Geomagnetic Field Variations in the Past: New Data, Applications and Recent Advances

In the last decades, palaeomagnetic research has provided important information about the past variation of the Earth's magnetic field (EMF) from its origin to the present day. However, questions regarding the origin and evolution of the EMF as well as the frequency and spatial distribution of its variations still remain open to debate. This Special Publication provides new insights into the study of the temporal and spatial evolution of the EMF presenting new data from palaeomagnetic and rock magnetic studies of archaeological materials, sediments and lavas. The papers presented cover a wide range of topics related to archaeology, stratigraphy and climate, including new data from several parts of the world, such as Europe, Africa, Australia, New Zealand, India and the Baltic Sea. This Special Publication aims to present an overview of the most recent secular variation studies and their use to disclose fundamental properties of the EMF evolution.
On the resolution of regional archaeomagnetism: untangling directional geomagnetic oscillations and data uncertainties using the French archaeomagnetic database for dates between AD 1000 and 1500 as a guide
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Published:September 23, 2020
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CiteCitation
Maxime Le Goff, Yves Gallet, 2020. "On the resolution of regional archaeomagnetism: untangling directional geomagnetic oscillations and data uncertainties using the French archaeomagnetic database for dates between AD 1000 and 1500 as a guide", Geomagnetic Field Variations in the Past: New Data, Applications and Recent Advances, E. Tema, A. Di Chiara, E. Herrero-Bervera
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Abstract
A complexity is emphasized in the distribution of French archaeomagnetic directions during the thirteenth and the fourteenth centuries AD. Data uncertainties, and the smoothing introduced when estimating an average secular variation curve, prevent scrutiny of the very nature of this complexity. It might correspond to a directional yaw, the nature of which would be compatible with the recent geomagnetic field evolution as traced by the gufm1 model. In order to emphasize this indeterminacy, a reference secular variation curve was constructed for dates between AD 1000 and 1500, including the yaw in question, and synthetic databases that mimic the accuracy and density characteristics of the true French archaeomagnetic database were considered for some of these. The synthetic curves hence obtained show that the dating accuracy of archaeomagnetic data is the crucial parameter for constructing a detailed secular variation path. The significant impact of the experimental data accuracy is also illustrated. Even more crucial is the fact that the precision of the data dating required to describe the directional variability over the century timescale largely exceeds the precision of the archaeological dates available for the structures generally studied. This highlights the intrinsic limitation of archaeomagnetism for regional reconstruction of century-scale geomagnetic field variations.
- Anthropocene
- archaeology
- Arctic region
- Cenozoic
- data bases
- data processing
- Europe
- France
- Holocene
- magnetic field
- magnetic properties
- magnetization
- natural remanent magnetization
- oscillations
- paleomagnetism
- polar wandering
- pole positions
- Quaternary
- remanent magnetization
- secular variations
- Western Europe