Geochemistry Geophysics Geosystems最新文献

{"title":"Using Kgen to Generate Cross-Verified Apparent Equilibrium Constants (K∗’s) for Palaeoseawater Carbonate Chemistry","authors":"Ross Whiteford,&nbsp;Oscar Branson,&nbsp;Dennis Mayk","doi":"10.1029/2023GC011417","DOIUrl":"https://doi.org/10.1029/2023GC011417","url":null,"abstract":"<p>Quantification of palaeo pH and palaeo CO₂ from marine proxies requires the use of apparent equilibrium constants (K^∗’s). The K^∗’s required to calculate seawater carbonate chemistry are described by empirically determined calibrations, and for palaeoseawater these calibrations must be adjusted to account for changes in seawater composition. There are a number of possible calibrations that can be used to calculate K^∗’s, and each software package for calculating carbonate chemistry separately implements these K^∗ calibrations, which are manually verified against previous implementations. Palaeo applications typically only implement a single calibration for each K^∗, but have additional complexity from the need to adjust each calibration for changing seawater composition through time. The fragmented approach to K^∗ calculation can result in unintended and difficult to resolve discrepancies between outputs calculated by different pieces of software. We present “Kgen,” a synchronised collection of three pieces of software to consistently calculate palaeoseawater K^∗’s in Python, R, and Matlab. Kgen provides a simple, and nearly identical interface in each language. Through use of a Continuous Integration/Continuous Delivery (CI/CD) pipeline, Kgen guarantees consistent outputs between languages by automatically cross-checking results from all three implementations. Unifying the approach to K^∗ calculation in this way provides an extensible platform for verifiable K^∗ generation for palaeoseawater, which can be integrated into existing carbon speciation calculators to improve the consistency of results.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"26 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023GC011417","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144244759","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":"Pulsed Injections of Metal-Rich Magmatic Fluids: Key Drivers of Mineralization in a Back-Arc Basin Hydrothermal System","authors":"Xia Zhang,&nbsp;Zhilei Sun,&nbsp;Yachun Cai,&nbsp;Yue Xu,&nbsp;Nengyou Wu,&nbsp;Hong Cao","doi":"10.1029/2025GC012318","DOIUrl":"https://doi.org/10.1029/2025GC012318","url":null,"abstract":"<p>Submarine magmatic–hydrothermal systems, where magmatic volatiles and fluids possibly serve as major sources of mineralization elements, have been extensively documented in numerous felsic-hosted hydrothermal fields. Previous studies have primarily focused on the contribution of magmatic volatiles in such hydrothermal systems. Although evidence has indicated that magmatic fluids have a greater capacity for transporting metals to overlying hydrothermal systems, their specific role in magmatic–hydrothermal systems remains inadequately understood. This study provides compelling evidence for the contribution of metal-rich magmatic fluid to the Minami–Ensei (ME) hydrothermal system. Pulsed injections of metal-rich magmatic fluids into the overlying hydrothermal system during mineralization process result in the elevated salinity (6.1–9.7 wt.% NaCl equiv) and <i>δ</i>¹⁸O values (1.1–8.0‰) in ME hydrothermal fluids, which are recorded by barite fluid inclusions and oxygen (O) isotope compositions, respectively. Laser-induced breakdown spectroscopy analysis indicated that the magmatic fluids injected into the ME were likely Fe-rich. Metal concentrations in magmatic fluids are several orders of magnitude higher than those in hydrothermal fluids generated via leaching, and their contribution to overlying hydrothermal systems can substantially enhance sulfide mineralization efficiency in magmatic–hydrothermal deposits. This study underscores the potential of magmatic–hydrothermal systems as promising targets for future sulfide ore exploration.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"26 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GC012318","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144237301","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":"3D Reconstruction of Complex Fault Systems From Volumetric Geodynamic Shear Zones Using Medial Axis Transform","authors":"Anthony Jourdon,&nbsp;Dave A. May,&nbsp;Jorge N. Hayek,&nbsp;Alice-Agnes Gabriel","doi":"10.1029/2025GC012169","DOIUrl":"https://doi.org/10.1029/2025GC012169","url":null,"abstract":"<p>Reconstructing fault surfaces from volumetric data is a longstanding challenge in geosciences. We present a novel 3D method based on the medial axis to transform a volumetric strain-rate invariant field from long-term geodynamic simulations into fault surfaces. In these geodynamic models, faults correspond to regions of locally high values of the second invariant of the strain-rate commonly referred to as shear zones. The proposed workflow begins by normalizing the strain-rate to define fault indicator field <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>ξ</mi>\u0000 </mrow>\u0000 <annotation> $xi $</annotation>\u0000 </semantics></math>. An iso-surface of a chosen <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>ξ</mi>\u0000 </mrow>\u0000 <annotation> $xi $</annotation>\u0000 </semantics></math> value is then extracted to form an envelope around the shear zones. Using the shrinking ball algorithm (Ma et al., 2012, https://doi.org/10.1007/s00371-011-0594-7), we compute the medial axis of this 3D envelope to generate a point cloud representing the geometric skeleton of the shear zones. We reconstruct fault surfaces by applying Delaunay triangulation followed by Laplacian smoothing. For models involving multiple intersecting faults, we perform a local principal component analysis (PCA) of the coordinates defining the medial axis and use the resulting eigenvectors to detect first-order orientation variations, enabling the separation and individualization of faults. We demonstrate the generality and robustness of the method by applying it several diverse 3D geodynamic scenarios: A single strike-slip fault, a branching strike-slip fault in a restraining bend, a dense strike-slip fault network, a rift system, and a subduction zone with a megathrust and a conjugate thrust fault.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"26 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GC012169","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144237300","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":"Thickening Cratonic Lithosphere by Horizontal Compression in the Presence of Surface Erosion and Sedimentation","authors":"Kristina Kublik,&nbsp;Claire A. Currie,&nbsp;D. Graham Pearson","doi":"10.1029/2025GC012194","DOIUrl":"https://doi.org/10.1029/2025GC012194","url":null,"abstract":"<p>Here we examine how lithospheric thickening is affected by active surface sedimentation and erosion in geodynamic models of craton formation—an aspect that has been neglected in previous models even though cratons may be the first landmasses to emerge above sea level. In our two-dimensional numerical models, inward horizontal velocities are imposed at the side boundaries of the model domain to induce thickening of the cratonic lithosphere by horizontal compression. Various rates of sedimentation and erosion are applied at the surface and the thickness of the lithosphere is monitored during the 50 Myr compression phase, and for 2 billion years after the imposed compression phase. In our models, surface processes act on the high-relief surface topography of the mobile belts adjacent to the cratonic nucleus. Erosion in the mobile belts during the compression alters lithosphere geodynamics, increasing the thickness of the mobile belt lithosphere to depths capable of supporting diamond growth. This enhanced thickening in the mobile belt regions limits shortening and thickening of the cratonic nucleus and the lithospheric thickness can vary by up to 15 km between models with different surface process rates.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"26 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GC012194","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144220040","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":"Origin of Silicic Magmatism at the Katla Volcanic Complex, South Iceland","authors":"Valentin R. Troll,&nbsp;Frances M. Deegan,&nbsp;Jussi S. Heinonen,&nbsp;Caroline Svanholm,&nbsp;Chris Harris,&nbsp;Christian M. Lacasse,&nbsp;Harri Geiger,&nbsp;Agata Poganj,&nbsp;Louise Thomas,&nbsp;Malin Andersson,&nbsp;Romain Meyer,&nbsp;Thorvaldur Thordarson","doi":"10.1029/2025GC012319","DOIUrl":"https://doi.org/10.1029/2025GC012319","url":null,"abstract":"<p>The Katla volcano is a bimodal caldera complex within Iceland's basalt-dominated Eastern Volcanic Zone. To unravel the petrogenesis of silica-rich rocks from Katla, we provide new δ¹⁸O values for almost 60 basaltic, intermediate, and high-silica eruptive rocks, including a number of partially melted felsic xenoliths. The basaltic samples display a range in bulk-rock δ¹⁸O values from +4.3 to +8.5‰ (<i>n</i> = 17) and the sparse intermediate samples from +4.1 to +5.9‰ (<i>n</i> = 3). In turn, silicic rock samples and feldspar separates range from +2.7 to +6.4‰ (<i>n</i> = 38), whereas felsic xenoliths yield the lowest values from −4.9 to −2.3‰ (<i>n</i> = 4). The majority (95%) of the Katla silicic volcanics have δ¹⁸O values below typical MORB (i.e., ≤5.0‰), ruling out an origin via closed-system fractional crystallization from the basaltic magmas. We utilized the new δ¹⁸O values to model possible assimilation and fractional crystallization (AFC) scenarios. The results indicate an early stage of FC/AFC at deep- to mid-crustal levels, followed by assimilation of low-δ¹⁸O hydrothermally altered sub-volcanic materials similar to the low-δ¹⁸O felsic xenoliths at shallow crustal levels. Such a two-stage magma evolution is consistent with available geophysical and geobarometry studies at Katla, indicating mid- to deep-crustal and shallow-crustal magma domains. Importantly, mafic rocks dominantly show MORB-like δ¹⁸O values, whereas low δ¹⁸O values occur essentially in silicic rocks only. This implies that the low-δ¹⁸O values at Katla are imposed by interaction with the Icelandic crust rather than reflecting low δ¹⁸O mantle sources.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"26 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GC012319","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144220039","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":"Variations in Event-Bed Thickness-Frequency Distributions Near Volcanic Islands: Indicators of Varied Geological Processes","authors":"Yu-Chun Chang,&nbsp;José C. F. Kling,&nbsp;Julie C. Schindlbeck-Belo,&nbsp;Neil C. Mitchell,&nbsp;Kan-Hsi Hsiung,&nbsp;Toshiya Kanamatsu","doi":"10.1029/2025GC012185","DOIUrl":"https://doi.org/10.1029/2025GC012185","url":null,"abstract":"<p>A variety of subaerial and submarine events, including mass-wasting and volcanism, can generate sediment gravity flows and fallout deposits that are preserved in deep-water stratigraphic records. This study examines whether event beds with differing depositional and transport histories exhibit distinct thickness-frequency distributions. Analyzing over 4,500 event beds from seven drilling sites near Montserrat, the Izu Arc, the Kyushu-Palau Ridge, and Gran Canaria, the analyses explore variations in event-bed characteristics across different climatic periods, volcanic stages, and geomorphological settings. Statistical methods include characterizing thickness-frequency distributions and assessing subset similarity using <i>t</i>-tests and smoothed distribution patterns. The data-driven results indicate discernible differences where dominant geological processes vary. For example, volcanic growth stages at the Kyushu–Palau Ridge produced thicker, coarser, and more frequent event beds compared with quiescent stages. Similarly, beds from the north slope of Gran Canaria—where submarine canyons enhanced sediment delivery—were nearly twice as thick as those from the south. In contrast, indistinguishable characteristics between the rear and frontal Izu Arc subsets after 3 Ma are attributed to the development of an extensional zone supplying material to both arc sides. Comparable distributions were also observed within intervals with minimal geological differences. The reliability of this analytical approach depends on high-quality sediment recovery, as drilling-related disturbances may obscure primary depositional signals. Beyond stratigraphic characterization, the method shows broader potential for identifying the provenance of volcanic glass shards through geochemical comparisons and for evaluating the statistical compatibility of data sets from neighboring sites, ensuring sufficient sample size for robust integrated analyses.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"26 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GC012185","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206900","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":"Massive Sulfide Deposition at the 13°30’N Oceanic Core Complex: Lessons Learned From Coupled Hydro-Thermo-Mechanical Modeling","authors":"Arne Glink,&nbsp;Jörg Hasenclever,&nbsp;Lars Rüpke,&nbsp;Matthias Hort,&nbsp;Sven Petersen","doi":"10.1029/2024GC012144","DOIUrl":"https://doi.org/10.1029/2024GC012144","url":null,"abstract":"<p>Young oceanic lithosphere created at mid-ocean spreading centers is subject to complex magmatic, tectonic and hydrothermal processes, especially in regions of widespread detachment faulting. This study focuses on the oceanic core complex (OCC) at the Mid Atlantic Ridge at 13°30’N. The OCC hosts the active Semenov-2 vent field and four inactive fields, including the exceptionally large Semenov-4 sulfide deposit (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>10 Mt), which is located near the emergence of a detachment fault. To study the relationship between tectonic detachment faulting and fluid circulation we couple models for mechanical deformation and hydrothermal fluid flow. Our aim is to identify the role of the detachment in controlling location and size of sulfide deposition. First, we develop a baseline model for the tectono-magmatic evolution of the OCC using a data-based sequence for magnitude and position of axial magmatic diking. The resulting history of tectonic deformation provides a dynamic framework for modeling hydrothermal flow through porous rock, incorporating regions of active faulting and seafloor topography evolution. We then examine the impact of various fault zone permeability structures and heat sources on hydrothermal sulfide deposition. Our results show that a combination of a topographic influence, anisotropic permeability along the fault zone, transient shallow heat sources and plume interactions can efficiently reorganize the hydrothermal system. Increasing horizontal distance between heat source and vent field, however, significantly reduces hydrothermal plume stability. Modeled mass flow rates suggest that vent fields like Semenov-4 and TAG result from the focusing of fluid flow across the entire along-axis extent of the detachment structure.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"26 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GC012144","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144190956","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":"Seismotectonics and Crustal Structure in the Southern Dominican Republic Offshore Margin: Implications on the Tsunami Potential","authors":"J. L. Granja-Bruña,&nbsp;J. M. Gorosabel-Araus,&nbsp;U. ten Brink,&nbsp;A. Muñoz-Martín,&nbsp;A. Rodríguez-Zurrunero,&nbsp;S. Leroy,&nbsp;A. López-Venegas,&nbsp;M. Llorente-Isidro,&nbsp;J. Macías Sánchez,&nbsp;C. Sánchez-Linares,&nbsp;A. Carbó-Gorosabel","doi":"10.1029/2024GC012092","DOIUrl":"https://doi.org/10.1029/2024GC012092","url":null,"abstract":"<p>Many coastal areas of the southern Dominican Republic experience considerable population pressure accompanied by important economic activity. The southern offshore margin is characterized by significant seismicity and active geological processes. Because of the proximity of the seismogenic and tsunamigenic areas to the coastal regions, large seismic events are likely to result in significant damage. The interpretation of seismotectonic, structural, and morphological data allowed us to characterize the tsunamigenic features. The major tectonic sources involve large shallow faults that are capable of producing earthquakes with magnitudes ranging from Mw7.0 to Mw8.1. These seismic sources could release enough energy to deform and occasionally rupture the seafloor: Muertos frontal thrust, Muertos mega-splay and the Muertos Trough fault zone. In addition, these tectonic sources show significant vertical seafloor deformation with the potential to generate tsunamis. The steeper seafloor slopes show frequent active gravitational processes, but generally have a relatively small size and their tsunamigenic potential is therefore low. However, the Complutense slump is an exception showing ≈30 km3 of mobilized material located along a large active fault. If a similar volume is rapidly mobilized in a single slope failure, it could generate a significant tsunami. The southern coast of the Dominican Republic faces a clear risk due to its proximity to potential tsunamigenic sources (30–50 km), resulting in a very short lead-time for warning. The results of this study provide basic information for future tsunami simulations that ultimately allow practical implementation of tsunami preparedness and protection, and for coastal planning and marine resource use.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"26 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024GC012092","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144190955","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":"Temporal Variations of the Oldest Emperor-Hawaiian Plume Signature Influenced by Interaction With Shallow Mantle Features","authors":"P. D. Kempton,&nbsp;C. Adam,&nbsp;A. D. Saunders,&nbsp;T. L. Barry","doi":"10.1029/2025GC012208","DOIUrl":"https://doi.org/10.1029/2025GC012208","url":null,"abstract":"<p>Hawaiian volcanoes &lt;∼7 Ma are believed to originate from two different portions of the deep mantle: Loa-trend volcanoes originate from within the Pacific Large Low Shear Velocity Province (LLSVP), whereas Kea-trend volcanoes tap ambient mantle adjacent to the LLSVP. To assess whether the Emperor-Hawaiian plume maintained this association throughout its history, we present new geochemical data (trace elements, Sr-Nd-Pb-Hf isotopes) and geodynamical modeling for Emperor Seamounts ranging from &gt;81 Ma (Meiji and Detroit Seamounts) to ∼50 Ma (Kōko Seamount). We show that Emperor seamounts differ from younger Hawaiian Islands in the abundance of isotopically depleted components. In ε_Hf-ε_Nd isotope space, Detroit lavas trend toward a high ε_Hf component similar to that observed in other mantle plumes (e.g., Iceland, Galápagos). This component originated deep within the mantle, possibly as a sheath surrounding the plume stem. Sampling of this component was facilitated by Detroit being ridge-proximal when it formed (∼81–76 Ma). Emperor seamounts younger than Suiko (∼68 Ma) were intraplate and located beneath progressively older, thicker lithospheres. Backtracked locations of Emperor seamounts lie up to 15° latitude north of the Pacific LLSVP. This suggests that the ancestral Emperor-Hawaiian plume was either (a) not initially associated with the Pacific LLSVP, (b) was deflected northward by shallow mantle features such that plume-ridge interactions dominated in the upper mantle or convective flow patterns modified the plume structure in the mid mantle, or (c) the edge of the Pacific LLSVP receded southward by more than 15° over the past ∼100 m.y.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"26 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GC012208","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144190911","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":"Sediment Depositional History and Processes for the Eurasian Basin Since 54 Ma, Arctic Ocean","authors":"Pingchuan Tan,&nbsp;Chunyang Wang,&nbsp;Fei Wang,&nbsp;Jiabiao Li","doi":"10.1029/2025GC012201","DOIUrl":"https://doi.org/10.1029/2025GC012201","url":null,"abstract":"<p>The Eurasian Basin in the Arctic Ocean, comprising the Amundsen and Nansen Basins separated by the Gakkel Ridge, has sediment deposits up to 4–5 km thick. However, its sedimentation history and processes remain poorly understood. Using 31 seismic profiles, we have estimated deposition rates for 54 Ma. From 54 to 45 Ma, the Nansen Basin averaged ∼15 cm/kyr, while the Amundsen Basin exhibited higher but variable rates (15–50 cm/kyr). From 45 to 20 Ma, the Amundsen Basin's rates decreased significantly, dropping to 6–7 cm/kyr (34–45 Ma) and ∼3.5 cm/kyr (20–34 Ma). Meanwhile, the Nansen Basin maintained higher rates (∼12 cm/kyr to ∼5 cm/kyr). After 20 Ma, sedimentation rates diverged further. The Nansen Basin stabilized at ∼5 cm/kyr and was significantly influenced by glaciation and iceberg rafting, while the Amundsen Basin continued to decline to ∼2 cm/kyr, with pelagic sediments dominated by sea-ice and iceberg rafting, and debris flows near the Lomonosov Ridge. The Nansen Basin's higher rates are likely due to its proximity to the Barents and Laptev Sea shelves, while the general declined rates across the basin are related to basin expansion, climate cooling, and reduced tectonic activity. Additionally, the Eurasian Basin's sedimentation is shaped by two phases of Siberian river activity. Before 45 Ma, the Lena and Indigirka rivers dominated, particularly near the eastern Laptev Sea Shelf. After 45 Ma, the Pyasina and Yenisey rivers became the main contributors, with significant sediment delivery through the St. Anna Trough. Sediment deposits (0.6–1 km) along the Gakkel Ridge (70°E−100°E) are also caused by these processes.</p>","PeriodicalId":50422,"journal":{"name":"Geochemistry Geophysics Geosystems","volume":"26 6","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025GC012201","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144171680","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}