Gravitational and magnetic models of the core–mantle boundary and their correlation

Abstract

On the basis of a technique for 3D potential field data inversion worked out by the author earlier, gravitational and magnetic models of the core–mantle boundary (CMB) have been developed. The gravitational model agrees quite well with seismological data. The magnetic model represents a homogeneously magnetized body with the same external magnetic field as the Earth’s core; the uplifts of its surface are related to regions with increased values of the magnetic field. The comparison of the models has revealed the correlation that regions exhibiting high magnetic field values in the Earth’s core correspond to depressions in the core–mantle boundary, as reconstructed from gravity data. This correlation has led us to an hypothesis about core material flow. To examine the hypothesis in an indirect way, CMB magnetic field models at various epochs inferred by assuming a non-magnetic mantle and a homogeneously magnetized core have been studied. Changes of their shape appear to confirm our hypothesis.