Long-term polarity stability and strength of the geomagnetic dipole

Autor:	Paul H. Roberts, Poorna C. Pal
Rok vydání:	1988
Předmět:	Paleomagnetism Multidisciplinary Earth's magnetic field Polarity (physics) Physics::Space Physics Dynamo theory Field strength Geophysics Magnetic anomaly Magnetic dipole Geology Physics::Geophysics Dynamo
Zdroj:	Nature. 331:702-705
ISSN:	1476-4687 0028-0836
DOI:	10.1038/331702a0
Popis:	Palaeomagnetically observed reversals so far provide the strongest evidence1 that reversals originate from processes of core magnetohydrodynamics (MHD), thus furnishing a crucial constraint for geomagnetic dynamo modelling. The long-term variations in reversal frequency, favouring2 independent mechanisms for the dynamo and its reversals, provide an added constraint. Here we present evidence for a correlation between polarity superchrons and palaeointensity data, and also marine-magnetic and MAGS AT anomalies. Our results indicate that the dipole moment is correlated to the reversal frequency, being appreciably greater during the fixed polarity superchrons. This new information derived from the reversal record provides fresh insight into the workings of the geodynamo, and also explains why the oceanic crust associated with the Cretaceous quiet zone carries such a strong thermoremanence.
Databáze:	OpenAIRE
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