ACS Earth and Space Chemistry最新文献

{"title":"Structural Investigation of Diprotonated Glycine, Diprotonated Glycine Methyl Ester, and Monoprotonated Glycinoyl Fluoride","authors":"Dirk Hollenwäger*,&nbsp;Yvonne Morgenstern,&nbsp;Lea Daumer,&nbsp;Valentin Bockmair and Andreas J. Kornath,&nbsp;","doi":"10.1021/acsearthspacechem.4c0020310.1021/acsearthspacechem.4c00203","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00203https://doi.org/10.1021/acsearthspacechem.4c00203","url":null,"abstract":"<p >Glycine and its methyl ester hydrochloride were investigated in superacidic media HF/<i>M</i>F₅ (<i>M</i> = As, Sb). The diprotonated species were obtained as [<i>M</i>F₆]⁻ salts (<i>M</i> = As, Sb). The colorless salts were characterized by vibrational spectroscopy, NMR spectroscopy, and single-crystal diffraction. Glycinoyl fluoride was isolated for the first time as a solid and characterized by vibrational spectroscopy, NMR spectroscopy, and single X-ray diffraction. Glycinoyl fluoride was investigated in the superacidic medium HF/MF₅ (<i>M</i> = As, Sb). The salts of the diprotonated species were obtained and characterized by vibrational spectroscopy. The experimental data are discussed together with quantum chemical calculations at the M06-2X/aug-cc-pVTZ level of theory.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A CAPRAM Modeling Study on the Role of Heterogeneous Reactions on Dust in Tropospheric Chemistry","authors":"Marvel B. E. Aiyuk,&nbsp;Erik H. Hoffmann,&nbsp;Andreas Tilgner,&nbsp;Ralf Wolke and Hartmut Herrmann*,&nbsp;","doi":"10.1021/acsearthspacechem.4c0015410.1021/acsearthspacechem.4c00154","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00154https://doi.org/10.1021/acsearthspacechem.4c00154","url":null,"abstract":"<p >A heterogeneous dust chemistry module was developed and coupled toward the near-explicit mechanism MCM. Model simulations were performed for different dust concentrations (low, high, and very high dust), and the most significant changes were modeled in HNO₃, by 99% for very high dust, forming surface nitrates. Surface photolysis of nitrates resulted in an increase in HONO. Chemical rate analyses revealed that the direct uptake on dust played only a minor role for most species, except N₂O₅, HNO₃, H₂O₂, and SO₂. Average SO₂ oxidation rates of 3 μg m^–3 h^–1 and 0.3 μg m^–3 h^–1 were modeled for dust loads of 196 μg m^–3 and 19.6 μg m^–3, which are higher than the reported aqueous-phase oxidation rates. Sensitivity simulations considering the uptake of only one compound revealed that the N₂O₅ and HNO₃ uptake had the strongest effects. The uptake of only HNO₃ with surface photolysis resulted in major increases in NO_<i>x</i>, OH, and HONO by 20%, 36%, and 5110%, respectively. Further sensitivity simulations with higher uptake coefficients showed that the uptake of O₃ could act as an indirect source of HONO because of higher NO_<i>x</i> and OH concentrations. The minimum required uptake coefficient for direct effects to occur (γ_min) was also determined for the main inorganic species and had values of 10^–6 for O₃ and SO₂ and 10^–4 for NO₂, thus suggesting that direct uptake of NO₂ on dust is an unimportant sink under urban conditions. Overall, this study shows the importance of photoenhanced uptake and uptake coefficient values in heterogeneous chemistry.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"FeC4H2: A Potential Astrophysical Molecule Featuring Planar Tetracoordinate Iron to Unveil the Mystery of Missing Iron in Interstellar Medium","authors":"Shilpa Shajan,&nbsp; and ,&nbsp;Krishnan Thirumoorthy*,&nbsp;","doi":"10.1021/acsearthspacechem.4c0017810.1021/acsearthspacechem.4c00178","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00178https://doi.org/10.1021/acsearthspacechem.4c00178","url":null,"abstract":"<p >The exploration of iron-containing species represents a prominent area in contemporary astrochemical investigations. Iron in the interstellar medium exhibits predominantly low concentrations, hinting at the potential presence of missing iron in either a condensed or molecular state. The FeC₄H₂ neutral system has been investigated using computational calculations, emphasizing the hypothesis that missing iron may exist as iron–carbon hydride compounds or their higher order. A total of 61, 46, and 36 stationary points have been identified on the potential energy surface (PES) of the FeC₄H₂ in the singlet, triplet, and quintet electronic states, respectively, showcasing the existence of a planar tetracoordinate iron (ptFe). A linear geometry represents the global minimum on the PES of FeC₄H₂ as observed in the quintet ground electronic state. Meanwhile, the ptFe geometry is identified as the second most stable isomer in the quintet electronic state, which is the lowest energy solely in the singlet electronic state. Further, the observed ptFe geometry closely resembles the experimentally detected FeC₄ molecule in the gas phase. In light of its similarity to FeC₄ and the recent detection of FeC in the interstellar medium, the ptFe would be a potential astrophysical molecule that will also be identified in the gas phase. From that point of view, a comprehensive examination of the nature of chemical bonding of the ptFe geometry in the singlet, triplet, and quintet electronic states has been characterized, which dictates the stabilization of ptFe through multicenter bonding with surrounding carbon atoms. <i>Ab initio</i> molecular dynamics simulations revealed the dynamic stability of the system. Understanding the interstellar species with its structure and chemical bonding is an important aspect that would shed light on new insights into the experimental observations in the future.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Properties and Atmospheric Oxidation of Terebic Acid Aerosol","authors":"Kalliopi Florou,&nbsp;Agata Błaziak,&nbsp;Spiro Jorga,&nbsp;Petro Uruci,&nbsp;Christina N. Vasilakopoulou,&nbsp;Rafał Szmigielski and Spyros N. Pandis*,&nbsp;","doi":"10.1021/acsearthspacechem.4c0020110.1021/acsearthspacechem.4c00201","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00201https://doi.org/10.1021/acsearthspacechem.4c00201","url":null,"abstract":"<p >Terebic acid (C₇H₁₀O₄) is a biogenic secondary organic aerosol constituent, produced by the oxidation of first- and second-generation products of monoterpenes such as α<i>-</i>pinene, β-pinene, and Δ³-carene. It is a processed derivative of terpenylic acid and has been identified in aerosol samples from terrestrial and forest environments. The physicochemical properties of pure terebic acid aerosol were characterized using two different atmospheric simulation chambers and a suite of online particle and gas-phase instrumentation. Its mass spectrum, obtained by a high-resolution time-of-flight mass spectrometer, had characteristic peaks at mass-to-charge (<i>m</i>/<i>z</i>) ratios 81, 96, 100, 115, and 143, mainly related to oxygenated fragment ions. The density of terebic acid aerosol was 1.33 ± 0.20 g cm^–3, and its vaporization enthalpy was 85 kJ mol^–1. The estimated saturation concentration at 298 K of 2.6 ± 1.2 μg m^–3 places terebic acid in the semivolatile organic compound category. Oxidation of terebic acid aerosol by hydroxyl (OH) radicals resulted in a substantial reduction in organic aerosol (OA) mass concentration (up to 80%), with no significant alteration in the OA spectrum or aerosol O:C ratio, indicating negligible production of secondary OA. Gas-phase analysis detected the production of smaller compounds, such as acetone. The terebic acid oxidation products were mostly in the gas phase as fragmentation appears to dominate its reaction with OH radicals. The gas-phase reaction rate constant with OH was estimated to be 3 × 10^–12 cm³ molecule^–1 s^–1.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsearthspacechem.4c00201","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temperature and pH Affect the Sorption and Transformation of Dissolved Organic Carbon by Birnessite","authors":"Oluwadunsin Oyetunji, Dane Lamb, Oliver A. H. Jones, Suresh Subashchandrabose, Edward D. Burton","doi":"10.1021/acsearthspacechem.4c00125","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00125","url":null,"abstract":"Soil mineralogy plays a vital role in carbon storage. Birnessite is a widely occurring manganese oxide mineral. Despite its widespread occurrence, studies of the interactions between natural soil organic carbon and manganese oxide minerals are rare. This study investigated the influence of triclinic birnessite on the transformation of vermicompost-derived dissolved organic carbon (DOC) at different pHs (4 and 8) and temperatures (25 and 50 °C). Enhanced adsorption and transformation of DOC, particularly at pH 4 and 50 °C, were observed. The use of SUVA₂₅₄ and fluorescence spectroscopy showed that DOC sorption caused an increase in carbon aromaticity, with the highest degree observed at pH 4 at 50 °C. In particular, X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure C 1s characterization showed an 8-fold increase in aromaticity at 50 °C compared to the unreacted DOC, with esterification and/or etherification reactions also occurring at pH 4. The impact of DOC sorption on birnessite stability and transformations was also assessed via X-ray absorption near-edge structure spectroscopy, which revealed that reacted and unreacted triclinic birnessite showed modest changes to Mn II, III, and IV. Manganese K-edge extended X-ray absorption fine structure spectroscopy showed the increased formation of hexagonal birnessite at pH 4, the formation of manganite at pH 4 and 8, 50 °C, and the formation of up to 6% ramsdellite at pH 8, 25 °C. This study provides new insights into the role of birnessite in soil carbon storage and manganese mineral transformations under environmentally relevant conditions.","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sorption and Oxidative Degradation of Small Organic Molecules on Mn-Oxides─Effects of pH and Mineral Structures","authors":"Hui Li*,&nbsp;Benjamin Atkins,&nbsp;Sarah Williams,&nbsp;Hui Yin,&nbsp;Benjamin Reinhart and Elizabeth Herndon,&nbsp;","doi":"10.1021/acsearthspacechem.4c0016610.1021/acsearthspacechem.4c00166","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00166https://doi.org/10.1021/acsearthspacechem.4c00166","url":null,"abstract":"<p >Manganese (Mn)-oxides regulate carbon (C) cycling in soils by sorbing and oxidizing organic compounds. The composition of soil organic matter varies widely, and little is known about the reactivity of individual organic compounds with structurally diverse Mn-oxides under various environmentally relevant pH conditions. Here, we examined the affinity of six organic compounds for three Mn-oxides, comprised of layer (birnessite and hydrous Mn oxide HMO) or tunnel (cryptomelane) structures, at acidic (pH 4), slightly acidic (pH 6), and slightly alkaline (pH 8) conditions. Cryptomelane, with a higher specific surface area and point of zero charge, showed higher reactivity than that of HMO and birnessite. Interestingly, these Mn-oxides, although different in structures, decomposed each organic compound to form the same products. Citrate, pyruvate, ascorbate, and catechol induced reduction and dissolution of Mn-oxides. After the reaction, the average oxidation state of Mn in the solids was much lower at pH 4 than at pH 6 and 8, suggesting more reduction under more acidic conditions. Even when reacting with phthalate and propanol, which only sorbed to Mn-oxides but did not degrade, there was proton-promoted Mn dissolution under acidic conditions. These results suggest the significance of environmental pH and mineral structures in affecting the Mn–organic interactions and provide fundamental insights into a better understanding of the roles of Mn-oxides in regulating soil C cycling.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temperature and pH Affect the Sorption and Transformation of Dissolved Organic Carbon by Birnessite","authors":"Oluwadunsin Oyetunji,&nbsp;Dane Lamb*,&nbsp;Oliver A. H. Jones,&nbsp;Suresh Subashchandrabose and Edward D. Burton,&nbsp;","doi":"10.1021/acsearthspacechem.4c0012510.1021/acsearthspacechem.4c00125","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00125https://doi.org/10.1021/acsearthspacechem.4c00125","url":null,"abstract":"<p >Soil mineralogy plays a vital role in carbon storage. Birnessite is a widely occurring manganese oxide mineral. Despite its widespread occurrence, studies of the interactions between natural soil organic carbon and manganese oxide minerals are rare. This study investigated the influence of triclinic birnessite on the transformation of vermicompost-derived dissolved organic carbon (DOC) at different pHs (4 and 8) and temperatures (25 and 50 °C). Enhanced adsorption and transformation of DOC, particularly at pH 4 and 50 °C, were observed. The use of SUVA₂₅₄ and fluorescence spectroscopy showed that DOC sorption caused an increase in carbon aromaticity, with the highest degree observed at pH 4 at 50 °C. In particular, X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure C 1s characterization showed an 8-fold increase in aromaticity at 50 °C compared to the unreacted DOC, with esterification and/or etherification reactions also occurring at pH 4. The impact of DOC sorption on birnessite stability and transformations was also assessed via X-ray absorption near-edge structure spectroscopy, which revealed that reacted and unreacted triclinic birnessite showed modest changes to Mn II, III, and IV. Manganese K-edge extended X-ray absorption fine structure spectroscopy showed the increased formation of hexagonal birnessite at pH 4, the formation of manganite at pH 4 and 8, 50 °C, and the formation of up to 6% ramsdellite at pH 8, 25 °C. This study provides new insights into the role of birnessite in soil carbon storage and manganese mineral transformations under environmentally relevant conditions.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsearthspacechem.4c00125","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142449022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of Light and Condensate Oil Categories in a Complex Petroleum System by Fluorescence Parameters: A Case Study on the Northern Tazhong Uplift, Tarim Basin, China","authors":"Peng Cheng,&nbsp;Yuhao Ren and Shuang Yu*,&nbsp;","doi":"10.1021/acsearthspacechem.4c0011610.1021/acsearthspacechem.4c00116","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00116https://doi.org/10.1021/acsearthspacechem.4c00116","url":null,"abstract":"<p >Light and condensate oils are high-quality fossil energy sources. Because light and condensate oils have complex origins and are generally dominated by light hydrocarbons with few diagnostic biomarkers, conventional geochemical methods have difficulty identifying their categories, especially in complex petroleum systems. In this study, the fluorescence lifetime (τ_oil) and fluorescence spectral parameters (λ_max, Q_510/430, and Q_650/500) of light and condensate oils in the northern Tazhong Uplift of the Tarim Basin were systematically analyzed. The results indicate that the light and condensate oils in this area can be divided into three categories according to their fluorescence characteristics. For the TZ-I, TZ-II, and TZ-III oils, τ_oil progressively increases, and the fluorescence spectra gradually shift blue with decreases in Q_510/430, Q_650/500, and λ_max, which results from the successive decreases in gas invasion extent for the three types of Tazhong oils. Light hydrocarbons mainly consisting of saturated hydrocarbon fractions were carried by highly mature gaseous hydrocarbons from deep sources to relatively shallow reservoirs and mixed with early accumulated crude oils. The charged saturates reduced the fluorophore (polycyclic aromatic hydrocarbons, PHA) concentration in crude oil, weakened fluorescence quenching, and promoted fluorescence emission, which changed the fluorescence characteristics of crude oils. Correlation diagrams based on different fluorescence parameters as well as other parameters, including physical, geochemical, and associated gas parameters, provide a favorable method for determining light and condensate categories. Moreover, the fluorescence method exhibits great application potential for direct correlations between reservoir oils and inclusion oils in complex petroleum systems.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of Light and Condensate Oil Categories in a Complex Petroleum System by Fluorescence Parameters: A Case Study on the Northern Tazhong Uplift, Tarim Basin, China","authors":"Peng Cheng, Yuhao Ren, Shuang Yu","doi":"10.1021/acsearthspacechem.4c00116","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00116","url":null,"abstract":"Light and condensate oils are high-quality fossil energy sources. Because light and condensate oils have complex origins and are generally dominated by light hydrocarbons with few diagnostic biomarkers, conventional geochemical methods have difficulty identifying their categories, especially in complex petroleum systems. In this study, the fluorescence lifetime (τ_oil) and fluorescence spectral parameters (λ_max, Q_510/430, and Q_650/500) of light and condensate oils in the northern Tazhong Uplift of the Tarim Basin were systematically analyzed. The results indicate that the light and condensate oils in this area can be divided into three categories according to their fluorescence characteristics. For the TZ-I, TZ-II, and TZ-III oils, τ_oil progressively increases, and the fluorescence spectra gradually shift blue with decreases in Q_510/430, Q_650/500, and λ_max, which results from the successive decreases in gas invasion extent for the three types of Tazhong oils. Light hydrocarbons mainly consisting of saturated hydrocarbon fractions were carried by highly mature gaseous hydrocarbons from deep sources to relatively shallow reservoirs and mixed with early accumulated crude oils. The charged saturates reduced the fluorophore (polycyclic aromatic hydrocarbons, PHA) concentration in crude oil, weakened fluorescence quenching, and promoted fluorescence emission, which changed the fluorescence characteristics of crude oils. Correlation diagrams based on different fluorescence parameters as well as other parameters, including physical, geochemical, and associated gas parameters, provide a favorable method for determining light and condensate categories. Moreover, the fluorescence method exhibits great application potential for direct correlations between reservoir oils and inclusion oils in complex petroleum systems.","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fe/Mg-Silicate Chemical Gardens as Analogs to Silicate-Rich Hydrothermal Chimneys on Early Earth and Mars","authors":"Nancy A. Carman, Elisabeth M. Hausrath, Aaron Celestian, Julia Chavez, Ninos Hermis, Douglas E. LaRowe, Abigail A. Fraeman, Rachel Y. Sheppard, Christopher T. Adcock, Oliver Tschauner, Elizabeth B. Rampe, Roy Price, Laura M. Barge","doi":"10.1021/acsearthspacechem.4c00109","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00109","url":null,"abstract":"Hydrothermal systems have been proposed as environments for prebiotic chemistry on early Earth. Ancient Mars had surface water and could also have had hydrothermal vents supporting biological or prebiotic processes. The Strýtan hydrothermal field (SHF) in Iceland is a basalt-hosted alkaline vent that forms massive hydrothermal Mg-saponite chimneys and is a potential analog to basalt-hosted alkaline vents that may have existed at the Eridania basin on Mars, where Fe/Mg-phyllosilicate deposits (e.g., saponite, talc, sepiolite, and serpentine) are thought to have formed from ancient hydrothermal activity. Chemical garden experiments have previously been used to simulate aspects of hydrothermal chimney growth for other types of vent systems; however, they have not been much used in this context of a silica-rich hydrothermal system. Here, we studied the formation of Fe/Mg-silicate injection chemical gardens simulating hydrothermal chimneys that represent analogs of precipitates that could have formed in SHF-like hydrothermal vents on early Earth and/or early Mars. We found that the Fe/Mg ratio of the exterior (ocean simulant) solutions influenced the simulated chimney chemistry under anoxic conditions and that the precipitates were enriched with Fe compared to the surrounding solution. Simulated chimney compositions as analyzed by Raman spectroscopy, scanning electron microscope-energy dispersive X-ray spectroscopy, X-ray diffraction, and visible–near-infrared reflectance spectroscopy were also affected by whether the chimneys were dried and/or heated post formation. Our data were suggestive of the presence of poorly ordered Mg-clay-like phases (e.g., sepiolite) in the simulated chimneys, along with amorphous/nanocrystalline Fe phases and Fe oxides/hydroxides, hydrated silica, hematite, halite, and gypsum. Saponite was not produced in our experiments because of an absence of Al in solution. Though we observed evidence for Mg-silicate and clay-like minerals in the chemical gardens, we only observed weak 12.5 Å peaks for Fe-silicate or Fe-containing clay-like minerals; however, amorphous silica and Fe oxides/hydroxides were confirmed, similar to what has been observed in previous chemical garden studies. This suggests that in SHF-like chimneys on early Earth and/or Mars, Mg would have been present as Mg-hydroxides and Mg-silicates (and, in the presence of additional geological components such as Al, likely saponite or other aluminous clay minerals), whereas Fe would be present as Fe or Fe:Mg-hydroxides. Such chimneys, containing both reactive Fe hydroxides as well as Mg-clay-like phases, would have increased potential for mineral-driven prebiotic chemical reactions.","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}