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Journal Articles Geophysical Journal International Year : 2018

True dipole wander

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Abstract

S U M M A R Y A fundamental assumption in palaeomagnetism is that the geomagnetic field closely approximates a geocentric axial dipole in time average. Here we use numerical dynamos driven by heterogeneous core-mantle boundary heat flux from a mantle global circulation model to demonstrate how mantle convection produces true dipole wander, rotation of the geomagnetic dipole on geologic timescales. Our heterogeneous mantle-driven dynamos show a dipole rotation about a near-equatorial axis in response to the transition in lower mantle heterogeneity from a highly asymmetric pattern at the time of supercontinent Pangea to a more symmetric pattern today. This predicted dipole rotation overlaps with a palaeomagnetically inferred rotation in the opposite direction and suggests that some events previously interpreted as true polar wander also include true dipole wander.
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Dates and versions

insu-02930249 , version 1 (05-03-2021)

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Peter Olson, Maylis Landeau, Evan Reynolds. True dipole wander. Geophysical Journal International, 2018, 215 (3), pp.1523 - 1529. ⟨10.1093/gji/ggy349⟩. ⟨insu-02930249⟩

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