Geochemistry Geophysics Geosystems最新文献

{"title":"Occurrence and Provenance of KREEP Components in Glassy Agglutinates From Chang'e-5 Lunar Regolith","authors":"Shuai Ma,&nbsp;Zhipeng Xia,&nbsp;Bingkui Miao","doi":"10.1029/2026GC012932","DOIUrl":"https://doi.org/10.1029/2026GC012932","url":null,"abstract":"<p>This study investigates the petrogenesis of glassy agglutinates in a polished section of the Chang'e-5 lunar regolith sample CE5C0800YJYX018GP through integrated petrographic, mineralogical, and geochemical analyses of four representative particles (18GP-01 to 18GP-04). The agglutinates contain diverse lithic clasts, including basaltic fragments, anorthositic fragments, and a barred olivine-rich fragment, together with glass fragments. Mineral clasts are dominated by plagioclase, pyroxene, olivine, and ilmenite, with minor apatite, troilite, and silica phases. The glassy matrix formed primarily through impact melting of basaltic materials and shows compositions comparable to those of low-Ti mare basalts from Oceanus Procellarum. In contrast, some glass domains exhibit strong enrichment in K (K₂O up to 1.37 wt.%), P (P₂O₅ up to 4.84 wt.%), and rare earth elements (ΣREE up to 3,196.1 ppm). These enriched domains display pronounced LREE enrichment, relatively flat HREEs, and negative Eu anomalies, similar to the KREEP-rich lunar regolith from Oceanus Procellarum. Given the KREEP-poor geochemical background of the Chang'e-5 landing site, these features are most consistent with an exotic origin rather than in situ evolution of local basalts, and are best explained as material derived from the Procellarum KREEP Terrane and transported by large impact events. The micrometer-scale, heterogeneous distribution of KREEP-rich domains, together with agglutinated melt glass, and cristobalite, provides clear evidence for impact-driven transport and mixing. These observations place new constraints on lunar material redistribution, the preservation of late-stage magmatic residues, and the thermal evolution of the Moon.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"27 7","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026GC012932","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148373243","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":"Forward Image Registration for Higher Level Interpretation of Zircon Provenance Based on Combined CL, U/Pb Age, and Geochemical Data","authors":"Marco A. Acevedo Zamora,&nbsp;Balz S. Kamber,&nbsp;John T. Caulfield,&nbsp;Charlotte M. Allen,&nbsp;Justin S. Freeman","doi":"10.1029/2025GC012671","DOIUrl":"https://doi.org/10.1029/2025GC012671","url":null,"abstract":"<p>Most detrital zircon studies generate grayscale cathodoluminescence (CL) images, U/Pb dates, and variably extensive trace element concentration data. Yet the combined information contained in these data is rarely used for a higher-level interpretation of zircon provenance, which still heavily relies on comparison of sample-wide U/Pb age spectra. Here, we present a novel forward image registration software solution that allows the assembly of spatially registered data (optical microscopy and CL texture/intensity/contrast/color; Pb/U ratios/ages; and trace element concentrations/ratios), enabling zircon provenance analysis with data science. The solution is based on open-source scripts that streamline instrument software with open-source bioinformatics image analysis software and our own image processing algorithms. Equipped with this toolset, the analyst can now visualize the full range of zircon data from the registered data set within a master table. A grid display of zircon objects can be sorted by the aforementioned variables allowing intuitive visual discovery of interdependence. Using an example from a modern large river drainage system, we illustrate that new groupings and patterns can be manually defined, compared, and discovered by interacting with all available criteria. A candidate-source hypothesis is provided for a low frequency zircon population with a granitic source rock from the literature on the basis of age, chemistry, and CL attributes. Such exploration could open the path to more unique and automated sediment provenance solutions using cluster-density-diagrams.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"27 7","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GC012671","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148381109","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":"Interface Deformation, Exhumation, and Underplating: The Role of Plate Velocity Changes Throughout the Evolution of a Subduction Zone","authors":"Valeria Turino,&nbsp;Adam F. Holt,&nbsp;Derek J. Neuharth,&nbsp;Ryan K. Stoner,&nbsp;Whitney M. Behr","doi":"10.1029/2026GC012942","DOIUrl":"https://doi.org/10.1029/2026GC012942","url":null,"abstract":"<p>Exhumed metamorphic rocks yield critical insights into the mechanical, chemical, and thermal structure of the plate interface that can be used to infer exhumation pathways and their evolution throughout a subduction zone's lifetime. Metamorphosed oceanic rocks often record exhumation and underplating over relatively punctuated time periods, which appear to be linked to specific stages of subduction. Although plate velocities also vary from one stage of subduction to the next, the influence of this time dependence on exhumation and underplating remains unclear. We therefore use 2-D time-dependent subduction models to investigate how evolving plate velocities affect the timing and distribution of exhumation and underplating. By extracting plate velocities from a freely evolving subduction model and imposing them on kinematically driven models, we isolate the effects of realistic velocity variations on interface processes without the complexity of a dynamically evolving slab. We also explore the role of interface strength by varying its rheology and composition. In our models, exhumation consistently initiates during a punctuated detachment event following decreases in subduction velocity. Shallow exhumation (&lt;50 km) occurs through corner flow within the accretionary prism, while deeper underplating (&lt;140 km) involves crustal slicing and detachment along the whole interface. Weak interfaces favor continuous and voluminous exhumation, whereas strong interfaces restrict it to brief, punctuated episodes. Underplating is discontinuous throughout but increases in volume as convergence slows. These findings demonstrate that time-dependent plate velocity variations exert significant control on interface processes and naturally generate punctuated exhumation and underplating consistent with the rock record.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"27 7","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026GC012942","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148373241","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":"The Origin of Carbonate Magmas Predating and Accompanying Main-Phase LIPs Eruptions","authors":"Cinzia G. Farnetani,&nbsp;Mark A. Richards","doi":"10.1029/2026GC012954","DOIUrl":"https://doi.org/10.1029/2026GC012954","url":null,"abstract":"&lt;p&gt;Some large igneous provinces (LIPs) are associated with precursory carbonatite eruptions. Models for precursory carbonatites invoking partial melting of a carbonate metasomatized lithosphere appear implausible, given the long time needed for heat conduction from the plume head. Instead, we consider that the plume, not the lithosphere, is the source of carbon. We explore a range of carbon concentrations in the plume source (196 &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;≤&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${le} $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; C &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;≤&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${le} $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; 440 ppm) and various melting depths of carbonate-bearing peridotite, depending on the mantle redox state. Our numerical simulations provide a fluid dynamically consistent evolution of the plume-lithosphere system and enable us to calculate the ascent velocity of carbonate melts. Moreover, we advect millions of passive tracers to follow the 3-D trajectories of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;CaCO&lt;/mtext&gt;\u0000 &lt;mn&gt;3&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CaCO}}_{3}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; melts. The term “precursory-C” indicates plume carbon that has reached sub-lithospheric depths (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;≤&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${le} $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;140 km) &lt;i&gt;before&lt;/i&gt; the onset of anhydrous silicate melting. For models with carbonatite melt produced at great depths (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;≥&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${ge} $&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;200 km), we find that the precursory-C flux can be up to 6 × &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mn&gt;10&lt;/mn&gt;\u0000 &lt;mn&gt;12&lt;/mn&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${10}^{12}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; mol(C)/yr during a time period of ∼2 Myr preceding the onset of anhydrous silicate melting. The considerable mass of precursory-C, up to 2 × &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msup&gt;\u0000 &lt;mn&gt;10&lt;/mn&gt;\u0000 &lt;mn&gt;17&lt;/mn&gt;\u0000 &lt;/msup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${10}^{1","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"27 7","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026GC012954","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148373084","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":"Thermodynamic Modeling of Lithium Enrichment During Partial Melting: The Importance of Partition Coefficients","authors":"Nicolas Riel,&nbsp;Owen M. Weller,&nbsp;Caroline R. Soderman,&nbsp;Elisa O. Costa,&nbsp;Matthew C. Morris,&nbsp;Evangelos Moulas,&nbsp;Boris J. P. Kaus","doi":"10.1029/2025GC012877","DOIUrl":"https://doi.org/10.1029/2025GC012877","url":null,"abstract":"&lt;p&gt;Predicting the partial melting conditions that generate Li-rich peraluminous melts is of major economic and societal importance. However, existing models disagree on the optimal conditions (e.g., pressure, temperature, protolith) and, consequently, on targets for exploration. A key source of divergence in model outcomes lies in the choices of partition coefficients used to describe lithium distribution between minerals and melt &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mfenced&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;D&lt;/mi&gt;\u0000 &lt;mtext&gt;Li&lt;/mtext&gt;\u0000 &lt;mtext&gt;mineral/melt&lt;/mtext&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mfenced&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $left({D}_{text{Li}}^{text{mineral/melt}}right)$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;. Here, we use thermodynamic modeling to simulate isobaric stepwise partial melting of a global compilation of pelite compositions, at crustal pressures and considering variable water saturation and melt extraction thresholds, to calculate melt lithium enrichment predicted by four recently published &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;D&lt;/mi&gt;\u0000 &lt;mtext&gt;Li&lt;/mtext&gt;\u0000 &lt;mtext&gt;mineral/melt&lt;/mtext&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${D}_{text{Li}}^{text{mineral/melt}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; sets. Our results quantify the conditions that maximize lithium enrichment. Depending on &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msubsup&gt;\u0000 &lt;mi&gt;D&lt;/mi&gt;\u0000 &lt;mtext&gt;Li&lt;/mtext&gt;\u0000 &lt;mtext&gt;mineral/melt&lt;/mtext&gt;\u0000 &lt;/msubsup&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${D}_{text{Li}}^{text{mineral/melt}}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; choices, the predicted optimal conditions range from high-pressure, low-temperature melting of wacke-like compositions, to intermediate-pressure, high-temperature melting of both wacke- and shale-like compositions, or in some cases show limited sensitivity to these parameters. Among these scenarios, the intermediate-pressure, high-temperature melting regimes (associated with biotite breakdown) are most consistent with existing geological and geochemical evidence from lithium-rich granite and pegmatites. Such behavior is produced when lithium is treated as strongly compatible in biotite relative to other minerals, such as is thought to be the case in fluorinated biotite. Moving forward, pressure-, temperature-, and composition-dependent lithium partitioning models—such as recently developed for biotite—will be crucial to accurately evaluate Li behavior in","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"27 7","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GC012877","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148373085","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":"Accretionary Prism and Forearc Deformation Driven by the Beata Ridge Indentation in Southern Hispaniola: Insights From the Offshore San Pedro Basin","authors":"J. M. Gorosabel-Araus,&nbsp;J. L. Granja-Bruña,&nbsp;P. Mann,&nbsp;A. Gallego-Mingo","doi":"10.1029/2026GC012935","DOIUrl":"https://doi.org/10.1029/2026GC012935","url":null,"abstract":"<p>The Cretaceous–Eocene island arc of Hispaniola is currently shortened between the Bahamas carbonate platform to the north and the thickened crust of the Caribbean Large Igneous Province (CLIP) to the south. Within this transpressional setting, the 15–22-km-thick, ∼100-km-wide Beata Ridge (BR), the thickest portion of the CLIP, acts as a mechanically strong, tectonic indenter controlling on upper-plate deformation in Hispaniola. Integration of marine seismic, multibeam bathymetry, gravity and magnetic anomalies, and onshore geological data reveals a ∼140-km-wide counterclockwise rotation belt in central Hispaniola and coeval clockwise rotations in the offshore San Pedro Basin (SPB). The tectonostratigraphic evolution of the SPB provides a continuous Cenozoic record of indentation-related deformation, documenting the transition from a Late Cretaceous back-arc basin to a Late Eocene–present forearc basin associated with the Peralta–Muertos accretionary prism. Seismic stratigraphic analysis identifies key indicators of indentation, including rapid subsidence, angular unconformities, fault reactivation, and progressive rotation of Miocene–Pliocene depocenters, which together constrain the timing and landward propagation of deformation. Our results suggest that indentation began earlier than previously proposed, likely in the middle Miocene, and evolved progressively over time. The observed deformation patterns are consistent with models of narrow (100–400 km) arc–ridge indentation systems, where the indenter width controls the curvature and extent of upper-plate deformation. These findings demonstrate that the Beata Ridge governs the kinematic evolution of the Hispaniola forearc system and provide a framework for understanding deformation in confined arc–ridge collision zones worldwide.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"27 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026GC012935","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148282153","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":"Response of the Nitrogen Isotopic Composition of Planktic Foraminifer Tissue to Surface Ocean Nutrient Cycling: A Case Study in the Northern South China Sea","authors":"Aaron L. Bieler,&nbsp;Lena Heins,&nbsp;Sandi M. Smart,&nbsp;Jassin Petersen,&nbsp;Tobias Eßmann,&nbsp;Birgit Gaye,&nbsp;Joanna J. Waniek,&nbsp;Daniel M. Sigman,&nbsp;Gerald H. Haug,&nbsp;Alfredo Martínez-García,&nbsp;Ralf Schiebel","doi":"10.1029/2025GC012815","DOIUrl":"https://doi.org/10.1029/2025GC012815","url":null,"abstract":"<p>This study presents data on geographically small-scale patterns of nitrogen (N) isotope signals (δ¹⁵N) within the northern South China Sea (SCS) imprinted on planktic foraminifers (PF). PF from net tows on the shelf, continental slope, and in pelagic waters from summer 2019 were analyzed for δ¹⁵N. PF tissue δ¹⁵N was observed to diverge from the subsurface nitrate supply. The divergences were shared by PF species at a given station and depth, and differed among regions, indicating an environmental (as opposed to physiological-biochemical) driver. Moreover, the divergences were consistent with N cycle processes occurring in the respective oceanographic environments. In the oligotrophic open northern SCS, the PF tissue δ¹⁵N of shallow-dwelling species was 1–2.4‰ lower than local subsurface nitrate δ¹⁵N. This likely reflects the documented tendency for upper ocean N pools to decrease in δ¹⁵N under intense euphotic zone N recycling. There may have also been low-δ¹⁵N inputs from N₂ fixation and/or atmospheric N deposition. On the continental slope, in a mixing-associated productivity plume, PF tissue δ¹⁵N was higher and varied around the subsurface nitrate supply, reflecting the ecosystem's consumption of nitrate entrained from the subsurface. Our data highlight the sensitivity of PF tissue δ¹⁵N to prevailing N cycling processes. Existing sediment data indicate that δ¹⁵N of PF microfossils dominantly reflects the δ¹⁵N of nitrate consumed in surface waters, but upper ocean studies such as ours show effects from seasonal and shorter-duration processes, that may lead to second-order controls on sedimentary PF δ¹⁵N.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"27 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GC012815","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148282388","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":"Integrating Olivine Diffusion Chronometry With Monitoring Data to Decipher the Magma Dynamics at the Submarine Fani Maoré Volcano","authors":"Karoline Brückel,&nbsp;Etienne Médard,&nbsp;Fidel Costa,&nbsp;Carole Berthod,&nbsp;Pauline Verdurme,&nbsp;Patrick Bachèlery,&nbsp;Lise Retailleau,&nbsp;Jean-Christophe Komorowski,&nbsp;Lucia Gurioli","doi":"10.1029/2025GC012568","DOIUrl":"https://doi.org/10.1029/2025GC012568","url":null,"abstract":"<p>Monitoring data are critical for understanding volcanic unrest and eruption, but they often lack the ability to constrain the pre-eruptive magma processes. As such, an increasing number of studies couple monitoring data with petrological tools to obtain insights into the causes and durations of magmatic processes. The 2018–2020 eruption of the submarine Fani Maoré (FM) volcano, Comoros Archipelago, is an excellent location to correlate diffusion chronometry with real-time monitoring data. Zoned olivine in FM testify that deep basanitic magma interacted with a more evolved reservoir. Diffusion modeling in olivine shows an increase in the magma interaction times (0.5–3 to ∼20 months) as the eruption progresses, implying that basanitic magma stalled near the more evolved reservoir. Additionally, two major intrusive events were identified—in March 2019 and March 2020. The first intrusion occurred as seismic and deformation signals decreased possibly due to enhanced mixing and unlocking of the more evolved mushy reservoir after intrusion. The second intrusion correlates with a change in the locations of seismic events before seismicity and deformation become minor, implying that this intrusion occurred before magma drainage and waning of the eruption. Lastly, by coupling diffusion geochronometry and geophysical monitoring, the magmatic reservoir at FM can be placed at a greater depth (∼30 km) than previously thought, which is consistent with seismic events. Hence, our integrated approach of petrologic tools and real-time monitoring aids in providing new insights into the magma storage locations and magma-mush interactions at submarine volcanos.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"27 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GC012568","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148386557","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":"Reconstructing the Exhumation and Paleo-Earthquake History of a Submarine Normal Fault From Preserved Markers at the Seafloor (Roseau Fault, Lesser Antilles, France)","authors":"Frédérique Leclerc,&nbsp;Jérémy Billant,&nbsp;Chloé Seibert,&nbsp;Javier Escartin,&nbsp;Nathalie Feuillet,&nbsp;Alex Hughes,&nbsp;Sabine Schmidt,&nbsp;Laurence Le Callonnec","doi":"10.1029/2026GC012905","DOIUrl":"https://doi.org/10.1029/2026GC012905","url":null,"abstract":"<p>Assessing seismic and tsunami hazards along coastlines requires understanding past earthquakes and their recurrence along active submarine faults. Subaqueous paleoseismology commonly relies on sediment cores and seismic reflection data, but these methods may be limited by local site conditions or data quality. To overcome these limitations, a new approach using submersible-based optical imagery can provide valuable insights into the paleoseismic history of submarine faults. In this study, we conducted a near-bottom geological survey using submersibles along the Roseau normal fault (Lesser Antilles, France). This fault can host a M7 event if broken entirely. In 2004, it generated the Mw6.3 Les Saintes earthquake that produced a prominent coseismic ribbon at its base. High-resolution submersible observations of the fault free face allowed mapping and characterizing detailed fault scarp morphologies, including new deformation markers such as abrasion bands, notches, roughness variations, dark bands, and uplifted sediments. These geomorphic markers form on the seafloor and are interpreted as records of fault scarp exhumation linked to changes in base level driven by sedimentation and tectonic activity. At one site, the observed morphology can be explained by three distinct earthquakes combined with episodes of rapid sedimentation. The penultimate earthquake produced a minimum vertical offset of 3 m, exceeding the 1.4 m slip associated with the 2004 event, indicating that it was at least as energetic. Sedimentation rates from nearby cores indicate that this penultimate event occurred much more recently than 2.8 kyr. These results demonstrate the value of submersible-based offshore fault studies for reconstructing seismic histories.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"27 6","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026GC012905","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148237863","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":"Late Jurassic Carbon Isotope Excursion (Middle Oxfordian Event) Paces With Astronomical Forcing in the Northwestern Tethys","authors":"Deyan Zhang,&nbsp;Su Li,&nbsp;Xu Yao,&nbsp;Chuanlong Mou,&nbsp;Ulrich Heimhofer","doi":"10.1029/2026GC012919","DOIUrl":"https://doi.org/10.1029/2026GC012919","url":null,"abstract":"<p>Marine carbonate carbon isotopes (δ¹³C), over orbital to multi-million-year timescales, provide critical insight into the carbon cycle connecting Earth's atmosphere, lithosphere, hydrosphere and biosphere. However, the influence of astronomical forcing on deep time carbon cycle dynamics remains poorly constrained. Here, we present a ∼8 Myr-long astrochronology based on a carbonate δ¹³C record from a Late Jurassic succession in the Lower Saxony Basin, Germany, northwestern Tethys. Astronomical tuning and spectral analyses reveal dominant 405-kyr cycles of the orbital eccentricity amplitude modulations, and 173-kyr and 1.2 Myr cycles of the obliquity amplitude modulations. The new astrochronology precisely dates one of the Late Jurassic carbon isotope excursions (Middle Oxfordian Event) from 159.0 to 157.2 Ma. Notably, the subordinate, low-amplitude positive δ¹³C excursions within the Event correlate with 405-kyr orbital eccentricity minima and 173-kyr obliquity maxima, whereas the negative shifts correspond to eccentricity maxima and obliquity minima. Our results demonstrate a binary carbon cycle response to orbital eccentricity and obliquity extremes in the northwestern Tethyan region. Low eccentricity likely maintains permanently wet seasons and high obliquity enhances monsoon-induced precipitation. Both mechanisms accelerate hydrological dynamics and subsequently intensify continental weathering and ¹²C-enriched organic carbon burial in marine sediments, leading to carbonate positive δ¹³C excursions. Conversely, high eccentricity generates strong dry-wet seasonality and low obliquity weakens precipitation, both of which decelerate organic carbon burial and ultimately cause negative δ¹³C shifts. These findings advance our understanding of how astronomical forcing modulates the Late Jurassic marine carbon cycle in the northwestern Tethys.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"27 6","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026GC012919","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148237917","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}