The magnetic signals recorded by rocks are key to understanding a range of fundamental problems in the Earth and Planetary sciences.
For example, the habitability of the early Earth, the timing of Inner Core nucleation and the role of magnetic fields in the Solar System formation. The understanding and interpretation of these magnetic signals has for the last 70 years, been reliant on Nobel-laureate Louis Néel’s 1949 theory for grains containing uniform magnetisations; however, it has been known for some time that magnetic signals of rocks are dominated by grains with non-uniform magnetic structures.
We are now on path to resolving this inconsistency. Within the last five years, through the use of advanced nanometric magnetic imaging methods and the development of new modelling algorithms, there has been a step-change in understanding of the magnetic signatures carried by real rocks. This has led to a bottom-up rethink of how we will interpret the magnetic signatures of rocks in the future, potentially giving rise to new interpretations of old and new problems.