English
 
Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Global evolution and dynamics of the geomagnetic field in the 15–70 kyr period based on selected paleomagnetic sediment records

Authors
/persons/resource/panovska

Panovska,  Sanja
2.3 Geomagnetism, 2.0 Geophysics, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum;

/persons/resource/monika

Korte,  M.
2.3 Geomagnetism, 2.0 Geophysics, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum;

Liu,  Jiabo
External Organizations;

/persons/resource/nowa

Nowaczyk,  N.
4.3 Climate Dynamics and Landscape Evolution, 4.0 Geosystems, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum;

External Ressource
No external resources are shared
Fulltext (public)

5008856.pdf
(Publisher version), 3MB

Supplementary Material (public)
There is no public supplementary material available
Citation

Panovska, S., Korte, M., Liu, J., Nowaczyk, N. (2021): Global evolution and dynamics of the geomagnetic field in the 15–70 kyr period based on selected paleomagnetic sediment records. - Journal of Geophysical Research: Solid Earth, 126, 12, e2021JB022681.
https://doi.org/10.1029/2021JB022681


Cite as: https://gfzpublic.gfz-potsdam.de/pubman/item/item_5008856
Abstract
Reconstructions of the geomagnetic field on long timescales are important to understand the geodynamo processes in the Earth’s core. The geomagnetic field exhibits a range of variations that vary from normal, dipole–dominated secular variation to geomagnetic excursions and reversals. These transitional events are associated with significant directional deviations and very low intensities. Here we present a new, global geomagnetic field model spanning the period 70–15 ka (GGFSS70) that includes three excursions: Norwegian–Greenland Sea, Laschamps, and Mono Lake/Auckland. The model is built from nine globally distributed, high–resolution, well–dated, sedimentary paleomagnetic records. The GGFSS70 indicates that the axial–dipole component changed sign for about 300 years in the middle of the Laschamps excursion (41.25–40.93 ka). The energy comparison at the Earth’s surface reveals that the axial–dipole energy is always higher than the non-axial-dipole except over the Laschamps. In the other two excursions, the axial-dipole is reduced by about one order of magnitude for the Norwegian–Greenland Sea excursion and less for the Mono Lake/Auckland. At the core–mantle boundary, the large–scale non-axial-dipole power is comparable to the axial-dipole power, except over the excursions when the axial-dipole decreases, though less clearly for the Mono Lake/Auckland excursion. The axial dipole moment over the 15–70 ka varies from 0 to 8 ×1022 Am2, with an average and standard deviation of 5.1±1.5 ×1022Am2. The Laschamps excursion is associated with growth and poleward movement of reversed flux patches and reversed field in the tangent cylinder at the excursion midpoint, which is not the case for the other two excursions.