Chemical Geology最新文献_第2页

A diagenetic shale source for lithium in oilfield brines: Insights from the Devonian Bakken–Three Forks system, Williston Basin 油田卤水中锂的成岩页岩来源：来自威利斯顿盆地泥盆系Bakken-Three Forks体系的见解

IF 3.9 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Chemical Geology

Pub Date : 2026-01-30 DOI: 10.1016/j.chemgeo.2026.123270

Kyle M. Henderson, Anthony E. Williams-Jones, Swapan Sahoo, Chunqing Jiang, Timothy O. Nesheim

引用次数: 0

Tracing arsenic and antimony in mining-impacted environments: New insights from antimony isotopes 在采矿影响的环境中追踪砷和锑：来自锑同位素的新见解

IF 3.9 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Chemical Geology

Pub Date : 2026-01-30 DOI: 10.1016/j.chemgeo.2026.123271

Colin Ferrari, Kevin B. White, Carol J. Ptacek, David W. Blowes

引用次数: 0

Extremely light Mo isotope compositions of the lower continental crust caused by fluid leaching 流体浸出引起的下大陆地壳极轻的Mo同位素组成

IF 3.9 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Chemical Geology

Pub Date : 2026-01-29 DOI: 10.1016/j.chemgeo.2026.123267

Ying Wei, Xiao-Long Huang, Yanjun Wang

引用次数: 0

Prolonged cooling of andesitic-dacitic lava flows produces optimal groundmass material for 40Ar/39Ar dating 安山岩-英安岩熔岩流的长期冷却为40Ar/39Ar定年提供了最佳的地面物质

IF 3.6 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Chemical Geology

Pub Date : 2026-01-28 DOI: 10.1016/j.chemgeo.2026.123268

Chris E. Conway , Andrew T. Calvert , Osamu Ishizuka , Seiko Yamasaki , Isoji Miyagi , Yumiko Harigane , Graham S. Leonard

Organizing the eruptive histories and petrogenetic models that underpin hazard assessments at active volcanoes typically requires high-precision ages for late Pleistocene to Holocene lava flows. In this study, features of an existing ⁴⁰Ar/³⁹Ar dataset for andesitic-dacitic rocks from Ruapehu volcano, Aotearoa New Zealand, were interrogated with new microanalytical data to identify the optimal groundmass material for age determination. To understand the behavior of K and Ar within the cooling melt of lavas during their emplacement, we examined and compared the petrological features of samples from the ice-chilled margin and interior of a lava flow. The groundmass of the rapidly cooled sample comprises non-vesicular rhyolitic glass and microlites of plagioclase, orthopyroxene, and magnetite. The sample from the flow interior has minimal amounts of groundmass glass, and interstices are instead occupied by sanidine and tridymite. Thermodynamic modelling supports the interpretation that sanidine crystallized as a stable groundmass phase during slow cooling of degassed melt in the interior zones of lavas that were insulated behind their glassy margins. Our evaluation of the age data shows that sanidine contributed high yields of radiogenic argon during step-heating experiments for samples collected from lava interiors, which enabled high-precision ⁴⁰Ar/³⁹Ar ages to be determined. Using Ruapehu as an example of an arc volcano affected by lava-ice interaction, we provide a basic field guide for identifying lava flows that contain groundmass sanidine at the expense of glass. Target outcrops also offer opportunities for reconstructing geomagnetic dynamics and volcano–climate relationships during the Pleistocene and Holocene.

组织喷发历史和构成活火山危险性评估基础的岩石成因模型，通常需要对晚更新世到全新世熔岩流进行高精度的年代测定。在这项研究中，研究人员利用新的微量分析数据，对新西兰鲁阿佩胡火山现有的40Ar/39Ar安山岩-英英质岩石数据集的特征进行了研究，以确定用于年龄测定的最佳地块材料。为了了解K和Ar在熔岩就位过程中冷却熔体中的行为，我们检查并比较了熔岩流冰封边缘和内部样品的岩石学特征。快速冷却样品的基质包括非囊状流纹岩玻璃和斜长石、正辉石和磁铁矿的微晶岩。来自流动内部的样品具有最少量的底质玻璃，而间隙则被苯胺和三钇石所占据。热力学模型支持这样一种解释，即在玻璃状边缘后面的熔岩内部区域脱气熔体缓慢冷却期间，sanidine结晶为稳定的基质相。我们对年龄数据的评估表明，在从熔岩内部收集的样品的阶梯加热实验中，sanidine贡献了高产量的放射成因氩，这使得高精度的40Ar/39Ar年龄得以确定。以鲁阿佩胡火山为例，研究了受熔岩-冰相互作用影响的弧火山，提供了一个基本的现场指南，用于识别含有地面物质的岩浆流，而牺牲了玻璃。目标露头也为重建更新世和全新世的地磁动力学和火山-气候关系提供了机会。

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引用次数: 0

Sulfate-driven anaerobic oxidation of methane in deeply buried sediments on the Southern Campbell Plateau 南坎贝尔高原深埋沉积物中硫酸盐驱动的甲烷厌氧氧化

IF 3.6 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Chemical Geology

Pub Date : 2026-01-27 DOI: 10.1016/j.chemgeo.2026.123269

Alex J. Reis , Vanessa Fichtner , Andrea M. Erhardt

Sulfur is a key component in the reduction of organic carbon in marine sediments. Sulfate-driven anaerobic oxidation of methane and microbial sulfate reduction are the leading processes driving the removal of organic carbon and sulfur from the environment. Microbial sulfate reduction has been well studied in most marine depositional environments, however, studies examining sulfate-driven anaerobic oxidation of methane are primarily limited to shallow burial or methane seep environments. Sediments recovered from IODP site U1553 on the southern Campbell Plateau demonstrate evidence of a deeply buried sulfate-methane transition zone (SMTZ). In this study, we identified a deep (> 500mbsf) sulfate-methane transition zone through the analysis of sulfur isotopes in sulfide minerals (d³⁴S_CRS). Three potential paleo-SMTZs were also identified as peaks in d³⁴S_CRS below the modern SMTZ, suggesting the changing seafloor and depositional conditions since the late Oligocene contributed to the upward migration of the SMTZ over time. Understanding the evolution of deep SMTZs and the processes associated with them will help further constrain how the sulfur and carbon cycles interact and drive carbon storage in marine sediments.

硫是海洋沉积物中有机碳减少的关键成分。硫酸盐驱动的甲烷厌氧氧化和微生物硫酸盐还原是驱动从环境中去除有机碳和硫的主要过程。微生物硫酸盐还原已经在大多数海洋沉积环境中得到了很好的研究，然而，对硫酸盐驱动的甲烷厌氧氧化的研究主要局限于浅埋或甲烷渗漏环境。从坎贝尔高原南部的IODP U1553遗址恢复的沉积物显示了深埋的硫酸盐-甲烷过渡带（SMTZ）的证据。通过对硫化物矿物（d34SCRS）中硫同位素的分析，确定了深部（> 500mbsf）硫酸盐-甲烷过渡带。3个潜在的古中第三纪过渡带的d34SCRS峰位于现代中第三纪过渡带下方，表明晚渐新世以来海底和沉积条件的变化促进了中第三纪过渡带的向上迁移。了解深层SMTZs的演化及其相关过程将有助于进一步限制硫和碳循环如何相互作用并驱动海洋沉积物中的碳储存。

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引用次数: 0

Hydrogen generation potential of peridotites and pyroxenites in ophiolitic settings 蛇绿岩背景下橄榄岩和辉石岩的产氢潜力

IF 3.6 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Chemical Geology

Pub Date : 2026-01-25 DOI: 10.1016/j.chemgeo.2026.123266

Vivian Azor de Freitas , Tiziano Boschetti , Isabelle Moretti , Alessandra Montanini

The partially serpentinized mantle bodies exposed in the western sector of the Northern Apennines, Italy, represent a favorable environment for natural hydrogen (H₂) studies, particularly Mt. Prinzera, which hosts a hyperalkaline spring containing dissolved H₂. A geochemical characterization of peridotite, pyroxenite, and serpentinite samples was carried out to reconstruct the past and present stages of serpentinization and to assess their H₂ generation potential. This study combined mineralogical, whole-rock compositional, and redox-state analyses, along with thermodynamic modeling of spring waters. The major serpentinization event associated with mantle exhumation in the Middle to Late Jurassic was marked by extensive replacement of olivine, clinopyroxene, orthopyroxene by serpentine and subordinate magnetite. Alteration was more intense in olivine than in pyroxenes, resulting in higher serpentinization degrees in peridotites (∼ 50 vol%), compared to pyroxenites (∼ 10 vol%). Mineralogical evidence suggests temperatures of approximately 220 °C and 300 °C for this stage. Currently, serpentinization and H₂ generation are likely active at Mt. Prinzera, with fluid-rock interactions involving particularly the oxidation of a small fraction of Fe²⁺-serpentine and/or magnetite, rather than the primary mineral assemblage. Thermodynamic equilibria, based on the activities obtained from the aqueous speciation, and the isotope composition of the hyperalkaline water were used to estimate the temperature at depth, which appears to be markedly low. Thus, serpentinization may occur either at the base of Mt. Prinzera or within a deeper, hidden ultramafic body. In addition, trapped H₂ accumulations originating from earlier serpentinization stages can also be considered.

意大利北部亚平宁西段暴露的部分蛇纹岩化地幔体为研究天然氢（H2）提供了有利的环境，特别是Prinzera山，它拥有一个含有溶解H2的高碱性泉。通过对橄榄岩、辉石岩和蛇纹岩样品的地球化学表征，重建了过去和现在的蛇纹岩化阶段，并评估了它们的生氢潜力。这项研究结合了矿物学、全岩成分和氧化还原状态分析，以及泉水的热力学模型。中晚侏罗世与地幔发掘相关的主要蛇纹岩化事件，标志着橄榄石、斜辉石、正辉石被蛇纹岩和次级磁铁矿广泛取代。橄榄石的蚀变比辉石更强烈，导致橄榄岩的蛇纹石化程度（~ 50 vol%）高于辉石岩（~ 10 vol%）。矿物学证据表明，这一阶段的温度约为220 °C和300 °C。目前，在Mt. Prinzera，蛇纹石化和H2生成很可能是活跃的，流体-岩石相互作用主要涉及一小部分Fe2+-蛇纹石和/或磁铁矿的氧化，而不是主要矿物组合。热力学平衡，基于从水形态得到的活度，以及高碱性水的同位素组成被用来估计深度温度，这似乎明显较低。此外，也可以考虑早期蛇纹岩阶段形成的圈闭H₂聚集。因此，蛇纹岩化可能发生在普林泽拉山的底部，也可能发生在一个更深的、隐藏的超镁铁质体中。

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引用次数: 0

Holocene–pleistocene provenance transitions in the Cauvery Delta, South India: Evidence from Sr-Nd isotopes 南印度柯韦里三角洲全新世-更新世物源转换：来自Sr-Nd同位素的证据

IF 3.6 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Chemical Geology

Pub Date : 2026-01-20 DOI: 10.1016/j.chemgeo.2026.123265

Malik Zubair Ahmad , Pramod Singh , S. Balakrishnan , Suhail Hussain Sheikh

We investigate temporal shifts in sediment provenance through comprehensive ⁸⁷Sr/⁸⁶Sr and εNd₀ analyses of two sediment cores (Uttrangudi and Porayar) from the Cauvery Delta, South India. We assessed the role of weathering intensity and source rock variability and glacial/interglacial climate phases using isotopic signatures. Isotopic data of two cores reveal distinct shifts in provenance between the Late Pleistocene and Holocene periods. Around ∼14 ka BP, the isotopic signatures indicate enhanced contributions from the Dharwar Craton, consistent with more efficient sediment transport from the distant upper catchment when the lower sea level exposed the continental shelf. In contrast, Holocene sediments (upper core sections) reflect a dominant contribution from the Southern Granulite Terrain, driven by intensified Northeast Monsoons. Our data shows that weathering intensity may influence isotopic compositions, with Nd isotopes being particularly sensitive to these post-depositional processes. The Porayar core exhibits an unusual inverse relationship in which finer fractions correspond to less radiogenic εNd₀ values. Our findings underscore the critical influence of source rock variability, Quaternary sea-level fluctuations, and climate-driven weathering intensity on the Sr-Nd isotopic composition of deltaic sediments.

本文通过对印度南部Cauvery三角洲两个沉积物岩心（Uttrangudi和Porayar）的87Sr/86Sr和εNd0的综合分析，探讨了沉积物物源的时间变化。我们利用同位素特征评估了风化强度、烃源岩变异和冰期/间冰期气候阶段的作用。两个岩心的同位素资料揭示了晚更新世与全新世之间物源的明显变化。在~ 14 ka BP左右，同位素特征表明来自Dharwar克拉通的贡献增强，这与当较低的海平面暴露大陆架时来自远上部集水区的更有效的沉积物输送相一致。全新世沉积物（上部岩心剖面）主要来自东北季风增强的南部麻粒岩地形。我们的数据表明，风化强度可能影响同位素组成，其中Nd同位素对这些沉积后过程特别敏感。Porayar岩心表现出不同寻常的反比关系，越细的岩心对应越小的放射性成因εNd0值。我们的发现强调了烃源岩变率、第四纪海平面波动和气候驱动的风化强度对三角洲沉积物Sr-Nd同位素组成的重要影响。

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引用次数: 0

CO2 fluxing and carbon assimilation by arc melts during magma–limestone interaction 岩浆-灰岩相互作用过程中弧熔体的CO2通量和碳同化作用

IF 3.6 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Chemical Geology

Pub Date : 2026-01-20 DOI: 10.1016/j.chemgeo.2026.123264

Frances M. Deegan , Manfredo Capriolo , Valentin R. Troll , Franz A. Weis , Sara Callegaro , Simone Colucci , Carmela Freda , Valeria Misiti , László E. Aradi , Henrik Skogby , Herlan Darmawan , Harri Geiger

Reworking of limestone (CaCO₃) by magma is an important source of carbon in volcanic arc emissions. However, while it is broadly understood that CO₂ is liberated during magma–limestone interaction, the degassing behaviour of calcite in silicate melts is less well constrained. In this study, we carried out microspectroscopic analysis of volatiles within fluid inclusions and glass (former melt) in the products of short-term experiments simulating limestone assimilation in mafic arc melt (T = 1200 °C, P = 0.5 GPa, runtimes of 0 to 300 s). The experimental products consist of partly to wholly assimilated limestone xenoliths enveloped by CaO-rich silicate glass (reacting melt) that grades into mafic glass (host melt). Micro- to milli-metric sized fluid-filled bubbles permeate the experimental products. This study reveals that limestone assimilation induces extremely fast apparent diffusivity of CO₂ (D_CO2 ≳ 10⁻⁷ m²/s) through both the reacting melt and the host melt. Volatile saturation is thus quickly reached, triggering nucleation of bubbles mainly containing CO₂ ± CO, CH₄, N₂, H₂, and H₂O. Crucially, we find that the host melt contains dissolved CO₂ from limestone, despite showing no other compositional evidence for limestone assimilation. Mafic melts in volcanic regions underlain by limestone may therefore mobilise and transport more carbon than previously thought, with implications for eruptive behaviour, volcanic CO₂ inventories, and long-term climate warming.

岩浆对石灰岩（CaCO3）的改造是火山弧排放碳的重要来源。然而，虽然人们普遍认为，在岩浆-石灰岩相互作用过程中，二氧化碳会被释放出来，但硅酸盐熔体中方解石的脱气行为却没有得到很好的约束。在本研究中，我们对模拟基性电弧熔体中石灰石同化的短期实验（T = 1200°C, P = 0.5 GPa，运行时间0 ~ 300 s）的产物中的流体包裹体和玻璃（前熔体）中的挥发物进行了显微光谱分析。实验产物由部分或全部同化的石灰石捕虏体组成，被富含cao的硅酸盐玻璃（反应熔体）包裹，并渐变成基性玻璃（主熔体）。微至毫米大小的充满流体的气泡渗透到实验产品中。研究表明，石灰石的同化作用使得CO2在反应熔体和宿主熔体中的表观扩散率都非常快（DCO2 > 10−7 m2/s）。从而迅速达到挥发饱和，触发主要含有CO2±CO、CH4、N2、H2和H2O的气泡成核。至关重要的是，我们发现宿主熔体中含有石灰石中溶解的二氧化碳，尽管没有其他石灰石同化的成分证据。因此，石灰岩下的火山地区的镁铁质融化可能比以前认为的动员和运输更多的碳，这对火山喷发行为、火山二氧化碳库存和长期气候变暖都有影响。

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引用次数: 0

Crystallization of REE phases within La-Na-(Ca)-Cl-(F)-C-H-O systems La-Na-(Ca)- cl -(F)- c - h - o体系中稀土相的结晶

IF 3.6 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Chemical Geology

Pub Date : 2026-01-16 DOI: 10.1016/j.chemgeo.2026.123255

Jingui Xu , Qifa Zhong , Wei Zhao , Dongzhou Zhang , Li Zhou , Yi Zhou , Wei Zhang , Wenge Zhou , Dawei Fan

Carbonatite-hosted rare earth element (REE) deposits provide the world's primary source of REEs. Understanding the relative stability of REE minerals within carbonatite systems is vital for deciphering the genesis of carbonatite-related REE deposits. Yet, experimental data of REE minerals at high pressure and high temperature conditions remain scarce. This study reports a series of crystallization experiments involving REE phases in the La-Na-(Ca)-Cl-(F)-C-H-O systems, conducted between 490 and 750 °C and at pressures of 0.3–0.5 GPa. In the F-free systems, Na-REE carbonate (carbocernaite) coexists with hydroxylbastnäsite and remains stable across the temperature range tested. The addition of Ca leads to their coexistence with calcite and induces a partial substitution 2Ca ↔ Na + La in carbocernaite. Increasing REE concentration promotes the formation of a completely new compound, a Cl-bearing REE carbonate (La₃(CO₃)₄Cl). In contrast, in the F-bearing systems, bastnäsite is the dominant REE phase, with elevated temperatures favoring the crystallization of REE fluoride (fluocerite, LaF₃). The addition of Ca results in bastnäsite coexisting with calcite and fluorite. Notably, Na-REE carbonates do not form in F-bearing runs, even at low F concentrations (∼0.9 wt%). These findings suggest two main implications: first, the formation of LaF₃ at higher temperatures relative to bastnäsite supports field evidence that fluocerite crystallizes at higher temperatures and serves as a precursor to bastnäsite. Second, the absence of Na-REE carbonates in F-bearing experiments may explain why some deposits have no evidence of former existence of Na-REE carbonates.

碳酸盐岩型稀土矿床是世界上稀土元素的主要来源。了解碳酸盐岩体系中稀土矿物的相对稳定性对于破解碳酸盐岩相关稀土矿床的成因至关重要。然而，在高压和高温条件下稀土矿物的实验数据仍然很少。本研究报道了一系列涉及La-Na-(Ca)- cl -(F)-C- h - o体系中稀土相的结晶实验，实验温度为490 ~ 750℃，压力为0.3 ~ 0.5 GPa。在无f体系中，Na-REE碳酸盐（碳石蜡）与hydroxylbastnäsite共存，并在测试温度范围内保持稳定。Ca的加入导致它们与方解石共存，并在碳碳石中引起2Ca↔Na + La的部分取代。稀土浓度的增加促进了一种全新化合物的形成，即含cl的稀土碳酸盐（La3(CO3)4Cl）。相反，在含f体系中，bastnäsite是主要的稀土相，温度升高有利于稀土氟化物（氟铈矿，LaF3）的结晶。Ca的加入使bastnäsite与方解石、萤石共存。值得注意的是，即使在低F浓度（~ 0.9 wt%）下，Na-REE碳酸盐也不会在含F流体中形成。这些发现提出了两个主要含义：首先，相对于bastnäsite， LaF3在更高温度下的形成支持了现场证据，即氟石在更高温度下结晶，并作为bastnäsite的前体。其次，含f实验中Na-REE碳酸盐的缺失可以解释为什么有些矿床没有Na-REE碳酸盐的证据。

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引用次数: 0

Epigenetic geochemical behavior of fluorine and beryllium in lepidolite residue 锂云石渣中氟、铍的表观地球化学行为

IF 3.6 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Chemical Geology

Pub Date : 2026-01-16 DOI: 10.1016/j.chemgeo.2026.123256

Huichun Gong , Pingchao Ke , Xiang Tan , Lingxiu Long , Yuanyong Qin , Lingling Xu , Jian Wang , Guangrong Li , Yipeng Zhou

The epigenetic geochemical behavior of critical metals in weathering environments is fundamental to understanding their mobility and cycling. This study systematically investigates the dissolution kinetics and aqueous speciation of fluoride (F⁻) and beryllium (Be²⁺) from lepidolite residues under simulated weathering conditions. Column leaching experiments revealed a distinct temporal fractionation: beryllium exhibited a rapid “burst” release with maximum rates reaching 1.55–2.83 mg/d during the initial weathering stage, governed by surface-reaction-limited kinetics (Elovich model), whereas fluoride displayed a sustained diffusion-controlled release (Shrinking Core model). Thermodynamic modeling identified a fluoride-promoted dissolution mechanism, where the formation of stable fluoro‑beryllium complexes (predominantly BeF₃⁻ and BeF₄²⁻) significantly enhances beryllium solubility by reducing free cation activity and preventing surface saturation. This coupled mobilization results in a significant geochemical anomaly, quantified by a Nemerow Pollution Index (P_n) of 22.62. The flow-weighted average concentration of beryllium (0.136 mg/L) exceeded environmental standards by 27-fold (0.005 mg/L limit), with peak concentrations during initial release reaching >1000-fold exceedance, confirming beryllium as the dominant toxicity driver. Furthermore, increasing the bulk density of the residue (from 1.39 to 1.95 g/cm³) was found to effectively retard these kinetics, reducing the cumulative beryllium flux by approximately 50%. These findings highlight the “dual-element” signature of lithium-extraction residues and underscore the controlling role of complexation in trace metal mobilization.

风化环境中关键金属的表观地球化学行为是了解其流动性和循环的基础。本研究系统地研究了在模拟风化条件下锂云母残留物中氟（F−）和铍（Be2+）的溶解动力学和水形态。柱淋溶实验显示出明显的时间分异：铍在初始风化阶段表现出快速的“爆发”释放，最大速率达到1.55-2.83 mg/d，受表面反应限制动力学（Elovich模型）控制，而氟化物则表现出持续的扩散控制释放（萎缩核模型）。热力学模型确定了氟化物促进的溶解机制，其中稳定的氟-铍配合物（主要是BeF3 -和BeF42 -）的形成通过降低自由阳离子活性和防止表面饱和显著提高了铍的溶解度。这种耦合动员导致了显著的地球化学异常，用Nemerow污染指数（Pn）为22.62来量化。铍的流量加权平均浓度（0.136 mg/L）超过环境标准27倍（0.005 mg/L限值），初始释放时的峰值浓度达到1000倍以上，证实了铍是主要的毒性驱动因素。此外，发现增加残渣的容重（从1.39 g/cm3增加到1.95 g/cm3）可以有效地延缓这些动力学，使累积铍通量减少约50%。这些发现突出了锂萃取残留物的“双元素”特征，并强调了络合在微量金属动员中的控制作用。

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引用次数: 0