Geochemical Transactions最新文献

{"title":"Dissolution and solubility of the calcium-nickel carbonate solid solutions [(Ca1−xNix)CO3] at 25 °C","authors":"Chengyou Ma,&nbsp;Xiaoke Nong,&nbsp;Fan Xu,&nbsp;Zongqiang Zhu,&nbsp;Peijie Nong,&nbsp;Fei Luo,&nbsp;Shen Tang,&nbsp;Lihao Zhang,&nbsp;Zhiqiang Kang,&nbsp;Yinian Zhu","doi":"10.1186/s12932-024-00096-6","DOIUrl":"10.1186/s12932-024-00096-6","url":null,"abstract":"<div><p>A series of the calcium-nickel carbonate solid solutions [(Ca_1−xNi_x)CO₃] were synthesized and their dissolution in N₂-degassed water (NDW) and CO₂-saturated water (CSW) at 25 °C was experimentally investigated. During dissolution of the synthetic solids (Ni-bearing calcite, amorphous Ca-bearing NiCO₃ and their mixtures), the Ni-calcite and the Ca-NiCO₃ dissolved first followed by the formation of the Ni-bearing aragonite-structure phases. After 240–300 days of dissolution in NDW, the water solutions achieved the stable Ca and Ni concentrations of 0.592–0.665 and 0.073–0.290 mmol/L for the solids with lower Ni/(Ca + Ni) mol ratios (X_Ni), or 0.608–0.721 and 0.273–0.430 mmol/L for the solids with higher X_Ni, respectively. After 240–300 days of dissolution in CSW, the water solutions achieved the stable Ca and Ni concentrations of 1.094–3.738 and 0.831–4.300 mmol/L, respectively. For dissolution in NDW and CSW, the mean values of log IAP (Ion activity products) in the final stable state (≈ log <i>K</i>_sp, Solubility product constants) were determined to be − 8.65 ± 0.04 and − 8.16 ± 0.11 for calcite [CaCO₃], respectively; − 8.50 ± 0.02 and − 7.69 ± 0.03 for the synthetical nickel carbonates [NiCO₃], respectively. In respect to the bulk composition of the (Ca_1−xNi_x)CO₃ solid solutions, the final log IAP showed the highest value when X_Ni = 0.10–0.30. Mostly, the mean values of log IAP increased with the increasing X_Ni in respect to the Ni-calcite, the Ni-aragonite and the amorphous Ca-Ni carbonate. The plotting of the experimental data on the Lippmann diagram for the (Ca_1−xNi_x)CO₃ solid solution using the predicted Guggenheim parameters of <i>a</i>₀ = 2.14 and <i>a</i>₁ = − 0.128 from a miscibility gap of X_Ni = 0.238 to 0.690 indicated that the solids dissolved incongruently and the final Ca and Ni concentrations in the water solutions were simultaneously limited by the minimum stoichiometric saturation curves for the Ni-calcite, Ni-aragonite and the amorphous Ca-Ni carbonate. During dissolution in NDW, the Ni²⁺ preferred to dissolve into the water solution and Ca²⁺ preferred to remain in the solid, while during dissolution in CSW for the solids with higher X_Ni, the Ca²⁺ preferred to dissolve into the water solution and Ni²⁺ preferred to remain in the solid. These findings provide valuable insights into understanding the mechanisms governing Ni geochemical cycle in natural environments.</p></div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"25 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geochemicaltransactions.biomedcentral.com/counter/pdf/10.1186/s12932-024-00096-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142750783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Silicate coprecipitation reduces green rust crystal size and limits dissolution-precipitation during air oxidation","authors":"Aaron R. Betts,&nbsp;Matthew H. H. Fischel,&nbsp;Anna Evers,&nbsp;Ryan Tappero,&nbsp;Donald L. Sparks","doi":"10.1186/s12932-024-00093-9","DOIUrl":"10.1186/s12932-024-00093-9","url":null,"abstract":"<div><p>Green rusts (GR) are mixed-valence iron (Fe) hydroxides which form in reducing redox environments like riparian and wetland soils and shallow groundwater. In these environments, silicon (Si) can influence Fe oxides’ chemical and physical properties but its role in GR formation and subsequent oxidative transformation have not been studied starting at initial nucleation. Green rust sulfate [GR(SO₄)] and green rust carbonate [GR(CO₃)] were both coprecipitated from salts by base titration in increasing % mol Si (0, 1, 10, and 50). The minerals were characterized before and after rapid (24 h) aqueous air-oxidation by x-ray diffraction (XRD), scanning electron microscopy (SEM), Fe extended x-ray absorption fine structure spectroscopy (EXAFS), and N₂-BET surface area. Results showed that only GR(SO4) or GR(CO3) was formed at every tested Si concentration. Increasing % mol Si caused decreased plate size and increased surface area in GR(CO3) but not GR(SO4). GR plate basal thickness was not changed at any condition indicating a lack of Si interlayering. Air oxidation of GR(SO4) at all % mol Si contents transformed by dissolution and reprecipitation into lepidocrocite and goethite, favoring ferrihydrite with higher % Si content. Air oxidation of GR(CO3) transformed into magnetite and goethite but increasing Si caused GR to oxidize while retaining its hexagonal plate structure via solid-state oxidation. Our results indicate that Si has the potential to cause GR to form in smaller particles and upon air oxidation, Si can either stabilize the plate structure or alter transformation to ferrihydrite.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"25 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geochemicaltransactions.biomedcentral.com/counter/pdf/10.1186/s12932-024-00093-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142521726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of the Arabian-Nubian Shield along the Marsa Alam-Idfu transect, Central-Eastern Desert, Egypt: geochemical implementation of zircon U-Pb geochronology","authors":"Sherif Mansour,&nbsp;Noriko Hasebe,&nbsp;Kamal Abdelrahman,&nbsp;Mohammed S. Fnais,&nbsp;Mohamed A. Gharib,&nbsp;Rabiou Habou,&nbsp;Akihiro Tamura","doi":"10.1186/s12932-024-00095-7","DOIUrl":"10.1186/s12932-024-00095-7","url":null,"abstract":"<div><p>The magmatic complex along the Marsa Alam-Idfu transect, Central-Eastern Desert of Egypt, represents the northern segment of the Arabian–Nubian Shield (ANS), which developed within the framework of the East African Orogen. The basement rocks of the Arabian-Nubian Shield have been developed through three distinct phases of magmatic activity: the island-arc, the syn-orogenic, and the post-orogenic phases. Transitioning of the magmatic phases from the syn-orogenic to the post-orogenic, identifies changing the tectonic regime from a compressional to an extensional setting. The scarcity of comprehensive regional geochronological data that rely on precise isochron methods, such as the zircon U-Pb technique, could limit the comprehensive understanding of this region’s geological and tectonic history. That would raise a number of uncertainties ranging from the timing of the different magmatic activities and timing of changes in the tectonic regime to the existence of the pre-Pan-African crust in the CED. Our study provides new insights into the aforementioned uncertainties through zircon U-Pb dating of different rock units along the Marsa Alam-Idfu transect, CED, Egypt. The resulting ages ranged from 729 ± 3 Ma to 570 ± 2 Ma, constraining the temporal evolution of the ANS in the studied region into (1) the island-arc phase, represented by a metamorphic sample with an age of 729 ± 3 Ma. (2) the syn-orogenic phase, represented by calc-alkaline and alkaline granitic samples with ages ranging from 699 ± 4 Ma to 646 ± 2 Ma. These two phases indicate initiation of the compressional subduction regime in the CED since 729 ± 3 Ma and being dominated till 646 ± 2 Ma. (3) the post-orogenic phase, represented by metavolcanics, volcanic rocks, and alkaline plutonic samples with ages ranging from 623 ± 3 Ma to 570 ± 2 Ma. This phase suggests dominance of the compressional-to-extensional tectonic transition setting from 623 ± 3 Ma to 600 ± 1 Ma along with the Dokhan volcanism and activation of post-collision tensional regime activated at 582 ± 3 Ma. Our findings discourage the proposed dominance of the island-arc and syn-orogenic phases in the CED and the classical restriction of older magmatic activity to calc-alkaline granitic rocks and younger magmatic activity to alkaline granitic rocks. Additionally, we identified evidence of local magmatic sources by dating five grains with Mesoproterozoic (pre-Arabian–Nubian Shield) xenocrysts with ages ranging from 1549 ± 4 to 1095 ± 25 Ma.</p></div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"25 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geochemicaltransactions.biomedcentral.com/counter/pdf/10.1186/s12932-024-00095-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142518677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probing atomic-scale processes at the ferrihydrite-water interface with reactive molecular dynamics","authors":"Ardalan Hayatifar,&nbsp;Simon Gravelle,&nbsp;Beatriz D. Moreno,&nbsp;Valerie A. Schoepfer,&nbsp;Matthew B. J. Lindsay","doi":"10.1186/s12932-024-00094-8","DOIUrl":"10.1186/s12932-024-00094-8","url":null,"abstract":"<div><p>Interfacial processes involving metal (oxyhydr)oxide phases are important for the mobility and bioavailability of nutrients and contaminants in soils, sediments, and water. Consequently, these processes influence ecosystem health and functioning, and have shaped the biological and environmental co-evolution of Earth over geologic time. Here we employ reactive molecular dynamics simulations, supported by synchrotron X-ray spectroscopy to study the molecular-scale interfacial processes that influence surface complexation in ferrihydrite-water systems containing aqueous <span>({text {MoO}_4}^{2-})</span>. We validate the utility of this approach by calculating surface complexation models directly from simulations. The reactive force-field captures the realistic dynamics of surface restructuring, surface charge equilibration, and the evolution of the interfacial water hydrogen bond network in response to adsorption and proton transfer. We find that upon hydration and adsorption, ferrihydrite restructures into a more disordered phase through surface charge equilibration, as revealed by simulations and high-resolution X-ray diffraction. We observed how this restructuring leads to a different interfacial hydrogen bond network compared to bulk water by monitoring water dynamics. Using umbrella sampling, we constructed the free energy landscape of aqueous <span>({text {MoO}_4}^{2-})</span> adsorption at various concentrations and the deprotonation of the ferrihydrite surface. The results demonstrate excellent agreement with the values reported by experimental surface complexation models. These findings are important as reactive molecular dynamics opens new avenues to study mineral-water interfaces, enriching and refining surface complexation models beyond their foundational assumptions.</p><h3>Graphic Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"25 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geochemicaltransactions.biomedcentral.com/counter/pdf/10.1186/s12932-024-00094-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142490574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Water quality assessment of Upper Ganga and Yamuna river systems during COVID-19 pandemic-induced lockdown: imprints of river rejuvenation","authors":"Sameer K. Tiwari,&nbsp;Jairam Singh Yadav,&nbsp;Kalachand Sain,&nbsp;Santosh K. Rai,&nbsp;Aditya Kharya,&nbsp;Vinit Kumar,&nbsp;Pratap Chandra Sethy","doi":"10.1186/s12932-024-00092-w","DOIUrl":"10.1186/s12932-024-00092-w","url":null,"abstract":"<div><p>Clean river water is an essential and life-sustaining asset for all living organisms. The upper Ganga and Yamuna river system has shown signs of rejuvenation and tremendous improvement in the water quality following the nationwide lockdown due to the coronavirus pandemic. All the industrial and commercial activity was shut down, and there was negligible wastewater discharge from the industries. This article addresses the water quality assessment from the study area, which is based on the original data of physical parameters, major and trace elements, and stable isotopes (hydrogen and oxygen) systematics during the nationwide lockdown. The impact of the lockdown could be seen in terms of an increase in dissolved oxygen (DO). Water samples were collected from the Upper Ganga and Yamuna river basins (Alaknanda, Bhagirathi, and Tons rivers) during an eight-week lockdown in Uttarakhand, India. We discussed the signs of rejuvenation of riverine based on physical parameters, major ions, trace elements, isotopic ratios, and water pollution index (WPI). Results reveal that the water quality of the entire upper basins of the Ganga has significantly improved by 93%, reflecting the signs of self-rejuvenation of the rivers. Multivariate analysis suggests a negative factor loading for an anthropogenic element (<span>({NO}_{3}^{-})</span>), implying that they contribute little to the river water during the lockdown. Further, bicarbonate (<span>({HCO}_{3}^{-})</span>) is a dominant element in both river basins. The geochemical facies are mainly characterized by the (<span>({{Ca}^{2+} :{Mg}^{2+} : HCO}_{3}^{-})</span>) type of water, suggesting that silicate rock weathering dominates with little influence from carbonate weathering in the area. The positive factor loadings of some cations, like<span>({HCO}_{3}^{-})</span>,<span>({Ca}^{2+})</span>, and <span>({Mg}^{2+})</span> reflect their strong association with the source of origin in the lockdown phases. Stable isotopic reveals that the glaciated region contributed the most to the river basin, as evidenced by the low d-excess in riverine water compared to anthropogenic contributions. Rivers can self-rejuvenate if issues of human influence and anthropogenic activities are adequately resolved and underline our responsibility for purifying the ecosystem. We observed that this improvement in the river water quality will take a shorter time, and quality will deteriorate again when commercial and industrial activity resumes.</p></div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"25 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geochemicaltransactions.biomedcentral.com/counter/pdf/10.1186/s12932-024-00092-w","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142329231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Mn2+ concentration on the growth of δ-MnO2 crystals under acidic conditions","authors":"Liyan Bi,&nbsp;Haoran Hu,&nbsp;Lei Wang,&nbsp;Zuran Li,&nbsp;Fangdong Zhan,&nbsp;Yongmei He,&nbsp;Yanqun Zu,&nbsp;Yuan Li,&nbsp;Xinran Liang","doi":"10.1186/s12932-024-00091-x","DOIUrl":"10.1186/s12932-024-00091-x","url":null,"abstract":"<div><p>δ-MnO₂ is an important component of environmental minerals and is among the strongest sorbents and oxidants. The crystalline morphology of δ-MnO₂ is one of the key factors affecting its reactivity. In this work, δ-MnO₂ was initially synthesized and placed in an acidic environment to react with Mn²⁺ and undergo a crystalline transformation. During the transformation of crystalline δ-MnO₂, kinetic sampling was conducted, followed by analyses of the structures and morphologies of the samples. The results showed that at pH 2.5 and 4, δ-MnO₂ nanoflakes spontaneously self-assembled into nanoribbons via edge-to-edge assembly in the initial stage. Subsequently, these nanoribbons attached to each other to form primary nanorods through a face-to-face assembly along the <i>c</i>-axis. These primary nanorods then assembled along the (001) planes and lateral surfaces, achieving further growth and thickening. Since a lower pH is more favorable for the formation of vacancies in δ-MnO₂, δ-MnO₂ can rapidly adsorb Mn²⁺ directly onto the vacancies to form tunnel walls. At the same time, the rapid formation of the tunnel walls leads to a quick establishment of hydrogen bonding between adjacent nanoribbons, enabling the assembly of these nanoribbons into primary nanorods. Therefore, in a solution with the same concentration of Mn²⁺, the structure transformation and morphology evolution of δ-MnO₂ to α-MnO₂ occur faster at pH 2.5 than at pH 4. These findings provide insights into the mechanism for crystal growth from layer-based to tunnel-based nanorods and methods for efficient and controlled syntheses of nanomaterials.</p></div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"25 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geochemicaltransactions.biomedcentral.com/counter/pdf/10.1186/s12932-024-00091-x","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142329233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of hydrochemical characteristic, water quality and associated health risks of metals and metalloids in water resources in the vicinity of Akamkpa quarry district, southeastern, Nigeria","authors":"George E. Ikpi,&nbsp;Therese N. Nganje,&nbsp;Aniekan Edet,&nbsp;Christopher I. Adamu,&nbsp;Godswill A. Eyong","doi":"10.1186/s12932-024-00090-y","DOIUrl":"10.1186/s12932-024-00090-y","url":null,"abstract":"<div><p>Quarrying of rock aggregates generates produced water that, if not handled properly will be a source of pollution for nearby water bodies, thus affecting the chemistry of the water. This study examined the chemistry, impact of quarrying activities on water resources and the health consequences/risks posed by ingestion of the water by humans in the Akamkpa quarry region in southeastern Nigeria. Thirty (30) water samples consisting of pond water, stream water, hand dug wells, and borehole samples were collected and analyzed for their physicochemical parameters using standard methods. The results obtained from the analyses indicated that the water was moderately acidic, fresh, and not salty, with many parameters below the recommended standards with Ca²⁺, and HCO₃⁻ being the dominant ions present in the water resources. Rock weathering processes including silicate weathering as illustrated by hydrochemical facies, cross plots, and Gibbs diagrams are the dominant mechanisms influencing the quality and major ions chemistry of the water resources with minor contributions from dissolution, anthropogenic activities, and ion exchange. Ca-Mg-SO₄-Cl and Na–K-HCO₃⁻ are the most important water types. Although the water quality index shows that the water is suitable for human use and irrigation, the mean values of As, Cd, Pb, and Se are above the acceptable limits. Additionally, the calculated contamination factor revealed the water resources are moderate to highly contaminated by As, Cd, Cr, Mo, Pb, Sb, and Se, and are therefore unsuitable for consumption with regards to these parameters. However, the residual sodium carbonate and water hazard index (WHI) values showed that 38% to 90% of sites in the quarry area were unsuitable for cultivation, 10–30% were in the low to medium impact category, and 60% were classified as risky and are from high to very high impact category. A non-cancer study of inhabitants living in the vicinity of the quarry area indicated that 6.7% of the sites have values greater than one, indicating that it may endanger the health of the people. Therefore, constant monitoring of the water quality is recommended as long-term use of contaminated water can harm humans, plants, and soils.</p></div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"25 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geochemicaltransactions.biomedcentral.com/counter/pdf/10.1186/s12932-024-00090-y","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142174083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrothermal alteration processes in monzogranite: a case study from the Eastern Desert of Egypt: implications from remote sensing, geochemistry and mineralogy","authors":"Amira M. El Tohamy","doi":"10.1186/s12932-024-00089-5","DOIUrl":"10.1186/s12932-024-00089-5","url":null,"abstract":"&lt;div&gt;&lt;p&gt;The South Eastern Desert (SED) of Egypt is one of the most promising areas in Egypt; it is widely explored for exploring the rare earth elements (REEs) and uranium-bearing ores. It is a main part of the Arabian-Nubian Shield (ANS). Therefore, the present study concerns with Sikait-Nugrus area as one of the most prolific sites in this region. The study provides a detailed geological, structural, and mineralogical investigation of the monzogranites to describe and characterize the various alteration types and sequence. For this purpose, remote sensing, geochemical and petrographical techniques were applied. The remote sensing technique helped in constructing a detailed geologic map of the study area to follow up strictly the alteration zone of the Sikait-Nugrus area. Petrographically, the granites predominates in the study area, they are described as slightly and highly altered monzogranites. The slightly altered one is composed mainly of quartz (~ 20–35%), alkali feldspar (~ 25–30%), plagioclase (~ 25–30%), and mica (~ 5–15%), while accessory minerals are represented by zircon and monazite. On the other hand, the portion of this granite close to the shearing zone is intensively altered and characterized by sericitization as the main alteration processes. This sheared portion is characterized by accessory minerals as, uranothorite, allanite, fluorite and Nb-minerals (ishikawaite). Minerlogically, the altered monzogranites are predominated by the following mineral groups: (1) radioactive minerals as uranyl silicates (soddyite, uranophane and kasolite), and thorium minerals (thorite and uranothorite), (2) Nb–Ta minerals (betafite, plumbobetafite, columbite, fergusonite, and aeschynite), (3) REE minerals (monazite, cheralite and xenotime), and (4) zircon and fluorite as accessory minerals. Geochemically, the recorded pattern of the REEs tetrad effect (M-type) for the highly altered samples indicate that these granites are highly evolved and affected by late stage of hydrothermal alteration and the effective water-rich alteration processes that connected to intensive physico-chemical changes. The total REE concentrations equal 241.8 and 249.75 ppm for the highly and slightly altered samples. A significant mass change (MC) was analyzed by the isocon technique (22.95 &amp; 11.11) and volume change (VC) (1.8 &amp;-7.99) for the highly and slightly altered samples, respectively. The mass balance calculations and the isocon diagrams revealed that some major oxides were removed from the slightly altered monzogranites and transformed later into highly altered monzogranites with increasing the alteration intensity due to the impacts of hydrothermal alteration processes. The studied area is virgin, where no detailed studies have been applied to this region. It is extendable to other parts of the Arabian-Nubian Shield in around the Red Sea in Egypt, Sudan, Saudi Arabia and Yemen. The applied technical workflow is also extendible to other surface analogue","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"25 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geochemicaltransactions.biomedcentral.com/counter/pdf/10.1186/s12932-024-00089-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142080109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prebiotic thiol-catalyzed thioamide bond formation","authors":"Andrew S. Hyde,&nbsp;Christopher H. House","doi":"10.1186/s12932-024-00088-6","DOIUrl":"10.1186/s12932-024-00088-6","url":null,"abstract":"<div><p>Thioamide bonds are important intermediates in prebiotic chemistry. In cyanosulfidic prebiotic chemistry, they serve as crucial intermediates in the pathways that lead to the formation of many important biomolecules (e.g., amino acids). They can also serve as purine and pyrimidine precursors, the two classes of heterocycle employed in genetic molecules. Despite their importance, the formation of thioamide bonds from nitriles under prebiotic conditions has required large excesses of sulfide or compounds with unknown prebiotic sources. Here, we describe the thiol-catalyzed formation of thioamide bonds from nitriles. We show that the formation of the simplest of these compounds, thioformamide, forms readily in spark-discharge experiments from hydrogen cyanide, sulfide, and a methanethiol catalyst, suggesting potential accumulation on early Earth. Lastly, we demonstrate that thioformamide has a Gibbs energy of hydrolysis (<span>(Delta G^{circ }_r)</span>) comparable to other energy-currencies on early Earth such as pyrophosphate and thioester bonds. Overall, our findings imply that thioamides might have been abundant on early Earth and served a variety of functions during chemical evolution.</p></div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"25 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11299287/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141888952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Element mobility during basalt-water-CO2 interaction: observations in natural systems vs. laboratory experiments and implication for carbon storage","authors":"Pierangelo Romano,&nbsp;Lorenzo Brusca,&nbsp;Marcello Liotta","doi":"10.1186/s12932-024-00087-7","DOIUrl":"10.1186/s12932-024-00087-7","url":null,"abstract":"<div><p>Today, carbon dioxide removal from the atmosphere is the most ambitious challenge to mitigate climate changes. Basalt rocks are abundant on the Earth’s surface (≈ 10%) and very abundant in the ocean floors and subaerial environments. Glassy matrix and minerals constituting these rocks contain metals (Ca²⁺, Mg²⁺, Fe²⁺) that can react with carbonic acid to form metal carbonates (CaCO₃, MgO₃ and FeCO3). Here, we present a data compilation of the chemical composition of waters circulating in basalt aquifers worldwide and the results of simple basalt-water-CO₂ experiments. Induced or naturally occurring weathering of basalts rocks release elements in waters and elemental concentration is closely dependent on water CO₂ concentration (and hence on water pH). We also performed two series of experiments where basaltic rock powder interacts with CO₂-charged waters for one month at room temperature. Laboratory experiments evidenced that in the first stages of water-rock interaction, the high content of CO₂ dissolved in water accelerates the basalt weathering process, releasing in the water not only elements that can form carbonate minerals but also other elements, which depending on their concentration can be essential or toxic for life. Relative mobility of elements such as Fe and Al, together with rare earth elements, increases at low pH conditions, while it decreases notably at neutral pH conditions. The comparison between experimental findings and natural evidence allowed to better understand the geochemical processes in basaltic aquifers hosted in active and inactive volcanic systems and to discuss these findings in light of the potential environmental impact of CO₂ storage in mafic and ultramafic rocks.</p></div>","PeriodicalId":12694,"journal":{"name":"Geochemical Transactions","volume":"25 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://geochemicaltransactions.biomedcentral.com/counter/pdf/10.1186/s12932-024-00087-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140943385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}