Geochimica et Cosmochimica Acta最新文献

{"title":"Pervasive and rapid enrichment of nitrogen in newly erupted oceanic basalt","authors":"Juan Felipe Bustos-Moreno, Tobias B. Weisenberger, Ryoji Tanaka, Hiroshi Kitagawa, Gray E. Bebout","doi":"10.1016/j.gca.2026.08.015","DOIUrl":"https://doi.org/10.1016/j.gca.2026.08.015","url":null,"abstract":"The alteration of oceanic crust by seawater is a critical sink in the global nitrogen (N) cycle, yet the mechanisms and timescales of N enrichment remain poorly constrained. We present N concentrations and isotope compositions from a 192-meter drill core (SE-02b) retrieved from the then 50-year-old Surtsey Island in Iceland, a pristine analog for rapid alteration of young oceanic basalt. The altered basaltic tuffs show significant N enrichment (average 11 ± 8 μg/g), relative to unaltered Icelandic basalt glasses (0.028 ± 0.026 μg/g) and MORB (∼1.1 to 1.5 μg/g), matching the global average for altered oceanic crust (11 μg/g; ranging in ages from 5 to 170 Ma). Nitrogen isotope compositions (δ<ce:sup loc=\"post\">15</ce:sup>N<ce:inf loc=\"post\">air</ce:inf> = −1.7 ± 4.6 ‰) are primarily consistent with incorporation of seawater- and meteoric-derived ammonium (NH<ce:inf loc=\"post\">4</ce:inf><ce:sup loc=\"post\">+</ce:sup>), more likely into secondary K-minerals, palagonitized glass and smectites throughout the core. To a lesser extent, N could be incorporated into Na/Ca-minerals such as analcime in the meteoric water altered zone and sulphates such as anhydrite and gypsum when present. Incorporation of NH<ce:inf loc=\"post\">4</ce:inf><ce:sup loc=\"post\">+</ce:sup> into secondary phases occurs with little isotope fractionation consistent with equilibrium fractionation between clay and aqueous NH<ce:inf loc=\"post\">4</ce:inf><ce:sup loc=\"post\">+</ce:sup>. We demonstrate that seawater-rock interaction alone can produce the ubiquitous background N enrichment of the oceanic crust without the addition of remobilized N from sedimentary sources. Such magnitude of enrichment is also observed via meteoric water alteration. Localized high enrichments in N in areas of enhanced fluid flow at core SE-02b with exceptionally low δ<ce:sup loc=\"post\">15</ce:sup>N values (as low as −20.1 ‰), are attributed to abiotic reduction of dissolved N<ce:inf loc=\"post\">2</ce:inf> under anoxic conditions and/or microbial activity. We propose that N incorporation into the oceanic crust can occur rapidly in days to decades rather than at a constant rate over geologic time. This has major implications for N transfer in subduction zones, N exchange between the oceanic crust, seawater and the atmosphere and for planetary habitability.","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"13 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148767491","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}

{"title":"The impact of the stability of white mica on 40Ar diffusion during laboratory incremental heating: implications for the interpretation of 40Ar/39Ar step-heating dates","authors":"Vidar Jakobsson, Richard Spikings, Stefan Farsang","doi":"10.1016/j.gca.2026.08.014","DOIUrl":"https://doi.org/10.1016/j.gca.2026.08.014","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"40 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148716461","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}

{"title":"Zn isotope fractionation during sorption on alumina mediated by humic acid","authors":"Wenxian Gou, Xiaoyu Li, Ying Chen, Lan Jiang, Zhaofeng Zhang, Yi Huang","doi":"10.1016/j.gca.2026.08.013","DOIUrl":"https://doi.org/10.1016/j.gca.2026.08.013","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"39 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148716458","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}

{"title":"Aluminium drives hydrogen incorporation in pyrolitic lower mantle: constraints from a combined FTIR-ERDA-nanoSIMS analysis","authors":"Siddharth Khan, Nathalie Bolfan-Casanova, Maximilien Verdier-Paoletti, Hélène Bureau, Hicham Khodja, Ana E. Pradas del Real, Denis Andrault","doi":"10.1016/j.gca.2026.08.011","DOIUrl":"https://doi.org/10.1016/j.gca.2026.08.011","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"372 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148716520","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}

{"title":"Magnitude of stable iron isotope fractionation limited by multiple stages of terrestrial core formation","authors":"Gabriel Nathan, Seth A. Jacobson","doi":"10.1016/j.gca.2026.08.006","DOIUrl":"https://doi.org/10.1016/j.gca.2026.08.006","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"7 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148716457","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}

{"title":"Calcium isotopic compositions of the lower continental crust estimated from lower-crustal xenoliths and Archean terrain","authors":"Huange Ren, Ganglan Zhang, Chunfei Chen, Lanping Feng, Zhenyi Liu, Frédéric Moynier, Yongsheng Liu","doi":"10.1016/j.gca.2026.07.040","DOIUrl":"https://doi.org/10.1016/j.gca.2026.07.040","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"44 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148716469","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}

{"title":"Experimental constraints on lithium isotope systematics in Porites corals: robustness of Li/Mg and δ7Li paleoceanographic proxies","authors":"Toshihiro Yoshimura, Wenshuai Li, Xiao-Ming Liu","doi":"10.1016/j.gca.2026.07.043","DOIUrl":"https://doi.org/10.1016/j.gca.2026.07.043","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"15 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148716463","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}

{"title":"Selenium isotope constraints on sediment–oceanic crust interaction during slab deserpentinization","authors":"Juan Muñoz-Alfaro, Stephan König, Claudio Marchesi, Romain Tilhac, María Isabel Varas-Reus, José Alberto Padrón-Navarta, Vicente López Sánchez-Vizcaíno, Ronny Schoenberg, Carlos J. Garrido","doi":"10.1016/j.gca.2026.07.049","DOIUrl":"https://doi.org/10.1016/j.gca.2026.07.049","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"26 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148716464","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}

{"title":"The solubility and speciation of REE phosphate endmembers (CePO4 and YPO4) in Cl-rich aqueous fluids from 350 to 450 °C and implications for natural systems","authors":"Charles T. Kershaw, Nicole C. Hurtig, Alexander P. Gysi, Artas A. Migdisov, Laura E. Waters, Daniel Harlov","doi":"10.1016/j.gca.2026.08.001","DOIUrl":"https://doi.org/10.1016/j.gca.2026.08.001","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"31 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148716472","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}

{"title":"Internal water and organic matter increase calcite clumped isotope reactivity","authors":"Zeyang Sun, Jingxiang Cheng, Sarbajit Banerjee, Ethan L. Grossman","doi":"10.1016/j.gca.2026.07.038","DOIUrl":"https://doi.org/10.1016/j.gca.2026.07.038","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"4 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148716471","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}