Ebbing, J. et al.: Pitfalls and possibilities studying the magnetic lithosphere from space. Annual meeting of the German Geophysical Society, Münster, March 2016

Ebbing, J., E. Baykiev and W. Szwillus:

Pitfalls and possibilities studying the magnetic lithosphere from space. Annual meeting of the German Geophysical Society, Münster, March 2016. View poster

Satellite magnetic data have an increasing resolution and their global coverage make them ideal to study the magnetic lithosphere of the Earth. The lithospheric magnetic field is related to the magnetization in the lithosphere and the depth to the magnetic sources itself. The base of the magnetic lithosphere is linked to the Curie temperature, which relates the magnetic lithosphere and the thermal state of the lithosphere. Conventionally, the Moho boundary depth is taken as the maximum magnetic depth and the long-wavelength magnetic field is interpreted to estimate the deepest magnetic sources.

However, the lithospheric magnetic field is derived by removing, at least, a core field contribution, which dominates the long-wavelength signal, which as well relates to the deepest magnetic source. We demonstrate the overlap of long-wavelength signal content by forward modelling the magnetic field from a lithosphere based on gravity, seismological and heat-flow data against data in satellite height.

The model shows that for parts of the world it is reasonable to assume that parts of the upper mantle are magnetized. The large anomalies at satellite height cannot be explained with conventional models of crustal magnetization. However, the impact of core and lithosphere field separation is significant as well. The use of magnetic gradients might help to establish better models of lithosphere magnetization, which in turn allow to update core field contributions. The ongoing Swarm satellite mission will hopefully allow to validate the different field contributions with a higher degree of confidence.