Physics of the Earth and Planetary Interiors最新文献

{"title":"Physics-informed neural networks for the improvement of platform magnetometer measurements","authors":"Kevin Styp-Rekowski ,&nbsp;Ingo Michaelis ,&nbsp;Monika Korte ,&nbsp;Claudia Stolle","doi":"10.1016/j.pepi.2024.107283","DOIUrl":"10.1016/j.pepi.2024.107283","url":null,"abstract":"<div><div>High-precision space-based measurements of the Earth's magnetic field with a good spatiotemporal coverage are needed to analyze the complex system of our surrounding geomagnetic field. Dedicated magnetic field satellite missions like the Swarm mission form the backbone of research, providing high-precision data with limited coverage. Many satellites carry so-called platform magnetometers that are part of their attitude and orbit control systems. These can be re-calibrated by considering different behaviors of the satellite system, hence reducing their relatively high initial noise originating from their rough calibration. These platform magnetometer data obtained from satellite missions not dedicated to geomagnetic fields complement high-precision data from the Swarm mission by additional coverage in space, time, and magnetic local times. In this work, we present an extension to a previous machine learning approach for automatic in-situ calibration of platform magnetometers. We introduce a new physics-informed layer incorporating the Biot-Savart formula for dipoles that can efficiently correct artificial disturbances due to electric current-induced magnetic fields evoked by the satellite itself. We demonstrate how magnetic dipoles can be co-estimated in a neural network for the calibration of platform magnetometers and thus enhance the machine learning-based approach to follow known physical principles. Here, we describe the derivation and assessment of re-calibrated datasets for two satellite missions, GOCE and GRACE-FO, which are made publicly available. Compared to the reference model, we achieved an average residual of about 7 nT for the GOCE mission and 4 nT for the GRACE-FO mission across all three components combined in the low- and mid-latitudes.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"358 ","pages":"Article 107283"},"PeriodicalIF":2.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Pebble accretion and siderophile element partitioning between Earth's mantle and core","authors":"Peter L. Olson,&nbsp;Zachary D. Sharp,&nbsp;Susmita Garai","doi":"10.1016/j.pepi.2024.107295","DOIUrl":"10.1016/j.pepi.2024.107295","url":null,"abstract":"<div><div>Pebble accretion is an efficient mechanism for early terrestrial protoplanet growth and differentiation. Metal-silicate partitioning of moderately siderophile elements offers constraints on the role of pebble accretion in Earth's formation and the segregation of its core. Here, we determine pebble accretion properties of the proto-Earth that are consistent with metal-silicate partitioning measurements and siderophile abundances in the mantle and core. We combine a pebble accretion model that includes mass balances for siderophile abundances in the mantle and core of a growing terrestrial protoplanet with experimentally-determined partition functions for seven moderately siderophile elements: Ni, Co, V, Cr, Mo, Mn, and W. Mantle and core abundances of these elements during pebble accretion are calculated, as well as changes to their abundances following the addition of large and giant impactors built with pebbles. Model results are compared to the estimated abundances of these elements in Earth's primitive mantle and core. We find that metal-silicate partitioning of these elements is especially sensitive to the total mass of accreted pebbles. Best fits to primitive mantle and core siderophile abundances are found in cases where the proto-Earth accreted with pebbles to approximately 0.6 times its present mass under slightly reducing conditions, then added the remaining mass via one or more impactors with the same composition. We also find that pebbles consisting of chondritic components (chondrules, metal grains, AOAs, and CAIs) generally yield better partitioning results compared to pebbles made from chondrites.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"358 ","pages":"Article 107295"},"PeriodicalIF":2.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 method for simultaneously determining Earth's magnetic field and mantle conductivity models using MSS-1 and Swarm satellite magnetic data","authors":"Hongbo Yao,&nbsp;Juyuan Xu,&nbsp;Keke Zhang","doi":"10.1016/j.pepi.2024.107296","DOIUrl":"10.1016/j.pepi.2024.107296","url":null,"abstract":"<div><div>The magnetospheric primary and its Earth mantle-induced fields are essential components of geomagnetic field models. Previous geomagnetic field modeling methods typically use a fixed <em>a priori</em> Earth's mantle conductivity model to account for the induced field. This treatment may reduce accuracy, as electromagnetic induction depends on conductivity models. Here, we propose a new method that simultaneously determines the mantle conductivity model during geomagnetic field modeling. This method has the advantages of (i) self-consistently accounting for the induced field in geomagnetic field modeling, and (ii) simultaneously providing valuable information on Earth's internal structure. We implement the method into a new computationally parallel field modeling framework, which scales nearly linearly up to a large number of MPI cores. The Macau Science Satellite-1 (MSS-1), primarily aiming to accurately measure the Earth's magnetic field, was successfully launched on May 21, 2023. We apply our method to the magnetic data from MSS-1 as well as Swarm satellites and obtain the first self-consistent models of Earth's magnetic field and mantle conductivity. We also investigate how different conductivity models affect geomagnetic field modeling. Our results show that a fixed <em>a priori</em> conductivity model introduces field differences of about 2–4 nT in magnetic field models. These field differences, which are larger than the measuring accuracy of modern geomagnetic satellites, can be avoided by our method.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"358 ","pages":"Article 107296"},"PeriodicalIF":2.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Late-stage Deccan eruption from multiple shallow magma chambers through vertical flow along fissures: Insights from magnetic fabric analysis of the Pachmarhi dyke swarm","authors":"Garima Shukla ,&nbsp;Jyotirmoy Mallik ,&nbsp;Yadav Krishna ,&nbsp;Sayandeep Banerjee","doi":"10.1016/j.pepi.2024.107285","DOIUrl":"10.1016/j.pepi.2024.107285","url":null,"abstract":"<div><div>The Pachmarhi dyke swarm, located in the eastern part of the Narmada-Satpura-Tapi dykes belonging to the Deccan Continental Flood Basalt, are studied using the Anisotropy of Magnetic Susceptibility (AMS) technique. This research aims to determine the direction and sense of magma flow within the dykes, providing insights into the depth, number, and location of magma chambers, as well as the geodynamics of their plumbing system. Petrography and rock magnetism analyses revealed a mixture of high- and low-titanium magnetite particles, predominantly of pseudo-single domain nature (with a smaller proportion of multi-domain dominated) grains are primary remanence carriers. We identified four distinct types of magnetic fabric (I-IV) within the Pachmarhi dykes. The K₁-axis being parallel to the dyke plane, and the intersection of the imbrication angle of magnetic foliation (for oblate fabric) and magnetic lineation (for prolate fabric) was used to discern the direction of magma flow. This analysis revealed multiple trends of magma flow, ranging from vertical/sub-vertical to inclined. The flow fabric provides valuable information about the presence of multiple shallow sub-crustal magma chambers. This interpretation aligns with prior independent gravity and 3-D density modelling studies, which indicates the presence of dense mafic magma bodies at depths of 4 to 8 km along the Narmada-Tapi intraplate rift zone. These findings are similar to those observed in the Nandurbar-Dhule dyke swarms in the western region of the Narmada-Satpura-Tapi dykes. Consequently, we can infer that the emplacement of dykes in the Pachmarhi region of the Narmada-Son-Lineament, which likely served as feeders for the late-stage Deccan volcanism, was primarily facilitated by a “polycentric flow” mechanism. In this process, magma was injected vertically from multiple shallow magma chambers through crustal fissures, potentially feeding into the late-stage Deccan flow units, such as the Ambenali or Mahabaleshwar Formations.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"357 ","pages":"Article 107285"},"PeriodicalIF":2.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanisms of seismic attenuation beneath Bhutan Himalaya","authors":"Abhisek Dutta ,&nbsp;Rahul Biswas ,&nbsp;Chandrani Singh","doi":"10.1016/j.pepi.2024.107279","DOIUrl":"10.1016/j.pepi.2024.107279","url":null,"abstract":"<div><div>We have analyzed 614 high quality local earthquake (1.5 <span><math><mo>≤</mo></math></span><span><math><msub><mi>M</mi><mi>l</mi></msub></math></span> (local magnitude) <span><math><mo>≤</mo></math></span> 5.5) data recorded by temporary GANSSER network of 44 broadband stations to investigate the attenuation mechanism of Bhutan Himalaya. Initially, the single isotropic scattering model is applied to study the coda wave attenuation (<span><math><msubsup><mi>Q</mi><mi>c</mi><mrow><mo>−</mo><mn>1</mn></mrow></msubsup></math></span>). Subsequently, we have used the Multiple Lapse Time Window Analysis (MLTWA) to estimate the relative contribution of scattering (<span><math><msubsup><mi>Q</mi><mi>sc</mi><mrow><mo>−</mo><mn>1</mn></mrow></msubsup></math></span>) and intrinsic (<span><math><msubsup><mi>Q</mi><mi>i</mi><mrow><mo>−</mo><mn>1</mn></mrow></msubsup></math></span>) attenuation to the total attenuation (<span><math><msubsup><mi>Q</mi><mi>t</mi><mrow><mo>−</mo><mn>1</mn></mrow></msubsup></math></span>) under the assumption of multiple isotropic scattering with uniform half space medium. The analysis has been carried out for five different central frequencies within the range of 1.5 to 18 Hz. All the estimated values of <span><math><mi>Q</mi></math></span> exhibit high frequency dependent nature. Interestingly, scattering attenuation is found to be the dominant factor attenuating the seismic waves in the crust of Bhutan Himalaya which is different from the rest of the Himalayas except Garwhal–Kumaun Himalaya and the adjacent Sikkim Himalaya. This strongly suggests that the relative role of both scattering and intrinsic attenuation varies across the Himalaya and is likely to be associated with the structural variabilities among different segments. The role of Main Himalayan Thrust (<span><math><mi>MHT</mi></math></span>) in changing the differential stress regime across the region could be the major cause of the intra-crustal deformation which resulted in the predominance of scattering attenuation in the crust of Bhutan Himalaya.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"357 ","pages":"Article 107279"},"PeriodicalIF":2.4,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Waves in Earth's core and geomagnetic field forecast","authors":"N. Gillet ,&nbsp;F. Dall'Asta ,&nbsp;P.-O. Amblard ,&nbsp;R. Claveau ,&nbsp;J. Aubert","doi":"10.1016/j.pepi.2024.107284","DOIUrl":"10.1016/j.pepi.2024.107284","url":null,"abstract":"<div><div>We use advanced numerical geodynamo series to derive a reduced stochastic model of the dynamics at the surface of Earth's core. Considering order 3 autoregressive (AR-3) processes allows to replicate the simulated spatiotemporal spectrum over a broad range of time-scales, spanning millennia to a fraction of year, including the cut-off found for periods shorter than approximately 2 years and associated with magnetic dissipation. We show how to derive such a forward model from a variety of input simulation series, and present its implementation into the pygeodyn data assimilation algorithm, based on a sequential ensemble method. The updated scheme is applied to perform magnetic field hindcasts and core flow reanalyses. For all observable length-scales, the rate of change of the observed magnetic field is most of the time accounted for within the spread of the forward model trajectories. AR-3 predictions on average supersede by about 35 % linear extrapolations on short (2 yr) time-scales, reducing high-frequency spurious variations in reanalysed flow motions. This improvement is reduced to <span><math><mo>≈</mo><mn>10</mn><mo>%</mo></math></span> for 5 yr increments, with a large variability from one epoch to the other depending on the overall curvature of the magnetic field evolution. We perform a reanalysis over the period 1880–2023 covered by observatory and satellite records. We find enhanced kinetic energy in three period ranges around 12.5, 6.5 and 3.5 years. At all three periods, fluid motions share geometrical properties compatible with quasi-geostrophic magneto-Coriolis waves: equatorial symmetry, larger amplitude near the equator, flow dominated by low azimuthal wave number and modulated in longitude, phase speed much faster than the fluid velocity and decreasing with the period. At 6.5 yr period we trace back to the mid-1990's the patterns previously detected from satellite data. We also find in the 1960–70's a similar wave-train, possibly in link with the 1969 geomagnetic jerk. The AR-3 model, in conjunction with early satellite records, likely helps isolate such coherent features on interannual time-scales. Similar wave-like motions also show up at 3.5 yr period around 1970 and during the past decades. At periods around 12.5 yr we detect recurrent patterns starting as far back as 1920, and modulated over decadal time-scales. Our results show growing evidence for core dynamics governed by the presence of hydro-magnetic waves over a wide range of periods. This may allow deterministic and/or empirical descriptions of the signal that may help sound deep Earth's properties, and improve predictions of the magnetic field evolution.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"357 ","pages":"Article 107284"},"PeriodicalIF":2.4,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Three-dimensional velocity structure of the MS 6.0 Luxian earthquake source region and adjacent areas based on a dense seismic array","authors":"Guangyao Cai ,&nbsp;Weilai Wang ,&nbsp;Jianping Wu ,&nbsp;Guijuan Lai ,&nbsp;Long Zhang ,&nbsp;Jingjing Bao ,&nbsp;Huijie Liu","doi":"10.1016/j.pepi.2024.107281","DOIUrl":"10.1016/j.pepi.2024.107281","url":null,"abstract":"<div><div>On September 16, 2021, an <em>M</em>_S 6.0 earthquake struck Luxian County in the Sichuan basin. To investigate the regional velocity structure and its relationship with seismic activity, we gathered seismic phase data from permanent stations for events occurring between January 2009 and April 2021 as well as data from a dense mobile seismic array that operated from April 2021 to July 2023. Utilizing Double-Difference tomography, we have determined well-constrained earthquake relocations and have derived a detailed 3D velocity structure. Many of the earthquakes exhibit linear clustering patterns, with an average depth of 4.3 km and a NE-SW orientation. Approximately 96 % of the seismic events occurred within a depth range of 0–7 km. The early aftershock sequence of the Luxian event also displayed a linear trend, with a length of 6 km but with an ESE orientation. The mainshock occurred at a depth of 6.2 km, located at the northwestern end of the aftershock sequence. The aftershock sequence along with other linear seismic clusters, predominantly occurred within regions characterized by high seismic velocities and low Poisson's ratios, both within the sedimentary cover above the crystalline basement. The heterogeneity of the velocity structure likely plays a significant role in controlling the occurrence of moderate-to-strong earthquakes in the deeper parts of the study region, which deepens the existing understanding from previous research: pre-existing faults, their scales, and their slip-tendencies under the present-day regional and reservoir-scale stress fields are also controlling factors for induced earthquakes, especially larger ones. We have identified five areas where moderate-to-strong earthquakes are speculated to have a higher likelihood of occurrence. These findings hold considerable importance for local seismic hazard assessments.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"357 ","pages":"Article 107281"},"PeriodicalIF":2.4,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Finite fault inversion and hybrid broadband simulation of strong-motion records from the May 28, 2004, Baladeh, Iran, earthquake (Mw = 6.2)","authors":"Reza Alikhanzadeh ,&nbsp;Hamid Zafarani ,&nbsp;Navid Kheirdast","doi":"10.1016/j.pepi.2024.107282","DOIUrl":"10.1016/j.pepi.2024.107282","url":null,"abstract":"<div><div>Tehran, the capital of Iran, is widely recognized as one of the world's most earthquake-vulnerable cities. Since there are no recorded ground motions of large earthquakes in the Tehran area, for seismological and earthquake engineering purposes, simulated ground motions may be useful in understanding the earthquake characteristics. On the other hand, ground motion simulation validation is an important and necessary task toward establishing the efficacy of physics-based ground motion simulations for seismic hazard analysis and earthquake engineering applications. This article presents a validation of the hybrid broadband ground motion simulation methodology through simulation of Baladeh 2004 earthquake (Mw 6.2). This earthquake occurred On May 28, 2004, in the Baladeh region in the North of Iran. This earthquake is remarkable because it was the first instrumentally recorded large earthquake near Tehran. In this paper, for the first time, we obtain slip distribution on the fault plane by finite fault inversion based on the neuro-fuzzy finite-fault approach. Next a hybrid broadband simulation of ground motion recorded during the main shock of the Baladeh earthquake is done. Then a combination of the finite difference method (0.1–1.0 Hz) and the stochastic finite fault method (1.0–20.0 Hz) is used for quantifying ground motion values. The validity of the results is checked by some empirical GMPEs, a quantitative score of Anderson, 2004, and also model bias of Graves and Pitarka (2010).</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"357 ","pages":"Article 107282"},"PeriodicalIF":2.4,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Azimuthal seismic anisotropy of the Iran plateau: Insights from ambient noise analysis","authors":"Ramin Movaghari ,&nbsp;Javan Doloei Gholam ,&nbsp;Khaled Hessami","doi":"10.1016/j.pepi.2024.107280","DOIUrl":"10.1016/j.pepi.2024.107280","url":null,"abstract":"<div><div>The continental lithosphere of the Iran plateau is complicated by many tectonic processes that affected both the Arabian and Eurasian plates before and after their convergence. To investigate the deformation mechanisms of the crust and mantle lithosphere, we directly invert Rayleigh wave phase velocity dispersion data (5–60 s) for a 3-D shear wave velocity and depth-dependent azimuthal anisotropy model using ambient noise tomography from the surface down to 100 km with data recorded in 84 seismic stations. The shear wave velocity maps reveal a reasonable match with geological domains and agree with those previously published. The projections of the fast axes of Rayleigh wave azimuthal anisotropy in the subcrustal lithosphere allowed us to divide the Iran plateau into two main regions: the Zagros Mountains and the rest of the country. Furthermore, the anisotropy pattern illustrates a prominent contrast between the NW and SE Zagros Mountains. In both the crust and subcrustal lithosphere, the NW Zagros shows relatively weak but coherent azimuthal anisotropy in the NE-SW direction (i.e., orogen-perpendicular orientation). We ascribe the orogen-perpendicular fast axis in NW Zagros to stress-induced anisotropy. However, in the SE Zagros, the north-northwest orientations of the fast axes are attributed to the N-S trending basement structures, which are inherited from the Pan-African construction phase. The azimuthal anisotropy pattern displays an overall NW-SE trend dominant over the rest of the country. This NW-SE direction can be explained by an NW-SE extension due to transpressional deformation beneath Central Iran resulting from the oblique indentation of the Arabian plate into Eurasia. Nevertheless, strike-parallel anisotropy directions along the western and central Alborz Mountains throughout the entire lithosphere may be related to pure shear deformation. The persistence of azimuthal anisotropy patterns in the crust and subcrustal lithosphere implies that the whole lithosphere deforms coherently in the NW Zagros, west Iran, the Alborz Mountains, and across the Lut block. However, strong contrasts between the crustal and subcrustal pattern of anisotropy observed in the SE Zagros as well as in north Central Iran suggest that in these regions, the crust and the underlying mantle lithosphere do not deform coherently. A strong correlation between the Rayleigh wave anisotropy directions at subcrustal depths and the anisotropy patterns estimated from the shear-wave core phases suggests that in many places over the plateau, the SKS directions may have been dominated by the deformation of the lithosphere.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"357 ","pages":"Article 107280"},"PeriodicalIF":2.4,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lithospheric magnetic structure of cratonic regions in Central-Eastern China inferred from aeromagnetic anomalies: Insights into magnetization in the uppermost mantle","authors":"Yuanyuan Li ,&nbsp;Yushan Yang ,&nbsp;Jiwen Teng ,&nbsp;Tianyou Liu ,&nbsp;Yafen Yan","doi":"10.1016/j.pepi.2024.107276","DOIUrl":"10.1016/j.pepi.2024.107276","url":null,"abstract":"<div><div>Most of the subcontinental lithospheric mantle (SCLM) beneath Proterozoic cratons consists of refertilized Archaean SCLM. Variations in SCLM composition and its physical properties significantly affect the stabilization and preservation of the ancient continents. In this paper, aeromagnetic data are analyzed to reveal the magnetic structure of the lithospheric mantle beneath two major Precambrian blocks in central-eastern China, i.e., the Upper Yangtze Block (UYB) and Ordos Block (OB). After being reduced to the pole, the Fourier power spectrum of the aeromagnetic anomalies is calculated to determine the depth to magnetic sources. Considering the lower spatial resolution of the power spectral analysis in dealing with the long-wavelength aeromagnetic anomalies, we applied the scale-normalized continuous wavelet transform (CWT) on the magnetic data to trace the magnetic sources, with special focus on deeper ones. Synthetical model of a magnetic layer and application to the profile data validate the effectiveness of this scale normalization scheme in improving the wavenumber/spatial resolution in the CWT scalogram.</div><div>In order to present a detailed magnetic structure, we carried out 2.5D forward modeling work on the magnetic data of a 2280 km-long nearly N-S profile across the UYB and OB. Due to the inherent ambiguity in the modeling results, the CWT-based spectral analysis is successfully adopted to provide source depth constraints for the initial model. The constrained forward modeling results indicate strong inhomogeneities among main tectonic blocks of studied area, like humans have different fingerprints. The magnetization of OB is larger than that of UYB since its Archean to Paleoproterozoic metamorphic basement are widely exposed at the surface, while the Precambrian basement of UYB is mostly overlain by unmetamorphosed Sinian cover and weakly metamorphosed Neoproterozoic strata. The most interesting aspect is that deep-seated magnetic sources might reside in the uppermost mantle of UYB and OB, suggesting vertical layering in the SCLM in cold cratonic regions.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"357 ","pages":"Article 107276"},"PeriodicalIF":2.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}