New archaeointensity data from Western Europe: an improved description of the 800 AD intensity bump
Archaeomagnetic data indicate that during the past 2500 years there have been periods of rapid geomagnetic field intensity fluctuations interspersed with periods of almost constant field strength. The occurrence and the behaviour of these changes are under discussion and the challenge now is to prec...
| Autores: | , , , , , , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2012 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/86973 |
| Acceso en línea: | http://hdl.handle.net/10261/86973 |
| Access Level: | acceso abierto |
| Palabra clave: | Archaeomagnetism Archaeointensity secular variation dipole moment Thellier Europe |
| Sumario: | Archaeomagnetic data indicate that during the past 2500 years there have been periods of rapid geomagnetic field intensity fluctuations interspersed with periods of almost constant field strength. The occurrence and the behaviour of these changes are under discussion and the challenge now is to precisely describe them. The aim of this study is to obtain an improved description of the sharp geomagnetic intensity change that took place in Western Europe around 800 AD. For this purpose 13 precisely dated early medieval Spanish pottery fragments, 4 archaeological French kilns and 3 collections of bricks used for the construction of different French historical buildings with ages ranging between 330 and 1260 AD have been studied. Classical Thellier experiments performed on 164 specimens, and including anisotropy of thermoremanent magnetisation and cooling rate corrections, gave 119 reliable results. The ten new high-quality mean archaeointensities obtained together with previously published data from Western Europe that we deem to be the most reliable, confirm the existence of an intensity maximum of ~85 ¿T centred at ~800 AD and related to intensity changes up to 25 ¿T per century. The new data also suggest that a previous abrupt intensity change occurred in Western Europe around 625 AD. |
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