Applied Geochemistry最新文献_第10页

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 : 2025-12-01 Epub 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。

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引用次数: 0

Contrasting cadmium isotope compositions in sediments from the eastern and western new Britain Trench: Implications for source tracing and marine geochemical cycling 新不列颠海沟东部和西部沉积物中镉同位素组成对比：来源示踪和海洋地球化学循环的意义

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2025-12-01 Epub Date: 2025-11-14 DOI: 10.1016/j.apgeochem.2025.106632

Qiang Dong , Cailing Xiao , Yong Liang , Jingqian Xie , Min Luo , Yanwei Liu , Yingying Guo , Yingming Li , Yongguang Yin , Yong Cai , Guibin Jiang

Trench sediments are recognized as a major sink in the marine cadmium (Cd) budget, however, the sources and biogeochemical cycling of Cd in hadal environments remain poorly constrained. This study investigated Cd concentrations and isotope compositions (δ^114/110Cd) in surface sediments (1553–8931 m water depth) from the western and eastern New Britain Trench. Cd concentrations ranged from 105 to 245 μg kg⁻¹, with δ^114/110Cd from −0.26 ‰ to −1.34 ‰, significantly lighter than deep seawater. Isotope tracing reveals that detrital Cd (in the crystalline mineral matrix) accounts for 34–84 % in the western and 64–87 % in the eastern transect. The δ^114/110Cd_non-detrital in shallow sediments differed markedly between western (−0.39 ‰) and eastern (−2.18 ‰) trenches, suggesting distinct sources. Terrigenous inputs, relatively enriched heavy Cd isotopes, dominate in the west, while biogenic particles sinking are likely dominant source in the east. Sedimentary δ^114/110Cd increased in the eastern transect with depth due to stepwise scavenging of light isotopes, whereas in the western transect it first decreased and then increased, reflecting variations in sediment components and redox conditions. These findings underscore the combined effects of source heterogeneity and depositional processes on Cd isotopes composition in trench sediments, offering new insights into deep-ocean metal cycling.

海沟沉积物被认为是海洋镉（Cd）收支的主要汇，然而，对潮环境中Cd的来源和生物地球化学循环的研究仍然很少。本文研究了新不列颠海沟西部和东部表层沉积物（1553 ~ 8931 m水深）中Cd的浓度和同位素组成（δ114/110Cd）。Cd浓度范围为105 ~ 245 μ kg - 1， δ114/110Cd浓度范围为- 0.26‰~ - 1.34‰，显著低于深海。同位素示踪表明，碎屑Cd（在结晶矿物基质中）在西部占34 - 84%，在东部占64 - 87%。西部海沟（- 0.39‰）和东部海沟（- 2.18‰）浅层沉积物δ114/ 110cdnon -碎屑含量差异显著，表明沉积物来源不同。西部以陆源输入为主，重Cd同位素相对富集，东部可能以生物颗粒沉降为主。东部样带沉积δ114/110Cd随深度增大，主要是由于轻同位素的逐步清除作用，而西部样带沉积δ114/110Cd先减小后增大，反映了沉积物组分和氧化还原条件的变化。这些发现强调了来源非均质性和沉积过程对海沟沉积物中Cd同位素组成的综合影响，为研究深海金属循环提供了新的见解。

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引用次数: 0

Estimation of flow dynamics of saline groundwater in a coastal geothermal region based on B–Li–Cl classification and geochemical measurements 基于B-Li-Cl分类和地球化学测量的滨海地热区含盐地下水流动动力学估算

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2025-12-01 Epub Date: 2025-11-12 DOI: 10.1016/j.apgeochem.2025.106625

Tsuyoshi Shintani , Keiichi Tomita , Noritoshi Morikawa

Coastal geothermal saline groundwater (SGW) in Quaternary volcanic regions represents an important geothermal resource, but its complex chemical compositions often obscure its origin and dynamics. This study aims to elucidate the SGW dynamics in the coastal plain of Hakodate, Hokkaido, in Japan using the B–Li–Cl to delineate water-rock interactions and diagenesis, and to classify SGW type. Major dissolved components and stable isotopes (δ²H, δ¹⁸O) are susceptible to freshwater dilution, limiting their diagnostic utility. The B–Li–Cl composition allowed for the classification of SGW into three types (Type 1, 2, and 3). Types 1 and 2 were influenced by direct seawater contributions and other origins such as diagenesis and volcanic gas, respectively. Type 3, with higher B (Boron) and Li (Lithium) concentrations than the other SGW, is distributed in the geothermal region, and reflects seawater modified by interaction with rocks at 175 ± 25 °C. Integration of chemical equilibrium modeling and geothermometer supports this geochemical evolution of the SGWs. Additionally, hydrogeological analyses have estimated that the flow dynamics of Type 3 waters are recharged through fractures near offshore submarine volcanic vents that migrate to deeper subsurface regions. These findings offer new insights into coastal hydrothermal systems in the study area. The Li and B concentrations serve as effective tracers for elucidating the origin of SGW in coastal geothermal regions, and their application is expected to lead to a more comprehensive understanding of SGW flow dynamics.

第四纪火山岩区沿海含盐地热地下水是一种重要的地热资源，但其复杂的化学成分往往使其起源和动态变得模糊不清。本研究旨在利用B-Li-Cl描述日本北海道函馆沿海平原的水-岩相互作用和成岩作用，并对SGW类型进行分类。主要溶解成分和稳定同位素（δ2H, δ18O）易受淡水稀释的影响，限制了它们的诊断效用。B-Li-Cl组成允许将SGW分为三种类型（类型1,2和3）。类型1和类型2分别受到海水直接贡献和成岩作用、火山气等其他成因的影响。类型3分布在地热区，B （Boron）和Li （Lithium）的浓度高于其他SGW，反映了175±25℃时海水与岩石相互作用的改变。化学平衡模型和地温计的结合支持了SGWs的地球化学演化。此外，水文地质分析估计，3型水的流动动力学是通过海上海底火山口附近的裂缝补充的，这些裂缝迁移到更深的地下区域。这些发现为研究区沿海热液系统提供了新的认识。Li和B浓度是阐明沿海地热区SGW成因的有效示踪剂，它们的应用有望使人们对SGW流动动力学有更全面的了解。

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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 : 2025-12-01 Epub 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。

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引用次数: 0

Radon levels in soil and in groundwater in the Alhama de Murcia fault area, Spain 西班牙Alhama de Murcia断裂带土壤和地下水中的氡水平

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2025-12-01 Epub Date: 2025-11-04 DOI: 10.1016/j.apgeochem.2025.106612

Victòria Moreno , Joan Bach , Mario Zarroca , Eulàlia Masana , Lluís Font , Rogelio Linares

Radon and CO₂ in groundwater, radon and thoron in soil, soil radon exhalation rates, and electrical resistivity imaging were measured in the Alhama de Murcia Fault area. The study aims to (i) characterize radon levels in groundwater and soil and (ii) assess whether variations in gas emissions are related to the presence of an active fault. Forty water sampling points exhibited ²²²Rn concentrations ranging from 0.4 to 66.8 Bq/L, while 22 soil points along two profiles crossing the fault showed low annual mean values of (8 ± 1) kBq m⁻³ and (12 ± 2) kBq m⁻³. Soil radon exhalation rates at the two profiles, (36 ± 8) and (53 ± 12) Bq m⁻² h⁻¹, respectively, are consistent with these concentrations. Spatial variability of soil radon along both profiles, [1–22] kBq m⁻³, appears associated with the main fault location. Temporal variations of ²²²Rn recorded at a monitoring station from early 2013 to mid-2015 closely match punctual measurements. While fluctuations are largely controlled by barometric pressure and atmospheric temperature, detailed analyses combining multiple radon anomaly detection methods indicate a possible influence of nearby seismic events.

在Alhama de Murcia断裂带测量了地下水中的氡和CO2、土壤中的氡和钍、土壤氡呼出率和电阻率成像。这项研究的目的是：(1)确定地下水和土壤中的氡水平的特征；(2)评估气体排放的变化是否与活动断层的存在有关。40个水样点的222Rn浓度在0.4 ~ 66.8 Bq/L之间，22个土壤点的222Rn浓度在（8±1）kBq m−3和（12±2）kBq m−3之间，年平均值较低。两个剖面的土壤氡呼出率分别为（36±8）和（53±12）Bq m−2 h−1，与这些浓度一致。土壤氡沿两个剖面的空间变异性[1-22]kBq m−3似乎与主断层位置有关。从2013年初到2015年中，一个监测站记录的222Rn的时间变化与准时测量结果非常吻合。虽然波动在很大程度上受气压和大气温度的控制，但结合多种氡异常检测方法的详细分析表明，附近地震事件可能对其产生影响。

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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 : 2025-12-01 Epub 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。

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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 : 2025-12-01 Epub 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。

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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 : 2025-12-01 Epub 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。

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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 : 2025-12-01 Epub 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。

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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 : 2025-12-01 Epub 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。

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引用次数: 0