Applied Geochemistry最新文献

Metal Transport through Century-Old Waste Rock 通过百年废石的金属运输

IF 3.5 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-10-15 DOI: 10.1016/j.apgeochem.2026.107128

Andrew Hicks, Colleen O. Harper, Richard T. Amos

The potential for waste rock from mining activities to leach poor quality drainage has been well documented. However, despite the potential for leaching to occur over many decades or centuries, few studies have investigated the relevant geochemical processes over long timescales. This study looks at the porewater geochemistry from a ∼10 Ktonne waste-rock pile at an abandoned prospecting property, the Ore Chimney mine, that has been in place for approximately 100 years. Waste-rock samples were collected at 0.5 m intervals from three trenches that transected the ∼5 m depth of the pile; samples were centrifuged to extract porewaters and analyzed for standard geochemical parameters, anions, cations, and metals. The geochemical modelling software PHREEQC was used to explore possible secondary controls on porewater chemistry. The results indicate near-neutral pH throughout the depth of the waste rock and abundant alkalinity (average: 58.6 mg/L CaCO₃), indicating that carbonate buffering is still active within the waste rock. Zn concentrations, as high as 87.5 ppm (16.5 ppm on average), accounted for 92% [M] of heavy metals and is attributed to the oxidative dissolution of sphalerite, the primary sulfide mineral in the waste rock. The preferential weathering of sphalerite over pyrite produces less acidity and plays a large role in maintaining carbonates and neutral pH in the system. Despite the long period of weathering within the Ore Chimney waste rock, weathering processes are similar to those observed in other waste-rock studies and differences in geochemical parameters are largely ascribed to differences in lithology, principally sulfide mineralogy and carbonate content, rather than the age of the waste-rock. High alkalinity levels suggest that the dissolution of calcite and dolomite controlpH, and Pb, Zn, Cd, and Cu concentrations in the porewaters. Results from this study indicate that the source lithology of sulfides plays a strong role in weathering. This study shows that a detailed understanding of in situ solid- and aqueous-phase geochemistry is required to delineate waste-rock weathering as a function of long-term exposure.

采矿活动产生的废石有可能渗入质量差的排水系统，这一点已有充分的记录。然而，尽管淋溶可能在几十年或几个世纪内发生，但很少有研究在长时间尺度上调查相关的地球化学过程。这项研究着眼于在一个废弃的勘探地点，即已经存在了大约100年的矿石烟囱矿，从一个~ 10千吨的废岩堆中提取的孔隙水地球化学。废石样品每隔0.5 m从三个沟中收集，这些沟横切桩的~ 5 m深度；样品离心提取孔隙水，分析标准地球化学参数、阴离子、阳离子和金属。利用地球化学建模软件PHREEQC探索孔隙水化学可能的次生控制因素。结果表明，整个废石深度的pH值接近中性，碱度丰富（平均CaCO3为58.6 mg/L），表明废石内部仍有碳酸盐岩缓冲作用。锌含量高达87.5 ppm（平均16.5 ppm），占重金属含量的92% [M]，是由废岩中原生硫化物矿物闪锌矿氧化溶解所致。闪锌矿对黄铁矿的优先风化作用产生较少的酸性，对维持体系中的碳酸盐和中性pH起很大作用。尽管矿烟囱废岩风化期长，但风化过程与其他废岩研究中观察到的相似，地球化学参数的差异主要归因于岩性的差异，主要是硫化物矿物学和碳酸盐含量的差异，而不是废岩的年龄。高碱度表明方解石和白云石的溶解控制了孔隙水中ph、Pb、Zn、Cd和Cu的浓度。研究结果表明，硫化物的来源岩性在风化过程中起重要作用。这项研究表明，需要对原位固相和水相地球化学进行详细的了解，以描绘废物岩石风化作为长期暴露的函数。

{"title":"Metal Transport through Century-Old Waste Rock","authors":"Andrew Hicks, Colleen O. Harper, Richard T. Amos","doi":"10.1016/j.apgeochem.2026.107128","DOIUrl":"10.1016/j.apgeochem.2026.107128","url":null,"abstract":"<div><div>The potential for waste rock from mining activities to leach poor quality drainage has been well documented. However, despite the potential for leaching to occur over many decades or centuries, few studies have investigated the relevant geochemical processes over long timescales. This study looks at the porewater geochemistry from a ∼10 Ktonne waste-rock pile at an abandoned prospecting property, the Ore Chimney mine, that has been in place for approximately 100 years. Waste-rock samples were collected at 0.5 m intervals from three trenches that transected the ∼5 m depth of the pile; samples were centrifuged to extract porewaters and analyzed for standard geochemical parameters, anions, cations, and metals. The geochemical modelling software PHREEQC was used to explore possible secondary controls on porewater chemistry. The results indicate near-neutral pH throughout the depth of the waste rock and abundant alkalinity (average: 58.6 mg/L CaCO3), indicating that carbonate buffering is still active within the waste rock. Zn concentrations, as high as 87.5 ppm (16.5 ppm on average), accounted for 92% [M] of heavy metals and is attributed to the oxidative dissolution of sphalerite, the primary sulfide mineral in the waste rock. The preferential weathering of sphalerite over pyrite produces less acidity and plays a large role in maintaining carbonates and neutral pH in the system. Despite the long period of weathering within the Ore Chimney waste rock, weathering processes are similar to those observed in other waste-rock studies and differences in geochemical parameters are largely ascribed to differences in lithology, principally sulfide mineralogy and carbonate content, rather than the age of the waste-rock. High alkalinity levels suggest that the dissolution of calcite and dolomite controlpH, and Pb, Zn, Cd, and Cu concentrations in the porewaters. Results from this study indicate that the source lithology of sulfides plays a strong role in weathering. This study shows that a detailed understanding of in situ solid- and aqueous-phase geochemistry is required to delineate waste-rock weathering as a function of long-term exposure.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"211 ","pages":"Article 107128"},"PeriodicalIF":3.5,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149203156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Assessment for co-production of critical metals (lithium, copper, strontium) and geothermal heat in various geological formations of the North German basin 对德国北部盆地不同地质构造中关键金属（锂、铜、锶）和地热的联合生产进行评估

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-03-01 Epub Date: 2026-02-03 DOI: 10.1016/j.apgeochem.2026.106725

Simona Regenspurg , Anika Thomas , Nina Pogarell , Jessica A. Stammeier , Franziska D.H. Wilke , Valby van Schijndel

Several sedimentary formations and lithologies such as limestone from the Muschelkalk or sandstone from the Bunter or from the Rotliegend are considered for geothermal exploitation in the North German Basin. The production and analysis of geothermal fluids from deep wells in this area already showed an increased content of certain critical raw materials (CRM) in some brines indicating that a co-production of geothermal heat and CRM could be economically interesting. In this study, the overall potential of 23 geological formations for CRM co-production of the 4 km deep geothermal well from the Groβ Schönebeck site was assessed with focus on the CRM elements lithium (Li), copper (Cu), and strontium (Sr). For this, the total elemental content of 23 rocks samples from different depths between 1.4 and 4.1 km was determined. Highest Sr was identified in the limestones of Muschelkalk (2330 mg/kg) and Werra formation (2980 mg/kg). Copper was mainly enriched in the Kupferschiefer (214 mg/kg) and the Upper Rotliegend sandstones (79 mg/kg), and Li mainly in the Rotliegend conglomerates (up to 200 mg/kg).

To determine how strong and to which minerals these CRM are bound within the rocks, leaching and sequential extraction experiments were performed on five selected formation rock samples that are considered either for geothermal exploitation (Muschelkalk, Buntsandstein, Rotliegend sandstone) and/or as potential source for the CRMs Li, Cu, Sr (Permo-Carboniferous volcanic rocks, Ohre anhydrite). These experiments revealed that Sr was predominantly bound to carbonates indicating incorporation in calcite minerals. For Cu no clear source rock was identified although a volcanic origin seems most likely. Lithium was strongly bound to all investigated rocks (<5 % of total Li was extractable) indicating a binding to the silicate phases.

一些沉积地层和岩性，如Muschelkalk的石灰岩或Bunter或Rotliegend的砂岩，被认为可以在北德意志盆地进行地热开采。该地区深井地热流体的生产和分析已经表明，某些盐水中某些关键原料（CRM）的含量有所增加，这表明地热和CRM的联合生产可能具有经济效益。在这项研究中，对Groβ Schönebeck站点4 km深地热井的23个地质层进行了CRM联合生产的总体潜力评估，重点评估了CRM元素锂（Li）、铜（Cu）和锶（Sr）。为此，测定了来自1.4 ~ 4.1 km不同深度的23个岩石样品的总元素含量。Muschelkalk组灰岩Sr最高，为2330 mg/kg， Werra组灰岩Sr最高，为2980 mg/kg。铜主要富集于Kupferschiefer砂岩（214 mg/kg）和上Rotliegend砂岩（79 mg/kg）， Li主要富集于Rotliegend砾岩（高达200 mg/kg）。为了确定这些CRM在岩石中的强度和与哪些矿物结合，对五个选定的地层岩石样品进行了浸出和连续提取实验，这些岩石样品被认为是地热开采（Muschelkalk, Buntsandstein， Rotliegend砂岩）和/或作为CRM Li， Cu， Sr的潜在来源（二叠石炭系火山岩，Ohre硬石膏）。这些实验表明，锶主要与碳酸盐结合，表明在方解石矿物中掺入。对于铜，没有明确的烃源岩，尽管火山起源似乎是最有可能的。锂与所有被研究的岩石紧密结合（总锂的5%可提取），表明与硅酸盐相结合。

{"title":"Assessment for co-production of critical metals (lithium, copper, strontium) and geothermal heat in various geological formations of the North German basin","authors":"Simona Regenspurg , Anika Thomas , Nina Pogarell , Jessica A. Stammeier , Franziska D.H. Wilke , Valby van Schijndel","doi":"10.1016/j.apgeochem.2026.106725","DOIUrl":"10.1016/j.apgeochem.2026.106725","url":null,"abstract":"<div><div>Several sedimentary formations and lithologies such as limestone from the Muschelkalk or sandstone from the Bunter or from the Rotliegend are considered for geothermal exploitation in the North German Basin. The production and analysis of geothermal fluids from deep wells in this area already showed an increased content of certain critical raw materials (CRM) in some brines indicating that a co-production of geothermal heat and CRM could be economically interesting. In this study, the overall potential of 23 geological formations for CRM co-production of the 4 km deep geothermal well from the Groβ Schönebeck site was assessed with focus on the CRM elements lithium (Li), copper (Cu), and strontium (Sr). For this, the total elemental content of 23 rocks samples from different depths between 1.4 and 4.1 km was determined. Highest Sr was identified in the limestones of Muschelkalk (2330 mg/kg) and Werra formation (2980 mg/kg). Copper was mainly enriched in the Kupferschiefer (214 mg/kg) and the Upper Rotliegend sandstones (79 mg/kg), and Li mainly in the Rotliegend conglomerates (up to 200 mg/kg).</div><div>To determine how strong and to which minerals these CRM are bound within the rocks, leaching and sequential extraction experiments were performed on five selected formation rock samples that are considered either for geothermal exploitation (Muschelkalk, Buntsandstein, Rotliegend sandstone) and/or as potential source for the CRMs Li, Cu, Sr (Permo-Carboniferous volcanic rocks, Ohre anhydrite). These experiments revealed that Sr was predominantly bound to carbonates indicating incorporation in calcite minerals. For Cu no clear source rock was identified although a volcanic origin seems most likely. Lithium was strongly bound to all investigated rocks (<5 % of total Li was extractable) indicating a binding to the silicate phases.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"200 ","pages":"Article 106725"},"PeriodicalIF":3.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147424688","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 controls on silicification and biofilm stabilization in an intertidal hydrothermal spring: evidence from Puertecitos, Baja California 潮间带热液泉中硅化和生物膜稳定的地球化学控制：来自下加利福尼亚州Puertecitos的证据

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-03-01 Epub Date: 2026-02-17 DOI: 10.1016/j.apgeochem.2026.106736

Yorfrank Arellano-Ramírez , Enrique Iñiguez , Rufina Hernández-Martínez , Juan I. Sánchez-Ávila , Thomas G. Kretzschmar

Intertidal hydrothermal systems provide natural laboratories for investigating near-surface geochemical and microbial interactions. Here, we integrate field measurements (temperature, pH, and electrical conductivity), PHREEQC-based saturation index (SI) modeling, and SEM/EDS analyses to quantify how temperature, redox (pe), and seawater mixing regulate mineral precipitation and microbial preservation in the intertidal hydrothermal spring at Puertecitos, Baja California. Major-ion chemistry was measured for the two endmembers (YAPU01, YAPU16). The intermediate stations are described using in situ T–pH–EC as mixing proxies. Modeling of vent-proximal water (YAPU01; 73 °C, pe ≈ 0 and pe = 8.41) and marine-influenced rim water (YAPU16; 32.7 °C, pe = 8.41) shows persistent silica supersaturation across the natural temperature window, which strengthens upon cooling. Oxidation stabilizes Fe-oxyhydroxides at lower temperatures, whereas carbonates and gypsum reach supersaturation primarily within the cooler, marine-influenced apron. SEM/EDS observations reveal 1) abundant filamentous and bacillary morphotypes at ∼60 °C that decline to near zero by ∼46-50 °C, 2) biofilm dominance at ≤41-33 °C, and 3) silica matrices with carbon co-localized to rods and bacilli, consistent with microbial templating and progressive silicification. In contrast, Ba-free, C/N poor elongated fabrics are interpreted as nondiagnostic sinter textures. Together, these results define a process framework in which abiotic silica precipitation is pervasive but microbially templated, and additional Fe-oxide-gypsum-carbonate pathways emerge with cooling and redox evolution. This integrated geochemical-textural approach clarifies shoreline diagenesis, biosignature preservation potential, and trace element scavenging at the hydrothermal-marine interface.

潮间带热液系统为研究近地表地球化学和微生物相互作用提供了天然实验室。在这里，我们整合了现场测量（温度、pH值和电导率）、基于phreeqc的饱和指数（SI）模型和SEM/EDS分析，以量化温度、氧化还原（pe）和海水混合如何调节下加利福尼亚州Puertecitos潮间带热液泉的矿物沉淀和微生物保存。测定了两个端元（YAPU01, YAPU16）的主离子化学性质。用原位T-pH-EC作为混合代理来描述中间站。对近端水（YAPU01; 73°C, pe≈0,pe = 8.41）和受海洋影响的边缘水（YAPU16; 32.7°C, pe = 8.41）的模拟显示，在整个自然温度窗内，二氧化硅持续过饱和，冷却后这种过饱和会增强。氧化作用在较低温度下稳定铁氧氢氧化物，而碳酸盐和石膏主要在较冷的、受海洋影响的围裙内达到过饱和。SEM/EDS观察显示1)在~ 60°C时丰富的丝状和细菌形态，在~ 46-50°C时下降到接近零，2)在≤41-33°C时生物膜优势，以及3)碳与棒和杆菌共定位的二氧化硅基质，与微生物模板化和渐进硅化一致。相反，不含钡、碳氮比差的拉长织物被解释为非诊断烧结织构。总之，这些结果定义了一个过程框架，其中非生物二氧化硅沉淀普遍存在，但微生物模板化，并且随着冷却和氧化还原演化出现了额外的铁-氧化石膏-碳酸盐岩途径。这种综合的地球化学-结构方法澄清了海岸线成岩作用、生物特征保存潜力以及热液-海洋界面的微量元素清除。

{"title":"Geochemical controls on silicification and biofilm stabilization in an intertidal hydrothermal spring: evidence from Puertecitos, Baja California","authors":"Yorfrank Arellano-Ramírez , Enrique Iñiguez , Rufina Hernández-Martínez , Juan I. Sánchez-Ávila , Thomas G. Kretzschmar","doi":"10.1016/j.apgeochem.2026.106736","DOIUrl":"10.1016/j.apgeochem.2026.106736","url":null,"abstract":"<div><div>Intertidal hydrothermal systems provide natural laboratories for investigating near-surface geochemical and microbial interactions. Here, we integrate field measurements (temperature, pH, and electrical conductivity), PHREEQC-based saturation index (SI) modeling, and SEM/EDS analyses to quantify how temperature, redox (pe), and seawater mixing regulate mineral precipitation and microbial preservation in the intertidal hydrothermal spring at Puertecitos, Baja California. Major-ion chemistry was measured for the two endmembers (YAPU01, YAPU16). The intermediate stations are described using in situ T–pH–EC as mixing proxies. Modeling of vent-proximal water (YAPU01; 73 °C, pe ≈ 0 and pe = 8.41) and marine-influenced rim water (YAPU16; 32.7 °C, pe = 8.41) shows persistent silica supersaturation across the natural temperature window, which strengthens upon cooling. Oxidation stabilizes Fe-oxyhydroxides at lower temperatures, whereas carbonates and gypsum reach supersaturation primarily within the cooler, marine-influenced apron. SEM/EDS observations reveal 1) abundant filamentous and bacillary morphotypes at ∼60 °C that decline to near zero by ∼46-50 °C, 2) biofilm dominance at ≤41-33 °C, and 3) silica matrices with carbon co-localized to rods and bacilli, consistent with microbial templating and progressive silicification. In contrast, Ba-free, C/N poor elongated fabrics are interpreted as nondiagnostic sinter textures. Together, these results define a process framework in which abiotic silica precipitation is pervasive but microbially templated, and additional Fe-oxide-gypsum-carbonate pathways emerge with cooling and redox evolution. This integrated geochemical-textural approach clarifies shoreline diagenesis, biosignature preservation potential, and trace element scavenging at the hydrothermal-marine interface.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"200 ","pages":"Article 106736"},"PeriodicalIF":3.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147424684","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

Pore-scale reactive transport for assessing permeability changes on CO2 capture and storage 孔隙尺度反应输运评估CO2捕获和储存的渗透率变化

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-03-01 Epub Date: 2026-02-10 DOI: 10.1016/j.apgeochem.2026.106728

Jeremy T. First , Yuliana Zapata , Srivatsa Mudumba Ramana , Glen L. Gettemy , Jonathan Hodgkinson

Reactive transport modeling has increasingly become a key simulation capability in the risk management of subsurface operations, particularly when dealing with reactive fluids, such as monitoring of CO₂ plume migration in carbon capture and storage (CCS) operations. The pore-scale complexities and mineral distribution play a fundamental role in the dynamic porosity and permeability exhibited by a rock upon invasion of a reactive fluid. Here, we present an implementation of pore-scale reactive transport (PSRT) – using a generalized rate law that can be extended to any mineral – for simulating the evolving pore geometry of a digital rock due to dissolution and precipitation reactions within the rock. We validate our implementation against a well-known single-mineral benchmark simulation case and previously published microfluidics experiments, before applying the framework to a realistic CCS scenario with multiple minerals using a

μ CT

image from an appraisal well in Texas. For our sandstone comprising calcite, quartz, clay, and feldspar, we show total dissolution of calcite and delayed, nominal dissolution of anorthite over a 2-hour time frame, resulting in a 41.1% relative increase in porosity and a 242% relative increase in permeability in the absence of grain compaction effects. We demonstrate the importance of 3D PSRT simulations for CCS scenarios by investigating the heterogeneity of mineral reaction rates. Our approach reveals relationships between porosity–permeability and porosity–tortuosity that would not be captured by lower-dimensional methods. We show that these relationships can be directly observed from PSRT simulations and interpreted via a streamline analysis of the evolving flow fields.

反应性输运建模日益成为地下作业风险管理的关键模拟能力，特别是在处理反应性流体时，例如监测碳捕集与封存（CCS）作业中的二氧化碳羽流迁移。孔隙尺度的复杂性和矿物分布对反应性流体侵入后岩石的动态孔隙度和渗透率起着基础性的作用。在这里，我们提出了一种孔隙尺度反应输运（PSRT）的实现-使用可以扩展到任何矿物的广义速率定律-模拟由于岩石内部溶解和沉淀反应而演变的数字岩石孔隙几何形状。我们通过一个著名的单矿物基准模拟案例和之前发表的微流体实验验证了我们的实现，然后使用德克萨斯州评价井的μCT图像将框架应用于具有多种矿物的现实CCS场景。对于由方解石、石英、粘土和长石组成的砂岩，我们发现方解石在2小时内完全溶解，钙长石在2小时内延迟溶解，导致孔隙度相对增加41.1%，渗透率相对增加242%，而没有颗粒压实作用。通过研究矿物反应速率的非均质性，我们证明了3D PSRT模拟对CCS情景的重要性。我们的方法揭示了孔隙度-渗透率和孔隙度-扭曲度之间的关系，这是低维方法无法捕捉到的。我们表明，这些关系可以从PSRT模拟中直接观察到，并通过流场演变的流线分析来解释。

{"title":"Pore-scale reactive transport for assessing permeability changes on CO2 capture and storage","authors":"Jeremy T. First , Yuliana Zapata , Srivatsa Mudumba Ramana , Glen L. Gettemy , Jonathan Hodgkinson","doi":"10.1016/j.apgeochem.2026.106728","DOIUrl":"10.1016/j.apgeochem.2026.106728","url":null,"abstract":"<div><div>Reactive transport modeling has increasingly become a key simulation capability in the risk management of subsurface operations, particularly when dealing with reactive fluids, such as monitoring of CO2 plume migration in carbon capture and storage (CCS) operations. The pore-scale complexities and mineral distribution play a fundamental role in the dynamic porosity and permeability exhibited by a rock upon invasion of a reactive fluid. Here, we present an implementation of pore-scale reactive transport (PSRT) – using a generalized rate law that can be extended to any mineral – for simulating the evolving pore geometry of a digital rock due to dissolution and precipitation reactions within the rock. We validate our implementation against a well-known single-mineral benchmark simulation case and previously published microfluidics experiments, before applying the framework to a realistic CCS scenario with multiple minerals using a <math><mrow><mi>μ</mi><mi>CT</mi></mrow></math> image from an appraisal well in Texas. For our sandstone comprising calcite, quartz, clay, and feldspar, we show total dissolution of calcite and delayed, nominal dissolution of anorthite over a 2-hour time frame, resulting in a 41.1% relative increase in porosity and a 242% relative increase in permeability in the absence of grain compaction effects. We demonstrate the importance of 3D PSRT simulations for CCS scenarios by investigating the heterogeneity of mineral reaction rates. Our approach reveals relationships between porosity–permeability and porosity–tortuosity that would not be captured by lower-dimensional methods. We show that these relationships can be directly observed from PSRT simulations and interpreted via a streamline analysis of the evolving flow fields.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"200 ","pages":"Article 106728"},"PeriodicalIF":3.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147424687","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

Groundwater helium isotope characteristics and source identification in Leizhou Peninsula, southern China 雷州半岛地下水氦同位素特征及来源识别

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-03-01 Epub Date: 2026-02-26 DOI: 10.1016/j.apgeochem.2026.106750

Shaoheng Li , Zuobing Liang , Werner Aeschbach , Dioni I. Cendón , Wen Wei , Qirui Wu , Di Tian , Rouyan Gong , Gang Zeng , Zaizhi Yang , Jianyao Chen , Linyao Dong

Helium isotopes, alongside radiocarbon (¹⁴C) dating and the elemental ratio ²⁰Ne/⁴He, were employed to investigate groundwater evolution in the Leizhou Peninsula, southern China. Groundwater samples were categorized into two groups based on corrected ¹⁴C age: Group Ⅰ (modern recharge, >75pMC) and Group Ⅱ (older groundwater, 1-75 pMC) with ages ranging up to ∼29,000 years BP. Helium isotope analysis revealed distinct sources: Group Ⅰ exhibited elevated ³He/⁴He ratios (>1 Ra) and tritiogenic ³He, reflecting atmospheric dominance, while Group Ⅱ showed lower ³He/⁴He ratios (<1 Ra) and radiogenic ⁴He accumulation, consistent with prolonged groundwater residence time and water-rock interaction. A notable exception was a volcanic island sample with anomalously high ³He/⁴He (∼3 Ra) and helium concentrations, indicating a localized mantle-derived helium contribution. A ternary mixing model quantified helium sources, demonstrating increasing crustal contributions (1-52%) with groundwater age. Moreover, dissolved ⁴He concentrations show a positive correlation with corrected ¹⁴C ages, yielding a radiogenic ⁴He accumulation rate of 2.76 × 10⁻⁹ ccSTP/g/ka, supporting ⁴He as a complementary groundwater chronometer. These findings emphasize time-dependent noble gas accumulation and mixing processes within the aquifer system, offering insights for sustainable groundwater management in the study area.

利用氦同位素、放射性碳（14C）定年和元素比20Ne/4He对雷州半岛地下水演化进行了研究。地下水样品根据校正后的14C年龄分为两组：Ⅰ组（现代补给，>75pMC）和Ⅱ组（更古老的地下水，1- 75pMC），年龄范围可达~ 29,000年BP。氦同位素分析显示了不同的来源：Ⅰ组表现出较高的3He/4He比率（>1 Ra）和三生源性3He，反映了大气优势，而Ⅱ组表现出较低的3He/4He比率（<1 Ra）和放射性成因的4He积累，与地下水停留时间延长和水岩相互作用一致。一个值得注意的例外是火山岛样品，其3He/4He （~ 3ra）和氦浓度异常高，表明局部地幔源氦贡献。三元混合模型量化了氦源，表明地壳对氦源的贡献随着地下水年龄的增加而增加（1-52%）。此外，溶解的4He浓度与校正后的14C年龄呈正相关，产生的放射性成因4He积累速率为2.76 × 10−9 ccSTP/g/ka，支持4He作为补充地下水计时器。这些发现强调了含水层系统中随时间变化的稀有气体聚集和混合过程，为研究区域的可持续地下水管理提供了见解。

{"title":"Groundwater helium isotope characteristics and source identification in Leizhou Peninsula, southern China","authors":"Shaoheng Li , Zuobing Liang , Werner Aeschbach , Dioni I. Cendón , Wen Wei , Qirui Wu , Di Tian , Rouyan Gong , Gang Zeng , Zaizhi Yang , Jianyao Chen , Linyao Dong","doi":"10.1016/j.apgeochem.2026.106750","DOIUrl":"10.1016/j.apgeochem.2026.106750","url":null,"abstract":"<div><div>Helium isotopes, alongside radiocarbon (14C) dating and the elemental ratio 20Ne/4He, were employed to investigate groundwater evolution in the Leizhou Peninsula, southern China. Groundwater samples were categorized into two groups based on corrected 14C age: Group Ⅰ (modern recharge, >75pMC) and Group Ⅱ (older groundwater, 1-75 pMC) with ages ranging up to ∼29,000 years BP. Helium isotope analysis revealed distinct sources: Group Ⅰ exhibited elevated 3He/4He ratios (>1 Ra) and tritiogenic 3He, reflecting atmospheric dominance, while Group Ⅱ showed lower 3He/4He ratios (<1 Ra) and radiogenic 4He accumulation, consistent with prolonged groundwater residence time and water-rock interaction. A notable exception was a volcanic island sample with anomalously high 3He/4He (∼3 Ra) and helium concentrations, indicating a localized mantle-derived helium contribution. A ternary mixing model quantified helium sources, demonstrating increasing crustal contributions (1-52%) with groundwater age. Moreover, dissolved 4He concentrations show a positive correlation with corrected 14C ages, yielding a radiogenic 4He accumulation rate of 2.76 × 10−9 ccSTP/g/ka, supporting 4He as a complementary groundwater chronometer. These findings emphasize time-dependent noble gas accumulation and mixing processes within the aquifer system, offering insights for sustainable groundwater management in the study area.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"200 ","pages":"Article 106750"},"PeriodicalIF":3.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147424691","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

Factors affecting surface precipitate solubility products of nickel at the montmorillonite-water interface 影响蒙脱石-水界面镍表面沉淀溶解度产物的因素

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-03-01 Epub Date: 2026-02-25 DOI: 10.1016/j.apgeochem.2026.106751

Chaoran Huo, Yang Wu, Chiyu Zhang, Yibing Ma

Surface precipitates of metals at soil-water interfaces were identified. Recently, the surface precipitate apparent solubility product (K_sp’) of nickel (Ni) at the montmorillonite-water interface was first determined using the Langmuir-precipitation model, enabling quantitative prediction of Ni partitioning. Factors affecting interface surface precipitation are critical for thermodynamic and mechanistic understanding but remain unstudied. In the present study, the nickel hydroxide's K_sp’ at the montmorillonite-water interface under varying pH, temperature (T), and montmorillonite concentrations were investigated. It was found that K_sp’ decreased significantly with increases in the pH and montmorillonite concentration: pK_sp’ increased by 0.03 per 0.1 pH increase and by 0.04 per 1 g L⁻¹ montmorillonite concentration increase. The values of K_sp’ ranged from 2.19 × 10⁻¹⁷ to 5.25 × 10⁻¹⁷, which were 39 to 91 times lower than the solubility product (K_sp, 2.00 × 10⁻¹⁵) of Ni(OH)₂ in a pure water system. Thermodynamic parameters (enthalpy change, ΔH⁰ = 36.62 kJ mol⁻¹; entropy change, ΔS⁰ = 0.438 kJ/(mol·K); Gibbs free energy change, ΔG⁰ < 0) indicate that surface precipitation is an endothermic reaction overall with an increase in entropy, contrary to precipitation in pure water, and is spontaneous (T > 84K). These findings can effectively predict Ni retention at soil-water interfaces, addressing critical gaps in conventional environmental risk assessments of surface precipitation mechanisms.

确定了土壤-水界面金属的表面沉淀。最近，镍（Ni）在蒙脱石-水界面的表面沉淀表观溶解度积（Ksp '）首次使用Langmuir-precipitation模型确定，从而能够定量预测Ni的分配。影响界面表面沉淀的因素对热力学和机理的理解至关重要，但尚未得到研究。本文研究了不同pH、温度(T)和蒙脱土浓度下，氢氧化镍在蒙脱土-水界面处的Ksp '。随着pH和蒙脱土浓度的增加，Ksp′显著降低：pH每增加0.1，pKsp′增加0.03；蒙脱土浓度每增加1 g ，pKsp′增加0.04。Ksp′值为2.19 × 10−17 ~ 5.25 × 10−17，比Ni(OH)2在纯水体系中的溶解度产物（Ksp, 2.00 × 10−15）低39 ~ 91倍。热力学参数(焓变ΔH0 = 36.62 kJ mol−1；熵变ΔS0 = 0.438 kJ/(mol·K)；Gibbs自由能变化ΔG0 <； 0)表明，表面沉淀总体上是一个熵增加的吸热反应，与纯水中的沉淀相反，是自发的（T >； 84K）。这些发现可以有效地预测土壤-水界面的Ni保留，解决地表降水机制传统环境风险评估的关键空白。

{"title":"Factors affecting surface precipitate solubility products of nickel at the montmorillonite-water interface","authors":"Chaoran Huo, Yang Wu, Chiyu Zhang, Yibing Ma","doi":"10.1016/j.apgeochem.2026.106751","DOIUrl":"10.1016/j.apgeochem.2026.106751","url":null,"abstract":"<div><div>Surface precipitates of metals at soil-water interfaces were identified. Recently, the surface precipitate apparent solubility product (Ksp’) of nickel (Ni) at the montmorillonite-water interface was first determined using the Langmuir-precipitation model, enabling quantitative prediction of Ni partitioning. Factors affecting interface surface precipitation are critical for thermodynamic and mechanistic understanding but remain unstudied. In the present study, the nickel hydroxide's Ksp’ at the montmorillonite-water interface under varying pH, temperature (T), and montmorillonite concentrations were investigated. It was found that Ksp’ decreased significantly with increases in the pH and montmorillonite concentration: pKsp’ increased by 0.03 per 0.1 pH increase and by 0.04 per 1 g L−1 montmorillonite concentration increase. The values of Ksp’ ranged from 2.19 × 10−17 to 5.25 × 10−17, which were 39 to 91 times lower than the solubility product (Ksp, 2.00 × 10−15) of Ni(OH)2 in a pure water system. Thermodynamic parameters (enthalpy change, ΔH0 = 36.62 kJ mol−1; entropy change, ΔS0 = 0.438 kJ/(mol·K); Gibbs free energy change, ΔG0 < 0) indicate that surface precipitation is an endothermic reaction overall with an increase in entropy, contrary to precipitation in pure water, and is spontaneous (T > 84K). These findings can effectively predict Ni retention at soil-water interfaces, addressing critical gaps in conventional environmental risk assessments of surface precipitation mechanisms.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"200 ","pages":"Article 106751"},"PeriodicalIF":3.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147425011","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

Temperature-constrained sorption of inorganic and organic selenium by Fe-oxide minerals: Significance for selenium bioavailability in Earth's critical zone 铁氧化物矿物对无机和有机硒的温度约束吸附：对地球临界带硒生物利用度的意义

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-03-01 Epub Date: 2026-02-14 DOI: 10.1016/j.apgeochem.2026.106733

Kunfu Pi , Qianyong Liang , Yiqun Gan , Yaping Zhang , Tao Gu , Li Zhang

Temperature influences hydrobiogeochemical processes and consequent fate of selenium (Se) in the Earth's critical zone. Quantitative understanding of the temperature-constrained sorption behaviors of both inorganic and organic Se species, however, is critically lacking. Using ferrihydrite and goethite as comparative sorbents in batch experiments under wide ranges of environmental temperature (5-40 °C) and pH (5-9), we mechanistically identify the effects of temperature on sorption kinetics and thermodynamics of four key Se species: selenate (Se(VI)) and selenite (Se(IV)) as inorganic Se oxyanions, as opposed to DL-selenocystine (SeCys) and DL-selenomethionine (SeMet) as organic Se zwitterions. Although sorption of the four Se species occurred more rapidly on ferrihydrite than on goethite, increasing temperature overall reduced Se retention by Fe-oxide minerals. Despite the overall rapid sorption observed for all Se species, model-derived rate constants demonstrate higher sorption rates for ferrihydrite than goethite, and this kinetic contrast is amplified as temperature increases. Temperature-dependent kinetic fitting indicates that sorption of Se(IV), Se(VI), and SeCys is more consistent with surface reaction-controlled (activation-controlled) complexation than SeMet, which shows weaker temperature sensitivity agreeing with less specific interaction. Thermodynamic parameters derived from the revised Langmuir isotherms indicate exothermic Se sorption on Fe oxides and affinity shift with temperature, pH, and Se speciation. A diffuse-layer surface complexation model captures the observed temperature and pH dependence by accounting for coupled changes in aqueous Se speciation, surface protonation (thus effective site availability), and surface complexation thermodynamic constants. Therefore, temperature as a key driver of Se sorption plays a nonnegligible role in controlling Se mobility and potential bioavailability in the critical zone.

温度影响地球临界带的水生物地球化学过程和硒（Se）的命运。然而，对无机和有机硒的温度约束吸附行为的定量理解是非常缺乏的。在较宽的环境温度（5-40℃）和pH（5-9）范围内，采用水合铁和针铁矿作为对比吸附剂，研究了温度对硒酸盐（Se(VI)）和亚硒酸盐（Se(IV)）作为无机硒氧离子的吸附动力学和热力学的影响，而硒半胱氨酸（SeCys）和硒代蛋氨酸（SeMet）作为有机硒两性离子的吸附动力学和热力学的影响。虽然四种硒在水合铁上的吸附速度比在针铁矿上更快，但温度升高总体上降低了氧化铁矿物对硒的保留。尽管观察到所有Se物种的整体快速吸附，但模型推导的速率常数表明，水合铁的吸附速率高于针铁矿，并且随着温度的升高，这种动力学对比被放大。温度相关的动力学拟合表明，与SeMet相比，Se（IV）、Se（VI）和SeCys的吸附更符合表面反应控制（活化控制）络合作用，其温度敏感性较弱，特异性相互作用较小。根据修正的Langmuir等温线得出的热力学参数表明，Se在Fe氧化物上的放热吸附和亲和力随温度、pH和Se形态的变化而变化。扩散层表面络合模型通过考虑水中硒形态、表面质子化（因此有效位点可用性）和表面络合热力学常数的耦合变化，捕获了观察到的温度和pH依赖性。因此，温度作为硒吸附的关键驱动因素，在控制临界区硒的迁移率和潜在生物利用度方面起着不可忽视的作用。

{"title":"Temperature-constrained sorption of inorganic and organic selenium by Fe-oxide minerals: Significance for selenium bioavailability in Earth's critical zone","authors":"Kunfu Pi , Qianyong Liang , Yiqun Gan , Yaping Zhang , Tao Gu , Li Zhang","doi":"10.1016/j.apgeochem.2026.106733","DOIUrl":"10.1016/j.apgeochem.2026.106733","url":null,"abstract":"<div><div>Temperature influences hydrobiogeochemical processes and consequent fate of selenium (Se) in the Earth's critical zone. Quantitative understanding of the temperature-constrained sorption behaviors of both inorganic and organic Se species, however, is critically lacking. Using ferrihydrite and goethite as comparative sorbents in batch experiments under wide ranges of environmental temperature (5-40 °C) and pH (5-9), we mechanistically identify the effects of temperature on sorption kinetics and thermodynamics of four key Se species: selenate (Se(VI)) and selenite (Se(IV)) as inorganic Se oxyanions, as opposed to DL-selenocystine (SeCys) and DL-selenomethionine (SeMet) as organic Se zwitterions. Although sorption of the four Se species occurred more rapidly on ferrihydrite than on goethite, increasing temperature overall reduced Se retention by Fe-oxide minerals. Despite the overall rapid sorption observed for all Se species, model-derived rate constants demonstrate higher sorption rates for ferrihydrite than goethite, and this kinetic contrast is amplified as temperature increases. Temperature-dependent kinetic fitting indicates that sorption of Se(IV), Se(VI), and SeCys is more consistent with surface reaction-controlled (activation-controlled) complexation than SeMet, which shows weaker temperature sensitivity agreeing with less specific interaction. Thermodynamic parameters derived from the revised Langmuir isotherms indicate exothermic Se sorption on Fe oxides and affinity shift with temperature, pH, and Se speciation. A diffuse-layer surface complexation model captures the observed temperature and pH dependence by accounting for coupled changes in aqueous Se speciation, surface protonation (thus effective site availability), and surface complexation thermodynamic constants. Therefore, temperature as a key driver of Se sorption plays a nonnegligible role in controlling Se mobility and potential bioavailability in the critical zone.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"200 ","pages":"Article 106733"},"PeriodicalIF":3.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147424690","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

Hydrogeochemical processes driving elevated Arsenic and Fluoride in the Texas Gulf Coast Aquifer 水文地球化学过程导致德克萨斯州墨西哥湾沿岸含水层中砷和氟化物升高

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-03-01 Epub Date: 2026-01-29 DOI: 10.1016/j.apgeochem.2026.106713

Hailey N. Goodwin , Taehyun Roh , Reid Buskirk , D. Kirk Nordstrom , Franco Marcantonio , Peter S.K. Knappett

Dissolved arsenic (As) and fluoride (F) concentrations frequently exceed the United States Environmental Protection Agency (US EPA) drinking water standards in groundwater wells screened within the three aquifers (Chicot, Evangeline, Jasper) that comprise the Gulf Coast Aquifer (GCA) in Texas. The primary objective of this study is to identify the hydrological and geochemical processes that mobilize dissolved groundwater As and F in each aquifer across a north-south climate gradient from humid to semi-arid. Comprehensive chemistry was analyzed from 1164 water samples taken from 534 wells between 2002 and 2022 and reported in a public database of the Texas Water Development Board (TWDB). Surface and geologic sources of As and F were tested by observing their spatial correlation to land use and geologic layers. Multivariate analysis revealed that in the Northern and Central climate zones As covaries with dissolved iron (Fe) and/or manganese (Mn), whereas F varies with bicarbonate (HCO₃), sodium (Na), and pH. In the Southern climate zone As and F covary with vanadium (V). Plausible chemical reactions that generated As and F were analyzed with geochemical plots and stoichiometric inverse modeling. The dissolved products of silicate hydrolysis and cation exchange were evident along all flowpaths. The removal of Ca from solution through cation exchange drives calcite and fluorite dissolution, which is inferred to be the primary source of F to groundwater in the Northern and Central climate regions, whereas the reductive dissolution Fe- and Mn-oxides releases dissolved As. Arsenic and F are released to Southern aquifers primarily by silicate weathering of the Catahoula Formation volcanic ash layers. This study reveals the changing drivers of As and F release across a 650 km wide region with varying geology and climate. Understanding these drivers is important for deciding the best strategy for avoiding consumption of the polluted groundwater or making the contamination worse through land use or groundwater pumping.

在构成德克萨斯州墨西哥湾沿岸含水层（GCA）的三个含水层（Chicot、Evangeline、Jasper）内筛选的地下水水井中，溶解的砷（As）和氟(F)浓度经常超过美国环境保护局（US EPA）的饮用水标准。本研究的主要目的是确定在南北气候梯度从湿润到半干旱的每个含水层中动员溶解地下水As和F的水文和地球化学过程。综合化学分析了2002年至2022年间从534口井中采集的1164个水样，并在德克萨斯州水资源开发委员会（TWDB）的公共数据库中进行了报告。通过观察As和F与土地利用和地质层的空间相关性，对其地表和地质来源进行了检验。多变量分析表明，在北部和中部气候区，As与溶解铁（Fe）和/或锰（Mn）共变，而F与碳酸氢盐（HCO3）、钠（Na）和ph共变。在南部气候区，As和F与钒(V)共变。利用地球化学图和化学计量逆模型分析了产生As和F的可能化学反应。各流道均有明显的硅酸盐水解和阳离子交换溶解产物。通过阳离子交换从溶液中去除Ca驱动方解石和萤石溶解，推断这是北部和中部气候区地下水中F的主要来源，而铁和锰氧化物的还原性溶解释放溶解的As。砷和F主要通过卡塔胡拉组火山灰层的硅酸盐风化作用释放到南部含水层。该研究揭示了在650公里宽的不同地质和气候区域内砷和氟释放的变化驱动因素。了解这些驱动因素对于决定避免消耗受污染地下水或通过土地利用或地下水开采使污染恶化的最佳策略非常重要。

{"title":"Hydrogeochemical processes driving elevated Arsenic and Fluoride in the Texas Gulf Coast Aquifer","authors":"Hailey N. Goodwin , Taehyun Roh , Reid Buskirk , D. Kirk Nordstrom , Franco Marcantonio , Peter S.K. Knappett","doi":"10.1016/j.apgeochem.2026.106713","DOIUrl":"10.1016/j.apgeochem.2026.106713","url":null,"abstract":"<div><div>Dissolved arsenic (As) and fluoride (F) concentrations frequently exceed the United States Environmental Protection Agency (US EPA) drinking water standards in groundwater wells screened within the three aquifers (Chicot, Evangeline, Jasper) that comprise the Gulf Coast Aquifer (GCA) in Texas. The primary objective of this study is to identify the hydrological and geochemical processes that mobilize dissolved groundwater As and F in each aquifer across a north-south climate gradient from humid to semi-arid. Comprehensive chemistry was analyzed from 1164 water samples taken from 534 wells between 2002 and 2022 and reported in a public database of the Texas Water Development Board (TWDB). Surface and geologic sources of As and F were tested by observing their spatial correlation to land use and geologic layers. Multivariate analysis revealed that in the Northern and Central climate zones As covaries with dissolved iron (Fe) and/or manganese (Mn), whereas F varies with bicarbonate (HCO3), sodium (Na), and pH. In the Southern climate zone As and F covary with vanadium (V). Plausible chemical reactions that generated As and F were analyzed with geochemical plots and stoichiometric inverse modeling. The dissolved products of silicate hydrolysis and cation exchange were evident along all flowpaths. The removal of Ca from solution through cation exchange drives calcite and fluorite dissolution, which is inferred to be the primary source of F to groundwater in the Northern and Central climate regions, whereas the reductive dissolution Fe- and Mn-oxides releases dissolved As. Arsenic and F are released to Southern aquifers primarily by silicate weathering of the Catahoula Formation volcanic ash layers. This study reveals the changing drivers of As and F release across a 650 km wide region with varying geology and climate. Understanding these drivers is important for deciding the best strategy for avoiding consumption of the polluted groundwater or making the contamination worse through land use or groundwater pumping.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"200 ","pages":"Article 106713"},"PeriodicalIF":3.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147425008","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

Applied Geochemistry Recognizes Excellence in Peer Review: 2025 Awards 应用地球化学表彰同行评议卓越：2025奖

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-03-01 Epub Date: 2026-02-26 DOI: 10.1016/j.apgeochem.2026.106735

Zimeng Wang , Elisa Sacchi , Philippe Van Cappellen , Yanxin Wang

引用次数: 0

Boron and oxygen isotopes fractionation between borate minerals and fluids and implications for borate deposit formation 硼酸矿物和流体之间的硼氧同位素分馏及其对硼酸矿床形成的影响

IF 3.4 3区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Applied Geochemistry

Pub Date : 2026-03-01 Epub Date: 2026-02-13 DOI: 10.1016/j.apgeochem.2026.106732

Da-Sheng Zuo , Hai-Zhen Wei , Jian-Jun Lu , M.R. Palmer , A.E. Williams-Jones , Jun-Lin Wang , Shao-Yong Jiang , Ke Yang , He-Feng Lin , Simon V. Hohl , Yi-Chu Chen

<div><div>Boron and oxygen isotope studies have the potential to reveal important information regarding the formation of the borate minerals that form in non-marine evaporite deposits and are the major economic source of boron. In particular, boron isotopes can provide information concerning the source of boron and the pH conditions during borate precipitation, and oxygen isotopes can be used to constrain crystallization temperatures and the extent of evaporation of the brines. However, quantitative application of boron and oxygen isotope studies of borate minerals are hindered by the lack of isotope fractionation factors for both isotopes. Experimental determination of these values is difficult because of the problem of achieving equilibrium conditions at low temperatures. Hence, this work systematically calculates the reduced partition function ratios (RPFRs, β values) of boron and oxygen isotopes in borate minerals and brine using density functional theory. The results indicate that the 103lnβ among these minerals decreases in the sequence of borax ≈ kernite > ulexite ≈ probertite > teruggite > hydroboracite > kurnakovite > colemanite > priceite > pinnoite > howlite for boron isotopes and in the order of howlite > hydroboracite priceite > colemanite > kernite > probertite > pinnoite > ulexite > teruggite > kurnakovite > borax for oxygen isotopes. These 103lnβ values for boron isotopes are primarily influenced by the BO3/BO4 ratio in borate minerals while the chemical composition (cationic type) has a subordinate effect. Thus, the temperature dependence of boron isotope fractionation between borate minerals and fluids at pH of 8.60 has been derived as following: Δ11Bborax-fluid = - 0.0016 T2 + 0.1375T - 4.2902, Δ11Bcolemanite-fluid = - 0.0016 T2 + 0.1525T - 8.5653 and Δ11Bulexite-fluid = - 0.0017 T2 + 0.1724T - 13.7696. The impact of fluid pH on boron isotope fractionation is also significant, where the pH dependent boron isotope fractionation at 298.15 K can be quantified as: Δ11Bborax-fluid = <math><mrow><mfrac><msup><mn>10</mn><mrow><mn>8.597</mn><mo>−</mo><mi>p</mi><mi>H</mi></mrow></msup><mrow><mn>1</mn><mo>+</mo><msup><mn>10</mn><mrow><mn>8.597</mn><mo>−</mo><mi>p</mi><mi>H</mi></mrow></msup></mrow></mfrac><mo>×</mo><mn>25.8853</mn><mo>−</mo><mn>11.1907</mn></mrow></math>, Δ11Bcolemanite-fluid = <math><mrow><mfrac><msup><mn>10</mn><mrow><mn>8.597</mn><mo>−</mo><mi>p</mi><mi>H</mi></mrow></msup><mrow><mn>1</mn><mo>+</mo><msup><mn>10</mn><mrow><mn>8.597</mn><mo>−</mo><mi>p</mi><mi>H</mi></mrow></msup></mrow></mfrac><mo>×</mo><mn>25.8853</mn><mo>−</mo><mn>2.526</mn></mrow></math>, Δ11Bulexite-fluid = <math><mrow><mfrac><msup><mn>10</mn><mrow><mn>8.597</mn

硼和氧同位素研究有可能揭示有关非海相蒸发岩矿床中形成的硼酸矿物形成的重要信息，这些矿物是硼的主要经济来源。特别是，硼同位素可以提供有关硼的来源和硼酸盐沉淀过程中的pH条件的信息，氧同位素可以用来约束结晶温度和卤水的蒸发程度。然而，硼酸矿物的硼氧同位素研究的定量应用受到缺乏同位素分馏因子的阻碍。由于在低温下达到平衡条件的问题，这些值的实验测定是困难的。因此，本文利用密度泛函理论系统地计算了硼酸盐矿物和卤水中硼、氧同位素的减配函数比（RPFRs， β值）。结果表明：硼同位素中103lnβ含量的递减顺序为：硼砂≈角晶石>；钙辉石≈长辉石>；土辉石>；水硼辉石>；库尔纳云母>； colemanite > priceite >；菱辉石>；钙辉石>；钙辉石>；钙辉石>；氧同位素中103lnβ含量的递减顺序为：硼辉石>；水硼辉石>；钙辉石>；钙辉石>；辉辉石>；辉辉石>；辉辉石>；辉辉石>；辉辉石>；硼同位素的103lnβ值主要受硼酸矿物中BO3/BO4比值的影响，而化学成分（阳离子型）的影响次要。因此，在pH = 8.60时硼酸矿物与流体之间硼同位素分馏的温度依赖性为：Δ11Bborax-fluid = - 0.0016 T2 + 0.1375T - 4.2902， Δ11Bcolemanite-fluid = - 0.0016 T2 + 0.1525T - 8.5653， Δ11Bulexite-fluid = - 0.0017 T2 + 0.1724T - 13.7696。流体pH对硼同位素分馏的影响也很显著，其中298.15 K时pH依赖的硼同位素分馏可以量化为：Δ11Bborax-fluid = 108.597−pH1+108.597−pH×25.8853−11.1907，Δ11Bcolemanite-fluid = 108.597−pH1+108.597−pH×25.8853−2.526，Δ11Bulexite-fluid = 108.597−pH1+108.597−pH×25.8853−7.8217。与碱性条件下的流体相相比，重同位素11B更倾向于分馏成硼酸盐矿物，而在中性和酸性盐水条件下则倾向于分馏成流体相。计算出的分馏因子与瑞利分馏模型和扩散模型相结合，有助于解释硼同位素的空间变化，并约束Kirka和Kramer两个典型硼酸矿床的成因。利用方解石和钙硼酸盐共生矿物对中的氧同位素，提出了一种可靠的地温计。

{"title":"Boron and oxygen isotopes fractionation between borate minerals and fluids and implications for borate deposit formation","authors":"Da-Sheng Zuo , Hai-Zhen Wei , Jian-Jun Lu , M.R. Palmer , A.E. Williams-Jones , Jun-Lin Wang , Shao-Yong Jiang , Ke Yang , He-Feng Lin , Simon V. Hohl , Yi-Chu Chen","doi":"10.1016/j.apgeochem.2026.106732","DOIUrl":"10.1016/j.apgeochem.2026.106732","url":null,"abstract":"<div><div>Boron and oxygen isotope studies have the potential to reveal important information regarding the formation of the borate minerals that form in non-marine evaporite deposits and are the major economic source of boron. In particular, boron isotopes can provide information concerning the source of boron and the pH conditions during borate precipitation, and oxygen isotopes can be used to constrain crystallization temperatures and the extent of evaporation of the brines. However, quantitative application of boron and oxygen isotope studies of borate minerals are hindered by the lack of isotope fractionation factors for both isotopes. Experimental determination of these values is difficult because of the problem of achieving equilibrium conditions at low temperatures. Hence, this work systematically calculates the reduced partition function ratios (RPFRs, β values) of boron and oxygen isotopes in borate minerals and brine using density functional theory. The results indicate that the 103lnβ among these minerals decreases in the sequence of borax ≈ kernite > ulexite ≈ probertite > teruggite > hydroboracite > kurnakovite > colemanite > priceite > pinnoite > howlite for boron isotopes and in the order of howlite > hydroboracite priceite > colemanite > kernite > probertite > pinnoite > ulexite > teruggite > kurnakovite > borax for oxygen isotopes. These 103lnβ values for boron isotopes are primarily influenced by the BO3/BO4 ratio in borate minerals while the chemical composition (cationic type) has a subordinate effect. Thus, the temperature dependence of boron isotope fractionation between borate minerals and fluids at pH of 8.60 has been derived as following: Δ11Bborax-fluid = - 0.0016 T2 + 0.1375T - 4.2902, Δ11Bcolemanite-fluid = - 0.0016 T2 + 0.1525T - 8.5653 and Δ11Bulexite-fluid = - 0.0017 T2 + 0.1724T - 13.7696. The impact of fluid pH on boron isotope fractionation is also significant, where the pH dependent boron isotope fractionation at 298.15 K can be quantified as: Δ11Bborax-fluid = <math><mrow><mfrac><msup><mn>10</mn><mrow><mn>8.597</mn><mo>−</mo><mi>p</mi><mi>H</mi></mrow></msup><mrow><mn>1</mn><mo>+</mo><msup><mn>10</mn><mrow><mn>8.597</mn><mo>−</mo><mi>p</mi><mi>H</mi></mrow></msup></mrow></mfrac><mo>×</mo><mn>25.8853</mn><mo>−</mo><mn>11.1907</mn></mrow></math>, Δ11Bcolemanite-fluid = <math><mrow><mfrac><msup><mn>10</mn><mrow><mn>8.597</mn><mo>−</mo><mi>p</mi><mi>H</mi></mrow></msup><mrow><mn>1</mn><mo>+</mo><msup><mn>10</mn><mrow><mn>8.597</mn><mo>−</mo><mi>p</mi><mi>H</mi></mrow></msup></mrow></mfrac><mo>×</mo><mn>25.8853</mn><mo>−</mo><mn>2.526</mn></mrow></math>, Δ11Bulexite-fluid = <math><mrow><mfrac><msup><mn>10</mn><mrow><mn>8.597</mn","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"200 ","pages":"Article 106732"},"PeriodicalIF":3.4,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147424686","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