Detailed Jaramillo field reversals recorded in lake sediments from Armenia – Lower mantle influence on the magnetic field revisited
While it is well established that the Earth's magnetic field is generated by a self sustaining dynamo that reversed its polarity at irregular intervals in the geological past, the very mechanisms causing field reversals remain obscure. Paleomagnetic reconstructions of polarity transitions have...
| Main Authors: | , , , |
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| Format: | Journal Article |
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Elsevier BV
2018
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| Online Access: | http://hdl.handle.net/20.500.11937/60093 |
| _version_ | 1848760578928017408 |
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| author | Kirscher, Uwe Winklhofer, M. Hackl, M. Bachtadse, V. |
| author_facet | Kirscher, Uwe Winklhofer, M. Hackl, M. Bachtadse, V. |
| author_sort | Kirscher, Uwe |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | While it is well established that the Earth's magnetic field is generated by a self sustaining dynamo that reversed its polarity at irregular intervals in the geological past, the very mechanisms causing field reversals remain obscure. Paleomagnetic reconstructions of polarity transitions have been essential for physically constraining the underlying mechanisms in terms of time scale, but thus far remain ambiguous with regard to the transitional field geometry. Here we present new paleomagnetic records from a rapidly deposited lacustrine sediment sequence with extraordinarily stable paleomagnetic signals, which has captured in unprecedented detail the bottom (reverse to normal: R–N) and top (normal to reverse: N–R) transitions of the Jaramillo subchron (at 1.072 Ma and at 0.988 Ma). The obtained virtual geomagnetic pole (VGP) path indicates an oscillatory transitional field behavior with four abrupt transequatorial precursory jumps across the Pacific. The distribution of VGP positions indicates regions of preferred occurrence. Our results are in agreement with previously proposed bands of transitional VGP occurrence over the Americas and Australia/northwest Pacific. Additionally, our VGP positions seem to avoid large low shear velocity provinces (LLSVPs) above the core mantle boundary (CMB). Thus, our data supports the idea that the transitional field geometry is controlled by heat flux heterogeneities at the CMB linked to LLSVPs. |
| first_indexed | 2025-11-14T10:18:01Z |
| format | Journal Article |
| id | curtin-20.500.11937-60093 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T10:18:01Z |
| publishDate | 2018 |
| publisher | Elsevier BV |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-600932018-04-24T03:39:24Z Detailed Jaramillo field reversals recorded in lake sediments from Armenia – Lower mantle influence on the magnetic field revisited Kirscher, Uwe Winklhofer, M. Hackl, M. Bachtadse, V. While it is well established that the Earth's magnetic field is generated by a self sustaining dynamo that reversed its polarity at irregular intervals in the geological past, the very mechanisms causing field reversals remain obscure. Paleomagnetic reconstructions of polarity transitions have been essential for physically constraining the underlying mechanisms in terms of time scale, but thus far remain ambiguous with regard to the transitional field geometry. Here we present new paleomagnetic records from a rapidly deposited lacustrine sediment sequence with extraordinarily stable paleomagnetic signals, which has captured in unprecedented detail the bottom (reverse to normal: R–N) and top (normal to reverse: N–R) transitions of the Jaramillo subchron (at 1.072 Ma and at 0.988 Ma). The obtained virtual geomagnetic pole (VGP) path indicates an oscillatory transitional field behavior with four abrupt transequatorial precursory jumps across the Pacific. The distribution of VGP positions indicates regions of preferred occurrence. Our results are in agreement with previously proposed bands of transitional VGP occurrence over the Americas and Australia/northwest Pacific. Additionally, our VGP positions seem to avoid large low shear velocity provinces (LLSVPs) above the core mantle boundary (CMB). Thus, our data supports the idea that the transitional field geometry is controlled by heat flux heterogeneities at the CMB linked to LLSVPs. 2018 Journal Article http://hdl.handle.net/20.500.11937/60093 10.1016/j.epsl.2017.12.010 Elsevier BV restricted |
| spellingShingle | Kirscher, Uwe Winklhofer, M. Hackl, M. Bachtadse, V. Detailed Jaramillo field reversals recorded in lake sediments from Armenia – Lower mantle influence on the magnetic field revisited |
| title | Detailed Jaramillo field reversals recorded in lake sediments from Armenia – Lower mantle influence on the magnetic field revisited |
| title_full | Detailed Jaramillo field reversals recorded in lake sediments from Armenia – Lower mantle influence on the magnetic field revisited |
| title_fullStr | Detailed Jaramillo field reversals recorded in lake sediments from Armenia – Lower mantle influence on the magnetic field revisited |
| title_full_unstemmed | Detailed Jaramillo field reversals recorded in lake sediments from Armenia – Lower mantle influence on the magnetic field revisited |
| title_short | Detailed Jaramillo field reversals recorded in lake sediments from Armenia – Lower mantle influence on the magnetic field revisited |
| title_sort | detailed jaramillo field reversals recorded in lake sediments from armenia – lower mantle influence on the magnetic field revisited |
| url | http://hdl.handle.net/20.500.11937/60093 |