Chemical Geology最新文献

{"title":"Intragranular to xenolith-scale water heterogeneity in mantle olivine: Insights into cratonic processes","authors":"Wenzhao Dong ,&nbsp;Yui Kouketsu ,&nbsp;Katsuyoshi Michibayashi","doi":"10.1016/j.chemgeo.2025.122694","DOIUrl":"10.1016/j.chemgeo.2025.122694","url":null,"abstract":"<div><div>This study presents Fourier Transform Infrared (FT-IR) mapping of olivine in mantle xenoliths from the Kaapvaal Craton, introducing methodological innovations for quantifying olivine water content. Our advancements include enabling direct Electron Backscatter Diffraction (EBSD) analysis of FT-IR-measured grains, and developing an automated calculation method to minimize serpentinization effects. This approach enables the calculation of the water content of olivine with high reliability and facilitates a point-to-point correlation between water content and crystallographic orientation. Analysis of garnet lherzolites (100–150 km depth) and spinel peridotites (∼60 km depth) revealed our method's effectiveness for olivine water contents above 40 ppm. Olivine in garnet lherzolites contained 40–210 ppm water, while olivine in spinel lherzolites exhibited contents below the detection limit, indicating heterogeneous water distribution in the Kaapvaal Craton mantle. We observed significant water content heterogeneity across multiple scales: intragranular, inter-grain, and xenolithic. Intragranular water content gradients up to 50 ppm were observed, with high-water olivine (&gt;120 ppm) tending to show gradients aligned with crystallographic axes, suggesting anisotropic water incorporation and diffusion processes. Variations in water content between olivine grains within xenoliths and across different microstructures in garnet lherzolites were also noted. This heterogeneity likely results from complex lithospheric mantle processes, including localized metasomatism and deformation. These findings have important implications for understanding cratonic stability, mantle dynamics, and water-related processes in the Earth's mantle, potentially facilitating small-scale metasomatism or deformation without compromising overall cratonic stability.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"680 ","pages":"Article 122694"},"PeriodicalIF":3.6,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143478741","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":"Subducted ophicarbonates as source for B-bearing diamond formation","authors":"E. Cannaò","doi":"10.1016/j.chemgeo.2025.122693","DOIUrl":"10.1016/j.chemgeo.2025.122693","url":null,"abstract":"<div><div>This study presents <em>in-situ</em> B isotope compositions (δ¹¹B) of antigorite from well-characterized ophicarbonates that underwent prograde to high-pressure (high-<em>P</em>) metamorphic evolution during the Alpine orogeny (300–500 °C and 0.6–2.3 GPa). The δ¹¹B values in antigorite are highly variable, ranging from <em>ca.</em> -8 to +7 ‰. Coupled with <em>in-situ</em> ⁸⁷Sr/⁸⁶Sr ratios of carbonates (ranging from 0.7065 to 0.7085), this B isotope variability may reflect either inherited oceanic imprints or re-equilibration with metamorphic fluids during subduction processes. These interpretations are further corroborated by <em>in-situ</em> REE and incompatible trace element data on antigorite. The devolatilization and densification of slab lithologies during subduction drive the recycling of slab and wedge materials into the Earth's mantle, contributing to its chemical heterogeneity. Remarkably, the δ¹¹B signatures of antigorite reported here overlap with the variability observed in B-bearing diamonds formed at transition zone/lower mantle depths, as well as in carbonatites and ocean island basalts (OIBs), suggesting a geochemical connection. Together with literature data, this study proposes that deeply subducted ophicarbonates may transform into carbonate-bearing secondary peridotites with geochemical features compatible with B-bearing diamonds. Deeply subducted ophicarbonates, with enriched trace element and isotopic signatures, may also act as reservoirs influencing mantle dynamics and the geochemical diversity of OIB and carbonatite mantle sources. These findings provide new constraints into the recycling of B and volatiles at convergent margins, extending to depths compatible with the lower mantle region.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"680 ","pages":"Article 122693"},"PeriodicalIF":3.6,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to “Study of olivine-hosted melt and spinel inclusions from the Song Da ultramafic volcanic suite, northern Vietnam: Compositions, crystallization temperatures, and origin of the low-Ti komatiite-like and high-Ti primary melts” [Chemical Geology 662 (2024) 122219]","authors":"Charbel Kazzy ,&nbsp;Alexander V. Sobolev ,&nbsp;Valentina G. Batanova ,&nbsp;Evgeny V. Asafov ,&nbsp;Eero Hanski ,&nbsp;Igor S. Puchtel ,&nbsp;Andrey E. Izokh ,&nbsp;Leonid V. Danyushevsky ,&nbsp;Vũ Hoàng Ly ,&nbsp;Can Pham-Ngoc ,&nbsp;Tran Tuan Anh","doi":"10.1016/j.chemgeo.2025.122678","DOIUrl":"10.1016/j.chemgeo.2025.122678","url":null,"abstract":"","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"679 ","pages":"Article 122678"},"PeriodicalIF":3.6,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420730","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":"Overcoming analytical limitations with 5-line multi-dynamic Nd isotope measurements by thermal ionisation mass spectrometry","authors":"C. Israel ,&nbsp;C. Chauvel ,&nbsp;T.-H. Luu ,&nbsp;E.C. Inglis ,&nbsp;D. Roberts","doi":"10.1016/j.chemgeo.2025.122686","DOIUrl":"10.1016/j.chemgeo.2025.122686","url":null,"abstract":"<div><div>The extinct ¹⁴⁶Sm<img>¹⁴²Nd radio-isotope chronometer is a valuable tool to study the first 500 Myr of Earth's history, although the entire range of variations of the ¹⁴²Nd/¹⁴⁴Nd ratio in terrestrial materials is on the order of 20 ppm only. The challenge is that measuring small isotope variations needs very high precision measurements (better than 5 ppm), which are difficult to obtain.</div><div>Here we present high-precision measurements of Nd isotope ratios performed over a period of three years using the latest generation Thermal Ionisation Mass Spectrometer (TIMS) developed by Nu Instruments – Nu TIMS. The Nu TIMS comprises 16 fixed Faraday cups and a zoom optics system that allow 5-line multi-dynamic analyses with the acquisition of three dynamic ratios for all Nd isotopes. This new method, coupled with an enhanced Nd⁺ signal provides precise measurements with internal errors lower than 2 ppm on ¹⁴²Nd/¹⁴⁴Nd.</div><div>We assess the performance of the method using multiple measurements of JNdi-1 and AMES Rennes Nd pure standards, together with rock reference materials. For example, typical JNdi-1 measurements performed over a period of 19 months average at ¹⁴²Nd/¹⁴⁴Nd = 1.1418299 ± 36 (2sd – 3.2 ppm), ¹⁴³Nd/¹⁴⁴Nd = 0.5121007 ± 10 (2.0 ppm), ¹⁴⁵Nd/¹⁴⁴Nd = 0.3484046 ± 6 (1.8 ppm), ¹⁴⁸Nd/¹⁴⁴Nd = 0.2415790 ± 10 (4.1 ppm) and ¹⁵⁰Nd/¹⁴⁴Nd = 0.2364481 ± 27 (11.3 ppm). With such precision and accuracy, subtle variations of ¹⁴²Nd/¹⁴⁴Nd ratios, as low as 3 ppm, can now be detected in natural samples.</div><div>Minute differences in ¹⁴⁵Nd/¹⁴⁴Nd, ¹⁴⁸Nd/¹⁴⁴Nd and ¹⁵⁰Nd/¹⁴⁴Nd ratios can now also be detected in natural samples, allowing better identification of nucleosynthetic anomalies in extra-terrestrial samples. For terrestrial samples, it allows detection of traces of samarium, and of nuclear field shift effect due to analytical issues. In particular, we demonstrate that some Sm is present in the JNdi-1 standard and affects both its ¹⁴⁸Nd/¹⁴⁴Nd and ¹⁵⁰Nd/¹⁴⁴Nd ratios, making a systematic interference correction necessary. By detecting the existence of nuclear field shift effect on Nd isotopes, we can now prevent mis-interpretations of ¹⁴²Nd/¹⁴⁴Nd deviations that could be wrongly attributed to radiogenic signatures acquired during the Hadean.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"680 ","pages":"Article 122686"},"PeriodicalIF":3.6,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143463775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic redox evolution in the middle-late Mesoproterozoic oceans","authors":"Wei Wei ,&nbsp;Huajian Wang ,&nbsp;Shuichang Zhang ,&nbsp;Lin-Hui Dong ,&nbsp;Dongdong Li ,&nbsp;Fang Huang","doi":"10.1016/j.chemgeo.2025.122685","DOIUrl":"10.1016/j.chemgeo.2025.122685","url":null,"abstract":"<div><div>The middle Proterozoic (ca. 1.8–0.8 Ga) was thought to be persistently static in eukaryotic biodiversity and oxygenation at the Earth's surface, until the Neoproterozoic Oxygenation Event (NOE). The conventional view of Boring Billion is being challenged by increasing evidence of frequently disturbed oxygenation events in the atmosphere and ocean at ca. 1.6–1.4 Ga, namely the Mesoproterozoic Oxygenation Event (MOE). However, marine redox information during the intermediate period between the MOE and NOE (the middle-late Mesoproterozoic) remains elusive. Here, we report V isotope compositions (δ⁵¹V) of black shales from the middle and upper Shennongjia subgroups in the Shennongjia micro-block, in order to reconstruct the evolution in global marine oxygenation extent during this poorly studied period. The δ⁵¹V values exhibit a large variability, which should have been caused by changes in local depositional environment and global marine oxygenation extent. Based on the sedimentary δ⁵¹V records and local redox information, we reconstruct temporary open-ocean seawater δ⁵¹V variation during the middle-late Mesoproterozoic. The result suggests several episodes of widespread marine oxygenation interspersed with extensive euxinia. It sheds new light into dynamic environmental and eukaryotic evolutions in the middle-late Mesoproterozoic oceans.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"679 ","pages":"Article 122685"},"PeriodicalIF":3.6,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437201","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":"Zircon solubility in silicate melts: New empirical models and thermodynamics","authors":"Alexander Borisov ,&nbsp;Leonid Aranovich ,&nbsp;Paula Antoshechkina","doi":"10.1016/j.chemgeo.2025.122682","DOIUrl":"10.1016/j.chemgeo.2025.122682","url":null,"abstract":"<div><div>Published experimental data on zircon (<em>Zrn</em>) solubility in silicate melts are critically evaluated to conclude that H₂O dissolved in the melts has no to minor effect on the <em>Zrn</em> solubility. The effect of pressure is small but resolvable. A new empirical equation describing zircon solubility in silicate melts as a function of temperature, pressure and melt composition, is derived based on the published experimental data. The new equation predicts log Zr (ppm) in the melts with a standard error of 0.087, which is equivalent to ca. 22 % error in the range from 178 to 61,370 ppm Zr, 750-1500 °C, and 0.001–25 kbar covered by the experiments. A new equation describing the relatively low-temperature range 750-1200 °C, more appropriate for application to natural magmatic rocks, is also suggested.</div><div>The new equation for temperature dependence of the standard Gibbs free energy of zircon melting reaction is derived for the first time. The equation is consistent with the high temperature phase diagram of the ZrO₂-SiO₂ system and predicts metastable zircon fusion temperature at T_fus = 2232 K. This equation is silicate melt model independent. Thermodynamic mixing properties of the zircon species in silicate melts consistent with the MELTS thermodynamic model retrieved by fitting 186 experimental data points, agree qualitatively with the empirical formulation and simple equations suggested by Bruce Watson and co-workers.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"679 ","pages":"Article 122682"},"PeriodicalIF":3.6,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429253","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":"Quantification of the REE3+ aqua ions and chloride species in aqueous fluids by in situ Raman spectroscopy using perturbations of the water band","authors":"Bryan J. Maciag ,&nbsp;Alexander P. Gysi ,&nbsp;Nicole C. Hurtig","doi":"10.1016/j.chemgeo.2025.122684","DOIUrl":"10.1016/j.chemgeo.2025.122684","url":null,"abstract":"<div><div>Acidic NaCl-rich aqueous fluids play a crucial role in forming hydrothermal rare earth elements (REE) mineral deposits. Aqueous REE mobility is mostly controlled by the stability of REE³⁺ and REE chloride species. Our current knowledge of REE speciation is based on solubility data, thermodynamic models and <em>in situ</em> spectroscopic measurements, sometimes coupled with molecular simulations. Here we investigate Nd and Yb speciation in pH 2 chloride-bearing solutions at 25 °C and 0.1 MPa with variable Cl/REE ratios using Raman spectroscopy in solutions with 0.1 to 0.6 mol/kg NdCl₃ or YbCl₃ and 0.2 to 3.2 mol/kg NaCl. Due to the challenges in resolving the REE-Cl band, we develop a new method using the water vibrational mode and multivariate curve resolution (MCR) analysis. The Raman spectra for the vibrational band of water (2700 to 3900 cm⁻¹) were collected at 25 °C and fitted by three Gaussian sub-peaks, then quantified using MCR analysis to de-convolute the water band into bulk H₂O and the perturbations caused by of Cl⁻, REE³⁺, and REE chloride species. REE speciation based on the perturbations of the water band indicates that REE³⁺ aqua ions dominate in acidic solutions at 25 °C, but up to ∼20 mol% YbCl²⁺ forms at high YbCl₃ concentrations. The new method is promising for quantifying <em>in situ</em> speciation of the REE³⁺ aqua ions and REE chloride species in aqueous fluids while providing information on the hydration of ions. This method improves our molecular level understanding of REE aqueous species and their role in REE mobilization during fluid-rock interaction.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"679 ","pages":"Article 122684"},"PeriodicalIF":3.6,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143512016","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":"Mo isotope evidence for the significance of subducted continental crust in formation of post-collisional porphyry Cu deposits","authors":"Jing Jing Fan ,&nbsp;Qiang Wang ,&nbsp;Xiao Ping Long ,&nbsp;Derek A. Wyman ,&nbsp;Andrew C. Kerr ,&nbsp;Jie Li ,&nbsp;Zi Long Wang ,&nbsp;Lin Gong ,&nbsp;Dong Jing Xu ,&nbsp;Qi Ji Yang ,&nbsp;Le Zhang ,&nbsp;Ze-Xian Cui","doi":"10.1016/j.chemgeo.2025.122683","DOIUrl":"10.1016/j.chemgeo.2025.122683","url":null,"abstract":"<div><div>Porphyry systems in continental collision belts contain substantial copper (Cu) and molybdenum (Mo) resources. However, unraveling their magma source compositions poses a significant challenge due to the superposition of previous oceanic subduction fingerprints. We report Mo isotope data on post-collisional (Oligocene–Miocene) Cu (Mo)-bearing porphyries (CBPs) and related barren-ore rocks (including Eocene granites and Miocene high-Mg diorites and ore-barren granites) in the eastern Gangdese belt, southern Tibet. The Eocene granites with high δ^98/95Mo values (0.37–0.58 ‰) and K₂O, Th contents originated from anoxic sediment-modified juvenile lower crust related to oceanic subduction. The Miocene high-Mg diorites with shoshonitic characteristic have extremely low δ^98/95Mo of −1.20 ‰ to −0.92 ‰, possibly deriving from a lithospheric mantle metasomatized by slab melts from subducted Indian crust. By contrast, the CBPs show moderate and variable δ^98/95Mo values (−0.85 ‰ to 0.34 ‰), reflecting either source or magma mixing of juvenile Asian lithosphere and subducting continental crust-derived melt components. The Miocene ore-barren granites have element compositions similar to the CBPs but are more Na-rich and have lower Th contents, slightly depleted Sr-Nd isotopes, and heavy Mo isotopes (−0.14 ‰ to 0.23 ‰), implying lower amounts of continental components in their magma source. Our Mo isotope data thus provides solid evidence for the incorporation of subducted Indian slab melts into the CBP magmas. Furthermore the CBPs contain more Indian components than the Miocene ore-barren granites, suggesting that the input of subducted continental crust melts is critical in the formation of post-collisional porphyry systems possibly by oxidizing the overlying fertile lithosphere.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"680 ","pages":"Article 122683"},"PeriodicalIF":3.6,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143444930","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":"Characterizing sedimentary organic carbon in a hydrothermal spreading center, the Escanaba Trough","authors":"Hope L. Ianiri,&nbsp;Pamela L. Campbell,&nbsp;Amy Gartman,&nbsp;Nancy G. Prouty","doi":"10.1016/j.chemgeo.2025.122679","DOIUrl":"10.1016/j.chemgeo.2025.122679","url":null,"abstract":"<div><div>Sediments in critical marine mineral environments are of wide importance due to their preservation of both marine minerals and organic carbon (OC) stocks. However, OC storage and cycling is often overlooked in mineral system studies. This work characterizes sedimentary OC within the Escanaba Trough, a hydrothermal sulfide system off the coast of northern California. By utilizing ROV-based push coring, we collected sediments near and far from high temperature, low temperature, and inactive vents. We applied a multipronged organic geochemical approach, measuring bulk sediment, OC fractions of varying labilities, and biomarkers to tease apart the storage, source, and cycling of OC within this complex system. In contrast to past work indicating a primarily terrestrial source to deeper, Pleistocene sediments, our results suggest a primarily marine source in surface sediments at least 50 m away from active venting. Near active venting, we see evidence of locally produced chemosynthetic OC in addition to the background marine source. This chemosynthetic OC appears to be rapidly remineralized and supports more complex deep-sea food webs compared to hemipelagic sites. Still, the greatest contribution of labile OC was observed at inactive vent sites, which we suggest is due to hydrothermal fluid alteration of more labile OC at actively venting sites. Depending on fluid temperature, hydrothermally altered OC is either preserved in the sediments as petroleum or migrated with fluid flow. Considering inactive sites are those most likely to be targeted by potential mining, we suggest additional studies could verify if these results apply at other sedimented seafloor massive sulfide systems.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"679 ","pages":"Article 122679"},"PeriodicalIF":3.6,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453028","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":"Methanogenesis rather than carbon dioxide production drives positive priming effects in anoxic sediments of saline lakes","authors":"Jian Yang ,&nbsp;Pingping Zhang ,&nbsp;Min Cai ,&nbsp;Mingxian Han ,&nbsp;Zenghui Wu ,&nbsp;Haiyi Xiao ,&nbsp;Jibin Han ,&nbsp;Xiying Zhang ,&nbsp;Hailiang Dong ,&nbsp;Hongchen Jiang","doi":"10.1016/j.chemgeo.2025.122680","DOIUrl":"10.1016/j.chemgeo.2025.122680","url":null,"abstract":"<div><div>Priming effect is an essential mechanism regulating global organic carbon storage. The generation of priming effects has been exclusively investigated in anoxic sediments of freshwater lakes and in oxic sediments of saline lakes. However the differences in priming effect generation between oxic and anoxic saline lake sediments remain unclear. Here, we investigated the effects of algal and grass organic matter additions on priming effects under oxic and anoxic conditions in saline lake sediments. Sediment microcosms from three saline lakes with different salinities were amended with algal (¹³C-labeled <em>Chlorella vulgaris</em>) and grass (¹³C-labeled <em>Festuca ovina</em>) organic matter and incubated under oxic and anoxic conditions for 7 days to estimate priming effect intensities for CO₂ and CH₄ production. The results showed that algal and grass organic matter additions promoted higher CO₂ production under anoxic conditions than under oxic conditions, with grass organic matter inducing more CO₂ production than algal organic matter. Under oxic conditions, both algal and grass OM additions induced positive priming effects for CO₂ production, while negative priming effects were observed under anoxic conditions. In contrast, positive priming effects for CH₄ production were found in all anoxic microcosms. Our study highlights the importance of OM mineralization and positive priming effects for CH₄ production in anoxic sediments of saline lakes, which should not be overlooked given the high global warming potential of CH₄ and the increasing anoxia in global lakes due to climate change.</div></div>","PeriodicalId":9847,"journal":{"name":"Chemical Geology","volume":"678 ","pages":"Article 122680"},"PeriodicalIF":3.6,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394338","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}