Article
Geosciences, Multidisciplinary
Z. Pastore, P. Lelievre, S. A. McEnroe, N. S. Church
Summary: Scanning Magnetic Microscopy (SMM) is an important magnetometry technique that helps us understand the origin of rock behavior. In this study, 3D magnetic vector inversion was used to quantify the remanent magnetization in a norite sample and it was found that the main source of magnetization is pyroxenes.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Yixiati Dilixiati, Eldar Baykiev, Joerg Ebbing
Summary: A novel approach combining aeromagnetic and satellite data is proposed, involving inversion for magnetic parameters and conversion into spherical harmonics. Testing on Magnetic Anomaly Maps of Australia shows good agreement with satellite data when replacing long-wavelength aeromagnetic data with satellite data.
Article
Geochemistry & Geophysics
M-A Dumais, L. Gernigon, O. Olesen, S. E. Johansen, M. Bronner
Summary: Insights into the evolution of the Knipovich Ridge and development of the Fram Strait were revealed from a recent aeromagnetic survey. Magnetic isochrons identified on either side of the present-day Knipovich Ridge significantly reduced the mapped extent of the oceanic domain, questioning the current understanding of the conjugate rifted margins. The analysis also unveiled a failed spreading system before a major spreading reorganization around magnetic chron C6 (circa 20 Ma) in the Fram Strait gateway.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geosciences, Multidisciplinary
Yanfeng Fan, Yang Zhang, Gaopeng Lu, Weitao Lyu, Hengyi Liu, Liangtao Xu, Dong Zheng
Summary: An altitude-triggered lightning flash was conducted in a field experiment in China, and the low-medium frequency magnetic field of the lightning was measured for the first time using a sensitive magnetic sensor. The measurements revealed that the magnetic field waveforms of precursors and sustained upward positive leaders showed a clear damped-oscillatory pattern, which was caused by propagation losses and reflections of the lightning current. The observations also indicated that the bidirectional leaders developed in an uncoordinated manner, with the sustained downward negative leader occurring about 5.5 ms after the sustained upward positive leader.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Raj Kumar, A. R. Bansal, Peter G. Betts, D. Ravat
Summary: Australia and North America are the only two continent-wide regions with complete magnetic anomaly spectrum, which can help address the debated issue of the existence and understanding of the magnetic state of the upper mantle. By re-assessing the depth to the base of magnetic sources in Australia using aeromagnetic data, varying estimates were found across different geological regions, with deeper estimates in some cratonic regions and shallower estimates in areas with high heat flow. This suggests a complex relationship between the depth of magnetic sources, temperature structure, mineralogy, petrology, and geological history.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Z. Pastore, S. A. McEnroe, N. S. Church, H. Oda
Summary: Distinct crustal remanent magnetic anomalies are a strong indicator of rocks with stable natural remanent magnetization carriers. High-resolution magnetometric scanning techniques can map magnetic sources at the mineral scale, identify different magnetic carriers, and analyze their magnetic response. Magnetic modeling results show consistent magnetization direction before and after demagnetization, with a decrease in magnetization intensity of approximately 30%.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geosciences, Multidisciplinary
Giovanni Florio, Salvatore Passaro, Giovanni de Alteriis, Federico Cella
Summary: In this study, a processing workflow is proposed to enhance the information content of aeromagnetic data. Through validation, it is shown that this workflow leads to more accurate interpretative results in the case of aeromagnetic anomalies.
Article
Geochemistry & Geophysics
Christian Emile Nyaban, Theophile Ndougsa-Mbarga, Marcelin Bikoro-Bi-Alou, Stella Amina Manekeng Tadjouteu, Stephane Patrick Assembe
Summary: This study conducted in the Lom series in Cameroon revealed major fault families, discussed depths of interpreted faults, local tectonic features, and deep structural models. Modeling of the crust structure revealed fault distribution and deep anomalies.
Review
Environmental Sciences
Eric C. Ferre, Ilya Kupenko, Fatima Martin-Hernandez, Dhananjay Ravat, Carmen Sanchez-Valle
Summary: Recent research has revealed the presence of magnetic materials in the mantle, particularly in the uppermost part, and experiments suggest that hematite and its polymorphs may have magnetic remanence. Analysis of aeromagnetic data confirms the existence of a magnetized layer below the crust-mantle boundary in various tectonic settings.
NATURE REVIEWS EARTH & ENVIRONMENT
(2021)
Article
Geochemistry & Geophysics
Mohammad Rezaie
Summary: Magnetic data inversion is crucial for interpretation, but traditional methods struggle with remanence; a new algorithm has been developed to improve the accuracy of sparse inversion models, proving geological acceptability on data sets with remanent magnetization.
PURE AND APPLIED GEOPHYSICS
(2021)
Article
Geosciences, Multidisciplinary
Guoming Gao, Quanming Lu, Jun Wang, Guofa Kang
Summary: By integrating data of gravimetry, aeromagnetic survey, and terrestrial heat flow, researchers have investigated the Moho depth, the Curie surface depth, and the thermal lithospheric thickness beneath the northeastern Tibetan Plateau (NETP) and adjacent regions. The results show that the NETP has a deep Moho but a shallow Curie surface, in contrast to other regions like the North China Plain, Ordos Basin, and Yangtze Block. The distribution of heat flow confirms the presence of a heat channel between different geological features, such as the Qinling Orogen, which connects various regions in China.
JOURNAL OF ASIAN EARTH SCIENCES
(2021)
Article
Geochemistry & Geophysics
Wenna Zhou, Qiang Li, Dailei Zhang, Hai Tang
Summary: We reveal a new crustal structure of the Gonghe-Guide Basin by utilizing EIGEN-6C4 satellite gravity and aeromagnetic data, aiming to further understand geothermal mechanisms. The gravity inversion results indicate distinct low-density regions in the middle-upper crust at depths of 15-35 km, most likely caused by partial melting. The magnetic inversion results show negative or no magnetism within a similar depth range, but high positive magnetism at shallow depths, which can be interpreted as granite.
PURE AND APPLIED GEOPHYSICS
(2023)
Article
Chemistry, Inorganic & Nuclear
Abbey J. Neer, Joanna Milam-Guerrero, Veronika A. Fischer, Michelle Zheng, Nicole R. Spence, Clayton Cozzan, Mingqiang Gu, James M. Rondinelli, Craig M. Brown, Brent C. Melot
Summary: We conducted a comparative study on the magnetic and crystal chemical properties of two Co2+-containing garnets. It was found that CaY2Co2Ge3O12 and NaCa2Co2V3O12 exhibited different magnetic structures and properties under similar external conditions. Crystal-chemistry analyses and density functional theory calculations were performed to explain these differences based on minor changes in the local environment of the Co ions.
INORGANIC CHEMISTRY
(2022)
Article
Environmental Sciences
Yuanguo Zhou, Peng Huang, Guoqing Yang, Shangqing Liang, Qiang Ren, Shiwei Tian
Summary: A spectral-element method based on Gauss-Lobatto-Legendre polynomials is presented to characterize the magnetic field induced by underwater pressure waves. The study shows that these magnetic fields can be used for monitoring ocean internal waves. Experimental analysis demonstrates that the signals of these magnetic fields can propagate for tens of kilometers and exist for hours, providing a theoretical basis for underwater target identification using high-sensitivity atomic magnetometers.
Article
Materials Science, Multidisciplinary
Santanu Pakhira, D. C. Johnston
Summary: The body-centered-tetragonal antiferromagnet EuGa4 is found to be a Weyl nodal-line semimetal exhibiting topological Hall effect below its reported antiferromagnetic ordering temperature T-N = 15-16.5 K, with an actual T-N = 16.4(2) K. EuGa4 shows A-type antiferromagnetic order below T-N, where the Eu2+ spin-7/2 moments are ferromagnetically aligned in the ab plane with the Eu moments in adjacent Eu planes along the c axis aligned antiferromagnetically. Low-field magnetization versus field data at T = 2 K reveals anomalous positive curvature up to a critical field Hc1, followed by a second-order transition. The theory explains the observed behavior at T = 2 K, where domains of A-type antiferromagnetic order with fourfold rotational symmetry occur in zero field.