Results 71 to 80 of about 1,386 (209)

Reconstruction of Core‐Surface Flows During the Last 3,300 Years

Geochemistry, Geophysics, Geosystems, Volume 27, Issue 3, March 2026.
Abstract Understanding the Earth's magnetic field evolution requires examining the fluid flow at the core‐mantle boundary that drives the changes over different timescales. The inversion process to derive core‐surface flow velocities from secular variation data encounters non‐uniqueness issues, necessitating a priori assumptions that yield different ...
Pablo Rivera, F. J. Pavón‐Carrasco, M. L. Osete   +2 more
wiley   +1 more source

Mantle cooling regulation and ancient geomagnetic field

Russian Journal of Earth Sciences, 2022
The joined core and mantle thermal evolution model of the Earth for 6 Gy is considered. The model describes evolution of the heat fluxes, temperature distribution in the Earth, energy available for the magnetic field generation. Using Monte Carlo method
Reshetnyak Maxim
doaj   +1 more source

Archeointensity Database and Geomagnetic Field Reference Curves for South America Over the Past 5 Millennia

Journal of Geophysical Research: Solid Earth, Volume 131, Issue 3, March 2026.
Abstract The study of variations in geomagnetic field intensity over time and space is crucial to understand the evolution of the geodynamo and its interactions with the Earth's surface. In this work, we introduce the SAGEOMAG (South America GEOMAGnetic) database, a comprehensive and updated repository of geomagnetic field intensity records derived ...
Victor J. O. Marum, Filipe Terra‐Nova, Gelvam A. Hartmann, Erwan Thébault, Plinio Jaqueto, Wilbor Poletti, Ricardo I. F. Trindade   +6 more
wiley   +1 more source

Evidence for Missing Geomagnetic Reversals From Geomagnetic Reversal Frequency Model Using Adaptive Kernel Density Estimation

Geophysical Research Letters, Volume 53, Issue 4, 28 February 2026.
Abstract The existence of missing geomagnetic reversals has been proposed, with potential for new magnetostratigraphic age controls. We estimate geomagnetic reversal frequency from 0 to 155 Ma using adaptive‐bandwidth kernel density estimation (AKDE) to evaluate data sparseness and to assess how reversal frequency changes when recently identified ...
Yutaka Yoshimura, Masakazu Fujii, Hideitsu Hino, Shotaro Akaho, Satoshi Kuriki, Osamu Ishizuka, Toshitsugu Yamazaki, Hyeon‐Seon Ahn, Tesfaye Kidane, Yuhji Yamamoto, Yo‐ichiro Otofuji   +10 more
wiley   +1 more source

Modelling the palaeo-evolution of the geodynamo

, 2009
International audienceAlthough it is known that the geodynamo has been operating for at least 3.2 Ga, it remains difficult to infer the intensity, dipolarity and stability (occurrence of reversals) of the Precam-brian magnetic field of the Earth.
Poitou, Charles, Charles Poitou, Aubert, Julien, Labrosse, Stéphane, St��phane Labrosse, Julien Aubert   +5 more
core   +1 more source

Self‐Consistent Models of Earth's Mantle and Core From Long‐Period Seismic and Tidal Constraints

Journal of Geophysical Research: Solid Earth, Volume 131, Issue 2, February 2026.
Abstract Here we illustrate the use of parameterized models to address fundamental questions about Earth's mantle and core structure. For this, we invert a large set of normal‐mode center frequencies and quality (attenuation) factors, along with astronomic‐geodetic data, for the radial anelastic seismic structure of the Earth.
F. D. Munch, J. Kemper, A. Khan, G. Helffrich, D. Giardini   +4 more
wiley   +1 more source

Magnetohydrodynamic turbulence and the geodynamo [PDF]

Physics of the Earth and Planetary Interiors, 2018
Abstract Ideal magnetohydrodynamic (MHD) turbulence contains an intrinsic statistical mechanism called ‘broken ergodicity’ for producing an energetic, large-scale, quasi-stationary coherent structure. Since MHD turbulence occurs in the Earth’s liquid outer core, the implication is that the Earth’s dipole magnetic field may be due to MHD turbulence ...
openaire   +1 more source

Reduced Geomagnetic Shielding During the Laschamps Excursion and Its Impact on Cosmic‐Ray‐Induced Atmospheric Radiation

Journal of Geophysical Research: Space Physics, Volume 131, Issue 2, February 2026.
Abstract The Laschamps geomagnetic excursion (≈41,000 years BP) was a period of significant weakening and incomplete reversal of the Earth's magnetic field. The weakening substantially reduced geomagnetic shielding against cosmic rays (CRs), which contribute to phenomena at Earth, such as cosmogenic isotope production, and atmospheric ionisation and ...
N. Larsen, I. Usoskin, A. Mishev, S. Koldobskiy, P. Väisänen   +4 more
wiley   +1 more source

Reconstructing Late Pleistocene to Prehistorical Holocene Geomagnetic Field Variations From La Palma Lava Flows (Canary Islands, Spain): Unraveling Viscous Components

Journal of Geophysical Research: Solid Earth, Volume 131, Issue 2, February 2026.
Abstract We present new vector paleomagnetic data from 13 radiometrically dated lava‐flows in southern La Palma (Canary Islands) spanning from 1 to 56 ka, which covers most of the Late Pleistocene to prehistoric Holocene volcanic record in the island.
Eva Vernet, Manuel Calvo‐Rathert, Ángel Carrancho, Yuhji Yamamoto, Lidia Rodríguez‐Méndez, Josep M. Parés, Vicente Soler   +6 more
wiley   +1 more source

Three distinct reversing modes in the geodynamo

, 2020
© 2016, Pleiades Publishing, Ltd.The data that describe the long-term reversing behavior of the geodynamo show strong and sudden changes in magnetic reversal frequency.
Gallet Y., Pavlov V.
core