Geochimica et Cosmochimica Acta最新文献

{"title":"Rare earth element geochemistry in saline alkaline lakes from the East African Rift, Kenya: the case of the “missing” Ce anomaly","authors":"Lukas Klose, Timmu Kreitsmann, Lydia A. Olaka, Moses O. Misongo, Michael Bau","doi":"10.1016/j.gca.2026.03.043","DOIUrl":"https://doi.org/10.1016/j.gca.2026.03.043","url":null,"abstract":"Many of the East African Rift Valley lakes are soda lakes that have attracted considerable research interest over the last decades with a focus on their extraordinarily high bioproductivity, high concentration of dissolved organic carbon (DOC), and diverse microbial communities. Yet, the distribution of trace metals, particularly dissolved rare earth elements (REE) and yttrium in these soda lake systems remain poorly constrained. We report data for surface water samples from eight rift valley lakes from the Kenyan part of the East African Rift. Speciation calculations accounting for both organic and inorganic complexation of REE were performed using PHREEQC by implementing the Humic Ion-Binding Model VII.","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"31 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147587134","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":"Controls on the cadmium isotopic compositions of marine sediments in the oligotrophic Western Pacific","authors":"Zheyuan Zhang, Tao Li, Tianyu Chen, Gang Yang, Jianfan Zheng, Yanguang Liu","doi":"10.1016/j.gca.2026.03.039","DOIUrl":"https://doi.org/10.1016/j.gca.2026.03.039","url":null,"abstract":"The oceanic biogeochemical cycle of cadmium (Cd) is classically interpreted through its nutrient-like distribution, yet major sinks balancing its isotopic budget remain debated. While Cd sequestration in sub-oxic/anoxic margin sediments has been emphasized, the role of vast expanses of oxic sediments is poorly constrained. This study presents Cd concentrations and stable isotope compositions (<ce:italic>δ</ce:italic><ce:sup loc=\"post\">114/110</ce:sup>Cd) of surface sediments from the oligotrophic Western Pacific (CJ09), spanning water depths of 2,100–5,580 m, to identify Cd hosts and assess their significance in the global Cd cycle. Results show significant enrichment of non-detrital Cd, primarily hosted in carbonate minerals, organic matter, and Mn oxides, with their relative proportions shifting systematically with depth. Specifically, near-complete loss of carbonate-derived Cd is observed during carbonate dissolution at depth, with limited re-adsorption by other phases. The bulk sedimentary Cd isotopic composition decreases from +0.14 ± 0.06‰ in shallow sediments (2,100–2,700 m) to +0.05 ±0.04‰ in intermediate sediments (4,700–5,580 m), and further to 0.00 ± 0.06‰ in deep sediments. Although Mn oxides dominate non-detrital Cd at deep sediments, the constrained <ce:italic>δ</ce:italic><ce:sup loc=\"post\">114/110</ce:sup>Cd of Mn oxides (+0.13 ± 0.05‰) is significantly higher than bulk <ce:italic>δ</ce:italic><ce:sup loc=\"post\">114/110</ce:sup>Cd values. Mass balance calculations further reveal an exceptionally light Cd isotopic composition (<ce:italic>δ</ce:italic><ce:sup loc=\"post\">114/110</ce:sup>Cd &lt; − 0.4‰) for the organic fraction to account for the low bulk <ce:italic>δ</ce:italic><ce:sup loc=\"post\">114/110</ce:sup>Cd values of deep sediments. This light isotope signature likely originates from the combined effects of rapid export via zooplankton fecal pellets, preferential adsorption of light Cd isotopes onto organic matter, and the delivery of a refractory, isotopically light subsurface particulate Cd pool to the seafloor in the oligotrophic Western Pacific. A first-order flux estimation suggests that Cd burial in these oxic, pelagic clays represents a non-negligible sink (∼2–18% of total input), which is characterized by isotopically lighter Cd compared to deepwater. This finding highlights that oxic sediments in the open ocean constitute a significant light isotopic sink, which must be incorporated into models to fully resolve the marine Cd isotopic mass balance.","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"59 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147587135","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":"Source-specific carbon dioxide production and acetoclastic methanogenesis upon anaerobic degradation of dissolved organic matter","authors":"Yongqiang Zhou, Jiayi Wu, Lei Zhou, Yunlin Zhang, Kyoung-Soon Jang, Liwei Zhang, José R. Paranaíba, Christopher C. Keneally, Justin D. Brookes, David P. Hamilton, Erik Jeppesen","doi":"10.1016/j.gca.2026.03.037","DOIUrl":"https://doi.org/10.1016/j.gca.2026.03.037","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"14 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147496673","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":"Iron (Fe) isotopes decipher Fe fate in acid mine drainage within a karst watershed","authors":"Yuhui Liu, Yafei Xia, Jing Sun, Lei Song, Ting Gao, Meng Qi, Chengshuai Liu","doi":"10.1016/j.gca.2026.03.035","DOIUrl":"https://doi.org/10.1016/j.gca.2026.03.035","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"270 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147495452","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":"Mechanistic insights into quinone-enhanced hydroxyl radical production during the oxygenation of Fe(II) minerals","authors":"Yingxiao Tian, Rong Chen, Peng Zhang, Songhu Yuan","doi":"10.1016/j.gca.2026.03.033","DOIUrl":"https://doi.org/10.1016/j.gca.2026.03.033","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"92 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147495454","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":"Climate signals in coral lipids: Temperature-driven variations in lipid distribution and δ13C of fatty acids","authors":"Yi Song, Jianrong Huang, Kefu Yu, Thomas J. Algeo, Xianyu Huang, Huan Yang, Jiabao Wang, Mingsi Zang, Yingzhao Wang","doi":"10.1016/j.gca.2026.03.036","DOIUrl":"https://doi.org/10.1016/j.gca.2026.03.036","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"15 1 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147495453","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":"Hematite records palaeo-seawater Zn isotopic compositions: Evidence from Zn isotopic fractionation during adsorption onto and incorporation into Fe (hydr)oxides","authors":"Xinran Yan, Chuanwei Zhu, Wenrui Song, Yunzhu Wu, Lisheng Gao, Wentao Wang, Hui Yin, Haifeng Fan, Hanjie Wen","doi":"10.1016/j.gca.2026.03.030","DOIUrl":"https://doi.org/10.1016/j.gca.2026.03.030","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"15 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147495459","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":"Uptake of ammonium and nitrate by calcium carbonate polymorphs","authors":"Rinat I. Gabitov, Peter M. Wynn, Catherine Wearing, Logan Carlson, Gombojav Ariunbold, Angel L. Jimenez-Arroyo, Elizabeth Bell, Nathan Halcovitch, Rooban V.K.G. Thirumalai","doi":"10.1016/j.gca.2026.03.032","DOIUrl":"https://doi.org/10.1016/j.gca.2026.03.032","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"37 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147495458","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":"Organic and isotopic indicators for sorting of sedimentary organic matter along a marginal submarine canyon","authors":"Hilary G. Close, Matthew D. McCarthy, Nancy G. Prouty","doi":"10.1016/j.gca.2026.03.029","DOIUrl":"https://doi.org/10.1016/j.gca.2026.03.029","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"16 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147495461","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 fluid/melt partitioning of Cu, Ag, and Au in felsic upper-crustal magmatic-hydrothermal systems","authors":"Ivano Gennaro, Alexandra Tsay, Zoltán Zajacz","doi":"10.1016/j.gca.2026.03.025","DOIUrl":"https://doi.org/10.1016/j.gca.2026.03.025","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"31 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2026-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147495463","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}