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Deep lithospheric and asthenospheric magnetic sources

We used to think that the sources of magnetic anomalies were all shallow (<10 km) however, recent high-quality satellite magnetic surveys show that anomalies arise from the integration of multiple sources at various distance from the earth’s surface. Shallow sources produce short wavelength anomalies whereas deep sources cause long wavelength anomalies.


In the past 15 years, I have led a change in the old paradigm that the mantle was too deep and too hot to be magnetic.


World Digital Magnetic Anomaly Map (WDMAM) (Erwan et al., 2010)


Lherzolite mantle xenolith cut by dark green clinopyroxene dikelet in the San Carlos volcanic field, Arizona (Ferré et al., 2020)


Long wavelength magnetic anomalies from the power spectrum of magnetic

Anomalies (Burton-Johnson et al., 2020)

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