Magnetizations stored in volcanic rocks are our only source of information on the past behavior of the Earth’s magnetic field. Therefore, unlocking the information in these natural archives is paramount to improve our understanding of rapid geomagnetic variations. A small portion of grains in volcanic rocks become magnetized when cooling in the Earth’s magnetic field, but they violate standard (Néel) theory on the acquisition and storage of magnetizations because of their size. The aim of my PhD project is to further develop a novel technique, Micro-Magnetic Tomography (MMT), to determine the magnetizations of individual particles in a non-magnetic matrix (i.e. a volcanic rock), with the ultimate goal to acquire paleomagnetic information by only considering signals from grains with known good magnetic properties and reject the contributions of ill-behaved grains.

The proof-of-concept of this new technique was recently put forward by the Paleomagnetic research team at Utrecht University. To establish MMT as a rock-magnetic tool we will use a Quantum Diamond Microscope that will be installed in paleomagnetic laboratory Fort Hoofddijk to produce magnetic surface scans of sample material. These measurements will be combined with high-resolution MicroCT scans to characterize and identify the magnetic grains of interest. Optimizations of the mathematic inversion routine will advance the accuracy and efficiency of the inversion that yields the individual magnetizations per grain.