Observed periodicities and the spectrum of field variations in Holocene magnetic records

TitleObserved periodicities and the spectrum of field variations in Holocene magnetic records
Publication TypeJournal Article
Year of Publication2013
AuthorsPanovska S., Finlay C.C, Hirt A.M
JournalEarth and Planetary Science Letters
Date Published2013/10
Type of ArticleArticle
ISBN Number0012-821X
Accession NumberWOS:000327418800010
Keywordsanalysis; dipole; earths core; flow; geomagnetic secular variation; geomagnetism; intensity; lake sediments; ma; paleomagnetic spectrum; paleomagnetic time-series; paleomagnetism; paleosecular variation; periodicity; scale; sediment record; wavelet

In order to understand mechanisms that maintain and drive the evolution of the Earth's magnetic field, a characterization of its behavior on time scales of centuries to millennia is required. We have conducted a search for periodicities in Holocene sediment magnetic records, by applying three techniques: multitaper spectral estimation, wavelet analysis and empirical mode decomposition. When records are grouped according to their geographical locations, we find encouraging consistency amongst the observed periods, especially in nearby inclination records. No evidence was obtained for discrete, globally observed, periods. Rather we find a continuous broadband spectrum, with a slope corresponding to a power law with exponent of -2.3 +/- 0.6 for the period range between 300 and 4000 yr. This is consistent with the hypothesis that chaotic convection in the outer core drives the majority of secular variation. (C) 2013 Elsevier B.V. All rights reserved.

Short TitleEarth Planet. Sci. Lett.
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