Geophysics

Piling on the magnetic field reversals

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Science  13 Mar 2015:
Vol. 347, Issue 6227, pp. 1214
DOI: 10.1126/science.347.6227.1214-e

The height of the dense chemical piles lying on the top of Earth's core may determine whether the magnetic field reverses polarity slowly or quickly. Amit and Olson try to explain changes in the frequency of field reversals found in the rock record by considering the thickness of these large lower mantle piles. Thicker piles allow more heat to flow out of the liquid metal core, which stimulates polarity reversals in the magnetic field. Thinner piles suppress heat flow and could explain the occasional long periods of stable magnetic field polarity found in the geologic record.

Earth Planet Sci. Lett. 10.1016/j.epsl.2015.01.013 (2015).

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