Geochimica et Cosmochimica Acta最新文献

{"title":"Neodymium isotopes in marginal seawater trace continental weathering inputs","authors":"Zhaojie Yu, Zehua Song, Xiaojie Tang, David J. Wilson, Germain Bayon, Yi Huang, Xiaoying Kang, Hualong Jin, Shiming Wan, Christophe Colin","doi":"10.1016/j.gca.2025.12.003","DOIUrl":"https://doi.org/10.1016/j.gca.2025.12.003","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"94 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145689930","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":"Evaluation of shallow-marine carbonates as archives of seawater cerium isotope composition: implications for paleoredox reconstruction","authors":"Mengchun Cao, Sihui Chen, Yi-Bo Lin, Ryoichi Nakada, Kai Sheng, Jian Cao, Shu-zhong Shen","doi":"10.1016/j.gca.2025.12.006","DOIUrl":"https://doi.org/10.1016/j.gca.2025.12.006","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"3 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145689921","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 determination of equilibrium sulfur isotope fractionation factors in the gas-silicate melt-sulfide liquid system","authors":"Shashank Prabha-Mohan ,&nbsp;Kenneth T. Koga ,&nbsp;Diego F. Narváez ,&nbsp;Estelle F. Rose-Koga ,&nbsp;Jabrane Labidi","doi":"10.1016/j.gca.2025.12.001","DOIUrl":"10.1016/j.gca.2025.12.001","url":null,"abstract":"<div><div>Sulfur, despite its minor presence (∼ 250 µg.g⁻¹) in the bulk silicate Earth, can exhibit high solubility in melts, up to 1.5 wt. %, depending on the melt’s oxidation state. Sulfur is also integral to the formation of economically significant metal ores. This study reports high-temperature equilibrium sulfur isotope fractionation between melt, sulfide, and gas phases using a dynamic 1-atm gas-mixing furnace. Equilibrium experiments conducted on a basaltic system at temperatures of 1200, 1300, and 1400 °C indicate that equilibrium sulfur isotope fractionation between a sulfide liquid and SO₂ gas is a linear function of oxygen concentration in the sulfide phase. The fractionation factor is expected to be close to 0 ‰, for a pure FeS sulfide liquid. The experiments also reveal an isotopic fractionation of S from – 0.49 ± 0.97 up to + 5.30 ± 0.59 ‰ between the silicate melt and sulfide liquid, with the silicate melt being enriched in ³⁴S. This variation was best modelled by combining compositional elements of sulfide liquid (oxygen and sulfur) and silicate melt (MgO and Na₂O). Our results show a new mechanism of sulfur isotope fractionation between silicate melt and sulfide liquid that results in isotopically heavier melts without sulfate due to the presence of oxygen in the sulfide liquid. Applying our model to Mid-Oceanic Ridge Basalts (MORBs) shows zero S isotope fractionation is expected when the composition of the sulfide liquid is between Fe_0.92S and Fe_0.86SO_0.05. This study shows that measurements of oxygen concentration in natural sulfides are required to accurately interpret sulfur isotope compositions during magma evolution.</div></div>","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"413 ","pages":"Pages 187-203"},"PeriodicalIF":5.0,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145690058","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 and theoretical investigation of antimony isotope fractionation during Sb(III) adsorption on iron (oxyhydr)oxides under anaerobic environment","authors":"Wenju Wang, Hai-Bo Qin, Jian-Ming Zhu, Hongtao He, Decan Tan, Peng Zhao, Yan Zhang, Chengshuai Liu, Yoshio Takahashi, Mingshi Wang","doi":"10.1016/j.gca.2025.11.050","DOIUrl":"https://doi.org/10.1016/j.gca.2025.11.050","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145658134","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":"Precipitation kinetics and C isotope fractionation of rhodochrosite at 298.15 K","authors":"Clancy Zhijian Jiang,&nbsp;Ziwei Liu,&nbsp;Nicholas J. Tosca","doi":"10.1016/j.gca.2025.12.002","DOIUrl":"10.1016/j.gca.2025.12.002","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Before the rise of atmospheric oxygen, the release and transport of soluble manganese ( &lt;figure&gt;&lt;img&gt;&lt;/figure&gt; ) represented the entry point of the earliest Mn cycle. The Mn cycle on early Earth is thought to have resembled that of Fe due to their geochemical similarities. However, kinetic data pertaining to &lt;figure&gt;&lt;img&gt;&lt;/figure&gt; mineralisation are lacking, and thus we lack a complete understanding of the fate of &lt;figure&gt;&lt;img&gt;&lt;/figure&gt; in aqueous systems on early Earth. This study investigates Mn mineralisation and precipitation kinetics through three processes at room temperature: (1) the homogeneous nucleation of rhodochrosite (MnCO&lt;sub&gt;3&lt;/sub&gt;) from oversaturated solutions, (2) seeded rhodochrosite crystal growth under varying solution chemistry, and (3) the competing homogeneous nucleation between rhodochrosite and &lt;figure&gt;&lt;img&gt;&lt;/figure&gt; -silicates in silica-rich solutions.&lt;/div&gt;&lt;div&gt;These experimental data show that homogeneous nucleation of rhodochrosite only takes place above a significantly elevated solution saturation (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;Ω&lt;/mi&gt;&lt;mo&gt;≳&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; 380). The rate of nucleation (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) can be described with a generalised rate law: &lt;span&gt;&lt;span&gt;&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;mi&gt;u&lt;/mi&gt;&lt;mi&gt;c&lt;/mi&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mstyle&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;/mstyle&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mstyle&gt;&lt;mi&gt;k&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mstyle&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mstyle&gt;&lt;mi&gt;s&lt;/mi&gt;&lt;/mstyle&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;147&lt;/mn&gt;&lt;mo&gt;exp&lt;/mo&gt;&lt;mfenced&gt;&lt;mrow&gt;&lt;mfrac&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;83&lt;/mn&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;mn&gt;974&lt;/mn&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mo&gt;log&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Ω&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;a&lt;/mi&gt;&lt;mi&gt;v&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/mfrac&gt;&lt;/mrow&gt;&lt;/mfenced&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;Once nucleated, the crystal growth rate (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;mi&gt;w&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;; BET-surface area normalised) can be delineated as a function of solution chemistry (1 &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mi&gt;Ω&lt;/mi&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; 380), following a rate law that reflects a mixed diffusion- (1st order) and surface reaction-controlled (2nd order) growth mechanism: &lt;span&gt;&lt;span&gt;&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;mi&gt;r&lt;/mi&gt;&lt;mi&gt;w&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mstyle&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;/mstyle&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mstyle&gt;&lt;mi&gt;k&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mstyle&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mstyle&gt;&lt;mi&gt;s&lt;/mi&gt;&lt;/mstyle&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;mo&gt;=&lt;","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"413 ","pages":"Pages 204-217"},"PeriodicalIF":5.0,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657977","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":"Fluid-silicate melt Cu isotope fractionation and its impact on δ65/63Cu heterogeneity in porphyry copper deposits and associated arc magmas","authors":"Jianping Li ,&nbsp;A.E. Williams-Jones ,&nbsp;Shitao Zhang ,&nbsp;Huayong Chen","doi":"10.1016/j.gca.2025.11.039","DOIUrl":"10.1016/j.gca.2025.11.039","url":null,"abstract":"<div><div>Fluid exsolution associated with arc magmatism at subduction zones is an essential process for the transfer of volatiles and enrichment of ore metals in the upper crust. As an incompatible and fluid-mobile element, Cu and its isotopes can be used as tracers of magmatic-hydrothermal activity and metal source. The isotopic fractionation of Cu between aqueous fluids and silicate magmas is still not well quantified. To shed light on this process, we evaluated the equilibrium isotope fractionation of Cu between aqueous fluids and coexisting silicate melts (Δδ⁶⁵Cu_fluid-melt) experimentally at 850℃ and 200 MPa for a variety of fluid and melt compositions. The results of these experiments show that low chlorinity (1 mol/kg H₂O) aqueous fluids are isotopically heavier with respect to Cu than the coexisting silicate melts, i.e., the Δδ⁶⁵Cu_fluid-melt values are from + 0.03 ‰ to + 0.17 ‰. These values correlate negatively with the alumina saturation index (ASI) of the melt. Increasing the fluid chlorinity decreases the preference of the heavy Cu isotopes for the fluid, leading to heavier Cu-isotopic values for the silicate melt, i.e., the Δδ⁶⁵Cu_fluid-melt value decreases from + 0.04 ‰ at a fluid chlorinity of ∼1 m ol/kg H₂O to −0.35 ‰ at a fluid chlorinity of ∼4 m ol/kg H₂O. We attribute this change to a change in the dominant Cu species in the fluid from CuCl⁰ to a Cu complex with a higher Cl ligand number, i.e., (Na, K)CuCl₃⁰. The results of our study suggest that it should be possible to use Δδ⁶⁵Cu_fluid-melt values to trace the evolution of Cu isotope composition in the exsolved fluid and residual magma and evaluate their possible effects on the Cu-isotopic signature of different parts of porphyry (±skarn) copper systems. The results may also find application in distinguishing between intrusions that have exsolved fluid (potentially fertile) from intrusions that have not exsolved fluid (potentially barren), and thereby provide an important tool for use in the exploration for deposits of this important commodity.</div></div>","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"413 ","pages":"Pages 1-17"},"PeriodicalIF":5.0,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657978","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":"Nickel isotopic evidence for potential deep magmatic sulfide ore bodies in orogenic settings","authors":"Peng-Yi Li ,&nbsp;Shui-Jiong Wang ,&nbsp;Fu-Ping Pei ,&nbsp;Guan-Wen Yu ,&nbsp;Bing-Qian Ding ,&nbsp;Zi-Cheng Guan ,&nbsp;Kai Song ,&nbsp;Wen-Liang Xu","doi":"10.1016/j.gca.2025.11.052","DOIUrl":"10.1016/j.gca.2025.11.052","url":null,"abstract":"<div><div>Ni isotopes have significant potential as the genetic indicators in magmatic Cu–Ni sulfide deposits. However, the mechanisms underlying Ni isotope fractionation in sulfide-bearing and sulfide-barren mafic–ultramafic intrusions remain poorly constrained. Here, we analyzed Ni isotopes of five mafic–ultramafic intrusions along the Changchun–Yanji suture zone in the southeastern Central Asian Orogenic Belt (CAOB). These mafic–ultramafic intrusions exhibit arc-like trace element characteristics, with enrichment in large-ion lithophile elements (LILEs) and depletion in high-field-strength elements (HFSEs), suggesting a metasomatized mantle source. Based on their spatial distribution and Ni isotopic compositions, these intrusions can be divided into two groups: the normal-Ni isotopic group, which includes sulfide-barren intrusions (Jiaohe, Badaohezi and Bakeshu) situated to the west of Dunhua–Mishan (Dun–Mi) Fault; and the heavy-Ni isotopic group including sulfide-bearing Piaohechuan No.4 and sulfide-barren Qinglinzi intrusions located near and to the east of the Dun–Mi Fault. The normal-Ni isotopic intrusions formed at ca. 222–246 Ma, and exhibit an average <em>δ</em>^60/58Ni value of +0.11 ‰ (2SD) comparable to that of the bulk silicate Earth (BSE). In contrast, the heavy-Ni isotopic intrusions formed at ca. 218 Ma, and show substantially high <em>δ</em>^60/58Ni values (avg. <em>δ</em>^60/58Ni of +0.36 ‰, 2SD). Notably, sulfide minerals from the Piaohechuan No.4 intrusion display lighter Ni isotopic compositions (<em>δ</em>^60/58Ni value of −0.32 to −0.80 ‰). In conclusion, the heavy-Ni isotopic intrusions were derived from highly oxidized lithospheric mantle and experienced light <em>δ</em>^60/58Ni sulfide segregation, as evidenced by Rayleigh fractionation modeling. The mechanisms underlying Ni isotope fractionation in sulfide-bearing and sulfide-barren mafic–ultramafic intrusions are sulfide segregation with light <em>δ</em>^60/58Ni values. Additionally, we conclude that the eastern region, characterized by a highly oxidized mantle, exhibits potential for Ni–Cu sulfide mineralization, and that the exploration of magmatic Ni–Cu sulfide deposits in orogenic settings should focus on the mafic–ultramafic intrusions with high <em>δ</em>^60/58Ni values.</div></div>","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"413 ","pages":"Pages 171-186"},"PeriodicalIF":5.0,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657979","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":"Recycled carbon in the mantle source of carbonatites: A magnesium isotopic perspective","authors":"Anupam Banerjee, Fang-Zhen Teng, M. Satish-Kumar, K.M. Preeti","doi":"10.1016/j.gca.2025.11.048","DOIUrl":"https://doi.org/10.1016/j.gca.2025.11.048","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"101 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657980","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":"Subduction erosion intensifying carbonate-rich material recycling revealed by Mg-Zn isotopic evidence from high-Mg andesites in central Tibet","authors":"Jialiang Li ,&nbsp;Wei-Qiang Ji ,&nbsp;Xiao-Chi Liu ,&nbsp;Jingao Liu ,&nbsp;Fu-Yuan Wu","doi":"10.1016/j.gca.2025.11.051","DOIUrl":"10.1016/j.gca.2025.11.051","url":null,"abstract":"<div><div>Subduction erosion has been suggested as a major process that transfers crustal material into the mantle at convergent systems. However, to date, few studies have attempted to establish a link between subduction erosion and deep carbon cycling. High-Mg andesites are thought as key magmatic markers of crust-mantle interaction. Here, we report elemental and Sr-Nd-Hf-Mg-Zn isotopic data for ca. 167–166 Ma high-Mg andesites from the DaruTso magmatic arc, central Tibet. The key geochemical observations, such as arc-type trace element patterns, high Th/La (0.46–0.58) and Th (12.0–13.8 ppm) contents, very enriched Sr-Nd-Hf isotope compositions ((⁸⁷Sr/⁸⁶Sr)_i = 0.7078–0.7088; ε<em>_Nd</em>(t) = −9.5 to −8.8; ε<em>_Hf</em>(t) = −7.4 to −5.7), and more variable Mg but heavier Zn isotopic compositions (δ²⁶Mg = −0.30 ‰ to −0.13 ‰; δ⁶⁶Zn = 0.35 ‰ to 0.46 ‰) than that of the mantle (δ²⁶Mg = −0.25 ± 0.04 ‰; δ⁶⁶Zn = 0.18 ± 0.05 ‰), imply that these lavas are derived from subarc mantle magma sources containing both recycled terrigenous siliciclastic and carbonate sediments. In addition, the inverse δ²⁶Mg-δ⁶⁶Zn correlations and their linear variations with CaO/Al₂O₃, CaO/TiO₂ and La/Sm are jointly interpreted to reflect carbonatitic metasomatism associated with the northern subduction of the Tethys Ocean. The co-variations between δ²⁶Mg-δ⁶⁶Zn and (⁸⁷Sr/⁸⁶Sr)_i-ε<em>_Nd</em>(t)-ε<em>_Hf</em>(t) provide evidence for the potential of both recycled terrigenous siliciclastic sediments and calcium carbonates to modify subarc mantle Mg-Zn isotopic compositions. These features, coupled with other independent geological archives, suggest DaruTso high-Mg magma generation via partial melting of eroded forearc carbonate-rich components and subsequent interaction with mantle peridotite. Evidently subduction erosion processes are key for transporting substantial quantities of carbonate-rich sediments into the Tethys subarc mantle, which may have helped drive high volcanic CO₂ emission rates over the Mesozoic. This study presents solid evidence of magmatic rock Mg-Zn isotopes for revealing the effect of subduction erosion on deep carbon cycle and provides a new perspective on the Earth’s long-term carbon cycles.</div></div>","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"413 ","pages":"Pages 156-170"},"PeriodicalIF":5.0,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657976","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":"Weathering of skarn deposits offsets decarbonation during Jurassic-Cretaceous mineralization in East Asia","authors":"Wei Liu, Xu Chu, Wenrong Cao, Bo Wan","doi":"10.1016/j.gca.2025.11.049","DOIUrl":"https://doi.org/10.1016/j.gca.2025.11.049","url":null,"abstract":"","PeriodicalId":327,"journal":{"name":"Geochimica et Cosmochimica Acta","volume":"27 1","pages":""},"PeriodicalIF":5.0,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145657981","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}