首页 > 最新文献

Geochimica et Cosmochimica Acta最新文献

英文 中文
Revisiting magnesium isotope constraints on the petrogenesis of the Fe-Ti oxide-bearing mafic–ultramafic intrusions
IF 4.5 1区 地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-01-15 DOI: 10.1016/j.gca.2024.09.025
Ping-Ping Liu , Ben Ma , Fang-Zhen Teng , Zhen-Chao Wang
Stable isotopes of metals, such as magnesium (Mg) and iron (Fe), typically undergo minimal fractionation at magmatic temperatures. However, in Fe-Ti oxide-bearing intrusions, significant Mg isotope fractionation (Δ26Mg values of up to 23 ‰) has been observed between silicates and Fe-Ti oxides. The mechanism responsible for this substantial fractionation remains unclear. This study presents Mg isotopic compositions for bulk rocks and mineral separates—including olivine, clinopyroxene, titanomagnetite, ilmenite—from sixteen Fe-Ti oxide ores in both the lower and the upper zones of the Baima layered mafic–ultramafic intrusion, as well as bulk rocks from three high-Ti basalts of the Emeishan large igneous province, SW China. Oxide ores from the lower zone and the lower section of the upper zone of the Baima intrusion are characterized by a low abundance of volatile-bearing minerals, such as apatite and hornblende. These ores exhibit δ26Mg values ranging from −0.30 to −0.14 ‰ for olivine, −0.26 to −0.06 ‰ for clinopyroxene, 0.16 to 0.60 ‰ for titanomagnetite and −0.33 to −0.21 ‰ for ilmenite, indicative of near-equilibrium fractionation. In contrast, oxide ores from the upper section of the upper zone exhibit a high abundance of volatile-bearing minerals and significantly different δ26Mg values, ranging from −0.19 to −0.05 ‰ for olivine, −0.25 to −0.10 ‰ for clinopyroxene, 0.57 to 0.60 ‰ for titanomagnetite and 0.86 to 2.34 ‰ for ilmenite, indicative of disequilibrium fractionation. A negative correlation between Fo content and δ26Mg value in olivine suggests that Mg isotopes fractionate as olivine undergoes fractional crystallization. Trapped liquid fractions, calculated based on Ce contents in apatite, suggest that rocks with high volatile-bearing mineral content have undergone re-equilibration with trapped liquids during cooling. The large disequilibrium Mg isotopic fractionation between silicates and Fe-Ti oxides is likely due to sub-solidus re-equilibration between minerals and trapped liquids. We propose that the extent of sub-solidus, diffusion-driven kinetic Mg isotopic fractionation in Fe-Ti oxide-bearing intrusions likely correlates with the volume of trapped liquids, which may serve as a significant medium accelerating ion exchange between silicates and Fe-Ti oxides. Moreover, mass balance calculations indicate that data of Mg isotopes on their own are insufficient to determine the petrogenesis of Fe-Ti oxides in layered intrusions. This insufficiency is primarily due to the low MgO content in titanomagnetite and ilmenite, where their separation causes minimal Mg isotopic fractionation of the melts.
{"title":"Revisiting magnesium isotope constraints on the petrogenesis of the Fe-Ti oxide-bearing mafic–ultramafic intrusions","authors":"Ping-Ping Liu ,&nbsp;Ben Ma ,&nbsp;Fang-Zhen Teng ,&nbsp;Zhen-Chao Wang","doi":"10.1016/j.gca.2024.09.025","DOIUrl":"10.1016/j.gca.2024.09.025","url":null,"abstract":"<div><div>Stable isotopes of metals, such as magnesium (Mg) and iron (Fe), typically undergo minimal fractionation at magmatic temperatures. However, in Fe-Ti oxide-bearing intrusions, significant Mg isotope fractionation (Δ<sup>26</sup>Mg values of up to 23 ‰) has been observed between silicates and Fe-Ti oxides. The mechanism responsible for this substantial fractionation remains unclear. This study presents Mg isotopic compositions for bulk rocks and mineral separates—including olivine, clinopyroxene, titanomagnetite, ilmenite—from sixteen Fe-Ti oxide ores in both the lower and the upper zones of the Baima layered mafic–ultramafic intrusion, as well as bulk rocks from three high-Ti basalts of the Emeishan large igneous province, SW China. Oxide ores from the lower zone and the lower section of the upper zone of the Baima intrusion are characterized by a low abundance of volatile-bearing minerals, such as apatite and hornblende. These ores exhibit δ<sup>26</sup>Mg values ranging from −0.30 to −0.14 ‰ for olivine, −0.26 to −0.06 ‰ for clinopyroxene, 0.16 to 0.60 ‰ for titanomagnetite and −0.33 to −0.21 ‰ for ilmenite, indicative of near-equilibrium fractionation. In contrast, oxide ores from the upper section of the upper zone exhibit a high abundance of volatile-bearing minerals and significantly different δ<sup>26</sup>Mg values, ranging from −0.19 to −0.05 ‰ for olivine, −0.25 to −0.10 ‰ for clinopyroxene, 0.57 to 0.60 ‰ for titanomagnetite and 0.86 to 2.34 ‰ for ilmenite, indicative of disequilibrium fractionation. A negative correlation between Fo content and δ<sup>26</sup>Mg value in olivine suggests that Mg isotopes fractionate as olivine undergoes fractional crystallization. Trapped liquid fractions, calculated based on Ce contents in apatite, suggest that rocks with high volatile-bearing mineral content have undergone re-equilibration with trapped liquids during cooling. The large disequilibrium Mg isotopic fractionation between silicates and Fe-Ti oxides is likely due to sub-solidus re-equilibration between minerals and trapped liquids. We propose that the extent of sub-solidus, diffusion-driven kinetic Mg isotopic fractionation in Fe-Ti oxide-bearing intrusions likely correlates with the volume of trapped liquids, which may serve as a significant medium accelerating ion exchange between silicates and Fe-Ti oxides. Moreover, mass balance calculations indicate that data of Mg isotopes on their own are insufficient to determine the petrogenesis of Fe-Ti oxides in layered intrusions. This insufficiency is primarily due to the low MgO content in titanomagnetite and ilmenite, where their separation causes minimal Mg isotopic fractionation of the melts.</div></div>","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"389 ","pages":"Pages 100-109"},"PeriodicalIF":4.5,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The role of scapolite-bearing granulites in sequestering and releasing sulfur: Implications for S isotope signatures of crustal fluids during lower-crustal exhumation
IF 4.5 1区 地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-01-13 DOI: 10.1016/j.gca.2025.01.010
Johannes Hammerli , Anthony I.S. Kemp , Anne-Sophie Bouvier , Roberta L. Rudnick , Pierre Boivin , Robert M. Holder , Thomas Chacko , Kevin Blake
To understand sulfur and carbon sequestration and release within the continental crust, scapolite minerals from a variety of granulite facies rocks were analyzed for their elemental composition and S isotope signatures. These high-grade scapolites host significant amounts of SO3 and CO2, up to approximately 5 wt% and 3 wt%, respectively, with δ34SVCDT from −3 to +10 ‰, and formed in relatively oxidizing environments characterized by low aH2O in which scapolite may form as a primary igneous mineral or via metamorphic reactions involving sulfides and silicates. The range of scapolite sulfur isotope compositions mirrors those observed in mantle xenoliths, suggesting transport of S from the mantle into the lower crust via fluids and melts. Although scapolite’s contribution to the global S and C cycles may be modest, it is significant in the context of sulfur fluxing from the mantle to the lower crust, particularly in its oxidized form. We estimate that at least 10 % of lower crustal sulfur is sequestered within scapolite. The exhumation of scapolite-bearing lower crustal rocks can therefore liberate substantial quantities of sulfur species and CO2, which may serve to both supply and compositionally buffer retrograde metamorphic fluids. These fluids may exhibit a range of S isotope compositions from mantle-like (δ34SVCDT ≈ 0 ‰) to relatively 34S-enriched signatures. Consequently, retrograde fluids may have S isotope signatures indistinguishable from those of mantle fluids, even in the absence of direct mantle S input during fluid formation. Exhumation of scapolite-bearing lower crust may facilitate element mobilization through S and Cl complexing, particularly with respect to base metals, within exhumed lower crustal sections, thus providing sources of metals and fluids in mid- to high-grade metamorphic rocks. Globally, scapolite-bearing lower crust may help balance the global sulfur cycle through catch-and-release from scapolite.
{"title":"The role of scapolite-bearing granulites in sequestering and releasing sulfur: Implications for S isotope signatures of crustal fluids during lower-crustal exhumation","authors":"Johannes Hammerli ,&nbsp;Anthony I.S. Kemp ,&nbsp;Anne-Sophie Bouvier ,&nbsp;Roberta L. Rudnick ,&nbsp;Pierre Boivin ,&nbsp;Robert M. Holder ,&nbsp;Thomas Chacko ,&nbsp;Kevin Blake","doi":"10.1016/j.gca.2025.01.010","DOIUrl":"10.1016/j.gca.2025.01.010","url":null,"abstract":"<div><div>To understand sulfur and carbon sequestration and release within the continental crust, scapolite minerals from a variety of granulite facies rocks were analyzed for their elemental composition and S isotope signatures. These high-grade scapolites host significant amounts of SO<sub>3</sub> and CO<sub>2</sub>, up to approximately 5 wt% and 3 wt%, respectively, with δ<sup>34</sup>S<sub>VCDT</sub> from −3 to +10 ‰, and formed in relatively oxidizing environments characterized by low <em>a</em>H<sub>2</sub>O in which scapolite may form as a primary igneous mineral or via metamorphic reactions involving sulfides and silicates. The range of scapolite sulfur isotope compositions mirrors those observed in mantle xenoliths, suggesting transport of S from the mantle into the lower crust via fluids and melts. Although scapolite’s contribution to the global S and C cycles may be modest, it is significant in the context of sulfur fluxing from the mantle to the lower crust, particularly in its oxidized form. We estimate that at least 10 % of lower crustal sulfur is sequestered within scapolite. The exhumation of scapolite-bearing lower crustal rocks can therefore liberate substantial quantities of sulfur species and CO<sub>2</sub>, which may serve to both supply and compositionally buffer retrograde metamorphic fluids. These fluids may exhibit a range of S isotope compositions from mantle-like (δ<sup>34</sup>S<sub>VCDT</sub> ≈ 0 ‰) to relatively <sup>34</sup>S-enriched signatures. Consequently, retrograde fluids may have S isotope signatures indistinguishable from those of mantle fluids, even in the absence of direct mantle S input during fluid formation. Exhumation of scapolite-bearing lower crust may facilitate element mobilization through S and Cl complexing, particularly with respect to base metals, within exhumed lower crustal sections, thus providing sources of metals and fluids in mid- to high-grade metamorphic rocks. Globally, scapolite-bearing lower crust may help balance the global sulfur cycle through catch-and-release from scapolite.</div></div>","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"392 ","pages":"Pages 175-194"},"PeriodicalIF":4.5,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143386854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Uranium isotope systematics of a low-productivity ferruginous ocean analog: Implications for the uranium isotope record of early Earth
IF 4.5 1区 地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-01-13 DOI: 10.1016/j.gca.2025.01.011
Geoffrey J. Gilleaudeau , Xinming Chen , Stephen J. Romaniello , Sajjad A. Akam , Chad Wittkop , Sergei Katsev , Ariel D. Anbar , Elizabeth D. Swanner
The uranium isotope (δ238U) paleo-redox proxy has emerged as a premier tool for understanding ocean oxygenation through Earth’s history. The fidelity of this important proxy depends, however, on our mechanistic understanding of the pathways that induce uranium isotope fractionation during U(VI) reduction to U(IV). Uranium reduction has been extensively studied in euxinic (anoxic + sulfidic) environments, yet relatively few constraints currently exist on δ238U fractionation in ferruginous (anoxic + iron-rich) environments, even though ferruginous conditions may have been a dominant feature of Earth’s oceans for much of the geologic past. Here, we present a comprehensive uranium isotope study of modern, meromictic, oligotrophic to mesotrophic, ferruginous Canyon Lake, Upper Peninsula, Michigan (USA), including investigation of a high-resolution profile of lake waters, lake inlet and outlet waters, and groundwater, as well as shallow cores through both oxic and ferruginous sediments. The key observation of this study is that the entire water column, oxic sediments, and ferruginous sediments have indistinguishable δ238U values near the composition of the upper continental crust. This implies a lack of δ238U fractionation in the low-productivity, ferruginous environments of Canyon Lake. We suggest that uranium cycling in Canyon Lake is dominated by adsorption and co-precipitation with iron oxides, with only a limited role for U(VI) reduction. These processes result partly from aqueous uranium speciation in the lake, with the dominance of UO2-CO3 complexes in the upper water column leading to a high partition coefficient of uranium during sorption to iron oxides. In addition, the dominance of CaUO2(CO3)32– and Ca2UO2(CO3)3(aq) in bottom waters kinetically inhibits U(VI) reduction by Fe(II)(aq). The lack of U(VI) reduction and hence δ238U fractionation in Canyon Lake, despite Fe(II)(aq) concentrations >1.5 mM, is potentially analogous to the lack of δ238U fractionation that occurred in the Archean and Proterozoic oceans, as indicated by the carbonate δ238U record. In contrast with predictions that U(VI) should be rapidly reduced and scavenged from the water column in the presence of Fe(II)(aq), our data suggest a limited role for U(VI) reduction and δ238U fractionation under the low-nutrient, low-productivity, ferruginous conditions that characterized the oceans on the early Earth.
{"title":"Uranium isotope systematics of a low-productivity ferruginous ocean analog: Implications for the uranium isotope record of early Earth","authors":"Geoffrey J. Gilleaudeau ,&nbsp;Xinming Chen ,&nbsp;Stephen J. Romaniello ,&nbsp;Sajjad A. Akam ,&nbsp;Chad Wittkop ,&nbsp;Sergei Katsev ,&nbsp;Ariel D. Anbar ,&nbsp;Elizabeth D. Swanner","doi":"10.1016/j.gca.2025.01.011","DOIUrl":"10.1016/j.gca.2025.01.011","url":null,"abstract":"<div><div>The uranium isotope (δ<sup>238</sup>U) paleo-redox proxy has emerged as a premier tool for understanding ocean oxygenation through Earth’s history. The fidelity of this important proxy depends, however, on our mechanistic understanding of the pathways that induce uranium isotope fractionation during U(VI) reduction to U(IV). Uranium reduction has been extensively studied in euxinic (anoxic + sulfidic) environments, yet relatively few constraints currently exist on δ<sup>238</sup>U fractionation in ferruginous (anoxic + iron-rich) environments, even though ferruginous conditions may have been a dominant feature of Earth’s oceans for much of the geologic past. Here, we present a comprehensive uranium isotope study of modern, meromictic, oligotrophic to mesotrophic, ferruginous Canyon Lake, Upper Peninsula, Michigan (USA), including investigation of a high-resolution profile of lake waters, lake inlet and outlet waters, and groundwater, as well as shallow cores through both oxic and ferruginous sediments. The key observation of this study is that the entire water column, oxic sediments, and ferruginous sediments have indistinguishable δ<sup>238</sup>U values near the composition of the upper continental crust. This implies a lack of δ<sup>238</sup>U fractionation in the low-productivity, ferruginous environments of Canyon Lake. We suggest that uranium cycling in Canyon Lake is dominated by adsorption and co-precipitation with iron oxides, with only a limited role for U(VI) reduction. These processes result partly from aqueous uranium speciation in the lake, with the dominance of UO<sub>2</sub>-CO<sub>3</sub> complexes in the upper water column leading to a high partition coefficient of uranium during sorption to iron oxides. In addition, the dominance of CaUO<sub>2</sub>(CO<sub>3</sub>)<sub>3</sub><sup>2–</sup> and Ca<sub>2</sub>UO<sub>2</sub>(CO<sub>3</sub>)<sub>3(aq)</sub> in bottom waters kinetically inhibits U(VI) reduction by Fe(II)<sub>(aq)</sub>. The lack of U(VI) reduction and hence δ<sup>238</sup>U fractionation in Canyon Lake, despite Fe(II)<sub>(aq)</sub> concentrations &gt;1.5 mM, is potentially analogous to the lack of δ<sup>238</sup>U fractionation that occurred in the Archean and Proterozoic oceans, as indicated by the carbonate δ<sup>238</sup>U record. In contrast with predictions that U(VI) should be rapidly reduced and scavenged from the water column in the presence of Fe(II)<sub>(aq)</sub>, our data suggest a limited role for U(VI) reduction and δ<sup>238</sup>U fractionation under the low-nutrient, low-productivity, ferruginous conditions that characterized the oceans on the early Earth.</div></div>","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"392 ","pages":"Pages 195-206"},"PeriodicalIF":4.5,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
NdPO4 solubility and aqueous Neodymium speciation in supercritical fluids: An experimental study at 500–700 °C and 1.7 kbar
IF 5 1区 地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-01-13 DOI: 10.1016/j.gca.2025.01.004
Debarati Banerjee, Laura E. Waters, Nicole C. Hurtig, Alexander P. Gysi, Daniel Harlov, Chen Zhu, Artaches Migdisov
A key aspect in the formation of rare earth elements (REE) deposits is the role of REE transport as aqueous REE complexes in supercritical hydrothermal solutions, where the nature of the aqueous complex is controlled by solution composition, temperature and pressure. Despite chloride being considered as one of the most abundant transporting ligands in magmatic-hydrothermal fluids, experimental investigations on the stability of aqueous REE chloride complexes are scarce above 300 °C. In this study, synthetic NdPO<ce:inf loc="post">4</ce:inf> crystals were reacted with non-saline and saline (0, 0.05 and 0.5 mNaCl), acidic (0.01 mHCl) aqueous solutions in a series of solubility experiments conducted at 500 − 700 °C and 1.7 kbar, where the solubilities were determined using a stable Nd isotope (<ce:sup loc="post">145</ce:sup>Nd isotope spike) dilution technique. NdPO<ce:inf loc="post">4</ce:inf> solubility ranges between 28 ppm and 10,858 ppm, where solubility increases with both temperature and salinity. At 500 °C, log mNdPO<ce:inf loc="post">4</ce:inf> increases from −3.93 to −1.60 and there is a strong correlation between NdPO<ce:inf loc="post">4</ce:inf> solubility and NaCl concentrations (slope of 1.2 ± 0.3), indicating stabilization of the Nd chloride aqueous complexes with a stoichiometry corresponding to NdCl<ce:sup loc="post">2+</ce:sup>. At 600 °C, this correlation is weaker (slope of 0.4, log mNdPO<ce:inf loc="post">4</ce:inf> increases from −2.63 to −1.88) indicating the stabilization of both Nd chloride and hydroxyl species controlling solubility. At 700 °C, NdPO<ce:inf loc="post">4</ce:inf> solubility is largely independent of NaCl concentration indicating that solubility is controlled by Nd hydroxyl complexes, where stoichiometry suggests the neutral Nd(OH)<ce:inf loc="post">3</ce:inf><ce:sup loc="post">0</ce:sup> species is dominant. The solubility product (<ce:italic>K</ce:italic><ce:inf loc="post">sp</ce:inf>) of NdPO<ce:inf loc="post">4</ce:inf> is derived from experimental data with the relation: log <ce:italic>K</ce:italic><ce:inf loc="post">sp</ce:inf> = -41.81 – 0.057<ce:italic>T</ce:italic> – 20987/<ce:italic>T</ce:italic>, with <ce:italic>T</ce:italic> temperature in Kelvin. Comparison of the measured Nd phosphate solubility to thermodynamic predictions using the available Helgeson-Kirkham-Flowers equation of state parameters for aqueous Nd complexes indicate that predictions are up to three orders of magnitude lower compared to experimental observations. This discrepancy is most pronounced in saline solutions, suggesting that thermodynamic properties of the REE chloride species in supercritical fluids require revision. Numerical simulations of fluid-rock interaction between acidic, saline fluids and a Strange Lake felsic mineral assemblage demonstrates that NdPO<ce:inf loc="post">4</ce:inf> solubility predictions from models are four to six orders of magnitude lower than those calculated based on empirical fits from experime
{"title":"NdPO4 solubility and aqueous Neodymium speciation in supercritical fluids: An experimental study at 500–700 °C and 1.7 kbar","authors":"Debarati Banerjee, Laura E. Waters, Nicole C. Hurtig, Alexander P. Gysi, Daniel Harlov, Chen Zhu, Artaches Migdisov","doi":"10.1016/j.gca.2025.01.004","DOIUrl":"https://doi.org/10.1016/j.gca.2025.01.004","url":null,"abstract":"A key aspect in the formation of rare earth elements (REE) deposits is the role of REE transport as aqueous REE complexes in supercritical hydrothermal solutions, where the nature of the aqueous complex is controlled by solution composition, temperature and pressure. Despite chloride being considered as one of the most abundant transporting ligands in magmatic-hydrothermal fluids, experimental investigations on the stability of aqueous REE chloride complexes are scarce above 300 °C. In this study, synthetic NdPO&lt;ce:inf loc=\"post\"&gt;4&lt;/ce:inf&gt; crystals were reacted with non-saline and saline (0, 0.05 and 0.5 mNaCl), acidic (0.01 mHCl) aqueous solutions in a series of solubility experiments conducted at 500 − 700 °C and 1.7 kbar, where the solubilities were determined using a stable Nd isotope (&lt;ce:sup loc=\"post\"&gt;145&lt;/ce:sup&gt;Nd isotope spike) dilution technique. NdPO&lt;ce:inf loc=\"post\"&gt;4&lt;/ce:inf&gt; solubility ranges between 28 ppm and 10,858 ppm, where solubility increases with both temperature and salinity. At 500 °C, log mNdPO&lt;ce:inf loc=\"post\"&gt;4&lt;/ce:inf&gt; increases from −3.93 to −1.60 and there is a strong correlation between NdPO&lt;ce:inf loc=\"post\"&gt;4&lt;/ce:inf&gt; solubility and NaCl concentrations (slope of 1.2 ± 0.3), indicating stabilization of the Nd chloride aqueous complexes with a stoichiometry corresponding to NdCl&lt;ce:sup loc=\"post\"&gt;2+&lt;/ce:sup&gt;. At 600 °C, this correlation is weaker (slope of 0.4, log mNdPO&lt;ce:inf loc=\"post\"&gt;4&lt;/ce:inf&gt; increases from −2.63 to −1.88) indicating the stabilization of both Nd chloride and hydroxyl species controlling solubility. At 700 °C, NdPO&lt;ce:inf loc=\"post\"&gt;4&lt;/ce:inf&gt; solubility is largely independent of NaCl concentration indicating that solubility is controlled by Nd hydroxyl complexes, where stoichiometry suggests the neutral Nd(OH)&lt;ce:inf loc=\"post\"&gt;3&lt;/ce:inf&gt;&lt;ce:sup loc=\"post\"&gt;0&lt;/ce:sup&gt; species is dominant. The solubility product (&lt;ce:italic&gt;K&lt;/ce:italic&gt;&lt;ce:inf loc=\"post\"&gt;sp&lt;/ce:inf&gt;) of NdPO&lt;ce:inf loc=\"post\"&gt;4&lt;/ce:inf&gt; is derived from experimental data with the relation: log &lt;ce:italic&gt;K&lt;/ce:italic&gt;&lt;ce:inf loc=\"post\"&gt;sp&lt;/ce:inf&gt; = -41.81 – 0.057&lt;ce:italic&gt;T&lt;/ce:italic&gt; – 20987/&lt;ce:italic&gt;T&lt;/ce:italic&gt;, with &lt;ce:italic&gt;T&lt;/ce:italic&gt; temperature in Kelvin. Comparison of the measured Nd phosphate solubility to thermodynamic predictions using the available Helgeson-Kirkham-Flowers equation of state parameters for aqueous Nd complexes indicate that predictions are up to three orders of magnitude lower compared to experimental observations. This discrepancy is most pronounced in saline solutions, suggesting that thermodynamic properties of the REE chloride species in supercritical fluids require revision. Numerical simulations of fluid-rock interaction between acidic, saline fluids and a Strange Lake felsic mineral assemblage demonstrates that NdPO&lt;ce:inf loc=\"post\"&gt;4&lt;/ce:inf&gt; solubility predictions from models are four to six orders of magnitude lower than those calculated based on empirical fits from experime","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"40 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The antimonite-thioantimonates-antimonate pathway: Insights from sulfidic hot springs and microbial culture experiments for a novel mechanism of abiotic antimonite oxidation 锑矿-硫锑酸盐-锑酸盐途径:硫化物温泉和微生物培养实验对非生物锑矿氧化新机制的见解
IF 5 1区 地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-01-12 DOI: 10.1016/j.gca.2025.01.007
Qinghai Guo, Junbiao Qian, Yu Li, Luxia Wang, Yue Meng, Britta Planer-Friedrich
Antimony speciation in natural waters is of great environmental significance, and mechanisms involved in antimonite oxidation have been a research hotspot during the past years. In the present study, a new antimonite oxidation mechanism, which could be responsible for occurrence of appreciable antimonate in sulfidic hot springs, was proposed. Within the investigated hydrothermal areas in the Yunnan-Sichuan-Tibet Geothermal Province, much more antimonate formed in the neutral to alkaline sulfidic hot springs with low EH values than in the acidic hot springs low in sulfide and with high EH values, and antimonite-oxidizing microorganisms were rare in both neutral to alkaline and acidic hot springs. Antimonite oxidation experiments designed according to the key hydrochemical and microbial parameters of these hot springs indicated that the antimonite oxidation rates were the highest under abiotic, anoxic and dark, and sulfidic conditions and at pH 10, and there was a significant positive relationship between the proportions of antimonate and thioantimonates in the experimental solutions. Moreover, antimonite was oxidized only to a quite low degree even under microbial culture conditions with microorganisms-bearing hot spring sediments being used. These results implied that the antimonite oxidation in the sulfidic hot springs could occur via thiolation of antimonite followed by further transformation of thioantimonates into antimonate. This antimonite-thioantimonates-antimonate pathway may be prevalent in some other sulfidic environments, like paddy soils, mining areas, or euxinic basins.
天然水体中锑的形成具有重要的环境意义,锑矿氧化机制是近年来研究的热点。本研究提出了一种新的锑矿氧化机制,该机制可能是硫化物温泉中产生可观锑酸盐的原因。在云南-川藏地热省热液区,低EH值的中性-碱性硫化物温泉中锑酸盐的形成明显多于高EH值的低硫化物酸性温泉,且在中性-碱性和酸性温泉中锑氧化微生物较少。根据这些温泉的关键水化学和微生物参数设计的锑矿氧化实验表明,在非生物、缺氧暗、硫化物和pH 10条件下,锑矿氧化率最高,且实验溶液中锑酸盐和硫锑酸盐的比例呈显著正相关。此外,即使在微生物培养条件下,使用含微生物的温泉沉积物,锑矿也只被氧化到很低的程度。这些结果表明,硫化物温泉中锑矿的氧化可能是通过硫代硫代锑酸盐转化为锑酸盐而发生的。这种锑矿-硫锑酸盐-锑酸盐途径可能普遍存在于其他一些硫化物环境中,如水稻土、矿区或含氧盆地。
{"title":"The antimonite-thioantimonates-antimonate pathway: Insights from sulfidic hot springs and microbial culture experiments for a novel mechanism of abiotic antimonite oxidation","authors":"Qinghai Guo, Junbiao Qian, Yu Li, Luxia Wang, Yue Meng, Britta Planer-Friedrich","doi":"10.1016/j.gca.2025.01.007","DOIUrl":"https://doi.org/10.1016/j.gca.2025.01.007","url":null,"abstract":"Antimony speciation in natural waters is of great environmental significance, and mechanisms involved in antimonite oxidation have been a research hotspot during the past years. In the present study, a new antimonite oxidation mechanism, which could be responsible for occurrence of appreciable antimonate in sulfidic hot springs, was proposed. Within the investigated hydrothermal areas in the Yunnan-Sichuan-Tibet Geothermal Province, much more antimonate formed in the neutral to alkaline sulfidic hot springs with low E<ce:inf loc=\"post\">H</ce:inf> values than in the acidic hot springs low in sulfide and with high E<ce:inf loc=\"post\">H</ce:inf> values, and antimonite-oxidizing microorganisms were rare in both neutral to alkaline and acidic hot springs. Antimonite oxidation experiments designed according to the key hydrochemical and microbial parameters of these hot springs indicated that the antimonite oxidation rates were the highest under abiotic, anoxic and dark, and sulfidic conditions and at pH 10, and there was a significant positive relationship between the proportions of antimonate and thioantimonates in the experimental solutions. Moreover, antimonite was oxidized only to a quite low degree even under microbial culture conditions with microorganisms-bearing hot spring sediments being used. These results implied that the antimonite oxidation in the sulfidic hot springs could occur via thiolation of antimonite followed by further transformation of thioantimonates into antimonate. This antimonite-thioantimonates-antimonate pathway may be prevalent in some other sulfidic environments, like paddy soils, mining areas, or euxinic basins.","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"25 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Revealing atomistic mechanism of lithium diffusion in montmorillonite structure: A molecular simulation study 揭示锂在蒙脱土结构中扩散的原子机制:分子模拟研究
IF 4.5 1区 地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-01-12 DOI: 10.1016/j.gca.2025.01.008
Qin Li , Xiandong Liu , Kai Wang , Yongxian Cheng , Zhe Yin , Rucheng Wang , Xiancai Lu
The Li-bearing clays have attracted increasing attention as an important resource for lithium (Li) recovery. But the mobility of Li in clay lattice structure remains unclear, which hinders understanding of Li enrichment in Li deposits and technical development of Li extraction from Li-bearing claystones. In this study, we employed molecular simulations to investigate Li+ diffusion between different sites in the montmorillonite lattice. The calculation indicates that Li+ diffusion from the montmorillonite interlayer space to the vacant octahedral site occurs on a time scale of hours at 200 °C, which well agrees with the available Hofmann-Klemen effect. Our results also reveal that isomorphic substitution plays an important role in the Hofmann-Klemen effect. At temperatures up to 200 °C, the structure of montmorillonite with octahedral substitutions collapses due to the diffusion of almost all of the interlayer Li+ into the octahedral sheets, whereas montmorillonite bearing tetrahedral substitutions could maintain 28 % Li+ in the interlayer and thus the interlayer space can be well kept. Heating the montmorillonite to 300 °C in a water vapor environment causes Li+ to reversibly diffuse out of the octahedral sheets. Besides, the dehydroxylation of montmorillonite significantly lowers the activation energy barrier of Li+ diffusion between the octahedral layer and the interlayer. The disclosed diffusion of Li in montmorillonite may partially explain the Li enrichment in Li-bearing claystone, such as swinfordite. The revealed Li+ diffusion mechanism in montmorillonite may also help design and improve the technology of extracting Li from Li-bearing clays.
含锂粘土作为一种重要的锂回收资源越来越受到人们的关注。但锂在粘土晶格结构中的迁移特性尚不清楚,这阻碍了对矿床中锂富集的认识和含锂粘土提锂技术的发展。在这项研究中,我们采用分子模拟来研究Li+在蒙脱土晶格中不同位置之间的扩散。计算结果表明,在200℃时,Li+从蒙脱土层间空间扩散到空的八面体位置发生在小时的时间尺度上,这与可用的Hofmann-Klemen效应很好地吻合。我们的研究结果还揭示了同构取代在Hofmann-Klemen效应中起着重要作用。当温度高达200℃时,具有八面体取代的蒙脱土由于层间几乎所有的Li+都扩散到八面体片中而结构崩溃,而具有四面体取代的蒙脱土可以在层间保持28%的Li+,从而可以很好地保持层间空间。在水蒸气环境下将蒙脱土加热到300℃,会导致Li+可逆地从八面体薄片中扩散出去。此外,蒙脱土的脱羟基作用显著降低了Li+在八面体层和层间扩散的活化能垒。锂在蒙脱石中的明显扩散可能部分解释了含锂粘土(如硅长石)中锂的富集。所揭示的Li+在蒙脱土中的扩散机制也有助于设计和改进从含锂粘土中提取Li的工艺。
{"title":"Revealing atomistic mechanism of lithium diffusion in montmorillonite structure: A molecular simulation study","authors":"Qin Li ,&nbsp;Xiandong Liu ,&nbsp;Kai Wang ,&nbsp;Yongxian Cheng ,&nbsp;Zhe Yin ,&nbsp;Rucheng Wang ,&nbsp;Xiancai Lu","doi":"10.1016/j.gca.2025.01.008","DOIUrl":"10.1016/j.gca.2025.01.008","url":null,"abstract":"<div><div>The Li-bearing clays have attracted increasing attention as an important resource for lithium (Li) recovery. But the mobility of Li in clay lattice structure remains unclear, which hinders understanding of Li enrichment in Li deposits and technical development of Li extraction from Li-bearing claystones. In this study, we employed molecular simulations to investigate Li<sup>+</sup> diffusion between different sites in the montmorillonite lattice. The calculation indicates that Li<sup>+</sup> diffusion from the montmorillonite interlayer space to the vacant octahedral site occurs on a time scale of hours at 200 °C, which well agrees with the available Hofmann-Klemen effect. Our results also reveal that isomorphic substitution plays an important role in the Hofmann-Klemen effect. At temperatures up to 200 °C, the structure of montmorillonite with octahedral substitutions collapses due to the diffusion of almost all of the interlayer Li<sup>+</sup> into the octahedral sheets, whereas montmorillonite bearing tetrahedral substitutions could maintain 28 % Li<sup>+</sup> in the interlayer and thus the interlayer space can be well kept. Heating the montmorillonite to 300 °C in a water vapor environment causes Li<sup>+</sup> to reversibly diffuse out of the octahedral sheets. Besides, the dehydroxylation of montmorillonite significantly lowers the activation energy barrier of Li<sup>+</sup> diffusion between the octahedral layer and the interlayer. The disclosed diffusion of Li in montmorillonite may partially explain the Li enrichment in Li-bearing claystone, such as swinfordite. The revealed Li<sup>+</sup> diffusion mechanism in montmorillonite may also help design and improve the technology of extracting Li from Li-bearing clays.</div></div>","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"392 ","pages":"Pages 165-174"},"PeriodicalIF":4.5,"publicationDate":"2025-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A chondritic Martian mantle revealed by the heavy noble gas composition of the chassignite NWA 8694 由chassignite NWA 8694的重惰性气体组成揭示的粒状火星地幔
IF 4.5 1区 地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-01-11 DOI: 10.1016/j.gca.2025.01.002
Sandrine Péron, Sujoy Mukhopadhyay
Accretion of volatile elements is a critical step to make a planet habitable. It is often assumed that terrestrial planets initially captured solar gases from the nebula, which are partially ingassed into their interior during the magma ocean phase, and then chondritic and/or cometary volatiles are delivered during the main accretion phase or after. Recent krypton isotopic measurements of the Martian meteorite Chassigny have however shown that chondritic volatiles were acquired on Mars in the first Myr of Solar System formation before nebular capture. Yet, Martian mantle is heterogeneous, with multiple reservoirs as evidenced with the hydrogen isotopic composition of shergottites, and it is unclear if this is also the case for noble gases. In this study, we investigate the noble gas (Ne, Ar, Kr, Xe) isotopic and elemental composition of the chassignite NWA 8694, which constitutes a link between chassignites and nakhlites, via laser step-heating in order to assess potential heterogeneities of the Martian mantle. Similar to Chassigny, we found evidence for high Ar, Kr and Xe abundances, potentially at least one order of magnitude higher than in the Earth’s mantle, in the NWA 8694 mantle source based on a low 40Ar/36Ar ratio. We also found a chondritic component and a Martian atmospheric component in NWA 8694, the latter with fractionated Ar/Kr/Xe elemental ratios compared to Mars’ atmosphere. This Martian atmosphere component was possibly introduced through aqueous alteration by surface fluids, as observed in MIL nakhlites. The chondritic component corresponds to the composition of the NWA 8694 mantle source and hence confirms previous observation in Chassigny. A chondritic Martian mantle is in stark contrast with the presence of solar Kr and Xe in the Martian atmosphere. This suggests that chondritic volatiles were delivered to terrestrial planets in the first Myr of Solar System formation in presence of the nebula. Solar gases in the atmosphere could have been captured from the nebula afterwards or delivered by material similar to comets. If captured from the nebula, it would require the solar gases to be trapped either in polar ice caps or the regolith so as not to be lost via hydrodynamic escape after the nebula dissipates. Alternatively, delivery of solar gases associated with comets could occur after cessation of hydrodynamic escape on Mars, but the one comet (67P/C-G) that has been measured so far does not show a pure solar-like Xe and Kr isotopic composition.
挥发性元素的吸积是使行星适宜居住的关键步骤。通常认为,类地行星最初从星云中捕获太阳气体,这些气体在岩浆海洋阶段部分进入它们的内部,然后在主要吸积阶段或之后,球粒陨石和/或彗星挥发物被释放出来。然而,最近对火星陨石Chassigny的氪同位素测量表明,在星云捕获之前,在太阳系形成的第一个Myr中,火星上获得了球粒状挥发物。然而,火星的地幔是不均匀的,有多个储层,这一点可以从shergotites的氢同位素组成中得到证明,目前还不清楚稀有气体是否也是如此。为了评估火星地幔的潜在非均质性,我们采用激光分步加热的方法,研究了构成chassignites和nakhites之间联系的chassignites NWA 8694的稀有气体(Ne, Ar, Kr, Xe)同位素和元素组成。与Chassigny类似,我们在NWA 8694地幔源中发现了高Ar, Kr和Xe丰度的证据,可能至少比地球的地幔高出一个数量级,基于低40Ar/36Ar比率。我们还在NWA 8694中发现了球粒成分和火星大气成分,后者与火星大气相比具有分馏的Ar/Kr/Xe元素比例。这一火星大气成分可能是通过地表流体的含水蚀变引入的,正如在MIL硅石中观察到的那样。球粒成分与NWA 8694地幔源的组成相对应,证实了Chassigny的观测结果。火星的球粒质地幔与火星大气中存在的太阳氪和氙形成鲜明对比。这表明在星云存在的情况下,球粒质挥发物在太阳系形成的第一个Myr时期被运送到类地行星上。大气中的太阳气体可能是后来从星云中捕获的,或者是由类似彗星的物质输送的。如果从星云中捕获,则需要将太阳气体捕获在极地冰盖或风化层中,以便在星云消散后不会通过流体动力学逃逸而丢失。另外,与彗星相关的太阳气体的输送可能发生在火星上流体动力学逸出停止之后,但迄今为止测量到的一颗彗星(67P/C-G)并没有显示出类似太阳的纯Xe和Kr同位素组成。
{"title":"A chondritic Martian mantle revealed by the heavy noble gas composition of the chassignite NWA 8694","authors":"Sandrine Péron,&nbsp;Sujoy Mukhopadhyay","doi":"10.1016/j.gca.2025.01.002","DOIUrl":"10.1016/j.gca.2025.01.002","url":null,"abstract":"<div><div>Accretion of volatile elements is a critical step to make a planet habitable. It is often assumed that terrestrial planets initially captured solar gases from the nebula, which are partially ingassed into their interior during the magma ocean phase, and then chondritic and/or cometary volatiles are delivered during the main accretion phase or after. Recent krypton isotopic measurements of the Martian meteorite Chassigny have however shown that chondritic volatiles were acquired on Mars in the first Myr of Solar System formation before nebular capture. Yet, Martian mantle is heterogeneous, with multiple reservoirs as evidenced with the hydrogen isotopic composition of shergottites, and it is unclear if this is also the case for noble gases. In this study, we investigate the noble gas (Ne, Ar, Kr, Xe) isotopic and elemental composition of the chassignite NWA 8694, which constitutes a link between chassignites and nakhlites, via laser step-heating in order to assess potential heterogeneities of the Martian mantle. Similar to Chassigny, we found evidence for high Ar, Kr and Xe abundances, potentially at least one order of magnitude higher than in the Earth’s mantle, in the NWA 8694 mantle source based on a low <sup>40</sup>Ar/<sup>36</sup>Ar ratio. We also found a chondritic component and a Martian atmospheric component in NWA 8694, the latter with fractionated Ar/Kr/Xe elemental ratios compared to Mars’ atmosphere. This Martian atmosphere component was possibly introduced through aqueous alteration by surface fluids, as observed in MIL nakhlites. The chondritic component corresponds to the composition of the NWA 8694 mantle source and hence confirms previous observation in Chassigny. A chondritic Martian mantle is in stark contrast with the presence of solar Kr and Xe in the Martian atmosphere. This suggests that chondritic volatiles were delivered to terrestrial planets in the first Myr of Solar System formation in presence of the nebula. Solar gases in the atmosphere could have been captured from the nebula afterwards or delivered by material similar to comets. If captured from the nebula, it would require the solar gases to be trapped either in polar ice caps or the regolith so as not to be lost via hydrodynamic escape after the nebula dissipates. Alternatively, delivery of solar gases associated with comets could occur after cessation of hydrodynamic escape on Mars, but the one comet (67P/C-G) that has been measured so far does not show a pure solar-like Xe and Kr isotopic composition.</div></div>","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"392 ","pages":"Pages 137-147"},"PeriodicalIF":4.5,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Mn(II)-induced phase transformation of Mn(IV) oxide in seawater
IF 5 1区 地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-01-11 DOI: 10.1016/j.gca.2025.01.014
Peng Yang, Ke Wen, Kevin A. Beyer, Wenqian Xu, Mengqiang Zhu
Manganese (Mn) oxides are key components of oceanic and lacustrine Mn nodules and influence metal cycling through oxidation and adsorption processes. Layered Mn oxides (LMOs) are the most common minerals in these nodules and the immediate products of microbially mediated Mn(II) oxidation by O<ce:inf loc="post">2</ce:inf>. LMOs can transform into tunneled Mn oxides (TMOs), Mn oxyhydroxides (MnOOH), or Mn(II,III) phase (Mn<ce:inf loc="post">3</ce:inf>O<ce:inf loc="post">4</ce:inf>). LMOs often concur with Mn(II) in the environment and the adsorption and oxidation of Mn(II) by LMOs can greatly promote the transformation of LMOs to those phases. However, the Mn(II)-promoted transformation of LMOs in seawater—rich in various cations (300 mM Na<ce:sup loc="post">+</ce:sup>, 10 mM K<ce:sup loc="post">+</ce:sup>, 50 mM Ca<ce:sup loc="post">2+</ce:sup>, and 10 mM Mg<ce:sup loc="post">2+</ce:sup>) remains poorly understood. We examined the transformation of δ-MnO<ce:inf loc="post">2</ce:inf> in artificial seawater (pH 8.2) under anoxic conditions with the Mn(II)/MnO<ce:inf loc="post">2</ce:inf> ratio (r) ranging from 0.08 to 3.83. To assess the effect of ionic strength (IS), parallel experiments were conducted in a mixed 530 mM NaCl and 10 mM KCl solution (having seawater ionic strength but without Ca<ce:sup loc="post">2+</ce:sup> and Mg<ce:sup loc="post">2+</ce:sup>) and in 100 mM NaCl solution as a control. At low r (0.08), δ-MnO<ce:inf loc="post">2</ce:inf> transformed into triclinic birnessite and a 4 × 4 TMO in 100 mM NaCl solution, which, however, was suppressed in seawater due to strong interactions of Ca<ce:sup loc="post">2+</ce:sup>/Mg<ce:sup loc="post">2+</ce:sup> with δ-MnO<ce:inf loc="post">2</ce:inf>. In the mixed 530 mM NaCl and 10 mM KCl solution (the same ionic strength as of seawater), the transformation occurred extensively but the products had lower crystallinity compared to in 100 mM NaCl solution. At the high Mn(II)/MnO<ce:inf loc="post">2</ce:inf> ratios (0.5 ≤ r ≤ 3.83), δ-MnO<ce:inf loc="post">2</ce:inf> transformed extensively into MnOOH phases and hausmannite (Mn<ce:inf loc="post">3</ce:inf>O<ce:inf loc="post">4</ce:inf>) in 100 mM NaCl solution. The seawater suppressed the transformation, but the suppression became weaker with increasing Mn(II)/MnO<ce:inf loc="post">2</ce:inf> ratio. For example, the transformation was completely suppressed at r = 0.5 but essentially negligible at r = 3.83. The suppression at these high Mn(II)/MnO<ce:inf loc="post">2</ce:inf> ratios was mainly ascribed to the influence of Ca<ce:sup loc="post">2+</ce:sup> and Mg<ce:sup loc="post">2+</ce:sup> rather than of the high IS, and the weaker suppression at the higher Mn(II)/MnO<ce:inf loc="post">2</ce:inf> ratio suggests stronger competition of Mn(II) with Ca<ce:sup loc="post">2+</ce:sup>/Mg<ce:sup loc="post">2+</ce:sup> for interacting with δ-MnO<ce:inf loc="post">2</ce:inf>. Moreover, the composition and crystallinity of the transformation products (i.e
锰(Mn)氧化物是海洋和湖泊锰结核的主要成分,通过氧化和吸附过程影响金属循环。层状锰氧化物(LMOs)是这些结核中最常见的矿物,也是微生物介导的二氧化锰(Mn(II))氧化作用的直接产物。层锰氧化物可转化为隧道锰氧化物(TMOs)、锰氧氢氧化物(MnOOH)或锰(II,III)相(Mn3O4)。环境中的 LMO 常与 Mn(II)同时存在,LMO 对 Mn(II)的吸附和氧化可极大地促进 LMO 向这些相的转化。然而,在富含各种阳离子(300 mM Na+、10 mM K+、50 mM Ca2+和10 mM Mg2+)的海水中,Mn(II)促进LMOs转化的情况仍然鲜为人知。我们研究了人工海水(pH 值为 8.2)中δ-MnO2 在缺氧条件下的转化情况,Mn(II)/MnO2 的比率(r)从 0.08 到 3.83 不等。为评估离子强度(IS)的影响,在 530 mM NaCl 和 10 mM KCl 混合溶液(具有海水离子强度,但不含 Ca2+ 和 Mg2+)和 100 mM NaCl 溶液(作为对照)中进行了平行实验。当 r 值较低时(0.08),δ-MnO2 在 100 mM NaCl 溶液中转化为三菱菱锰矿和 4 × 4 TMO,但在海水中由于 Ca2+/Mg2+ 与δ-MnO2 的强相互作用而被抑制。在 530 mM NaCl 和 10 mM KCl 混合溶液(与海水的离子强度相同)中,发生了广泛的转化,但与 100 mM NaCl 溶液相比,产物的结晶度较低。当 Mn(II)/MnO2 的比率较高时(0.5 ≤ r ≤ 3.83),δ-MnO2 在 100 mM NaCl 溶液中广泛转化为 MnOOH 相和霞石(Mn3O4)。海水抑制了转化,但随着 Mn(II)/MnO2 比率的增加,抑制作用减弱。例如,在 r = 0.5 时,转化被完全抑制,但在 r = 3.83 时,转化基本上可以忽略不计。在这些高 Mn(II)/MnO2 比率下的抑制作用主要归因于 Ca2+ 和 Mg2+ 的影响,而不是高 IS 的影响;在较高 Mn(II)/MnO2 比率下的抑制作用较弱,这表明 Mn(II) 与 Ca2+/Mg2+ 在与δ-MnO2 相互作用方面的竞争更激烈。此外,转化产物的组成和结晶度(即 MnOOH(α、β 和 γ)和 Mn3O4 的相对丰度)受到高离子强度以及 Ca2+ 和 Mg2+ 存在的影响。因此,尽管海水中 Ca2+ 和 Mg2+ 的浓度远低于 Na+,但它们对转化的影响却是主要的。我们的研究解释了为什么在海洋环境中 MnOOH 相、霞石和 TMO 不如 LMO 常见,部分原因是海水化学抑制了它们的形成。在所有锰氧化物中,LMOs 的金属吸附和氧化活性最高。因此,LMOs 在海洋环境中的高稳定性使锰氧化物对海洋中的金属循环产生了很大影响。
{"title":"Mn(II)-induced phase transformation of Mn(IV) oxide in seawater","authors":"Peng Yang, Ke Wen, Kevin A. Beyer, Wenqian Xu, Mengqiang Zhu","doi":"10.1016/j.gca.2025.01.014","DOIUrl":"https://doi.org/10.1016/j.gca.2025.01.014","url":null,"abstract":"Manganese (Mn) oxides are key components of oceanic and lacustrine Mn nodules and influence metal cycling through oxidation and adsorption processes. Layered Mn oxides (LMOs) are the most common minerals in these nodules and the immediate products of microbially mediated Mn(II) oxidation by O&lt;ce:inf loc=\"post\"&gt;2&lt;/ce:inf&gt;. LMOs can transform into tunneled Mn oxides (TMOs), Mn oxyhydroxides (MnOOH), or Mn(II,III) phase (Mn&lt;ce:inf loc=\"post\"&gt;3&lt;/ce:inf&gt;O&lt;ce:inf loc=\"post\"&gt;4&lt;/ce:inf&gt;). LMOs often concur with Mn(II) in the environment and the adsorption and oxidation of Mn(II) by LMOs can greatly promote the transformation of LMOs to those phases. However, the Mn(II)-promoted transformation of LMOs in seawater—rich in various cations (300 mM Na&lt;ce:sup loc=\"post\"&gt;+&lt;/ce:sup&gt;, 10 mM K&lt;ce:sup loc=\"post\"&gt;+&lt;/ce:sup&gt;, 50 mM Ca&lt;ce:sup loc=\"post\"&gt;2+&lt;/ce:sup&gt;, and 10 mM Mg&lt;ce:sup loc=\"post\"&gt;2+&lt;/ce:sup&gt;) remains poorly understood. We examined the transformation of δ-MnO&lt;ce:inf loc=\"post\"&gt;2&lt;/ce:inf&gt; in artificial seawater (pH 8.2) under anoxic conditions with the Mn(II)/MnO&lt;ce:inf loc=\"post\"&gt;2&lt;/ce:inf&gt; ratio (r) ranging from 0.08 to 3.83. To assess the effect of ionic strength (IS), parallel experiments were conducted in a mixed 530 mM NaCl and 10 mM KCl solution (having seawater ionic strength but without Ca&lt;ce:sup loc=\"post\"&gt;2+&lt;/ce:sup&gt; and Mg&lt;ce:sup loc=\"post\"&gt;2+&lt;/ce:sup&gt;) and in 100 mM NaCl solution as a control. At low r (0.08), δ-MnO&lt;ce:inf loc=\"post\"&gt;2&lt;/ce:inf&gt; transformed into triclinic birnessite and a 4 × 4 TMO in 100 mM NaCl solution, which, however, was suppressed in seawater due to strong interactions of Ca&lt;ce:sup loc=\"post\"&gt;2+&lt;/ce:sup&gt;/Mg&lt;ce:sup loc=\"post\"&gt;2+&lt;/ce:sup&gt; with δ-MnO&lt;ce:inf loc=\"post\"&gt;2&lt;/ce:inf&gt;. In the mixed 530 mM NaCl and 10 mM KCl solution (the same ionic strength as of seawater), the transformation occurred extensively but the products had lower crystallinity compared to in 100 mM NaCl solution. At the high Mn(II)/MnO&lt;ce:inf loc=\"post\"&gt;2&lt;/ce:inf&gt; ratios (0.5 ≤ r ≤ 3.83), δ-MnO&lt;ce:inf loc=\"post\"&gt;2&lt;/ce:inf&gt; transformed extensively into MnOOH phases and hausmannite (Mn&lt;ce:inf loc=\"post\"&gt;3&lt;/ce:inf&gt;O&lt;ce:inf loc=\"post\"&gt;4&lt;/ce:inf&gt;) in 100 mM NaCl solution. The seawater suppressed the transformation, but the suppression became weaker with increasing Mn(II)/MnO&lt;ce:inf loc=\"post\"&gt;2&lt;/ce:inf&gt; ratio. For example, the transformation was completely suppressed at r = 0.5 but essentially negligible at r = 3.83. The suppression at these high Mn(II)/MnO&lt;ce:inf loc=\"post\"&gt;2&lt;/ce:inf&gt; ratios was mainly ascribed to the influence of Ca&lt;ce:sup loc=\"post\"&gt;2+&lt;/ce:sup&gt; and Mg&lt;ce:sup loc=\"post\"&gt;2+&lt;/ce:sup&gt; rather than of the high IS, and the weaker suppression at the higher Mn(II)/MnO&lt;ce:inf loc=\"post\"&gt;2&lt;/ce:inf&gt; ratio suggests stronger competition of Mn(II) with Ca&lt;ce:sup loc=\"post\"&gt;2+&lt;/ce:sup&gt;/Mg&lt;ce:sup loc=\"post\"&gt;2+&lt;/ce:sup&gt; for interacting with δ-MnO&lt;ce:inf loc=\"post\"&gt;2&lt;/ce:inf&gt;. Moreover, the composition and crystallinity of the transformation products (i.e","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"10 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143055251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
High-precision SIMS analyses of initial 26Al/27Al in un-melted refractory inclusions: The search for multiple condensation episodes 未熔化的难熔夹杂物中初始26Al/27Al的高精度SIMS分析:寻找多重冷凝事件
IF 4.5 1区 地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-01-08 DOI: 10.1016/j.gca.2025.01.001
Glenn J. MacPherson , Alexander N. Krot , Kazuhide Nagashima , Marina Ivanova
Refractory inclusions formed via high temperature events during the earliest stages of the solar system evolution. Studies of short-lived radionuclide systems in the inclusions provide constraints on the timing and nature of these thermal events. High-precision SIMS data for initial 26Al/27Al ratio [(26Al/27Al)0] in a suite of seven un-melted refractory inclusions (fine-grained spinel-rich and Fluffy Type A CAIs) from CV (Vigarano type) carbonaceous chondrites – which we interpret as primary nebular condensates or their very close derivatives – yield six values close to the canonical ratio of 5.2 × 10−5 and one marginally lower but still almost within error of 5.0 × 10–5. We specifically looked for but did not find much lower values like those reported recently by Kawasaki et al. (2020), as low as 3.4 × 10–5. Interpreted in terms of chronology, the accumulated high precision data acquired by us and others within the past 15 years for normal, 26Al-rich CAIs show no evidence for a significant condensation event that would correspond to (26Al/27Al)0 of (3–4) × 10–5. Rather, there appears to have been one major thermal event resulting in extensive evaporation and condensation in the CAI-forming region corresponding to (26Al/27Al)0 of 5.2 × 10–5 resulting in formation of most normal refractory inclusion precursors. Subsequent smaller events over the succeeding ∼200,000 years caused thermal modification and melting of many of them. Inclusions such as that studied by Kawasaki et al. (2020) could have formed either in an early event prior to significant isotopic mixing in the CAI-forming region, or later than most refractory inclusions during a thermal event that is not well represented in the meteorite record. Refractory inclusions characterized by low (26Al/27Al)0, <1 × 10–5, such as FUN (Fractionation and Unidentified Nuclear effects) inclusions, PLACs (Platy Hibonite Crystals), and some corundum-, hibonite-, and grossite-rich CAIs formed during a much earlier heating event, likely prior to homogenization of 26Al in the early solar system. The initial 26Al/27Al values of such objects provide no quantitative chronological constraints.
在太阳系演化的早期阶段,高温事件形成的难熔包裹体。包裹体中短寿命放射性核素系统的研究为这些热事件的时间和性质提供了限制。来自CV (Vigarano型)碳质球粒陨石的7个未熔化的难熔夹杂物(细晶富尖晶石和蓬松型a CAIs)的初始26Al/27Al比值[(26Al/27Al)0]的高精度SIMS数据(我们将其解释为初级星云凝聚物或其非常接近的衍生物)得出了6个接近5.2 × 10 - 5的标准比值,1个略低,但仍几乎在5.0 × 10 - 5的误差范围内。我们专门寻找但没有发现像Kawasaki等人(2020)最近报道的低得多的值,低至3.4 × 10-5。从年代学的角度来看,我们和其他人在过去15年中积累的高精度数据显示,正常的富26Al CAIs没有明显的凝结事件,对应于(3-4)× 10-5的(26Al/27Al)0。相反,在(26Al/27Al)0 = 5.2 × 10-5的cai形成区,似乎发生了一次主要的热事件,导致了广泛的蒸发和冷凝,从而形成了大多数正常的难熔包体前体。在随后的~ 20万年里,随后发生的较小的事件导致了许多冰川的热变质和融化。Kawasaki等人(2020)研究的包裹体可能形成于cai形成区域中显著同位素混合之前的早期事件中,或者在陨石记录中没有很好地代表的热事件中,比大多数难熔包裹体更晚。以低(26Al/27Al)0, <;1 × 10-5为特征的难熔包裹体,如FUN(分选和未识别的核效应)包裹体,PLACs(片状Hibonite晶体),以及一些刚玉,Hibonite和富含粗石的cai形成于更早的加热事件中,可能在早期太阳系26Al均质化之前形成。这些物体的初始26Al/27Al值没有提供定量的时间限制。
{"title":"High-precision SIMS analyses of initial 26Al/27Al in un-melted refractory inclusions: The search for multiple condensation episodes","authors":"Glenn J. MacPherson ,&nbsp;Alexander N. Krot ,&nbsp;Kazuhide Nagashima ,&nbsp;Marina Ivanova","doi":"10.1016/j.gca.2025.01.001","DOIUrl":"10.1016/j.gca.2025.01.001","url":null,"abstract":"<div><div>Refractory inclusions formed via high temperature events during the earliest stages of the solar system evolution. Studies of short-lived radionuclide systems in the inclusions provide constraints on the timing and nature of these thermal events. High-precision SIMS data for initial <sup>26</sup>Al/<sup>27</sup>Al ratio [(<sup>26</sup>Al/<sup>27</sup>Al)<sub>0</sub>] in a suite of seven un-melted refractory inclusions (fine-grained spinel-rich and Fluffy Type A CAIs) from CV (Vigarano type) carbonaceous chondrites – which we interpret as primary nebular condensates or their very close derivatives – yield six values close to the canonical ratio of 5.2 × 10<sup>−5</sup> and one marginally lower but still almost within error of 5.0 × 10<sup>–5</sup>. We specifically looked for but did not find much lower values like those reported recently by <span><span>Kawasaki et al. (2020)</span></span>, as low as 3.4 × 10<sup>–5</sup>. Interpreted in terms of chronology, the accumulated high precision data acquired by us and others within the past 15 years for normal, <sup>26</sup>Al-rich CAIs show no evidence for a significant condensation event that would correspond to (<sup>26</sup>Al/<sup>27</sup>Al)<sub>0</sub> of (3–4) × 10<sup>–5</sup>. Rather, there appears to have been one major thermal event resulting in extensive evaporation and condensation in the CAI-forming region corresponding to (<sup>26</sup>Al/<sup>27</sup>Al)<sub>0</sub> of 5.2 × 10<sup>–5</sup> resulting in formation of most normal refractory inclusion precursors. Subsequent smaller events over the succeeding ∼200,000 years caused thermal modification and melting of many of them. Inclusions such as that studied by <span><span>Kawasaki et al. (2020)</span></span> could have formed either in an early event prior to significant isotopic mixing in the CAI-forming region, or later than most refractory inclusions during a thermal event that is not well represented in the meteorite record. Refractory inclusions characterized by low (<sup>26</sup>Al/<sup>27</sup>Al)<sub>0</sub>, &lt;1 × 10<sup>–5</sup>, such as FUN (Fractionation and Unidentified Nuclear effects) inclusions, PLACs (Platy Hibonite Crystals), and some corundum-, hibonite-, and grossite-rich CAIs formed during a much earlier heating event, likely prior to homogenization of <sup>26</sup>Al in the early solar system. The initial <sup>26</sup>Al/<sup>27</sup>Al values of such objects provide no quantitative chronological constraints.</div></div>","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"391 ","pages":"Pages 291-311"},"PeriodicalIF":4.5,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The chemical and isotopic characterization of the pyrite to pyrrhotite desulfidation reaction across the metamorphic gradient of a metasedimentary basin 变质沉积盆地中黄铁矿-磁黄铁矿脱硫反应的化学和同位素特征
IF 4.5 1区 地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2025-01-03 DOI: 10.1016/j.gca.2024.12.027
Bruna Coldebella , Crystal LaFlamme , Isaac S. Malta , Carl Guilmette , Guillaume Barré , Georges Beaudoin , Laure Martin , Dany Savard
During prograde metamorphism, sulfur is released through the pyrite to pyrrhotite desulfidation reaction. This process is believed to supply sulfur and metals to metamorphic fluids, potentially contributing to the formation of orogenic gold deposits. A deeper understanding of this reaction can therefore help unravel the mobility of sulfur, gold and other metals in metamorphic fluids during prograde metamorphism. We present a novel in situ study of multiple sulfur isotopes combined with trace elements, focused on the texturally-constrained pyrite to pyrrhotite desulfidation reaction. This reaction is documented in detail along a prograde, Barrovian metamorphic field gradient − increasing from the biotite through the garnet, staurolite, and sillimanite zones − recorded in the Pontiac Group metasedimentary sequence, which is fault-bound to the southern Abitibi Subprovince and its orogenic gold deposits. The prograde pyrite to pyrrhotite reaction texture, where pyrrhotite (Po) replaces corroded pyrite (Py1), is identified in rocks from the biotite and garnet metamorphic zones. Py1 and Po coexist in the staurolite zone without a clear textural relationship, and past the sillimanite isograd, Py1 is completely absent with Po in abundance. Py1 and/or Po are replaced by euhedral to subhedral, inclusion-free, late/retrograde pyrite (Py2) in all metamorphic zones. In situ trace element analysis of the sulfide assemblage reveals a decrease, with increasing metamorphic grade, in metal contents such as Au, Ag, Te, Bi, and Se, associated with the prograde replacement of Py1 by Po. Arsenic and Co are preserved and enriched in Py2, while Ni is concentrated in Po, and Cu is redistributed to chalcopyrite. In situ, multiple sulfur isotope analyses show no analytically distinguishable fractionation (δ34S shift of −0.1‰ ± 0.9 and a Δ33S shift of +0.06‰ ± 0.17) between Py1 and Po. These results indicate that the H2S produced by the desulfidation reaction retains the δ34S-Δ33S signature of Py1 across the biotite, garnet, and staurolite zones. This detailed examination of the textural and chemical evolution of sulfides highlights the role of desulfidation in metal mobility. The pyrite to pyrrhotite reaction can be an efficient mechanism for supplying sulfur, Au, Ag, Te, Bi and Se, and if synchronous with the release of fluids and deformation, mobilizing Au through the Earth’s crust.
在渐进变质过程中,硫通过黄铁矿到磁黄铁矿的脱硫反应释放出来。这一过程被认为为变质流体提供硫和金属,可能有助于造山带金矿床的形成。因此,对这一反应的更深入了解有助于揭示变质流体中硫、金和其他金属在进变质过程中的流动性。我们提出了一种新的多硫同位素结合微量元素的原位研究,重点研究了结构约束的黄铁矿到磁黄铁矿的脱硫反应。这种反应被详细地记录下来,沿着一个递进的巴罗维亚变质场梯度——从黑云母到石榴石、橄榄石和硅线石岩带——记录在Pontiac群变质沉积层序中,该层序与阿比提比省南部及其造山带金矿有断层联系。在黑云母变质带和石榴石变质带的岩石中发现了由磁黄铁矿(Po)取代腐蚀黄铁矿(Py1)的进阶黄铁矿到磁黄铁矿的反应结构。Py1与Po在闪石带中共存,没有明显的结构关系,在硅线质等格栅之后,Py1完全不存在,Po丰富。在所有变质带中,Py1和/或Po均被自面体至亚面体、无包裹体、晚期/逆行黄铁矿(Py2)所取代。硫化物组合的原位微量元素分析表明,随着变质程度的增加,Au、Ag、Te、Bi和Se等金属含量减少,与Py1逐渐被Po取代有关。砷和钴在Py2中保存富集,而Ni富集于Po中,Cu重分配到黄铜矿中。原位多重硫同位素分析表明,Py1和Po之间的δ34S位移为−0.1‰±0.9,Δ33S位移为+0.06‰±0.17,没有可分析区分的分馏关系。结果表明,脱硫反应产生的H2S在黑云母、石榴石和橄榄石带均保持Py1的δ34S-Δ33S特征。对硫化物的结构和化学演变的详细研究突出了脱硫在金属迁移中的作用。黄铁矿与磁黄铁矿的反应是提供硫、Au、Ag、Te、Bi和Se的有效机制,如果与流体的释放和变形同步,则通过地壳调动Au。
{"title":"The chemical and isotopic characterization of the pyrite to pyrrhotite desulfidation reaction across the metamorphic gradient of a metasedimentary basin","authors":"Bruna Coldebella ,&nbsp;Crystal LaFlamme ,&nbsp;Isaac S. Malta ,&nbsp;Carl Guilmette ,&nbsp;Guillaume Barré ,&nbsp;Georges Beaudoin ,&nbsp;Laure Martin ,&nbsp;Dany Savard","doi":"10.1016/j.gca.2024.12.027","DOIUrl":"10.1016/j.gca.2024.12.027","url":null,"abstract":"<div><div>During prograde metamorphism, sulfur is released through the pyrite to pyrrhotite desulfidation reaction. This process is believed to supply sulfur and metals to metamorphic fluids, potentially contributing to the formation of orogenic gold deposits. A deeper understanding of this reaction can therefore help unravel the mobility of sulfur, gold and other metals in metamorphic fluids during prograde metamorphism. We present a novel in situ study of multiple sulfur isotopes combined with trace elements, focused on the texturally-constrained pyrite to pyrrhotite desulfidation reaction. This reaction is documented in detail along a prograde, Barrovian metamorphic field gradient − increasing from the biotite through the garnet, staurolite, and sillimanite zones − recorded in the Pontiac Group metasedimentary sequence, which is fault-bound to the southern Abitibi Subprovince and its orogenic gold deposits. The prograde pyrite to pyrrhotite reaction texture, where pyrrhotite (Po) replaces corroded pyrite (Py<sub>1</sub>), is identified in rocks from the biotite and garnet metamorphic zones. Py<sub>1</sub> and Po coexist in the staurolite zone without a clear textural relationship, and past the sillimanite isograd, Py<sub>1</sub> is completely absent with Po in abundance. Py<sub>1</sub> and/or Po are replaced by euhedral to subhedral, inclusion-free, late/retrograde pyrite (Py<sub>2</sub>) in all metamorphic zones. In situ trace element analysis of the sulfide assemblage reveals a decrease, with increasing metamorphic grade, in metal contents such as Au, Ag, Te, Bi, and Se, associated with the prograde replacement of Py<sub>1</sub> by Po. Arsenic and Co are preserved and enriched in Py<sub>2</sub>, while Ni is concentrated in Po, and Cu is redistributed to chalcopyrite. In situ, multiple sulfur isotope analyses show no analytically distinguishable fractionation (δ<sup>34</sup>S shift of −0.1‰ ± 0.9 and a Δ<sup>33</sup>S shift of +0.06‰ ± 0.17) between Py<sub>1</sub> and Po. These results indicate that the H<sub>2</sub>S produced by the desulfidation reaction retains the δ<sup>34</sup>S-Δ<sup>33</sup>S signature of Py<sub>1</sub> across the biotite, garnet, and staurolite zones. This detailed examination of the textural and chemical evolution of sulfides highlights the role of desulfidation in metal mobility. The pyrite to pyrrhotite reaction can be an efficient mechanism for supplying sulfur, Au, Ag, Te, Bi and Se, and if synchronous with the release of fluids and deformation, mobilizing Au through the Earth’s crust.</div></div>","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"392 ","pages":"Pages 119-136"},"PeriodicalIF":4.5,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143020016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
期刊
Geochimica et Cosmochimica Acta
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1