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Intermittent non-axial dipolar-field dominance of twin Laschamp excursions
,
Takeshi Nakagawa ,
Hayato Matsushita,
Ikuko Kitaba,
Keitaro Yamada ,
Shota Tanabe,
Balázs Bradák ,
Masako Miki,
Danielle McLean,
Richard A. Staff ,
Victoria C. Smith ,
Paul Albert ,
Christopher Bronk Ramsey ,
Akiteru Yamasaki,
Junko Kitagawa,
Gordon Schlolaut,
Katsuya Gotanda,
Kosuke Tsumura,
Kaito Inagawa,
Koyo Kumazawa,
Haruka Abe,
Saki Sugo,
Koki Takahashi,
Atsumi Kitamura,
(Suigetsu 2014 Project)
Communications Earth & Environment, Volume: 3, Issue: 1
Swansea University Authors:
Danielle McLean, Paul Albert
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DOI (Published version): 10.1038/s43247-022-00401-0
Abstract
Geomagnetic excursions represent the dynamic nature of the geodynamo. Accumulated palaeomagnetic records indicate that such excursions are dominated by dipolar-fields, but exhibit different structures. Here we report a palaeomagnetic record from the varved sediments of Lake Suigetsu, central Japan,...
| Published in: | Communications Earth & Environment |
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| ISSN: | 2662-4435 |
| Published: |
Springer Science and Business Media LLC
2022
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| Online Access: |
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa59815 |
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| Abstract: |
Geomagnetic excursions represent the dynamic nature of the geodynamo. Accumulated palaeomagnetic records indicate that such excursions are dominated by dipolar-fields, but exhibit different structures. Here we report a palaeomagnetic record from the varved sediments of Lake Suigetsu, central Japan, which reveals fine structures in the Laschamp Excursion and a new post-Laschamp excursion that coincides with the Δ14C maxima. The record’s high-resolution chronology provides IntCal20 mid-ages and varve-counted durations. Both excursions comprise multiple subcentennial directional-swings. Simulations of filtering effects on sediment-magnetisations demonstrate that this high-resolution record replicates most of the features in existing, lower-resolution Laschamp excursion records, including the apparent clockwise open-loop of the virtual geomagnetic pole pass. The virtual geomagnetic poles during the ‘swing’ phases make four clusters centred in hemispherically-symmetric regions, three of which encompass the virtual geomagnetic poles associated with the Laschamp Excursion recorded in lavas at various locations. The stationary dipolar-field sources under each cluster should have intermittently dominated one after another during the excursions. |
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| College: |
Faculty of Science and Engineering |
| Funders: |
This study was supported by grants 15H02143, 16J10887, 18K03804 and 18H03609 from the Japan Society for the Promotion of Science |
| Issue: |
1 |