Simulated geomagnetic reversals and preferred virtual geomagnetic pole paths
The question of whether virtual geomagnetic poles (VGPs) recorded during reversals and excursions show a longitudinal preference is a controversial one amongst palaeomagnetists. One possible mechanism for such VGP clustering is the heterogeneity of heat flux at the core—mantle boundary (CMB). We use...
Published in: | Geophysical Journal International |
---|---|
Main Authors: | , |
Format: | Text |
Language: | English |
Published: |
Oxford University Press
2004
|
Subjects: | |
Online Access: | http://gji.oxfordjournals.org/cgi/content/short/157/3/1105 https://doi.org/10.1111/j.1365-246X.2004.02309.x |
id |
fthighwire:oai:open-archive.highwire.org:gji:157/3/1105 |
---|---|
record_format |
openpolar |
spelling |
fthighwire:oai:open-archive.highwire.org:gji:157/3/1105 2023-05-15T16:19:40+02:00 Simulated geomagnetic reversals and preferred virtual geomagnetic pole paths Kutzner, C. Christensen, U. R. 2004-06-01 00:00:00.0 text/html http://gji.oxfordjournals.org/cgi/content/short/157/3/1105 https://doi.org/10.1111/j.1365-246X.2004.02309.x en eng Oxford University Press http://gji.oxfordjournals.org/cgi/content/short/157/3/1105 http://dx.doi.org/10.1111/j.1365-246X.2004.02309.x Copyright (C) 2004, Oxford University Press Geomagnetism Rock Magnetism and Palaeomagnetism TEXT 2004 fthighwire https://doi.org/10.1111/j.1365-246X.2004.02309.x 2013-05-27T01:20:43Z The question of whether virtual geomagnetic poles (VGPs) recorded during reversals and excursions show a longitudinal preference is a controversial one amongst palaeomagnetists. One possible mechanism for such VGP clustering is the heterogeneity of heat flux at the core—mantle boundary (CMB). We use 3-D convection-driven numerical dynamo models with imposed non-uniform CMB heat flow that show stochastic reversals of the dipole field. We calculate transitional VGPs for a large number of token sites at the Earth's surface. In a model with a simple heat flux variation given by a Y 22 harmonic, the VGP density maps for individual reversals differ substantially from each other, but the VGPs have a tendency to fall around a longitude of high heat flow. The mean VGP density for many reversals and excursions shows a statistically significant correlation with the heat flow. In a model with an imposed heat flux pattern derived from seismic tomography we find maxima of the mean VGP density at American and East Asian longitudes, roughly consistent with the VGP paths seen in several palaeomagnetic studies. We find that low-latitude regions of high heat flow are centres of magnetic activity where intense magnetic flux bundles are generated. They contribute to the equatorial dipole component and bias its orientation in longitude. During reversals the equatorial dipole part is not necessarily dominant at the Earth's surface, but is strong enough to explain the longitudinal preference of VGPs as seen from different sites. Text Geomagnetic Pole HighWire Press (Stanford University) Geophysical Journal International 157 3 1105 1118 |
institution |
Open Polar |
collection |
HighWire Press (Stanford University) |
op_collection_id |
fthighwire |
language |
English |
topic |
Geomagnetism Rock Magnetism and Palaeomagnetism |
spellingShingle |
Geomagnetism Rock Magnetism and Palaeomagnetism Kutzner, C. Christensen, U. R. Simulated geomagnetic reversals and preferred virtual geomagnetic pole paths |
topic_facet |
Geomagnetism Rock Magnetism and Palaeomagnetism |
description |
The question of whether virtual geomagnetic poles (VGPs) recorded during reversals and excursions show a longitudinal preference is a controversial one amongst palaeomagnetists. One possible mechanism for such VGP clustering is the heterogeneity of heat flux at the core—mantle boundary (CMB). We use 3-D convection-driven numerical dynamo models with imposed non-uniform CMB heat flow that show stochastic reversals of the dipole field. We calculate transitional VGPs for a large number of token sites at the Earth's surface. In a model with a simple heat flux variation given by a Y 22 harmonic, the VGP density maps for individual reversals differ substantially from each other, but the VGPs have a tendency to fall around a longitude of high heat flow. The mean VGP density for many reversals and excursions shows a statistically significant correlation with the heat flow. In a model with an imposed heat flux pattern derived from seismic tomography we find maxima of the mean VGP density at American and East Asian longitudes, roughly consistent with the VGP paths seen in several palaeomagnetic studies. We find that low-latitude regions of high heat flow are centres of magnetic activity where intense magnetic flux bundles are generated. They contribute to the equatorial dipole component and bias its orientation in longitude. During reversals the equatorial dipole part is not necessarily dominant at the Earth's surface, but is strong enough to explain the longitudinal preference of VGPs as seen from different sites. |
format |
Text |
author |
Kutzner, C. Christensen, U. R. |
author_facet |
Kutzner, C. Christensen, U. R. |
author_sort |
Kutzner, C. |
title |
Simulated geomagnetic reversals and preferred virtual geomagnetic pole paths |
title_short |
Simulated geomagnetic reversals and preferred virtual geomagnetic pole paths |
title_full |
Simulated geomagnetic reversals and preferred virtual geomagnetic pole paths |
title_fullStr |
Simulated geomagnetic reversals and preferred virtual geomagnetic pole paths |
title_full_unstemmed |
Simulated geomagnetic reversals and preferred virtual geomagnetic pole paths |
title_sort |
simulated geomagnetic reversals and preferred virtual geomagnetic pole paths |
publisher |
Oxford University Press |
publishDate |
2004 |
url |
http://gji.oxfordjournals.org/cgi/content/short/157/3/1105 https://doi.org/10.1111/j.1365-246X.2004.02309.x |
genre |
Geomagnetic Pole |
genre_facet |
Geomagnetic Pole |
op_relation |
http://gji.oxfordjournals.org/cgi/content/short/157/3/1105 http://dx.doi.org/10.1111/j.1365-246X.2004.02309.x |
op_rights |
Copyright (C) 2004, Oxford University Press |
op_doi |
https://doi.org/10.1111/j.1365-246X.2004.02309.x |
container_title |
Geophysical Journal International |
container_volume |
157 |
container_issue |
3 |
container_start_page |
1105 |
op_container_end_page |
1118 |
_version_ |
1766006075575762944 |