Acta Geochimica最新文献

{"title":"Petrogenesis of late Cretaceous high Ba–Sr granodiorites, SE Lhasa block, China: implications for the reworking of juvenile crust and continental growth","authors":"Li-Hang Lin,&nbsp;Ren-Zhi Zhu,&nbsp;Shao-Cong Lai,&nbsp;Jiang-Feng Qin,&nbsp;Yu Zhu,&nbsp;Shao-Wei Zhao,&nbsp;Min Liu","doi":"10.1007/s11631-024-00708-z","DOIUrl":"10.1007/s11631-024-00708-z","url":null,"abstract":"<div><p>The high Ba–Sr rocks can provide significant clues about the evolution of the continent lithosphere, but their petrogenesis remains controversial. Identifying the Late Cretaceous high Ba–Sr granodiorites in the SE Lhasa Block could potentially provide valuable insights into the continent evolution of the Qinghai-Tibet Plateau. Zircon U–Pb ages suggest that the granodiorites were emplaced at 87.32 ± 0.43 Ma. Geochemically, the high Ba–Sr granodiorites are characterized by elevated K₂O + Na₂O contents (8.18–8.73 wt%) and K₂O/Na₂O ratios (0.99–1.25, mostly &gt; 1), and belong to high-K calc-alkaline to shoshonitic series. The Yonglaga granodiorites show notably high Sr (653–783 ppm) and Ba (1346–1531 ppm) contents, plus high Sr/Y (30.92–38.18) and (La/Yb)_N (27.7–34.7) ratios, but low Y (20.0–22.8 ppm) and Yb (1.92–2.19 ppm) contents with absence of negative Eu anomalies (δEu = 0.83–0.88), all similar to typical high Ba–Sr granitoids. The variable zircon <i>ε</i>Hf(<i>t</i>) values of − 4.58 to + 12.97, elevated initial ⁸⁷Sr/⁸⁶Sr isotopic ratios of 0.707254 to 0.707322 and low <i>ε</i>Nd(<i>t</i>) values of − 2.8 to − 3.6 with decoupling from the Hf system suggest that a metasomatized mantle source included significant recycled ancient materials. The occurrence of such high Ba–Sr intrusions indicates previous contributions of metasomatized mantle-derived juvenile material to the continents, which imply the growth of continental crust during the Late Cretaceous in the SE Lhasa. Together with regional data, we infer that the underplated mafic magma provides a significant amount of heat, which leads to partial melting of the juvenile crust. The melting of the metasomatized mantle could produce a juvenile mafic lower crust, from which the high Ba–Sr granitoids were derived from reworking of previous mafic crust during the Late Cretaceous (ca. 100–80 Ma) in the SE Lhasa.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 1","pages":"86 - 111"},"PeriodicalIF":1.4,"publicationDate":"2024-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143362179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unveiling Nb–Ta mineralization processes: Insight from quartz textural and chemical characteristics in the Songshugang deposit, Jiangxi Province, South China","authors":"Hengsong Zhang,&nbsp;Shaohao Zou,&nbsp;Xilian Chen,&nbsp;Deru Xu,&nbsp;Zhilin Wang,&nbsp;Yongwen Zhang,&nbsp;Hua Wang","doi":"10.1007/s11631-024-00705-2","DOIUrl":"10.1007/s11631-024-00705-2","url":null,"abstract":"&lt;div&gt;&lt;p&gt;The Songshugang deposit is a large Ta–Nb deposit in South China, with Ta–Nb mineralization associated genetically with the granite and pegmatite. A diversity of quartz from topaz–albite granite, quartz–mica pegmatite, quartz–feldspar pegmatite, and quartz–fluorite pegmatite at Songshugang was studied by CL and LA–ICP–MS in order to constrain enrichment mechanisms of Nb and Ta and to find geochemical indicators of quartz for rare metal deposits. Cathodoluminescence image illuminates a canvas of complexity, the quartz from topaz–albite granite, quartz–mica pegmatite, quartz–feldspar pegmatite, and quartz–fluorite pegmatite, exhibits numerous dark CL streaks, patches, and a series of healed fractures. These textures suggest that the rocks were fractured because of deep crustal pressure, and underwent later hydrothermal metasomatism and quartz filling. The quartz from quartz–fluorite pegmatite present limited patches or fractures but distinct growth bands, indicating that the melt fluid composition during the formation of quartz at this stage varies greatly and is less affected by mechanical fragmentation. The LA–ICP–MS analysis of quartz shows that there is a positive correlation between Al and Li in the quartz from topaz–albite granite, quartz–mica pegmatite, quartz–feldspar pegmatite, to quartz–fluorite pegmatite, indicating that Al mainly enters the quartz lattice through charge compensation substitution mechanism with Li. However, our data deviate from the theoretical Li:Al mass ratio of ~ 1:3.89 in quartz, indicating that there may be competition between H&lt;sup&gt;+&lt;/sup&gt; and Li in a water-rich magmatic environment. The quartz from topaz–albite granite is enriched in K and Na elements, and the quartz from quartz–fluorite pegmatite is enriched in fluorite with a low Ca content in quartz, further elucidating that these rocks were subjected to hydrothermal metasomatism. From topaz–albitite granite to quartz–fluorite pegmatite, Al, Li and Ge content and Al/Ti, Ge/Ti, Sb/Ti ratios in quartz gradually increased, but Ti content gradually decreased, reflecting the high evolution of magma, which can enrich rare metal elements. Based on the characteristics of quartz CL textures and trace elements in topaz–albite granite, quartz–mica pegmatite, quartz–feldspar pegmatite, and quartz–fluorite pegmatite, combined with the albitization and K-feldspathization of rocks, it is suggested that the Nb–Ta mineralization in Songshugang may be influenced by the combined action of magmatic crystallization differentiation and fluid metasomatism. By comparing the quartz in the Songshugang pluton with the quartz in the granite type and pegmatite type rare metal deposits recognized in the world, the Songshugang pegmatite share similarities with the LCT-type pegmatite. Combined with previous studies, the Ge/Ti &gt; 0.1 and Ti &lt; 10 ppm, as well as Al, Li, Ge, Sb, K, Na contents and Al/Ti, Sb/Ti ratios in quartz have the potential to be a powerful exploration marker fo","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 4","pages":"737 - 753"},"PeriodicalIF":1.4,"publicationDate":"2024-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rebuilding the theory of isotope fractionation for evaporation of silicate melts under vacuum condition","authors":"Jie Wang,&nbsp;Yun Liu","doi":"10.1007/s11631-024-00709-y","DOIUrl":"10.1007/s11631-024-00709-y","url":null,"abstract":"<div><p>Isotope effects are pivotal in understanding silicate melt evaporation and planetary accretion processes. Based on the Hertz–Knudsen equation, the current theory often fails to predict observed isotope fractionations of laboratory experiments due to its oversimplified assumptions. Here, we point out that the Hertz-Knudsen-equation-based theory is incomplete for silicate melt evaporation cases and can only be used for situations where the vaporized species is identical to the one in the melt. We propose a new model designed for silicate melt evaporation under vacuum. Our model considers multiple steps including mass transfer, chemical reaction, and nucleation. Our derivations reveal a kinetic isotopic fractionation factor (KIFF or <i>α</i>) <i>α</i>_{our model} = [<i>m</i>(¹species)/<i>m</i>(²species)]^0.5, where <i>m</i>(species) is the mass of the reactant of reaction/nucleation-limiting step or species of diffusion-limiting step and superscript 1 and 2 represent light and heavy isotopes, respectively. This model can effectively reproduce most reported KIFFs of laboratory experiments for various elements, i.e., Mg, Si, K, Rb, Fe, Ca, and Ti. And, the KIFF-mixing model referring that an overall rate of evaporation can be determined by two steps jointly can account for the effects of low <i>P</i>_H2 pressure, composition, and temperature. In addition, we find that chemical reactions, diffusion, and nucleation can control the overall rate of evaporation of silicate melts by using the fitting slope in ln(− ln<i>f</i>) versus ln(<i>t</i>). Notably, our model allows for the theoretical calculations of parameters like activation energy (<i>E</i>_a), providing a novel approach to studying compositional and environmental effects on evaporation processes, and shedding light on the formation and evolution of the proto-solar and Earth-Moon systems.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 4","pages":"661 - 676"},"PeriodicalIF":1.4,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141344907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theoretical study of kinetic isotope effects for vacancy diffusion of impurity in solids","authors":"Yuxi Jing,&nbsp;Xuefang Li,&nbsp;Yun Liu","doi":"10.1007/s11631-024-00706-1","DOIUrl":"10.1007/s11631-024-00706-1","url":null,"abstract":"<div><p>Theoretical studies of the diffusional isotope effect in solids are still stuck in the 1960s and 1970s. With the development of high spatial resolution mass spectrometers, isotopic data of mineral grains are rapidly accumulated. To dig up information from these data, molecular-level theoretical models are urgently needed. Based on the microscopic definition of the diffusion coefficient (<i>D</i>), a new theoretical framework for calculating the diffusional isotope effect (DIE_(v)) (in terms of <i>D</i>^<i>*</i><i>/D</i>) for vacancy-mediated impurity diffusion in solids is provided based on statistical mechanics formalism. The newly derived equation shows that the DIE_(v) can be easily calculated as long as the vibration frequencies of isotope-substituted solids are obtained. The calculated DIE_(v) values of ¹⁹⁹Au/¹⁹⁵Au and ⁶⁰Co/⁵⁷Co during diffusion in Cu and Au metals are all within 1% of errors compared to the experimental data, which shows that this theoretical model is reasonable and precise.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 5","pages":"959 - 970"},"PeriodicalIF":1.4,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141347607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemical analysis of organic matter associated with gold in ore deposits: A study of Kazakhstan and Hungary","authors":"Medet Junussov,&nbsp;Asif Mohammad,&nbsp;Sotirios Longinos","doi":"10.1007/s11631-024-00710-5","DOIUrl":"10.1007/s11631-024-00710-5","url":null,"abstract":"<div><p>This study comprises the relationship between organic matter (OM) and gold occurrence using two distinctive ore deposits of the Bakyrchik gold-sulfide deposit (Kazakhstan) and Western Mecsek uranium ore deposit (Hungary). The two ore deposits are identified as organic-rich sedimentary formations linked to the Variscan gold cycle globally. Characterizing OM is essential because it can act as a carrier for gold, influencing its distribution and behavior within the deposit. Understanding the nature and distribution of OM can provide insights into the processes of gold deposition and help optimize exploration and extraction strategies in mining operations. The primary objective is to characterize OM by identifying its elemental composition, thermal maturity, functional groups, and soluble fractions; and extract gold from OM using a two-step sequential extraction method (hydrogen peroxide and aqua regia) combined with geochemical techniques. Analytical and experimental results from samples of both ore deposits indicate the presence of finely disseminated solid bitumen and reworked vitrinite, originating from thermally matured (RmcRo%—3.76 in Bakyrchik; Ro%—2.25 in W-Mecsek) terrigenous high plants. Both deposits exhibit extremely low extractable bitumen yield and TOC (0.34% in Bakyrchik; 0.25 wt% in W-Mecsek), characterized by an aromatic carboxylic acid organic structure and a composition rich in sulfur-containing (1.17% in Bakyrchik; 5.81% in W-Mecsek) aromatic hydrocarbons. Gold occurrence and enrichment within OM were confirmed through the sequential extraction method employing ICP-OES and LA-ICP-MS techniques. The sequentially extracted gold content from OM reached up to 3 ppm in Bakyrchik and up to 3.28 ppm in Western Mecsek, accompanied by Ag (ranging from 0.01 to 0.32 ppm). Higher concentrations of Au (4 ppm) and Ag (27 ppm) were extracted from residue materials, which are likely associated with sulfide minerals. The presence of gold in OM was further validated using LA-ICP-MS. Gold bonding within OM structure, gold is preserved in the form of lattice gold or structurally bonded metal most likely within the aromatic hydrocarbon fractions of the OM in both the W-Mecsek and Bakyrchik deposits. These findings underscore the profound potential of ongoing exploration endeavors, offering pivotal revelations regarding the extraction and practical application of Au and Ag derived from OM within the geochemical framework of both ore deposits.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"44 1","pages":"23 - 35"},"PeriodicalIF":1.4,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141379660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental constraints on the formation of oxychlorine species by UV irradiation and mechanical pulverization on the lunar surface","authors":"Jiamei Li,&nbsp;Yu-Yan Sara Zhao,&nbsp;He Cui,&nbsp;Shuai-Yi Qu,&nbsp;Yanhua Peng,&nbsp;Yuhong Yang,&nbsp;Xiongyao Li","doi":"10.1007/s11631-024-00707-0","DOIUrl":"10.1007/s11631-024-00707-0","url":null,"abstract":"<div><p>Perchlorate and chlorate are present in various extraterrestrial celestial bodies throughout the solar system, such as Mars, the moon, and asteroids. To date, the origin mechanisms of perchlorate and chlorate on the Martian surface have been well-established; however, relatively little attention has been cast to airless bodies. Here, we experimentally investigated the potential oxidation mechanisms of chloride to chlorate and perchlorate, such as ultraviolet irradiation under H₂O- and O₂-free conditions and mechanical pulverization processes. Individual minerals, olivine, pyroxene, ilmenite, magnetite, TiO₂ and anhydrous ferric sulfate, and lunar regolith simulants (low Ti, CLRS-1; high-Ti, CLRS-2) and their metallic iron (Fe⁰) bearing counterparts were examined. We found that pulverization of dry matrix material-halite mixtures, even in the presence of O₂, does not necessarily lead to perchlorate and chlorate formation without involving water. Under photocatalytic and H₂O- and O₂-free conditions, olivine and pyroxene can produce oxychlorine (ClO_x⁻) species, although the yields were orders of magnitude lower than those under Martian-relevant conditions. Nanophase-Fe⁰ particles in the lunar regolith and the common photocatalyst TiO₂ can facilitate the ClO_x⁻ formation, but their yields were lower than those with olivine. The oxides ilmenite and magnetite did not efficiently contribute to ClO_x⁻ production. Our results highlight the critical role of H₂O in the oxidation chloride to chlorate and perchlorate, and provide essential insights into the environmental influence on the formation of oxychlorine species on different celestial bodies.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 4","pages":"625 - 637"},"PeriodicalIF":1.4,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141269227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genesis and geological significance of carbonate in Changdu Basin, Xizang, China: Constraints from geochemistry and C–O isotopes","authors":"Wenhua Han,&nbsp;Yongshou Li,&nbsp;Haizhou Ma,&nbsp;Huaide Cheng,&nbsp;Binkai Li,&nbsp;Qinyu Hai,&nbsp;Xuahai Ma","doi":"10.1007/s11631-024-00704-3","DOIUrl":"10.1007/s11631-024-00704-3","url":null,"abstract":"<div><p>Research on the origin of carbonates in Changdu Basin holds significant importance for understanding the regional potash formation model. Based on a comprehensive review of previous studies, field geological surveys, and laboratory investigations, this study analyzes the origin and properties of carbonates within the context of regional potash formation. Petrographic studies show that magnesite deposits, with the characteristics of sedimentary origin. The results of elemental geochemical analysis show that the carbonates in this area were formed in the sedimentary environment via evaporation followed by concentration, and the formation of magnesite was possibly caused by the substitution of calcium in the dolomite with magnesium-rich brine. The δ¹³C values of carbonats in the study area are between 5.9‰ and 9.1‰. The δ¹⁸O values of magnesite samples range from − 7.3‰ to − 1.3‰, and the δ¹⁸O values of dolomites range from − 10.3‰ to − 8.4‰. All the calculated Z values of oxygen isotopes of carbonates greater than 120. A comprehensive analysis of carbon and oxygen isotopes indicates that the magnesite was formed in a highly concentrated Marine sedimentary environment and does not show any relation with the metasomatism of hydrothermal fluids. The results on the correlation of magnesite with seawater and its sedimentary origin provide key information for explaining the migration direction of brine between the Changdu and Lanping–Simao Basins. The residual metamorphic seawater in the Changdu Basin migrated to the Lanping–Simao Basin, where potash underwent deposition. Whereas, magnesite and dolomite in the early stage of potash formation were left in the Changdu Basin.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 6","pages":"1192 - 1204"},"PeriodicalIF":1.4,"publicationDate":"2024-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Catagenetic type of manganese ores: REE and isotope (δ13C, δ18O) geochemical features (on the example of the Usa deposit, Russia)","authors":"Vladimir N. Kuleshov,&nbsp;Andrey Yu. Bychkov,&nbsp;Irina Yu. Nikolaeva,&nbsp;Maria E. Tarnopolskaia","doi":"10.1007/s11631-024-00701-6","DOIUrl":"10.1007/s11631-024-00701-6","url":null,"abstract":"<div><p>Chemical (REE and major elements) and isotope (δ¹³C, δ¹⁸O) composition of carbonate manganese ores and manganese-bearing carbonates of the Usa deposit (Siberia, Russia) were studied. Received data on the composition of REE exhibit both the distinct negative (Ce/Ce*_PAAS &lt; 1) and positive (Ce/Ce*_PAAS˃1) cerium anomalies and the positive Eu-anomaly (Eu/Eu*_PAAS˃1). Negative Eu-anomalies are not observed. The contents of Mn, Fe, REE, and Ce-anomalies show a positive correlation with each other. Ce-anomalies and the amount of manganese and REE in relation to the carbon isotope composition (δ¹³C) show a negative relationship and indicate that oxidized carbon of organic matter played an important role in the concentration of manganese and REE in manganese ores. The chemical and isotope composition of examined rocks indicates on secondary formation of Mn-ores. Two major phases and sources are distinguished in the ore-forming process characterized by different chemical (REE and ore elements) and isotope composition: (i) high-grade manganese ores (with high contents of REE and light carbon isotope composition) and (ii) low-grade manganese ores (with low contents of REE and heavy carbon isotope composition).</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 6","pages":"1133 - 1152"},"PeriodicalIF":1.4,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141107604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Can soil remediation agents synergistically mitigate rice Cd content and CH4 emission from karst paddies?","authors":"Wangbiao Lu,&nbsp;Guangneng Zeng,&nbsp;Weijun Luo,&nbsp;Jiangju Song,&nbsp;Maofei Ni,&nbsp;Shuangqin Guo,&nbsp;Qi Zhang,&nbsp;Chengling Huang,&nbsp;Cheng Yang,&nbsp;Haijun Du,&nbsp;Shijie Wang","doi":"10.1007/s11631-024-00696-0","DOIUrl":"10.1007/s11631-024-00696-0","url":null,"abstract":"<div><p>Rice (<i>Oryza sativa</i> L.) paddies are increasingly threatened by cadmium (Cd) pollution, and potentially serve as CH₄ emitters to the atmosphere. Remediation agents widely mitigate Cd pollution in paddy soil, however, we know little about their regulations on CH₄ emission. Here, via adding biochar (B), sulfhydryl-modified palygorskite (SMP), and selenium foliar fertilizer (SFF), we conducted a pot experiment to investigate soil and rice Cd contents together with <i>in</i>-<i>situ</i> CH₄ fluxes. Compared to CK, the addition of SMP, SFF, and B-SMP reduced Cd in brown rice by 25% to 50%, 25%, and 50% to 75%, respectively. Agents 7% B, 7% B-0.01% SMP, and SFF reduced CH₄ emissions by 8.46%, 5.30%, and 4.11%, respectively. CH₄ emission increased gradually along the growing season, with the cumulative CH₄ fluxes ranging between 338.82 and 619.13 kg hm⁻². Our results highlight that mixed 7% B-0.01% SMP and SFF showed collaborative effects on Cd remediation and CH₄ emission. This study reveals the feasibility of reducing Cd pollution and CH₄ emission in karst rice paddies, which hopes to supplement the knowledge of collaborative controls on soil remediation and carbon emission.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 6","pages":"1123 - 1132"},"PeriodicalIF":1.4,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141106762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The occurrence of metallic copper and redistribution of copper in the shocked Suizhou L6 chondrite","authors":"Xiande Xie,&nbsp;Xiangping Gu,&nbsp;Yiping Yang","doi":"10.1007/s11631-024-00703-4","DOIUrl":"10.1007/s11631-024-00703-4","url":null,"abstract":"<div><p>Copper possesses very strong chacophile properties, but under the conditions found in meteorites, its behavior is like that of siderophile elements. The Suizhou meteorite is a highly shocked L6 chondrite. Troilite and taenite are considered the main primary carrier of copper in this meteorite, and the post-shock thermal episode is considered the main reason that elemental Cu migrates from its original host phase and forms metallic grains. The Suizhou meteorite contains a few very thin shock melt veins. The occurrence and behavior of metallic copper in this meteorite were studied by optical microscopic examination, electron microprobe analyses, and high-resolution X-ray elemental intensity mapping. Our results show that metallic copper is abundant in the Suizhou chondritic rock. Metallic copper grains adjacent to small troilite grains inside FeNi metal are the most common occurrence, and those at the FeNi metal–troilite interface are the second most common case. The metallic copper grains occurring at the interface of FeNi metal/troililte and silicate are rather rare. Metallic copper grains are not observed within the Suizhou shock veins, Instead, Cu in elemental form is transferred through shock metamorphism into FeNi metal + troilite intergrowths. Four different occurrence types of Cu in the FeNi metal + troilite intergrowths have been identified: the concentrations of Cu in the FeNi + FeS intergrowths for four occurrence types are rather close, we estimate it might be lower than 1 wt%.</p></div>","PeriodicalId":7151,"journal":{"name":"Acta Geochimica","volume":"43 5","pages":"827 - 837"},"PeriodicalIF":1.4,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141117539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}