Relative intensities derived from a mid-Miocene record containing a reversal of the Earth’s magnetic field

Relative intensities derived from a mid-Miocene record containing a reversal of the Earth’s magnetic field

Tuinstra, K.B.

Molengraaff Fonds

2017

The reversal of the Earth’s magnetic field is a phenomenon that is not fully explained. Detailed volcanic records with high eruption rates that capture the behaviour of the Earth’s magnetic field, sampled in high resolution are scarce. Here we show the relative intensities of a mid-Miocene volcanic record, sampled in the East of Gran Canaria, in high resolution. These relative intensity data was obtained by using the pseudo-Thellier approach. Combining pseudo-Thellier and IZZI-Thellier data yields an absolute intensity record which can be used to track the intensity behaviour during paleodirectional changes. When comparing intensity results with paleodirectional data, we find intensities of ~5-10 μT during excursions and intensities of ~2-5 μT during the reversal that is recorded in the sampled sequence for this research. This data suggests that the intensity during reversals can be much lower than previously expected. VDM data that was computed, shows that the field strength of the Earth’s dipole was below 2 ×1022 Am2 before and during the reversal, and that it increases to 6 ×1022 Am2 directly after the reversal.

http://resolver.tudelft.nl/uuid:a94354c1-4d61-488c-8264-a731999503da

Utrecht University

Geoscience Reports

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