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Geomagnetism and Inferences for Core Motions

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Flow and Creep in the Solar System: Observations, Modeling and Theory

Part of the book series: NATO ASI Series ((ASIC,volume 391))

Abstract

Measurements of the geomagnetic field made over the last few centuries provide maps of changes of magnetic flux on the core surface. This reveals a stationary, rather symmetrical, pattern of four main concentrations of flux with superimposed secular variation, much of it in the form of westward drift in low latitudes across the Atlantic hemisphere. The secular change is interpreted in terms of fluid flow at the top of the core, and models of recent secular change have been inverted to give estimates of the flow pattern. The stationary field pattern could be generated by dynamo action deep within the core, and simple kinematic models produce the observed four-fold symmetry with flux concentration beneath downwelling fluid. Much remains to be understood about the dynamo action of even simple fluid motions. The overlying mantle may exert a significant influence on both surface flow and deep convection; simple model calculations suggest temperature or heat flux variations around the core-mantle boundary will drive thermal winds which penetrate deep into the core and strongly influence the main convection.

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Authors and Affiliations

  1. Department of Earth Sciences, University of Leeds, Leeds, LS2 9JT, UK

    David Gubbins

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  1. David Gubbins
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Editors and Affiliations

  1. Geophysical Institute and Department of Geology and Geophysics, University of Alaska, Fairbanks, AK, USA

    David B. Stone

  2. University of Alaska, Fairbanks, AK, USA

    S. K. Runcorn

  3. Physics Department, Imperial College, London, UK

    S. K. Runcorn

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© 1993 Springer Science+Business Media Dordrecht

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Gubbins, D. (1993). Geomagnetism and Inferences for Core Motions. In: Stone, D.B., Runcorn, S.K. (eds) Flow and Creep in the Solar System: Observations, Modeling and Theory. NATO ASI Series, vol 391. Springer, Dordrecht. https://doi.org/10.1007/978-94-015-8206-3_7

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  • DOI: https://doi.org/10.1007/978-94-015-8206-3_7

  • Publisher Name: Springer, Dordrecht

  • Print ISBN: 978-90-481-4245-3

  • Online ISBN: 978-94-015-8206-3

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