Pub Date : 2026-01-17DOI: 10.1016/j.apgeochem.2026.106707
Jean-Philippe Nicot, Lucy T. Ko, Roxana Darvari, Brent A. Elliott
We describe dissolved lithium content of water produced from the Haynesville Shale, a low-permeability, gas-producing formation of Jurassic age overlying the lithium-rich and stratigraphically close Smackover Formation. The 57 water samples and 5 rock samples were analyzed for major and minor elements and for stable water isotopes, and Li and Sr isotopes (selected samples). The samples show an average of 71.7 mg/L Li (16–125 mg/L range) for an average TDS of 126.7 g/L (55–206 g/L range). They also show that the Haynesville and Smackover dissolved lithium have distinct diagenetic pathways with a large gap in δ7Li values (3.27 ‰, n = 7 and 10.20 ‰, n = 4, respectively). However, δ7Li of Haynesville produced water and rock (−4.03 ‰, n = 5) are consistent with fractionation of lithium partitioned into clay minerals relative to the resident water. The Haynesville Shale strontium isotope 87Sr/86Sr ratio (0.70830, n = 5) is higher than that of the time-period sea (0.7070), and consistent with a clastic 87Sr increase in a closed system, but lower than that of the published Arkansas carbonate-rich Upper Smackover values (0.70895, n = 72), which denotes a stronger clastic influence there. Water isotopes confirm that the samples represent formation water and have been little impacted by hydraulic fracturing or water condensation during sampling. However, low water production combined with marginal Li concentrations does not make the Haynesville Shale a primary target for lithium production.
{"title":"Dissolved lithium content and aqueous geochemistry of the Haynesville Shale of East Texas and Northwest Louisiana","authors":"Jean-Philippe Nicot, Lucy T. Ko, Roxana Darvari, Brent A. Elliott","doi":"10.1016/j.apgeochem.2026.106707","DOIUrl":"10.1016/j.apgeochem.2026.106707","url":null,"abstract":"<div><div>We describe dissolved lithium content of water produced from the Haynesville Shale, a low-permeability, gas-producing formation of Jurassic age overlying the lithium-rich and stratigraphically close Smackover Formation. The 57 water samples and 5 rock samples were analyzed for major and minor elements and for stable water isotopes, and Li and Sr isotopes (selected samples). The samples show an average of 71.7 mg/L Li (16–125 mg/L range) for an average TDS of 126.7 g/L (55–206 g/L range). They also show that the Haynesville and Smackover dissolved lithium have distinct diagenetic pathways with a large gap in δ<sup>7</sup>Li values (3.27 ‰, n = 7 and 10.20 ‰, n = 4, respectively). However, δ<sup>7</sup>Li of Haynesville produced water and rock (−4.03 ‰, n = 5) are consistent with fractionation of lithium partitioned into clay minerals relative to the resident water. The Haynesville Shale strontium isotope <sup>87</sup>Sr/<sup>86</sup>Sr ratio (0.70830, n = 5) is higher than that of the time-period sea (0.7070), and consistent with a clastic <sup>87</sup>Sr increase in a closed system, but lower than that of the published Arkansas carbonate-rich Upper Smackover values (0.70895, n = 72), which denotes a stronger clastic influence there. Water isotopes confirm that the samples represent formation water and have been little impacted by hydraulic fracturing or water condensation during sampling. However, low water production combined with marginal Li concentrations does not make the Haynesville Shale a primary target for lithium production.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106707"},"PeriodicalIF":3.4,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024124","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}
Pub Date : 2026-01-17DOI: 10.1016/j.apgeochem.2026.106705
Leire Coloma, Iratxe Población, Julene Aramendia, Fernando Alberquilla, Jennifer Huidobro, Gorka Arana, Juan Manuel Madariaga
The study of meteorites is important for planetary sciences because, among other things, it can provide information about the geochemical composition of their celestial body of origin. Often, subsample preparation is required to investigate the internal regions of these meteorites. However, during this process, the use of various tools and reagents can introduce contaminants, which are not always fully removable. As a result, exogenous substances may be detected during subsequent geochemical characterization analyses. To prevent the problems that may arise from this issue, this study analyzes multiple Martian meteorites with the aim of identifying contaminants introduced during sample preparation processes. Raman spectroscopy, one of the techniques used for extraterrestrial sample analysis, was employed to detect these residues. Establishing a robust subsample preparation protocol is essential not only for future sample return missions, where the ability to prepare uncontaminated subsamples upon arrival on Earth will be critical for accurate scientific investigations, but also for the handling of any type of meteorite.
{"title":"Analysing the sample preparation process in meteorites and its impact on the pretreatment of returned samples to Earth","authors":"Leire Coloma, Iratxe Población, Julene Aramendia, Fernando Alberquilla, Jennifer Huidobro, Gorka Arana, Juan Manuel Madariaga","doi":"10.1016/j.apgeochem.2026.106705","DOIUrl":"10.1016/j.apgeochem.2026.106705","url":null,"abstract":"<div><div>The study of meteorites is important for planetary sciences because, among other things, it can provide information about the geochemical composition of their celestial body of origin. Often, subsample preparation is required to investigate the internal regions of these meteorites. However, during this process, the use of various tools and reagents can introduce contaminants, which are not always fully removable. As a result, exogenous substances may be detected during subsequent geochemical characterization analyses. To prevent the problems that may arise from this issue, this study analyzes multiple Martian meteorites with the aim of identifying contaminants introduced during sample preparation processes. Raman spectroscopy, one of the techniques used for extraterrestrial sample analysis, was employed to detect these residues. Establishing a robust subsample preparation protocol is essential not only for future sample return missions, where the ability to prepare uncontaminated subsamples upon arrival on Earth will be critical for accurate scientific investigations, but also for the handling of any type of meteorite.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106705"},"PeriodicalIF":3.4,"publicationDate":"2026-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974369","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}
Pub Date : 2026-01-16DOI: 10.1016/j.apgeochem.2026.106679
Wei Cao , Xianglan Kong , Jingdong Mao , Jianfang Hu , Yong Ran
Rising global temperature is exerting a notable effect on the photosynthetic process of marine algae, which in turn may affect the structure and distribution of marine primary producers on a global scale. Sea surface temperature exerts a multifaceted influence on the growth, composition and structure of dinoflagellate, as well as on inorganic carbon fixation. This paper investigates the effect of temperature change on the growth of one dinoflagellate specie Scrippsiella trochoidea, and examines the variations in the organic carbon structure of its cell wall. This study is pioneering in its exploration of the impact of temperature on the structural organisation of organic matter in the dinoflagellate, with a particular focus on methylene carbon. The results indicate that Scrippsiella trochoidea exhibits a propensity to synthesise elevated levels of aliphatic compounds and proteins, particularly long-chain aliphatic biopolymers, at elevated incubation temperature. Moverover, a highly positive correlation is identified between the incubation temperature and the methylene carbon structure in the alkyl carbon structure. Such compositional and structural changes can have a significant impact on the potential yield of oil and gas through the process of algal pyrolysis.
{"title":"Compositions and hydrocarbon generation potentials of Scrippsiella trochoidea under increasing temperature","authors":"Wei Cao , Xianglan Kong , Jingdong Mao , Jianfang Hu , Yong Ran","doi":"10.1016/j.apgeochem.2026.106679","DOIUrl":"10.1016/j.apgeochem.2026.106679","url":null,"abstract":"<div><div>Rising global temperature is exerting a notable effect on the photosynthetic process of marine algae, which in turn may affect the structure and distribution of marine primary producers on a global scale. Sea surface temperature exerts a multifaceted influence on the growth, composition and structure of dinoflagellate, as well as on inorganic carbon fixation. This paper investigates the effect of temperature change on the growth of one dinoflagellate specie <em>Scrippsiella trochoidea</em>, and examines the variations in the organic carbon structure of its cell wall. This study is pioneering in its exploration of the impact of temperature on the structural organisation of organic matter in the dinoflagellate, with a particular focus on methylene carbon. The results indicate that <em>Scrippsiella trochoidea</em> exhibits a propensity to synthesise elevated levels of aliphatic compounds and proteins, particularly long-chain aliphatic biopolymers, at elevated incubation temperature. Moverover, a highly positive correlation is identified between the incubation temperature and the methylene carbon structure in the alkyl carbon structure. Such compositional and structural changes can have a significant impact on the potential yield of oil and gas through the process of algal pyrolysis.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106679"},"PeriodicalIF":3.4,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024055","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}
Pub Date : 2026-01-16DOI: 10.1016/j.apgeochem.2026.106704
Yaping Zhang , Kunfu Pi , Xianjun Xie , Ziyi Xiao , Jianbo Shi , Qianyong Liang , Yuxia Li
Arsenic (As) mobility and fate in geogenic contaminated groundwater can be impacted by co-occurring microplastics and dissolved organic matter (DOM). However, molecular mechanisms and kinetic constraints underlying microplastics-DOM-As interactions remain to be deciphered. By employing polystyrene microplastics (PSMPs) as a representative type of microplastics found in Datong high-As groundwater (As >10 μg/L), this research investigated thermodynamically and kinetically adsorption of As(III) and As(V) by microplastics as well as the critical effects of DOM. At groundwater pH of 6.8, adsorption of both As species occurred via oxygen-containing functional groups on PSMPs surfaces, but As(V) adsorption was quicker and greater than As(III) due to macrocolloids-like nature of PSMPs. Humic acids (HA) and fulvic acids (FA) compete for adsorption sites, alter surface properties, and facilitate aggregation of PSMPs, thereby reducing available surface sites for As binding. Interactions among PSMPs, HA/FA, and As species lead to formation of complexes including PSMPs-FA/HA-As and FA/HA-As. Furthermore, HA and FA can change the diffusion coefficients and boundary layer thickness of As within PSMPs pores to alter adsorption kinetics. Our results provide novel mechanistic insights into joint roles of PSMPs and DOM in As mobilization/immobilization dynamics within geogenic contaminated groundwater. Moreover, this research consolidates theoretical foundation for understanding influences of emerging contaminants on environmental geochemical behaviors of geogenic As in pumped aquifers.
微塑料和溶解性有机物（DOM）的共存影响了砷在地源污染地下水中的迁移和归宿。然而，微塑料- dom - as相互作用的分子机制和动力学约束仍有待破译。以大同市高砷地下水（as >10 μg/L）中具有代表性的聚苯乙烯微塑料（PSMPs）为研究对象，研究了微塑料对as （III）和as (V)的热力学和动力学吸附以及DOM的临界效应。在地下水pH为6.8时，两种As均通过含氧官能团吸附在PSMPs表面，但由于PSMPs的大胶体性质，As(V)的吸附速度更快且大于As（III）。腐植酸（HA）和黄腐酸（FA）竞争吸附位点，改变表面性质，促进PSMPs聚集，从而减少可用的表面As结合位点。PSMPs、HA/FA和As之间的相互作用导致PSMPs-FA/HA-As和FA/HA-As复合物的形成。此外，HA和FA可以改变PSMPs孔隙中As的扩散系数和边界层厚度，从而改变吸附动力学。我们的研究结果为PSMPs和DOM在地质污染地下水中As的动员/固定动力学中的联合作用提供了新的机制见解。此外，本研究为认识新兴污染物对抽水蓄水层地质砷环境地球化学行为的影响奠定了理论基础。
{"title":"Influences of microplastic-dissolved organic matter-arsenic interactions on arsenic fate in geogenic contaminated groundwater: Mechanistic insights from kinetic-thermodynamic investigations and modeling","authors":"Yaping Zhang , Kunfu Pi , Xianjun Xie , Ziyi Xiao , Jianbo Shi , Qianyong Liang , Yuxia Li","doi":"10.1016/j.apgeochem.2026.106704","DOIUrl":"10.1016/j.apgeochem.2026.106704","url":null,"abstract":"<div><div>Arsenic (As) mobility and fate in geogenic contaminated groundwater can be impacted by co-occurring microplastics and dissolved organic matter (DOM). However, molecular mechanisms and kinetic constraints underlying microplastics-DOM-As interactions remain to be deciphered. By employing polystyrene microplastics (PSMPs) as a representative type of microplastics found in Datong high-As groundwater (As >10 μg/L), this research investigated thermodynamically and kinetically adsorption of As(III) and As(V) by microplastics as well as the critical effects of DOM. At groundwater pH of 6.8, adsorption of both As species occurred via oxygen-containing functional groups on PSMPs surfaces, but As(V) adsorption was quicker and greater than As(III) due to macrocolloids-like nature of PSMPs. Humic acids (HA) and fulvic acids (FA) compete for adsorption sites, alter surface properties, and facilitate aggregation of PSMPs, thereby reducing available surface sites for As binding. Interactions among PSMPs, HA/FA, and As species lead to formation of complexes including PSMPs-FA/HA-As and FA/HA-As. Furthermore, HA and FA can change the diffusion coefficients and boundary layer thickness of As within PSMPs pores to alter adsorption kinetics. Our results provide novel mechanistic insights into joint roles of PSMPs and DOM in As mobilization/immobilization dynamics within geogenic contaminated groundwater. Moreover, this research consolidates theoretical foundation for understanding influences of emerging contaminants on environmental geochemical behaviors of geogenic As in pumped aquifers.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106704"},"PeriodicalIF":3.4,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024059","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}
Pub Date : 2026-01-14DOI: 10.1016/j.apgeochem.2025.106674
Travis Batch , Caroline Tiddy , Adrienne Brotodewo , David Giles , Courteney Dhnaram , Vladimir Lisitsin
The chemistry of hydrothermal monazite can be used as an indicator of iron sulfide-copper-gold (ISCG) mineralisation based on a case study of the Kulthor deposit in the Cloncurry District. Monazite associated with mineralisation has elevated La, Nd and S, and a moderately negative chondrite-normalised Eu anomaly, and is typically polycrystalline and intimately associated with pyrite, pyrrhotite and chalcopyrite. Monazite from mineralised and unmineralised rocks can be separated on a plot of Ce versus La + Nd using a line with the equation y = 0.95x. Monazite that is found within unmineralised rocks is enriched in Y, Dy, Th and U relative to mineralised samples and have a strong negative chondrite-normalised Eu anomaly. A plot of Y versus Dy shows two distinct gradients for the monazite analyses, whereby monazite analyses in unmineralised rocks follow the gradient of 0.24 (r2 = 0.946), in contrast to mineralisation-associated and proximal monazite analyses which follow a gradient of 0.47 (r2 = 0.889). Monazite grains from unmineralised rocks have well defined, jagged grain boundaries and commonly contain inclusions of zircon, apatite, rutile and xenotime. Integration of monazite data from Kulthor with a previous study on the nearby Jericho ISCG deposit allowed development of geochemical discrimination diagrams for ISCG deposits whereby Ca/Th ratios >5 and S/Th ratios >0.1 are indicative of monazite associated with ISCG mineralisation.
{"title":"Monazite chemistry for iron sulfide-copper-gold exploration in the Mount Isa Province, Queensland, Australia","authors":"Travis Batch , Caroline Tiddy , Adrienne Brotodewo , David Giles , Courteney Dhnaram , Vladimir Lisitsin","doi":"10.1016/j.apgeochem.2025.106674","DOIUrl":"10.1016/j.apgeochem.2025.106674","url":null,"abstract":"<div><div>The chemistry of hydrothermal monazite can be used as an indicator of iron sulfide-copper-gold (ISCG) mineralisation based on a case study of the Kulthor deposit in the Cloncurry District. Monazite associated with mineralisation has elevated La, Nd and S, and a moderately negative chondrite-normalised Eu anomaly, and is typically polycrystalline and intimately associated with pyrite, pyrrhotite and chalcopyrite. Monazite from mineralised and unmineralised rocks can be separated on a plot of Ce versus La + Nd using a line with the equation y = 0.95x. Monazite that is found within unmineralised rocks is enriched in Y, Dy, Th and U relative to mineralised samples and have a strong negative chondrite-normalised Eu anomaly. A plot of Y versus Dy shows two distinct gradients for the monazite analyses, whereby monazite analyses in unmineralised rocks follow the gradient of 0.24 (r<sup>2</sup> = 0.946), in contrast to mineralisation-associated and proximal monazite analyses which follow a gradient of 0.47 (r<sup>2</sup> = 0.889). Monazite grains from unmineralised rocks have well defined, jagged grain boundaries and commonly contain inclusions of zircon, apatite, rutile and xenotime. Integration of monazite data from Kulthor with a previous study on the nearby Jericho ISCG deposit allowed development of geochemical discrimination diagrams for ISCG deposits whereby Ca/Th ratios >5 and S/Th ratios >0.1 are indicative of monazite associated with ISCG mineralisation.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106674"},"PeriodicalIF":3.4,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974773","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}
Pub Date : 2026-01-14DOI: 10.1016/j.apgeochem.2026.106701
Peng Lin , Karah Greene , Wei Xing , Steven Simner , Christina Logan , Richard Henry , Daniel I. Kaplan
<div><div>Risk assessment to evaluate long-term disposal for heavy metal and radioactive constituents at the subsurface engineered disposal facilities rely on distribution coefficients (<em>K</em><sub><em>d</em></sub> <em>=</em> <em>C</em><sub><em>solid</em></sub><em>/C</em><sub><em>liquid</em></sub>). Low-level solid and liquid radioactive waste is disposed in the subsurface environment using various cementitious engineered barriers. This study measured <em>K</em><sub><em>d</em></sub> values to quantify the sorption–including adsorption, absorption, and/or precipitation for multiple metals/radionuclides in subsurface sediments impacted by cementitious leachates representing different cement aging stages, experimentally introduced as Cs(I), Sr(II), Ni(II), Eu(III), Th(IV), U(VI), Cr(VI), and Tc(VII), serving as chemical analogs of different chemical groups. Simulated groundwater (Stage IV) was used as a baseline besides three leachate simulants: freshly made concrete leachate (Stage I), portlandite (Stage II), and calcite (Stage III) to calculate the cementitious leachate impact factor (<em>f</em><sub>CementLeach</sub>), defined as <em>K</em><sub><em>d</em></sub>-CementLeach/<em>K</em><sub><em>d</em></sub>-groundwater. Results showed significant changes in sorption between groundwater and leachate simulants. Monovalent cation analog Cs exhibited <em>K</em><sub><em>d</em></sub> values of 28–2390 L/kg (sandy) and 84–4230 L/kg (clayey), with <em>f</em><sub>CementLeach</sub> up to 62 in sandy sediments impacted by young grout leachate. Divalent cations (Ni and Sr) and trivalent/tetravalent cations (Eu, Th) also showed strong enhancements in high-pH cementitious leachate environments; for example, Eu <em>K</em><sub><em>d</em></sub> increased from 25 L/kg in Stage IV groundwater to >67000 L/kg in leachates. Tetravalent cation analog Th showed very strong sorption (>10000 L/kg) in young and aged leachates, consistent with prior trivalent cation trends (Eu). Enhanced retention of multivalent cations (e.g., Ni<sup>2+</sup>, Eu<sup>3+</sup>, Th<sup>4+</sup>, and UO<sub>2</sub><sup>2+</sup>) in cementitious leachate-impacted sediments reflects not only surface sorption processes but also precipitation under elevated pH conditions, particularly in young grout leachate environments. Such precipitation-driven mechanisms were not evident for Cs<sup>+</sup>. Across cement aging stages, enhanced (Stage III) and/or reduced sorption (Stage II) can be observed for anionic species CrO<sub>4</sub><sup>2−</sup>, while <sup>99</sup>TcO<sub>4</sub><sup>−</sup>, a key risk driver, displayed minimal sorption and negligible response to cementitious leachates. These results represent the first extensive dataset quantifying cementitious leachate effects on sorption to sediments for different types of cation and anion metal contaminants. It also underscores how the evolution of cementitious barriers reshapes groundwater chemistry, directly influencing the predicted mobil
{"title":"Age-dependent cementitious leachate effects on metal and radionuclide sorption to sediments from a subsurface waste-disposal site","authors":"Peng Lin , Karah Greene , Wei Xing , Steven Simner , Christina Logan , Richard Henry , Daniel I. Kaplan","doi":"10.1016/j.apgeochem.2026.106701","DOIUrl":"10.1016/j.apgeochem.2026.106701","url":null,"abstract":"<div><div>Risk assessment to evaluate long-term disposal for heavy metal and radioactive constituents at the subsurface engineered disposal facilities rely on distribution coefficients (<em>K</em><sub><em>d</em></sub> <em>=</em> <em>C</em><sub><em>solid</em></sub><em>/C</em><sub><em>liquid</em></sub>). Low-level solid and liquid radioactive waste is disposed in the subsurface environment using various cementitious engineered barriers. This study measured <em>K</em><sub><em>d</em></sub> values to quantify the sorption–including adsorption, absorption, and/or precipitation for multiple metals/radionuclides in subsurface sediments impacted by cementitious leachates representing different cement aging stages, experimentally introduced as Cs(I), Sr(II), Ni(II), Eu(III), Th(IV), U(VI), Cr(VI), and Tc(VII), serving as chemical analogs of different chemical groups. Simulated groundwater (Stage IV) was used as a baseline besides three leachate simulants: freshly made concrete leachate (Stage I), portlandite (Stage II), and calcite (Stage III) to calculate the cementitious leachate impact factor (<em>f</em><sub>CementLeach</sub>), defined as <em>K</em><sub><em>d</em></sub>-CementLeach/<em>K</em><sub><em>d</em></sub>-groundwater. Results showed significant changes in sorption between groundwater and leachate simulants. Monovalent cation analog Cs exhibited <em>K</em><sub><em>d</em></sub> values of 28–2390 L/kg (sandy) and 84–4230 L/kg (clayey), with <em>f</em><sub>CementLeach</sub> up to 62 in sandy sediments impacted by young grout leachate. Divalent cations (Ni and Sr) and trivalent/tetravalent cations (Eu, Th) also showed strong enhancements in high-pH cementitious leachate environments; for example, Eu <em>K</em><sub><em>d</em></sub> increased from 25 L/kg in Stage IV groundwater to >67000 L/kg in leachates. Tetravalent cation analog Th showed very strong sorption (>10000 L/kg) in young and aged leachates, consistent with prior trivalent cation trends (Eu). Enhanced retention of multivalent cations (e.g., Ni<sup>2+</sup>, Eu<sup>3+</sup>, Th<sup>4+</sup>, and UO<sub>2</sub><sup>2+</sup>) in cementitious leachate-impacted sediments reflects not only surface sorption processes but also precipitation under elevated pH conditions, particularly in young grout leachate environments. Such precipitation-driven mechanisms were not evident for Cs<sup>+</sup>. Across cement aging stages, enhanced (Stage III) and/or reduced sorption (Stage II) can be observed for anionic species CrO<sub>4</sub><sup>2−</sup>, while <sup>99</sup>TcO<sub>4</sub><sup>−</sup>, a key risk driver, displayed minimal sorption and negligible response to cementitious leachates. These results represent the first extensive dataset quantifying cementitious leachate effects on sorption to sediments for different types of cation and anion metal contaminants. It also underscores how the evolution of cementitious barriers reshapes groundwater chemistry, directly influencing the predicted mobil","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106701"},"PeriodicalIF":3.4,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974370","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}
Pub Date : 2026-01-14DOI: 10.1016/j.apgeochem.2026.106700
Enrique Iñiguez , Vladimir Mendoza-Lavaniegos , Thomas G. Kretzschmar
Coastal hydrothermal systems provide valuable analog environments for investigating microbial‒mineral interactions and preserving biosignatures under extreme physicochemical gradients. At the Puertecitos intertidal spring in Baja California, México, we conducted an integrated mineralogical, geochemical, and structural analysis of a hydrothermally altered ignimbrite to characterize endolithic microbial habitats and their fossilization potential. Thin section petrography, SEM, XRD, FTIR, and μXRF revealed a vertically zoned substrate, including an unaltered ignimbrite, a weathered alteration fringe, a dark sulfide-rich transition, and a crystalline barite–quartz assemblage. Elemental mapping (Fe, S, Ba, Sr, and As) and principal component analysis highlighted distinct geochemical domains shaped by episodic hydrothermal fluid pulses and seawater mixing. Microtomography (μCT) revealed very low total and open porosities (0.29 % and 0.017 %, respectively) but unexpectedly high permeabilities attributed to interconnected microfractures. SEM imaging revealed abundant and morphologically diverse microbial biosignatures, which were predominantly preserved in the crystalline and transition zones through rapid silicification and barite precipitation. These microenvironments, which are structured by mineral precipitation and permeability anisotropy, provide localized redox gradients and nutrient sources that support the preservation of chemolithotrophic endolithic communities. Our results demonstrate that hydrothermal fluid dynamics, mineral precipitation, and rock microstructure govern the habitability and fossilization potential of volcanic substrates in geothermal settings (temperature ranges from 32.7 to 73.7 °C and pH 6.7–8.1). The Puertecitos system offers a compelling terrestrial analog for studying microbial survival, mineral-driven weathering, and biosignature preservation on early Earth and Mars, emphasizing the importance of mineralogical interfaces and hydrothermal processes in structuring habitable niches in extreme environments.
{"title":"Endolithic environments in hydrothermally altered volcanic rocks from a coastal spring in Baja California, México: Mineralogical interfaces and the search for preserved biosignatures","authors":"Enrique Iñiguez , Vladimir Mendoza-Lavaniegos , Thomas G. Kretzschmar","doi":"10.1016/j.apgeochem.2026.106700","DOIUrl":"10.1016/j.apgeochem.2026.106700","url":null,"abstract":"<div><div>Coastal hydrothermal systems provide valuable analog environments for investigating microbial‒mineral interactions and preserving biosignatures under extreme physicochemical gradients. At the Puertecitos intertidal spring in Baja California, México, we conducted an integrated mineralogical, geochemical, and structural analysis of a hydrothermally altered ignimbrite to characterize endolithic microbial habitats and their fossilization potential. Thin section petrography, SEM, XRD, FTIR, and μXRF revealed a vertically zoned substrate, including an unaltered ignimbrite, a weathered alteration fringe, a dark sulfide-rich transition, and a crystalline barite–quartz assemblage. Elemental mapping (Fe, S, Ba, Sr, and As) and principal component analysis highlighted distinct geochemical domains shaped by episodic hydrothermal fluid pulses and seawater mixing. Microtomography (μCT) revealed very low total and open porosities (0.29 % and 0.017 %, respectively) but unexpectedly high permeabilities attributed to interconnected microfractures. SEM imaging revealed abundant and morphologically diverse microbial biosignatures, which were predominantly preserved in the crystalline and transition zones through rapid silicification and barite precipitation. These microenvironments, which are structured by mineral precipitation and permeability anisotropy, provide localized redox gradients and nutrient sources that support the preservation of chemolithotrophic endolithic communities. Our results demonstrate that hydrothermal fluid dynamics, mineral precipitation, and rock microstructure govern the habitability and fossilization potential of volcanic substrates in geothermal settings (temperature ranges from 32.7 to 73.7 °C and pH 6.7–8.1). The Puertecitos system offers a compelling terrestrial analog for studying microbial survival, mineral-driven weathering, and biosignature preservation on early Earth and Mars, emphasizing the importance of mineralogical interfaces and hydrothermal processes in structuring habitable niches in extreme environments.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106700"},"PeriodicalIF":3.4,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024058","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}
Pub Date : 2026-01-14DOI: 10.1016/j.apgeochem.2026.106687
Zhao Yan , Jin-Ting Kang , Weibiao Hsu , Fang Huang
Rapid and accurate identification for parent bodies of achondrites is crucial for planetary science research. In this study, we examined the performance of machine learning algorithms using bulk rock major element compositions to classify the origins of achondrites derived from the Moon, Mars, and asteroid 4 Vesta. Literature data on lunar basalts and anorthosites, Martian meteorites, and HED meteorites potentially originating from Vesta, are compiled and cleaned. Multiple machine-learning models were applied including a Tabular Prior-data Fitted Network (TabPFN) and six classical models including Decision Tree, Gradient Boosting, Support Vector Machine, Random Forest, K-Nearest Neighbors, and Multilayer Perceptron. All models demonstrate robust classification performances achieving over 95 % accuracy for the Test Set. Particularly, the K-Nearest Neighbors and TabPFN models achieve an accuracy exceeding 99 %. This study presents a new, automated method in identifying the parent body of achondrites through bulk rock major element data. While these models perform well, further analysis of feature importance is needed to provide deeper insights into the underlying geochemical controls, ensuring the method complements traditional approaches such as petrography and isotope analysis. To facilitate the broader use by meteorite collectors, cosmochemistry community and enthusiasts, a web interface has been developed to quickly apply this technique: https://geo-cosmo-chemistry.shinyapps.io/meteorites_classification/.
{"title":"Predicting differentiated achondrite parent bodies through machine learning: Insights from major element","authors":"Zhao Yan , Jin-Ting Kang , Weibiao Hsu , Fang Huang","doi":"10.1016/j.apgeochem.2026.106687","DOIUrl":"10.1016/j.apgeochem.2026.106687","url":null,"abstract":"<div><div>Rapid and accurate identification for parent bodies of achondrites is crucial for planetary science research. In this study, we examined the performance of machine learning algorithms using bulk rock major element compositions to classify the origins of achondrites derived from the Moon, Mars, and asteroid 4 Vesta. Literature data on lunar basalts and anorthosites, Martian meteorites, and HED meteorites potentially originating from Vesta, are compiled and cleaned. Multiple machine-learning models were applied including a Tabular Prior-data Fitted Network (TabPFN) and six classical models including Decision Tree, Gradient Boosting, Support Vector Machine, Random Forest, K-Nearest Neighbors, and Multilayer Perceptron. All models demonstrate robust classification performances achieving over 95 % accuracy for the Test Set. Particularly, the K-Nearest Neighbors and TabPFN models achieve an accuracy exceeding 99 %. This study presents a new, automated method in identifying the parent body of achondrites through bulk rock major element data. While these models perform well, further analysis of feature importance is needed to provide deeper insights into the underlying geochemical controls, ensuring the method complements traditional approaches such as petrography and isotope analysis. To facilitate the broader use by meteorite collectors, cosmochemistry community and enthusiasts, a web interface has been developed to quickly apply this technique: <span><span>https://geo-cosmo-chemistry.shinyapps.io/meteorites_classification/</span><svg><path></path></svg></span>.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106687"},"PeriodicalIF":3.4,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024123","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}
Pub Date : 2026-01-12DOI: 10.1016/j.apgeochem.2026.106695
Langfei Wei , Shaochen Yang , Ruolan Li , Rasheed Mohammed Abdul , Yanxin Hu , Haiyu Yan , Baolin Wang , Haiyan Hu , Ping Li
Rice consumption poses significant methylmercury (MeHg) exposure risks for residents in mercury (Hg) contaminated areas, yet the corresponding health risks in high geological background (HGB) regions remain overlooked. Here, we systematically evaluated rice Hg levels across two HGB karst regions (DH and XL) and a general background area (XN), and compared them with a Hg mining area (WWR). Despite soil total Hg (THg) concentrations in all study areas being below Chinese risk screening value (0.6 mg/kg, 6.5 < pH ≤ 7.5) and significantly lower than those in WWR, DH rice exhibited alarming THg levels (21.8 ± 13.1 ng/g, n = 131), with 48.5 % exceeding Chinese safety limit (20 ng/g). This was much higher than those from XL (3.26 ± 1.23 ng/g, n = 140), XN (1.91 ± 0.68 ng/g, n = 138), and even in WWR (14.2 ± 6.9 ng/g, n = 24). Furthermore, DH exhibited remarkably elevated MeHg bioaccumulation factors (BAFs) for rice grains (27.3 ± 14.6, n = 25) compared to XL (1.40 ± 1.00, n = 25) and WWR (7.88 ± 6.93, n = 24). Principal component analysis (PCA) integrated with MeHg BAFs and translocation factors (TFs) revealed exceptional MeHg bioaccumulation capacity in DH rice, predominantly attributed to elevated MeHg uptake through rice root system. Our findings highlight a potential underestimation of Hg levels in rice from HGB regions, and propose inhibiting root uptake from soil as a viable strategy to mitigate Hg accumulation in rice.
大米消费给汞污染地区居民带来了显著的甲基汞暴露风险，但高地质背景（HGB）地区的相应健康风险仍被忽视。在此，我们系统地评估了两个HGB岩溶区（DH和XL）和一般背景区（XN）的水稻汞水平，并将其与汞矿区（WWR）进行了比较。尽管所有研究区土壤全汞（THg）浓度均低于中国风险筛查值（0.6 mg/kg, 6.5 < pH≤7.5），且显著低于WWR，但DH水稻的THg水平达到了警戒线（21.8±13.1 ng/g, n = 131），其中48.5%超过中国安全限值（20 ng/g）。这远远高于XL(3.26±1.23 ng/g, n = 140)， XN(1.91±0.68 ng/g, n = 138)，甚至高于WWR（14.2±6.9 ng/g, n = 24）。此外，与XL（1.40±1.00,n = 25）和WWR（7.88±6.93,n = 24）相比，DH的MeHg生物积累因子（27.3±14.6,n = 25）显著提高。主成分分析（PCA）结合MeHg BAFs和转运因子（TFs）揭示了DH水稻的MeHg生物积累能力，这主要归因于水稻根系对MeHg的吸收增加。我们的研究结果强调了对HGB地区水稻中汞含量的潜在低估，并提出了抑制土壤对根系的吸收作为减轻水稻中汞积累的可行策略。
{"title":"Exceptional methylmercury bioaccumulation in rice grain from karst region with high geological background","authors":"Langfei Wei , Shaochen Yang , Ruolan Li , Rasheed Mohammed Abdul , Yanxin Hu , Haiyu Yan , Baolin Wang , Haiyan Hu , Ping Li","doi":"10.1016/j.apgeochem.2026.106695","DOIUrl":"10.1016/j.apgeochem.2026.106695","url":null,"abstract":"<div><div>Rice consumption poses significant methylmercury (MeHg) exposure risks for residents in mercury (Hg) contaminated areas, yet the corresponding health risks in high geological background (HGB) regions remain overlooked. Here, we systematically evaluated rice Hg levels across two HGB karst regions (DH and XL) and a general background area (XN), and compared them with a Hg mining area (WWR). Despite soil total Hg (THg) concentrations in all study areas being below Chinese risk screening value (0.6 mg/kg, 6.5 < pH ≤ 7.5) and significantly lower than those in WWR, DH rice exhibited alarming THg levels (21.8 ± 13.1 ng/g, n = 131), with 48.5 % exceeding Chinese safety limit (20 ng/g). This was much higher than those from XL (3.26 ± 1.23 ng/g, n = 140), XN (1.91 ± 0.68 ng/g, n = 138), and even in WWR (14.2 ± 6.9 ng/g, n = 24). Furthermore, DH exhibited remarkably elevated MeHg bioaccumulation factors (BAFs) for rice grains (27.3 ± 14.6, n = 25) compared to XL (1.40 ± 1.00, n = 25) and WWR (7.88 ± 6.93, n = 24). Principal component analysis (PCA) integrated with MeHg BAFs and translocation factors (TFs) revealed exceptional MeHg bioaccumulation capacity in DH rice, predominantly attributed to elevated MeHg uptake through rice root system. Our findings highlight a potential underestimation of Hg levels in rice from HGB regions, and propose inhibiting root uptake from soil as a viable strategy to mitigate Hg accumulation in rice.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106695"},"PeriodicalIF":3.4,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974374","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}
Pub Date : 2026-01-12DOI: 10.1016/j.apgeochem.2026.106696
Catherine Lerouge , Michaela Blessing , Marie Bonitz , Ana-Maria Fernández , Christine Flehoc , Nicolas Maubec , Guillaume Wille , David Jaeggi , Michael Kühn
In the framework of the hydrological survey of the Mont Terri anticline (Mont Terri rock Laboratory in the Folded Jura, Switzerland), a 58 m-deep borehole (BHS-1) was drilled through the Jurassic low permeability shale sequence. Dedicated sampling was carried out to characterize gases within a 13 m-thick unit of organic matter-rich Early Jurassic Rietheim black shales and adjacent units, including the underlying Beggingen aquifer. A cone-in-cone calcite, observed at the bottom of the black shale, as identified as an indicator of oil-window conditions and records a maximal burial temperature of ∼80–90 °C. Two fracture zones within the black shales, marked by calcite infillings, provide evidence for at least two episodes of water paleocirculations: (1) an early circulation between fractures at the top of black shales and the Main Fault, and (2) a later circulation between fracture zones within the black shales and the lower Beggingen aquifer. Gas migration was investigated within the complex geological context of regional uplift, Jura folding and thrusting, and associated water flows. Alkane data reveal a partial carbon isotope reversal of thermogenic gases within the black shales between the two fracture zones, strongly suggesting alkane migration linked to the second water paleocirculation episode.
在Mont Terri背斜水文调查的框架下（Mont Terri rock Laboratory In the褶皱Jura， Switzerland），钻了一个58 m深的井（BHS-1），穿过侏罗纪低渗透页岩层序。研究人员进行了专门的采样，以表征富含有机质的早侏罗世Rietheim黑色页岩及其邻近单元（包括Beggingen含水层）13 m厚单元中的气体特征。在黑色页岩底部观察到的锥中锥方解石被确定为油窗条件的指示物，并记录了最高埋藏温度为~ 80-90°C。黑色页岩中的两个裂缝带，以方解石充填为标志，为至少两期水古循环提供了证据：(1)黑色页岩顶部裂缝与主断层之间的早期循环，(2)黑色页岩裂缝带与Beggingen含水层下部之间的后期循环。在区域隆升、侏罗褶皱和逆冲以及相关水流的复杂地质背景下研究了天然气运移。烷烃数据显示，在两个断裂带之间的黑色页岩中，热成因气体的部分碳同位素反转，强烈表明烷烃运移与第二次水古循环事件有关。
{"title":"Impact of tectonics and fluid circulations on shale gas isotope geochemistry – A case study of the Rietheim Member at the Mont Terri anticline (Switzerland)","authors":"Catherine Lerouge , Michaela Blessing , Marie Bonitz , Ana-Maria Fernández , Christine Flehoc , Nicolas Maubec , Guillaume Wille , David Jaeggi , Michael Kühn","doi":"10.1016/j.apgeochem.2026.106696","DOIUrl":"10.1016/j.apgeochem.2026.106696","url":null,"abstract":"<div><div>In the framework of the hydrological survey of the Mont Terri anticline (Mont Terri rock Laboratory in the Folded Jura, Switzerland), a 58 m-deep borehole (BHS-1) was drilled through the Jurassic low permeability shale sequence. Dedicated sampling was carried out to characterize gases within a 13 m-thick unit of organic matter-rich Early Jurassic Rietheim black shales and adjacent units, including the underlying Beggingen aquifer. A cone-in-cone calcite, observed at the bottom of the black shale, as identified as an indicator of oil-window conditions and records a maximal burial temperature of ∼80–90 °C. Two fracture zones within the black shales, marked by calcite infillings, provide evidence for at least two episodes of water paleocirculations: (1) an early circulation between fractures at the top of black shales and the Main Fault, and (2) a later circulation between fracture zones within the black shales and the lower Beggingen aquifer. Gas migration was investigated within the complex geological context of regional uplift, Jura folding and thrusting, and associated water flows. Alkane data reveal a partial carbon isotope reversal of thermogenic gases within the black shales between the two fracture zones, strongly suggesting alkane migration linked to the second water paleocirculation episode.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"198 ","pages":"Article 106696"},"PeriodicalIF":3.4,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974375","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}
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