Chemical Geology最新文献

{"title":"Synthesis and characterization of glycolates and implications for the genesis of glycolate minerals","authors":"Mingyang Hu ,&nbsp;Jiawen Hu ,&nbsp;Bin Lian","doi":"10.1016/j.chemgeo.2026.123244","DOIUrl":"10.1016/j.chemgeo.2026.123244","url":null,"abstract":"<div><div>Glycolate minerals are a newly discovered family of organic minerals and have currently become the second largest family of organic minerals. Due to their short discovery history, no reports on the genesis mechanism of this type of organic mineral have been published. In this study, we synthesized the seven glycolate minerals that have been reported so far. Their physical and chemical properties were investigated, including synthesis conditions, thermal stability, and solubility. The δ¹³C and δ¹⁴C of the glycolate mineral lazaraskeite-<em>M</em>_<em>1</em>, the high-temperature phase of the first and most commonly occurring glycolate mineral lazaraskeite, was also tested. The results show that there are significant differences in the synthesis temperatures and thermal stabilities among the seven glycolates. Specifically, lazaraskeite-<em>M</em>_<em>2</em> can synthesized at −50 °C and transforms into lazaraskeite-<em>M</em>_<em>1</em> when the temperature exceeds 0 °C, while the synthesis temperature for glecklerite exceeds 30 °C, and jimkrieghite only forms when the temperature is above 55 °C. All synthesized glycolates exhibit high solubility, range from 5.4 mg/mL to 2350 mg/mL. Lazaraskeite-<em>M</em>_<em>1</em> has δ¹³C of −35.318 ‰ and δ¹⁴C of −986.1 ‰. Based on these findings, it is believed that glycolate group in lazaraskeite-<em>M</em>_<em>1</em> originated from C3 plants during the late Eocene, between BCE 37,775 and 37,252. The formation of glycolate minerals may involve the following stages: biosynthesis of glycolic acid – fluid dissolution of glycolic acid and cations – mineralization – phase transition and dehydration/dissolution and re-mineralization/bioweathering. This study provides important information for understanding the genesis mechanism and preservation conditions of glycolate minerals.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"703 ","pages":"Article 123244"},"PeriodicalIF":3.6,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 intermediate solid solution (ISS) of the Cu-Fe-S system: Phase equilibria calculation at elevated temperatures based on Gibbs energy modeling","authors":"Peter Waldner","doi":"10.1016/j.chemgeo.2026.123245","DOIUrl":"10.1016/j.chemgeo.2026.123245","url":null,"abstract":"<div><div>The phase equilibria of the Cu-Fe-S system are calculated from liquidus to medium temperatures based on Gibbs energy modeling of the intermediate solid solution (ISS). The compound energy formalism is used for a suitable thermodynamic model to account for the pronounced solid solution character of ISS. The obtained Gibbs energy as a function of composition and temperature allows the computation of complex phase relations with high-temperature modifications of bornite and pyrrhotite, pyrite and chalcopyrite, of which a Gibbs energy expression as a function of temperature is also provided. For the first time, a direct comparison is made public between the well-known experimental isoplethal phase diagram along the CuFe–S join, which was provided more than fifty years ago by <span><span>Barton (1973)</span></span>, and a thermodynamically computed phase diagram section. A detailed comparison with experimental phase equilibria data on the homogeneity range of ISS at 800 °C, 760 °C, 700 °C and 600 °C with calculated results is carried out. In total three isoplethal and four isothermal sections of the Cu-Fe-S phase diagram are computed, and the agreement with experimental data available in the literature ranges from fair to very satisfactory.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"703 ","pages":"Article 123245"},"PeriodicalIF":3.6,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145902349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 systematics of spreading ridge-arc collision – Philippine Sea CBF rift and the Izu-Bonin arc","authors":"Osamu Ishizuka ,&nbsp;Rex N. Taylor ,&nbsp;Taichi Sato ,&nbsp;Gen Shimoda ,&nbsp;Yumiko Harigane ,&nbsp;Susumu Umino ,&nbsp;Izumi Sakamoto ,&nbsp;Yuka Yokoyama ,&nbsp;Koki Mori ,&nbsp;Kenichiro Tani ,&nbsp;Yasuhiko Ohara ,&nbsp;Chris E. Conway","doi":"10.1016/j.chemgeo.2026.123232","DOIUrl":"10.1016/j.chemgeo.2026.123232","url":null,"abstract":"<div><div>Triple junctions between fundamental tectonic units are where different compositions and magmatic processes interact. We investigated the intersection of a spreading center with an island arc within the Philippine Sea Plate, i.e. an arc-ridge-arc triple junction, using a combination of submersible sampling and shipboard geophysics. We use Ar<img>Ar dating, elemental concentrations and Sr-Nd-Pb radiogenic isotope ratios to constrain the structure, age and origin of magmatism as spreading interacted with the arc.</div><div>Between 33 and 31 Ma the tip of the West Philippine Basin spreading center was in the back-arc west of the Kyushu-Palau arc. Spreading volcanism had mantle-like Ce/Pb and Th/Ce indicating a lack of slab flux. Radiogenic isotopes form a trajectory towards low ¹⁴³Nd/¹⁴⁴Nd and high ^20xPb/²⁰⁴Pb, but extend to Δ²⁰⁸Pb/²⁰⁴Pb &gt; 85 which corresponds to an EM-2-like mantle component rather than pelagic sediment input from the slab.</div><div>The final stage of spreading-related activity occurred between 31 and 28.5 Ma when the spreading axis rotated from NW-SE to <em>E</em>-W and propagated eastwards into the arc. It resulted in magmatism contemporaneous with the adjacent frontal arc. This final magmatism extended the radiogenic isotopic trajectories observed in the earlier spreading towards less radiogenic Pb and higher ¹⁴³Nd/¹⁴⁴Nd, i.e. towards MORB from the EM-2 component. However, during the final stage magmatism La/Sm, Nb/Zr increased while Pb and Sr isotopes became progressively more radiogenic, demonstrating a progressive decrease in the degree of partial melting and preferential tapping of the EM-2 component. This change in melt generation and composition appears a common process at the end of spreading.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"703 ","pages":"Article 123232"},"PeriodicalIF":3.6,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145902350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A survey of methoxyl and methyl isotopic clumping in a variety of biologic and synthetic materials","authors":"Rebekah S. Sprengel ,&nbsp;Max K. Lloyd ,&nbsp;Daniel A. Stolper","doi":"10.1016/j.chemgeo.2026.123243","DOIUrl":"10.1016/j.chemgeo.2026.123243","url":null,"abstract":"<div><div>Stable isotope measurements are important tracers of sample origins and formational conditions, including distinguishing between samples formed via synthetic vs. biological pathways. Here we present results that establish the ability of multiply substituted isotopologues, colloquially termed clumped isotopes, of methoxyl and methyl groups (Δ¹³CH₂D and Δ¹²CHD₂) can be used to distinguish biologically- from synthetically- generated materials and related to these (bio)chemical formational pathways. Specifically, we demonstrate that there is a large distinction between Δ¹³CH₂D values of plant-derived methoxyl groups vs. synthetic groups, including in the same molecule (e.g., vanillin). These distinctions are independent of bulk methoxyl and methyl hydrogen and carbon isotopic compositions. We discuss the processes that can generate these differences as well as implications for the study of methane clumped isotopes in the environment.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"703 ","pages":"Article 123243"},"PeriodicalIF":3.6,"publicationDate":"2026-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145897545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Salinity and geochemical proxy responses to volcanism in small rift lakes: Insights from the Lower Cretaceous Erlian Basin","authors":"Wei Si ,&nbsp;Dujie Hou ,&nbsp;Xiong Cheng ,&nbsp;Zhe Zhao ,&nbsp;Ronghua Zheng ,&nbsp;Xiuli Wei ,&nbsp;Piao Wu","doi":"10.1016/j.chemgeo.2026.123242","DOIUrl":"10.1016/j.chemgeo.2026.123242","url":null,"abstract":"<div><div>The Early Cretaceous Erlian Basin, characterized by small-scale lacustrine sedimentary systems and <em>syn</em>-depositional volcanism, provides an exceptional setting to evaluate how volcanic forcing modulates lacustrine salinity. Through integrated organic/inorganic geochemical analyses (biomarkers, reduced sulfur/total organic carbon ratios [S/C], major and trace elements, carbonate isotopes) of volcanic ash-rich strata, this study demonstrates that volcanic forcing regulates lacustrine salinity through mineral dissolution, climatic feedbacks, chemical weathering, and hydrological alteration. Moderate volcanism elevates salinity (from brackish to saline) through ionic influx and evaporative concentration. However, large-scale eruptions (&gt;40 m tuff) reduce salinity via sulfate aerosol-driven cooling, increased rainfall, and tectonic subsidence-induced lake expansion. Conventional salinity proxies (carbonate isotope, elements, and biomarkers) exhibit reduced reliability under volcanic influence and diagenetic alteration. Elemental indicators (B/Ga, Sr/Ba) exhibit diagnostic correlations: positive (pristine deposition), negative (volcanic ash input), and non-significant (diagenetic overprinting). Boron concentrations correlate directly with volcaniclastic flux rather than ambient water salinity. Notably, biomarker parameters exhibit non-linear evolutionary trends under intense volcaniclastic input, requiring multi-proxy validation for reliable paleo-salinity reconstruction. This study establishes a volcanic-lacustrine salinity dynamics model, highlighting the interplay between eruption magnitude, climatic responses, and basin hydrology. The findings enhance paleoclimate reconstruction in volcanic terrains and provide insights into organic matter accumulation in volcanically active lacustrine basins.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"703 ","pages":"Article 123242"},"PeriodicalIF":3.6,"publicationDate":"2026-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145893632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal and inter-estuarine Sr cycling controlled by water mixing and hydrogenous sediments: Low 87Sr/86Sr in groundwater loss via the Gulf of Cambay","authors":"Abul Qasim ,&nbsp;Satinder Pal Singh","doi":"10.1016/j.chemgeo.2025.123231","DOIUrl":"10.1016/j.chemgeo.2025.123231","url":null,"abstract":"<div><div>Radiogenic Sr isotopes are widely used to quantify the coastal water balance and to determine the terrestrial Sr contributions to the oceans. Here, we present the novel seasonal distributions of dissolved Sr concentration and ⁸⁷Sr/⁸⁶Sr in the Gulf of Cambay estuarine waters (surface and subsurface samples, <em>n</em> = 189) collected during 2016–2017. The primary objective is to elucidate the seasonal and anthropogenic forcings of dissolved Sr cycling in the modernized Narmada and Tapi estuaries, specifically to quantify the less radiogenic Sr contribution from terrestrial groundwater discharge (TGD), which leaches extensive continental flood basalt (Deccan Trap) and ancient limestone deposits in the hinterland. The seasonal scatter plots of salinity versus dissolved Sr exhibit significant and strong correlations (r² ≥ 0.99; <em>p</em>-value &lt;0.0001) in the estuarine surface waters. However, the seasonal mixing of modern seawater and river waters fails to explain the reproducible and systematic variations in dissolved Sr concentration and ⁸⁷Sr/⁸⁶Sr, particularly during non-monsoon seasons. The estuarine Sr isotope budget reveals the vital roles of TGD and hydrogenous sediments, along with a possibility of minor anthropogenic input. The internally recycled Sr, most likely from hydrogenous sediments, reflects the riverine isotopic signature in the Narmada estuary during the monsoon and post-monsoon seasons, while it reflects the seawater signature in the Tapi estuary, irrespective of the seasons. In the Narmada estuary, the TGD fluxes of ∼2.1–3.8 × 10⁷ m³/d, 2.7 × 10⁶ m³/d, and ∼ 5.8 × 10⁵ m³/d are calculated for the monsoon, post-monsoon, and pre-monsoon seasons, respectively. The TGD contribution is not essentially required in the water-stressed Tapi estuary. The collective riverine and TGD flux-weighted Sr supplies of ∼1.9–2.3 × 10⁸ mol/y (⁸⁷Sr/⁸⁶Sr ∼ 0.70959–0.70964) and ∼ 5.2–8.5 × 10⁷ mol/y (⁸⁷Sr/⁸⁶Sr ∼ 0.70878–0.70885) from the isotopically heterogeneous Narmada and Tapi estuaries, respectively, ultimately go to the Arabian Sea. Assuming an order of magnitude higher recycled seawater component as compared to TGD and the average Sr composition of vicinal groundwater, both estuaries together have the potential to contribute a massive supply of less radiogenic Sr ∼1.3–1.8 × 10⁹ mol/y (⁸⁷Sr/⁸⁶Sr ∼ 0.70891–0.70895), which is equivalent to ∼0.3–0.5 % of the global marine radiogenic Sr isotope budget.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"703 ","pages":"Article 123231"},"PeriodicalIF":3.6,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145893635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Calcite TLM as a new natural reference material for in situ U-Pb geochronology and its geological implications","authors":"Tianyi Li ,&nbsp;Ranran Chen ,&nbsp;Shitou Wu ,&nbsp;Rolf L. Romer ,&nbsp;Nick M.W. Roberts ,&nbsp;Kerstin Drost ,&nbsp;David Chew ,&nbsp;Marcel Guillong ,&nbsp;Qian Ma ,&nbsp;Yahui Yue ,&nbsp;Shuangjian Li ,&nbsp;Bohang Xie ,&nbsp;Ahmatjan Abdurahman ,&nbsp;Hao Wang ,&nbsp;Huixi Lin ,&nbsp;Yueheng Yang ,&nbsp;Xusheng Guo","doi":"10.1016/j.chemgeo.2025.123230","DOIUrl":"10.1016/j.chemgeo.2025.123230","url":null,"abstract":"<div><div>Calcite (CaCO₃) forms in a wide variety of geological environments as both a primary and secondary mineral phase and may contain sufficient U for U-Pb geochronology. The limited availability of well-characterized calcite reference materials, however, has impeded its broader application in microanalysis. In this study, a natural calcite sample (TLM) was characterized and assessed as a potential primary reference material for in situ U-Pb geochronology. U-Pb isotopic analyses were conducted across nine independent laboratories using laser ablation (Q, SF, MC)-ICP-MS and isotope dilution (ID)-TIMS, to examine the homogeneity and to determine the U-Pb age of TLM. Calcite TLM has an age homogeneity at the level of ∼ 1.0 %, as indicated by multiple analyses from different laboratories. ID-TIMS analysis of 14 aliquots yielded an intercept age of 222.5 ± 2.8 Ma (2 s) with an initial ²⁰⁷Pb/²⁰⁶Pb value of 0.8380 ± 0.0013. Calcite TLM has an age uncertainty of 1.28 %, which is considerably lower than that of WC-1 (∼2.5 %). Calcite TLM has U and Pb contents of ∼0.35 μg g⁻¹ and ∼ 0.02 μg g⁻¹. Additional C and O stable isotope, radiogenic Sr isotope and trace element compositional data indicate that calcite TLM is likely sourced from meteoric water and indicate that the recurrent karstification may have affected the studied area as late as the Triassic.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"703 ","pages":"Article 123230"},"PeriodicalIF":3.6,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145895534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 evolution of phototrophic Fe(II)-oxidizing bacteria shaping the distribution of iron-bound phosphorus in water columns","authors":"Shan Huang ,&nbsp;Yuanyuan Ren ,&nbsp;Chao Peng ,&nbsp;Chao Zhong ,&nbsp;Jiahao Chen ,&nbsp;Yurong Deng ,&nbsp;Geng Wu ,&nbsp;Yuanyuan Liu ,&nbsp;Hailiang Dong ,&nbsp;Juan Liu","doi":"10.1016/j.chemgeo.2025.123229","DOIUrl":"10.1016/j.chemgeo.2025.123229","url":null,"abstract":"<div><div>The evolution of Fe(II)-oxidizing microorganisms has been closely linked to the evolution of Earth's iron biogeochemical cycle and redox history. However, its impact on the coupled biogeochemical cycling of iron and phosphorus, particularly the distribution of iron-bound phosphate (P_Fe) in water columns, remains largely unexplored. This study elucidates the distinct Fe(II) oxidation mechanisms of the anoxygenic <em>Rhodobacter ferrooxidans</em> SW2 and the oxygenic <em>Synechococcus</em> sp. PCC 7002, along with the properties, transformation processes, and phosphate interactions of their biogenic iron (oxyhydr)oxides. SW2-mediated Fe(II) oxidation via iron oxidase drove sequential transformation from ferrihydrite to green rust and then to goethite. The resulting cell-mineral aggregates had a large hydrodynamic diameter (<em>D</em>_<em>h</em>, up to 26 μm), a high Fe/C ratio (∼2.5), and a rapid sedimentation rate (up to 57.7 m/day), efficiently transporting P_Fe to deep-sea sediments. In contrast, PCC 7002 indirectly oxidized Fe(II) via oxygen production, forming poorly crystalline iron (oxyhydr)oxides stabilized by extracellular polymeric substances. The resultant small aggregates (<em>D</em>_<em>h</em> = ∼6.9 μm), with a slower sedimentation rate (∼3.9 m/day), exhibited high phosphorus retention and were susceptible to dissimilatory iron reduction, facilitating P_Fe recycling in surface waters. These findings suggest that biogenic iron (oxyhydr)oxides from anoxygenic iron oxidizers act as carriers, transporting phosphorus to deep sediments, whereas those from oxygenic cyanobacteria function as phosphorus traps in surface waters. This study provides new insights into how the evolution of Fe(II)-oxidizing microorganisms reshapes P_Fe cycling and distribution in water columns, emphasizing the need to integrate microbiological and geochemical perspectives in understanding Earth's biogeochemical cycles.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"703 ","pages":"Article 123229"},"PeriodicalIF":3.6,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145883388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insights from XAS, FTIR, and PHREEQC into mono- and poly-vanadate (V(V)O43−) adsorption to Hematite","authors":"Jing Zhang ,&nbsp;Victoria S. Coker ,&nbsp;J. Frederick W. Mosselmans ,&nbsp;Thomas L. Goût ,&nbsp;Luís A.E. Batista de Carvalho ,&nbsp;Samuel Shaw","doi":"10.1016/j.chemgeo.2025.123228","DOIUrl":"10.1016/j.chemgeo.2025.123228","url":null,"abstract":"<div><div>Vanadium (V) is a widespread trace element in the environment. At high concentration, due to anthropogenic emission such as mining activities and fossil fuels, it can be toxic to marine systems and terrestrial plants. However, the geochemical behaviour of V remains poorly understood. Here, this study aimed to understand the molecular scale V speciation, adsorption behaviour and bonding mechanisms of V(V) onto hematite as a function of geochemical factors (pH, ionic strength, and V(V) concentration), applying a multi-technique approach comprising aqueous chemical analysis and XAS supported by ATR-FTIR and PHREEQC geochemical speciation calculations. From these data, tetrahedral monovanadate formed a corner-sharing bidentate surface complex at 1.20 mM V(V) and pH 9 and 0.12 mM V(V) at all pH, while octahedral decavanadate formed at a V(V) concentration of 1.20 mM and pH &lt; 7. The dominant coordination environment changed gradually from a mixture of octahedrally and tetrahedrally coordinated V at pH 3 to tetrahedral monovanadate at pH 9. These results demonstrate the marked effects of pH and initial V concentration on V(V) speciation at hematite surfaces, in turn affording predictions of the environmental behaviour of heavy metals released during a variety of anthropogenic activities (e.g. mining) across a range of geochemical conditions. It is envisioned these results will contribute to strategies for the treatment of lands contaminated with heavy metals predominantly through adsorption processes (e.g. mine sites).</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"702 ","pages":"Article 123228"},"PeriodicalIF":3.6,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145845298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Global variation in Cr-spinel trace elements","authors":"Emil Akseli Koskinen Tonboe ,&nbsp;Ikuya Nishio ,&nbsp;Pedro Waterton","doi":"10.1016/j.chemgeo.2025.123227","DOIUrl":"10.1016/j.chemgeo.2025.123227","url":null,"abstract":"<div><div>The major element composition of Cr-spinel [(Mg,Fe²⁺)(Cr,Al,Fe³⁺)₂O₄] has long been used to infer the petrogenesis and tectonic setting of its host rocks. However, overlaps in major element compositions and susceptibility of Mg and Fe²⁺ to secondary alteration limit its diagnostic utility. In contrast, some trace elements may be particularly diagnostic of certain petrogenic processes or retain primary signatures even when major elements are modified, offering a complementary tool for petrogenetic interpretation. However, a comprehensive evaluation of the systematics of trace elements in Cr-spinel has not yet been undertaken.</div><div>This study compiles major and trace element data from Cr-spinel-bearing samples worldwide to assess global variability and to identify robust geochemical indicators. Based on a larger, more representative set of Mid-Ocean Ridge Basalt (MORB) spinel data we present new MORB spinel normalization values and a recommended element order for spinel multi-element plots. We document systematic variations in trace elements (Sc, Ga, V, Ni, Mn) with Cr# (Cr# = Cr/(Cr + Al) mol.), particularly in mantle-derived spinels, and show that these trends reflect mantle depletion. Melting models and regression of literature partition coefficients demonstrate that partitioning of Sc, Ga, Ni, Mn, and Ti is likely compositionally controlled.</div><div>We also show that Cr-spinels from lavas and intrusions can be distinguished based on late-stage re-equilibration with interstitial melt, evident from the low Ru and Cu contents and Sc/Ga ratios in Cr-spinels from intrusions. Our findings highlight the potential of trace element systematics in Cr-spinel as a powerful tool for reconstructing the petrogenesis of mafic-ultramafic rocks.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"702 ","pages":"Article 123227"},"PeriodicalIF":3.6,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145845306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}