Concept information
Preferred term
magnetic anomaly
Definition
- In geophysics, a magnetic anomaly is a local variation in the Earth's magnetic field resulting from variations in the chemistry or magnetism of the rocks. When rocks rich in ferromagnetic bodies are put in place, they fossilise the existing magnetic field. In all oceans, positive and negative anomalies are organised in parallel bands. The positive anomalies are due to a magnetisation of the basalts during their cooling in the same direction as the current field, the two values adding up. The negative anomalies are due to a magnetisation of the basalts in a field opposite to the current field, during a pole reversal. The fact that these bands remain parallel shows that the location of the poles has remained more or less always around the current position. (Adapted from: https://en.wikipedia.org/wiki/Magnetic_anomaly and translated from: https://fr.wikipedia.org/wiki/Anomalie_magn%C3%A9tique)
Broader concept
In other languages
-
French
URI
http://data.loterre.fr/ark:/67375/QX8-QHMB9QPX-5
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