Journal of Geophysical Research: Solid Earth最新文献

{"title":"Validation of Ps-P Tomography for Obtaining 3D Crustal VP/VS With Small-N Data Sets: An Application to the Mount St. Helens Magmatic System","authors":"Daniel Evan Portner,&nbsp;Jonathan R. Delph,&nbsp;Eric Kiser,&nbsp;Geoffrey A. Abers,&nbsp;Alan Levander,&nbsp;Guanning Pang","doi":"10.1029/2024JB029642","DOIUrl":"10.1029/2024JB029642","url":null,"abstract":"<p>The high sensitivity of <i>V</i>_<i>P</i><i>/V</i>_<i>S</i> to the presence of melt makes images of <i>V</i>_<i>P</i><i>/V</i>_<i>S</i> structure particularly useful in magmatic systems, but detailed three-dimensional models of <i>V</i>_<i>P</i><i>/V</i>_<i>S</i> structure in magmatic systems are often restricted to the upper crust where there is a concentration of seismic sources used for imaging. <i>Ps-P</i> tomography is a new technique that has been used to image three-dimensional crustal-scale variations in <i>V</i>_<i>P</i><i>/V</i>_<i>S</i> in regions with limited seismic instrumentation. We apply the <i>Ps-P</i> tomography technique to a well-constrained, independently imaged magmatic setting, Mount St. Helens, to outline the efficacy and limitations of this imaging approach. Our <i>Ps-P</i> tomography model reveals previously imaged high <i>V</i>_<i>P</i><i>/V</i>_<i>S</i> upper crustal magma reservoirs beneath active volcanic systems at Mount St. Helens, Mount Adams and the Indian Heaven Volcanic Field and low <i>V</i>_<i>P</i><i>/V</i>_<i>S</i> anomalies associated with crystallized plutons. Our model also provides new <i>V</i>_<i>P</i><i>/V</i>_<i>S</i> constraints in the lower crust that reveal a high <i>V</i>_<i>P</i><i>/V</i>_<i>S</i> anomaly connecting the Mount St. Helens and Mount Adams reservoirs and a low <i>V</i>_<i>P</i><i>/V</i>_<i>S</i> anomaly associated with lower crustal cumulates or mafic accreted terranes. Decimation tests further show that first order <i>V</i>_<i>P</i><i>/V</i>_<i>S</i> structure is recoverable using as few as four recording seismometers. These images resemble those of independent, higher resolution images from traditional techniques, highlighting the utility of <i>Ps-P</i> tomography for imaging three-dimensional variations of <i>V</i>_<i>P</i><i>/V</i>_<i>S</i> throughout the crust, including in data-poor settings or with arrays not designed for structural seismic investigations, such as many volcano monitoring networks.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029642","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247164","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":"MFF-DenseNet: Densely Connected Convolutional Network With Multi-Scale Feature Fusion for Magnetotelluric Noise Suppression","authors":"Jiayu Wang,&nbsp;Jin Li,&nbsp;Hui Zhou,&nbsp;Xiaolin Zhao,&nbsp;Jingtian Tang","doi":"10.1029/2024JB028869","DOIUrl":"10.1029/2024JB028869","url":null,"abstract":"<p>Magnetotelluric (MT) is a geophysical technique for detecting subsurface electrical structures. However, MT data collected in areas with frequent human activity often encounter various types of electromagnetic (EM) noise, which can mask or distort the signals we aim to analyze. Over the past decades, data processing methods based on deep learning has become the focus of multiple disciplines. Training neural networks to identify and handle noise has been proven effective in reducing the impact of noise. Therefore, ensuring the neural network accurately learns the noise and signal characteristics during the training is crucial. Against this background, we propose a multi-scale feature fusion technique based on the densely connected network and apply it to processing MT data. First, we construct a data set resembling the noise in field data and use it to train the network. Leveraging dense connections, we extract feature maps of EM noise from noisy data and utilize Spatial Pyramid Pooling to integrate feature maps of various scales, enabling the network to capture features of the noise precisely. At the same time, we reduce the computation of feature fusion by introducing the Channel-wise Squeezed Layer to compress the channels of the feature maps. Ultimately, we apply the trained model to the field noisy data. The results of synthetic and field data demonstrate that our method suppresses low-amplitude and continuous high-amplitude noise while preserving low-frequency valuable signal. Apparent resistivity-phase curves and polarization direction shows a noticeable improvement in the mid and low-frequency bands with our method.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247161","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":"Reconstruction of Magma Plumbing System and Regional Magmatic Processes via Chemical and Structural Zoning of Biotite in Rhyolite from Long Valley, CA","authors":"Jiaxin Xi,&nbsp;Yiping Yang,&nbsp;Huifang Xu,&nbsp;Haiyang Xian,&nbsp;Fabin Pan,&nbsp;Shan Li,&nbsp;Shuo Xue,&nbsp;Yonghua Cao,&nbsp;Jianxi Zhu,&nbsp;Hongping He","doi":"10.1029/2024JB029205","DOIUrl":"10.1029/2024JB029205","url":null,"abstract":"<p>Minerals with compositional zoning in volcanic products are widely used to decipher the history of magmatic evolution. However, structural information, which reflects physical conditions and crystallization equilibrium, has often been overlooked. This study presents the first report on the structural zoning of deep-derived biotite phenocrysts through investigations of metaluminous rhyolite from Long Valley, CA. Biotite is enriched in Si, Mg, and K and depleted in Fe³⁺, Ti, and Al^IV in core zones compared with rims. In situ structural analyses, including micro X-ray diffraction, Raman spectroscopy, and transmission electron microscopy, were conducted to identify cores with perfect 2<i>M</i>₁ polytype and disordered rims of biotite. The results demonstrate the effectiveness of these methods in revealing various (micro)polytypes of a single species, which occur at different crystallization temperatures, pressures, supersaturation levels, and oxygen fugacities. The concept of structural zoning is introduced here to describe the different structural features distributed systematically in various parts of minerals. By combining structural and chemical zoning, we illustrate a two-step growth for samples: equilibrium crystallization of the highly ordered cores in a deep magma reservoir with high temperature and pressure, followed by rapid growth of disordered rims during magma mixing in a crystal mush. We further discuss the implications of these findings for reflecting the plumbing system structure and eruption history of rhyolitic magma over extended periods. Our study underscores the remarkable sensitivity of structural zoning in delineating the crystallization conditions of minerals and documenting the environmental changes within magma.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Reference Model of Crustal Thickness and Vp/Vs of Western Canada","authors":"Quan Zhang,&nbsp;Yunfeng Chen,&nbsp;Yu Jeffrey Gu,&nbsp;Claire Currie,&nbsp;Pascal Audet,&nbsp;Hersh Gilbert,&nbsp;Derek L. Schutt,&nbsp;Gabriela Fernández-Viejo,&nbsp;Yangkang Chen","doi":"10.1029/2024JB029387","DOIUrl":"10.1029/2024JB029387","url":null,"abstract":"<p>The Canadian Cordillera marks a transition region from the current plate boundary through the Phanerozoic Cordilleran orogen to the Precambrian cratons. Knowledge of the subsurface structure of western Canada has been greatly advanced by seismological investigations during the past two decades, pioneered by the Lithoprobe project and, more recently, by regional passive seismic arrays. In this study, we construct a new model (WCANM22) of crustal thickness and P- to S-wave velocity ratio, or <i>V</i>_<i>p</i>/<i>V</i>_<i>s</i>, by compiling receiver function data from 473 stations and existing constraints from over 2,600-km long active source experiments. Our model covers a broad swath (about 1/4) of the land area of North America (105°–140°W, 48°–72°N) and shows an overall flat Moho beneath the Cordillera with an average depth of ∼36 km and a standard deviation of 3 km across orogenic belts. This study provides a comprehensive catalog of <i>V</i>_<i>p</i>/<i>V</i>_<i>s</i> in western Canada and reveals a moderate correlation between Poisson's ratio and the age of crustal domains. The average <i>V</i>_<i>p</i>/<i>V</i>_<i>s</i> values are 1.72, 1.79, and 1.82 for the Phanerozoic Cordillera, Proterozoic Cratons, and Archean-aged Medicine Hat Block, respectively, suggesting continued modifications to crustal composition through episodic tectonothermal events. This distinct trend in western Canada sheds new light on the debated role of secular changes in the composition of continental crust.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247222","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":"CSRM-1.0: A China Seismological Reference Model","authors":"Xiao Xiao,&nbsp;Shihua Cheng,&nbsp;Jianping Wu,&nbsp;Weilai Wang,&nbsp;Li Sun,&nbsp;Xiaoxin Wang,&nbsp;Jiayu Ma,&nbsp;Yinghua Tong,&nbsp;Xiaofeng Liang,&nbsp;Xiaobo Tian,&nbsp;Hongyi Li,&nbsp;Qi-Fu Chen,&nbsp;Sheng Yu,&nbsp;Lianxing Wen","doi":"10.1029/2024JB029520","DOIUrl":"https://doi.org/10.1029/2024JB029520","url":null,"abstract":"<p>High-resolution seismic model is crucial for advancing our understandings on geological processes and enhancing seismic hazard mitigation programs. We construct a high-resolution China Seismological Reference Model (CSRM-1.0) in the top 100 km of the crust and uppermost mantle in continental China following a top-down construction process. The employed seismic constraints include <i>P-</i>wave polarization angle from tele-seismic event, short-period Rayleigh wave ellipticity from ambient noise, long-period Rayleigh wave ellipticity from earthquake data, receiver function, empirical Green's function from ambient noise, Rayleigh wave phase/group velocity dispersion curves from regional earthquakes, and <i>Pn</i>-wave travel time extracted from seismic data of 4,435 stations. CSRM-1.0 has a spatial crustal resolution of ∼60 km beneath the north-south seismic belt and trans-North China orogen regions and ∼120 km beneath the rest of continental China, and a spatial mantle resolution of ∼300 km. CSRM-1.0 exhibits prominent velocity heterogeneities in the crust and uppermost mantle and an eastward thinning of the crust, geographically correlating with geological settings. CSRM-1.0 improvements include accurate estimation of shallow seismic structure, increased spatial resolution and improved model accuracy. Crustal composition inferred from CSRM-1.0 exhibits a general transition from a felsic upper crust to a mafic lower crust. Mafic rocks in the lower crust are found predominantly along inter-block boundaries and sporadically within the interiors of blocks, likely resulted from preferential inter-block intrusions of magmas related to various oceanic plate subductions and the Emeishan mantle plume. This study contributes seismic constraints and CSRM-1.0 to the CSRM product center (http://chinageorefmodel.org) as a backbone open-access geophysical cyberinfrastructure.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029520","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142273132","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":"High-Pressure Melting Experiments of Fe3C and a Thermodynamic Model of Fe-C Liquids for the Earth's Core","authors":"T. Komabayashi,&nbsp;C. McGuire,&nbsp;S. Thompson,&nbsp;G. D. Bromiley,&nbsp;A. Bravenec,&nbsp;A. Pakhomova","doi":"10.1029/2024JB029641","DOIUrl":"10.1029/2024JB029641","url":null,"abstract":"<p>Melting experiments of Fe₃C were conducted to 85 GPa in laser-heated diamond anvil cells with in situ X-ray diffraction and post-experiment textural observation. From the determined pressure-temperature conditions of the melting curve for Fe₃C, together with literature data on the melting point of diamond and eutectic point of the system Fe-Fe₃C/Fe₇C₃ under high pressures, we established a self-consistent thermodynamic model for high-pressure melting of the system Fe-C including the mixing parameters for liquids. The results show that mixing of Fe and C liquids is negatively nonideal from 1 bar to the pressure at the center of the Earth. The departure from ideal mixing becomes progressively larger with increasing pressure, which leads to greatly stabilized liquids under core pressures. The modeled carbon content in eutectic melts under core pressures is 3.3–4.4 wt%. From the Gibbs free energy, we derived an internally consistent parameters for Fe-C outer cores which included the crystallizing points at their bottoms, isentropic thermal profiles, and densities and longitudinal seismic wave speeds (<i>Vp</i>). While the addition of carbon in excess of the eutectic melt composition effectively reduces the density of iron liquid, the <i>Vp</i> of iron liquid is not greatly changed. Therefore, the low density and high <i>Vp</i> of PREM relative to pure iron cannot be reconciled by an Fe-C liquid. Therefore, the Earth's core cannot be approximated by the system Fe-C and should include another light element.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029641","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142246262","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":"Imaging Attenuation From Array Analysis of Surface Waves","authors":"Xueyang Bao,&nbsp;Nian Wang","doi":"10.1029/2023JB028649","DOIUrl":"10.1029/2023JB028649","url":null,"abstract":"<p>Anelastic attenuation provides key insight in our understanding of thermal and rheological structures and the associated deformation and dynamic mechanisms of the Earth's deep interior. Unfortunately, attenuation tomography is advanced far behind wave-speed tomography due to the challenge in properly excluding the complex effects of elastic heterogeneities on seismic wave amplitude. By taking advantage of phase tracking in seismic array analysis, here we derive a new theory of Helmholtz tomography that well accounts for attenuation, source radiation, and scattering, etc., and present a technique called Helmholtz Multi-Event Tomography (HelMET) to retrieve the attenuation properly. The effectiveness of this method is then validated by synthetic inversions. Our synthetic seismograms are calculated using a newly developed three-dimensional finite-difference algorithm that accounts for physical dispersion and dissipation in anelastic media and remains accurate and stable even if strong attenuation exists. Compared to the traditional method poorly performed in the synthetic inversion, the HelMET well recovers the input attenuation anomalies, suggesting that this method can be used to successfully isolate attenuation from the complicated effects of elastic heterogeneities. Our results underline the implication of the new theory and method in accurately imaging high-resolution attenuation structures and unambiguously interpreting the anelastic heterogeneities of the Earth by array-based earthquake and ambient noise data with inexpensive computation.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142237181","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":"Mechanical Energy Dissipation During Seismic Dynamic Weakening in Calcite-Bearing Faults","authors":"Stefano Aretusini,&nbsp;Arantzazu Nuñez Cascajero,&nbsp;Chiara Cornelio,&nbsp;Xabier Barrero Echevarria,&nbsp;Elena Spagnuolo,&nbsp;Alberto Tapetado,&nbsp;Carmen Vazquez,&nbsp;Giulio Di Toro,&nbsp;Massimo Cocco","doi":"10.1029/2024JB028927","DOIUrl":"10.1029/2024JB028927","url":null,"abstract":"<p>Earthquakes are frictional instabilities caused by the shear stress decrease, that is, dynamic weakening, of faults with slip and slip rate. During dynamic weakening, shear stress depends on slip, slip rate, and temperature, according to constitutive laws governing the earthquake rupture process. In the laboratory, technical limitations in measuring temperature during frictional instabilities inhibit the investigation and interpretation of shear stress evolution. Here we conduct high velocity friction experiments on calcite-bearing simulated faults, both on bare-rock and on gouge samples, at 20–30 MPa normal stress, 1–6 m/s slip rate and 1–20 m total slip. Seismic slip pulses are reproduced by imposing boxcar and regularized Yoffe slip rate functions. We measured, together with shear stress, slip, and slip rate, the temperature evolution on the fault by employing an innovative two-color fiber optic pyrometer. The comparison between modeled and measured temperature reveals that for calcite-bearing faults the heat sink caused by decarbonation reaction controls the temperature evolution. In bare-rocks, energy is dissipated as frictional heat, and temperature increase is buffered by the heat sink of the calcite decarbonation reaction. In gouges, energy is dissipated as frictional heat and for plastic deformation processes, balanced by the heat sink caused by the decarbonation reaction enhanced by the mechanochemical effect. Our results suggest that in calcite-bearing rocks, a common fault zone material for earthquake sources in the continental crust at shallow depth, the type of fault materials (bare-rocks vs. gouges) controls the energy dissipation during seismic slip.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB028927","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142237179","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":"Deriving Flow Velocity and Initial Concentration From Liesegang-Like Patterns","authors":"Chong Liu,&nbsp;Victor M. Calo,&nbsp;Klaus Regenauer-Lieb,&nbsp;Manman Hu","doi":"10.1029/2024JB029379","DOIUrl":"10.1029/2024JB029379","url":null,"abstract":"<p>Zebra rocks, characterized by their striking reddish-brown stripes, rods, and spots of hematite (Fe-oxide), showcase complex self-organized patterns formed under far-from-equilibrium conditions. Despite their ease of recognition, the underlying mechanisms of pattern-forming processes remain elusive. We introduce a novel advection-dominated phase-field model that effectively replicates the Liesegang-like patterns observed in Zebra rocks. This numerical model leverages the concept of phase separation, a well-established principle governing Liesegang phenomena in a two-dimensional setting. Our findings reveal that initial solute concentration and fluid flow velocity are critical determinants in pattern morphologies. We quantitatively explain the spacing and width of a specific Liesegang-like pattern category. Furthermore, the model demonstrates that vanishingly low initial concentrations promote the formation of oblique patterns, with inclination angles influenced by rock heterogeneity. Additionally, we establish a quantitative relationship between band thickness and geological parameters for orthogonal bands. This enables the characterization of critical geological parameters based solely on static patterns observed in Zebra rocks, providing valuable insights into their formation environments. The diverse patterns in Zebra rocks share similarities with morphologies observed on early Earth and Mars, such as banded iron formations and hematite spherules. Our model, therefore, offers a plausible explanation for the formation mechanisms of these patterns and presents a powerful tool for deciphering the geochemical environments of their origin.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029379","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142237178","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":"Tracing the Oxidizing State and Element-Mobilizing Fluids in Continental Subduction Zones: Insights From the Granitic Melt-Eclogite Interface","authors":"Jing Lei,&nbsp;Ye Tian,&nbsp;Yilin Xiao,&nbsp;Dong-Bo Tan,&nbsp;Li-Juan Xu,&nbsp;Qinxia Wang,&nbsp;Wangye Li","doi":"10.1029/2023JB028480","DOIUrl":"10.1029/2023JB028480","url":null,"abstract":"<p>Fluids in subduction zones significantly influence element mobility, isotope fractionation, and mass transfer. However, unraveling the source, composition, and redox state of fluids in continental subduction zones poses a significant challenge. This study focuses on a granitic melt-eclogite contact interface, along with adjacent granite and eclogite from the Sulu ultrahigh-pressure metamorphic belt in East China. The interface exhibits complex mineral assemblages, enriched rare earth elements (REEs), and high field strength elements (HFSEs). Zircon grains from the interface show an age of ∼217 ± 9 Ma, slightly later than peak metamorphism, along with the presence of coesite inclusions. These findings suggest that the interfacial fluid likely formed from the mixing of granitic anatectic melt and aqueous fluid from the eclogite during the initial exhumation of the Sulu terrane. The interaction resulted in the eclogite acquiring substantial REEs and HFSEs, suggesting the interfacial fluid's effective element-transporting capability and potential supercritical fluid properties. Zircon Ce anomaly and Fe³⁺/Fe²⁺ oxybarometer data indicate a highly oxidizing interfacial fluid, analogous to arc magmas in oxygen fugacity. This led to the preferential loss of isotopically heavier Cr from the eclogite during fluid-eclogite interaction, evidenced by heavier Cr isotopic compositions in the interface (δ⁵³Cr = −0.04 to −0.05‰) compared to adjacent eclogite (δ⁵³Cr as low as −0.11‰). In summary, our results highlight the presence of strong oxidizing and element-mobilizing fluids in continental subduction zones, offering insights into supercritical fluid recognition and the genesis of oxidizing arc magmas in subduction zones.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"129 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142235559","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}