‰, respectively, indicating a meteoric origin for the sampled water. Variations in δ²H and δ¹⁸O values of 0.2 ‰–0.8 ‰ emerged one or two months before and after low-magnitude seismicity within 50 km of quake epicentres between November 2023 and January 2024. The helium and carbon isotopic compositions of the water samples suggested that He and CO₂ gases released from the geothermal wells mainly originated from the mantle and crustal, indicating a relationship between local deep faults and geothermal water circulation. It was concluded that the variations of the hydrochemical and isotopic compositions in geothermal waters were related to crustal fractures caused by seismic activity. Ground water stored in different reservoirs would flow along active faults, forming a channel system, then mix together. This resulted in changes to the water's chemical composition during earthquakes. By capturing anomalies in long-term geothermal observation wells during seismic evolution, this work provides insights into fault-fluid coupling in the capital area of China and other similar active seismic areas.

地震相关的水化学和同位素变化在地震活动区被广泛报道。为了研究北京地区（首都地区）地震相关的水化学异常，在2022 - 2024年间，每3天采集一次后好窑、松山地热井和赤城泉的960个水样。测定了地热水中主要离子浓度和稳定同位素（δ2H和δ18O）组成。结果表明，Na+、SO42−和Cl−浓度在地震活动期出现异常。δ2H值在- 95‰~ - 84‰之间，δ18O值在- 13.5‰~ - 11.0‰之间，为大气源。2023年11月至2024年1月，震源50 km范围内低震级地震前后1 ~ 2个月，δ2H和δ18O值出现0.2‰~ 0.8‰的变化。水样的氦、碳同位素组成表明，地热井释放的He和CO2气体主要来源于地幔和地壳，表明了局部深断裂与地热水循环的关系。地热水水化学和同位素组成的变化与地震活动引起的地壳断裂有关。储存在不同水库中的地下水将沿着活动断层流动，形成一个水道系统，然后混合在一起。这导致地震期间水的化学成分发生了变化。通过在地震演化过程中捕获长期地热观测井的异常，对中国首都地区和其他类似地震活跃区的断层-流体耦合提供了新的认识。

{"title":"Chemical and isotopic variations of geothermal water record the enhanced water-rock interactions after seismicity in the western capital region of China","authors":"Shujuan Su , Chang Lu , Ying Li , Xiaocheng Zhou , Mingbo Yang , Zhaofei Liu , Jia Ren","doi":"10.1016/j.apgeochem.2025.106592","DOIUrl":"10.1016/j.apgeochem.2025.106592","url":null,"abstract":"<div><div>Earthquake-related hydrochemical and isotopic changes are widely reported in active seismic areas. To investigate the hydrochemical anomalies related to earthquake events in the Beijing region of China (capital area), 960 water samples were collected from the Houhaoyao and Songshan geothermal wells, and the Chicheng spring every three days between 2022 and 2024. Major ion concentrations and stable isotope compositions (δ<sup>2</sup>H and δ<sup>18</sup>O) in the geothermal water were determined. The results showed anomalies in Na<sup>+</sup>, SO<sub>4</sub><sup>2−</sup> and Cl<sup>−</sup> concentrations during seismic activity periods. The δ<sup>2</sup>H and δ<sup>18</sup>O values ranged from −95 ‰ to −84 ‰ and from −13.5 ‰ to −11.0 ‰, respectively, indicating a meteoric origin for the sampled water. Variations in δ<sup>2</sup>H and δ<sup>18</sup>O values of 0.2 ‰–0.8 ‰ emerged one or two months before and after low-magnitude seismicity within 50 km of quake epicentres between November 2023 and January 2024. The helium and carbon isotopic compositions of the water samples suggested that He and CO<sub>2</sub> gases released from the geothermal wells mainly originated from the mantle and crustal, indicating a relationship between local deep faults and geothermal water circulation. It was concluded that the variations of the hydrochemical and isotopic compositions in geothermal waters were related to crustal fractures caused by seismic activity. Ground water stored in different reservoirs would flow along active faults, forming a channel system, then mix together. This resulted in changes to the water's chemical composition during earthquakes. By capturing anomalies in long-term geothermal observation wells during seismic evolution, this work provides insights into fault-fluid coupling in the capital area of China and other similar active seismic areas.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"194 ","pages":"Article 106592"},"PeriodicalIF":3.4,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145360234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Petroleum-fuelled methanogenesis and microbial hydrocarbon oxidation at an abandoned oil well 废弃油井中以石油为燃料的甲烷生成与微生物烃类氧化

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2025-10-13 DOI: 10.1016/j.apgeochem.2025.106589

Martin Blumenberg, Sebastian Jordan , Georg Scheeder, Martin Krüger, Stefan Schloemer

Here, we present a geochemical study of the soil above a plugged oil well (‘Elwerath’), which was drilled in the early 1920s and is located near Hannover (Germany). At this site ∼40 mg methane per hour is emitted. Geochemical analyses of the soil gas confirm the presence of thermogenic natural gas (with up to 8 % methane and 600 ppm ethane in the soil gas) and the δ¹³C of the methane indicates that most of the emitted methane is thermogenic (δ¹³C −47.1 ‰ VPDB). In addition to natural gas, we also found petroleum in the soil, accounting for up to 80 % of the total soil organic carbon. Detailed soil gas and organic geochemical analyses of extracts from the soil confirm a strong similarity with the old petroleum reservoir. Our data suggest a complex mosaic of gas-altering effects that cannot be explained by admixture with biogenic methane alone, but are rather dominated by microbial degradation of oil and natural gas components (e.g. propane oxidation). Most likely O₂ availability controls the microbial degradation of petroleum close to the ‘Elwerath’ well, because the strongest degree of degradation, with the lowest petroleum content, is found in the upper, well aerated soil horizons. The gas geochemistry and isotopic composition of the soil gases also indicate anaerobic processes, such as methanogenesis, probably with petroleum as carbon source. These processes must have taken place significantly deeper than the top meter sampled, where O₂ was still detectable. CO₂ emissions appear to be negatively affected by the oil contamination, most likely due to the inhibition of natural microbial respiration by toxic effects. While processes in the deeper biosphere appear to play a role here, it is clear that the microbial processes in the soil surrounding the well also regulate the composition and quantity of oil and gas. In conclusion, (i) the high degree of degradation of natural gas and oil in the soil, and (ii) the low methane emissions, indicate that only little hydrocarbon is leaking and that a ‘microbial hydrocarbon filter’ is established and active.

在这里，我们展示了对一口堵塞的油井（“Elwerath”）上方土壤的地球化学研究，该油井位于德国汉诺威附近，于20世纪20年代初钻探。在这个地方，每小时排放约40毫克甲烷。土壤气体的地球化学分析证实了热成因天然气的存在（土壤气体中甲烷含量高达8%，乙烷含量为600 ppm），甲烷的δ13C表明大部分甲烷是热成因的（δ13C−47.1‰VPDB）。除了天然气，我们还在土壤中发现了石油，占土壤有机碳总量的80%。详细的土壤气体分析和土壤萃取物的有机地球化学分析证实了其与古油藏的相似性。我们的数据表明，复杂的气体改变效应不能单独用生物甲烷的混合物来解释，而是由石油和天然气成分的微生物降解（例如丙烷氧化）所主导。最有可能的是，氧的有效性控制着Elwerath井附近石油的微生物降解，因为在通风良好的上层土壤层中，降解程度最强，石油含量最低。土壤气体的地球化学和同位素组成也显示出厌氧过程，如甲烷生成，可能以石油为碳源。这些过程一定发生在比顶部采样更深的地方，那里仍然可以检测到氧气。二氧化碳排放似乎受到石油污染的负面影响，很可能是由于有毒作用抑制了天然微生物的呼吸作用。虽然深层生物圈的过程似乎在这里发挥了作用，但很明显，油井周围土壤中的微生物过程也调节着石油和天然气的组成和数量。综上所述，(i)天然气和石油在土壤中的降解程度高，（ii）甲烷排放量低，表明只有很少的碳氢化合物泄漏，“微生物碳氢化合物过滤器”已经建立并起作用。

{"title":"Petroleum-fuelled methanogenesis and microbial hydrocarbon oxidation at an abandoned oil well","authors":"Martin Blumenberg, Sebastian Jordan , Georg Scheeder, Martin Krüger, Stefan Schloemer","doi":"10.1016/j.apgeochem.2025.106589","DOIUrl":"10.1016/j.apgeochem.2025.106589","url":null,"abstract":"<div><div>Here, we present a geochemical study of the soil above a plugged oil well (‘Elwerath’), which was drilled in the early 1920s and is located near Hannover (Germany). At this site ∼40 mg methane per hour is emitted. Geochemical analyses of the soil gas confirm the presence of thermogenic natural gas (with up to 8 % methane and 600 ppm ethane in the soil gas) and the δ<sup>13</sup>C of the methane indicates that most of the emitted methane is thermogenic (δ<sup>13</sup>C −47.1 ‰ VPDB). In addition to natural gas, we also found petroleum in the soil, accounting for up to 80 % of the total soil organic carbon. Detailed soil gas and organic geochemical analyses of extracts from the soil confirm a strong similarity with the old petroleum reservoir. Our data suggest a complex mosaic of gas-altering effects that cannot be explained by admixture with biogenic methane alone, but are rather dominated by microbial degradation of oil and natural gas components (e.g. propane oxidation). Most likely O<sub>2</sub> availability controls the microbial degradation of petroleum close to the ‘Elwerath’ well, because the strongest degree of degradation, with the lowest petroleum content, is found in the upper, well aerated soil horizons. The gas geochemistry and isotopic composition of the soil gases also indicate anaerobic processes, such as methanogenesis, probably with petroleum as carbon source. These processes must have taken place significantly deeper than the top meter sampled, where O<sub>2</sub> was still detectable. CO<sub>2</sub> emissions appear to be negatively affected by the oil contamination, most likely due to the inhibition of natural microbial respiration by toxic effects. While processes in the deeper biosphere appear to play a role here, it is clear that the microbial processes in the soil surrounding the well also regulate the composition and quantity of oil and gas. In conclusion, (i) the high degree of degradation of natural gas and oil in the soil, and (ii) the low methane emissions, indicate that only little hydrocarbon is leaking and that a ‘microbial hydrocarbon filter’ is established and active.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"194 ","pages":"Article 106589"},"PeriodicalIF":3.4,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145413805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Physicochemical, hydromechanical, and Cs retention properties of Ca-bentonite treated with Ca(OH)2 saturated solution at 150°C for up to 2 years Ca(OH)2饱和溶液在150°C下处理长达2年的Ca-膨润土的物理化学、流体力学和Cs保留性能

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2025-10-08 DOI: 10.1016/j.apgeochem.2025.106586

Ji Hoon Lee , Ho Young Jo , Jang-Soon Kwon

Understanding the performance of bentonite buffer materials in the presence of cement leachates at > 100°C is required for optimizing the design of deep geological repositories for high-level radioactive wastes. This study investigated the effects of exposure to a Ca(OH)₂ saturated solution at 150°C on Ca-bentonite, focusing on how mineralogical changes in the bentonite affect its physicochemical, swelling and hydraulic, and cesium (Cs) retention properties, which are key attributes for buffer materials. Analytical techniques, including X-ray diffraction, nuclear magnetic resonance, thermal gravimetry and differential thermal analyses, indicated calcium silicate hydrate (CSH) formation. Despite this alteration, cation exchange and Cs retention capacities were largely unaffected. Swelling pressure tests on compacted bentonite specimens (dry density: 1.6 Mg/m³) prepared from hydrothermally treated bentonite showed a reduction in swelling pressure. However, no significant difference in the hydraulic conductivity occurred. X-ray photoelectron spectroscopy analysis of the compacted bentonite specimen indicated consistent Cs retention across the specimen with no effluent detected over a one-year permeation period, suggesting that the specimens were still absorbing fluid. Overall, Ca-bentonite treated with a Ca(OH)₂ saturated solution at 150°C for up to two years showed minimal CSH formation and minor changes in physicochemical, hydraulic, and Cs retention properties, with a slight reduction in swelling pressure.

了解膨润土缓冲材料在100°C下水泥渗滤液存在下的性能，是优化高放射性废物深层地质处置库设计所必需的。本研究研究了Ca(OH)2饱和溶液在150°C下对Ca-膨润土的影响，重点研究了膨润土的矿物学变化对其物理化学、膨胀和水力以及铯（Cs）保留性能的影响，这些性能是缓冲材料的关键属性。包括x射线衍射、核磁共振、热重和差热分析在内的分析技术表明水合硅酸钙（CSH）的形成。尽管发生了这种变化，但阳离子交换和Cs保留能力在很大程度上没有受到影响。经水热处理的膨润土压实试样（干密度：1.6 Mg/m3）的膨胀压力试验表明，膨润土的膨胀压力降低。然而，水力导电性没有显著差异。压实的膨润土样品的x射线光电子能谱分析表明，在一年的渗透期内，样品中没有检测到流出物，因此样品仍在吸收流体。总的来说，Ca(OH)2饱和溶液在150°C下处理两年的Ca-膨润土，CSH的形成很少，物理化学、水力和Cs保留性能的变化很小，膨胀压力略有降低。

{"title":"Physicochemical, hydromechanical, and Cs retention properties of Ca-bentonite treated with Ca(OH)2 saturated solution at 150°C for up to 2 years","authors":"Ji Hoon Lee , Ho Young Jo , Jang-Soon Kwon","doi":"10.1016/j.apgeochem.2025.106586","DOIUrl":"10.1016/j.apgeochem.2025.106586","url":null,"abstract":"<div><div>Understanding the performance of bentonite buffer materials in the presence of cement leachates at > 100°C is required for optimizing the design of deep geological repositories for high-level radioactive wastes. This study investigated the effects of exposure to a Ca(OH)<sub>2</sub> saturated solution at 150°C on Ca-bentonite, focusing on how mineralogical changes in the bentonite affect its physicochemical, swelling and hydraulic, and cesium (Cs) retention properties, which are key attributes for buffer materials. Analytical techniques, including X-ray diffraction, nuclear magnetic resonance, thermal gravimetry and differential thermal analyses, indicated calcium silicate hydrate (CSH) formation. Despite this alteration, cation exchange and Cs retention capacities were largely unaffected. Swelling pressure tests on compacted bentonite specimens (dry density: 1.6 Mg/m<sup>3</sup>) prepared from hydrothermally treated bentonite showed a reduction in swelling pressure. However, no significant difference in the hydraulic conductivity occurred. X-ray photoelectron spectroscopy analysis of the compacted bentonite specimen indicated consistent Cs retention across the specimen with no effluent detected over a one-year permeation period, suggesting that the specimens were still absorbing fluid. Overall, Ca-bentonite treated with a Ca(OH)<sub>2</sub> saturated solution at 150°C for up to two years showed minimal CSH formation and minor changes in physicochemical, hydraulic, and Cs retention properties, with a slight reduction in swelling pressure.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"194 ","pages":"Article 106586"},"PeriodicalIF":3.4,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Geochemical evolution of sediments in Huanghua Depression, North China Plain: Implications for weathering, provenance, and paleoclimate since the Oligocene 华北平原黄骅坳陷渐新世以来沉积物地球化学演化及其风化、物源和古气候意义

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2025-10-08 DOI: 10.1016/j.apgeochem.2025.106585

Jianzhou Yang , Yong Li , Zhuang Duan , Jianguo Li , Kai Li , Jingjing Gong

This study presents a geochemical analysis of 91 sediment samples from the CZKZ01 borehole in the Huanghua Depression, North China Plain, to explore paleoclimatic evolution and sediment provenance since the Oligocene. Major, trace, and rare earth elements (REEs) were analyzed to assess chemical weathering intensity, provenance characteristics, and paleoenvironmental changes. Results show that the Oligocene sediments experienced intense chemical weathering (CIA = 80.1), which gradually decreased over time (CIA = 67.4 in the Pliocene, 66.4 in the Miocene, and 63.0 in the Quaternary). The primary source of sediments was felsic igneous rocks, with REE patterns indicating contributions from metamorphosed sedimentary-volcanic rocks and Mesozoic acidic igneous rocks of the Taihang Mountains, along with nearby uplifted Mesozoic sedimentary units, resulting in compositions resembling the upper continental crust (UCC). Above 120 m depth, elemental compositions become more homogeneous, reflecting increasing input from the modern Yellow River. Redox-sensitive elemental ratios indicate generally oxic depositional conditions since the Oligocene, with a gradual shift from brackish to freshwater environments beginning in the Miocene. Paleoclimatic proxies suggest a transition from warm, humid conditions in the Oligocene–Pliocene to colder, drier climates in the Quaternary, linked to the uplift of the Tibetan Plateau and global cooling events. This study provides crucial insights into sedimentary processes and climate evolution in the late Cenozoic North China Plain.

本文对华北平原黄骅坳陷CZKZ01钻孔的91份沉积物样品进行地球化学分析，探讨渐新世以来的古气候演化和沉积物物源。主要元素、痕量元素和稀土元素分析用于评价化学风化强度、物源特征和古环境变化。结果表明，渐新世沉积物经历了强烈的化学风化作用（CIA = 80.1），随着时间的推移，CIA逐渐减小（上新世CIA = 67.4，中新世CIA = 66.4，第四纪CIA = 63.0）。沉积物的主要来源为长英质火成岩，稀土元素分析表明，太行山变质沉积-火山岩和中生代酸性火成岩以及附近隆起的中生代沉积单元对沉积物的贡献，形成了类似于上陆壳（UCC）的成分。在120 m以上深度，元素组成更加均匀，反映了现代黄河输入的增加。氧化还原敏感元素比值表明渐新世以来的沉积环境普遍为含氧环境，中新世开始由微咸环境逐渐转变为淡水环境。该研究为研究晚新生代华北平原的沉积过程和气候演化提供了重要依据。

{"title":"Geochemical evolution of sediments in Huanghua Depression, North China Plain: Implications for weathering, provenance, and paleoclimate since the Oligocene","authors":"Jianzhou Yang , Yong Li , Zhuang Duan , Jianguo Li , Kai Li , Jingjing Gong","doi":"10.1016/j.apgeochem.2025.106585","DOIUrl":"10.1016/j.apgeochem.2025.106585","url":null,"abstract":"<div><div>This study presents a geochemical analysis of 91 sediment samples from the CZKZ01 borehole in the Huanghua Depression, North China Plain, to explore paleoclimatic evolution and sediment provenance since the Oligocene. Major, trace, and rare earth elements (REEs) were analyzed to assess chemical weathering intensity, provenance characteristics, and paleoenvironmental changes. Results show that the Oligocene sediments experienced intense chemical weathering (CIA = 80.1), which gradually decreased over time (CIA = 67.4 in the Pliocene, 66.4 in the Miocene, and 63.0 in the Quaternary). The primary source of sediments was felsic igneous rocks, with REE patterns indicating contributions from metamorphosed sedimentary-volcanic rocks and Mesozoic acidic igneous rocks of the Taihang Mountains, along with nearby uplifted Mesozoic sedimentary units, resulting in compositions resembling the upper continental crust (UCC). Above 120 m depth, elemental compositions become more homogeneous, reflecting increasing input from the modern Yellow River. Redox-sensitive elemental ratios indicate generally oxic depositional conditions since the Oligocene, with a gradual shift from brackish to freshwater environments beginning in the Miocene. Paleoclimatic proxies suggest a transition from warm, humid conditions in the Oligocene–Pliocene to colder, drier climates in the Quaternary, linked to the uplift of the Tibetan Plateau and global cooling events. This study provides crucial insights into sedimentary processes and climate evolution in the late Cenozoic North China Plain.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"194 ","pages":"Article 106585"},"PeriodicalIF":3.4,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0