Magnetic fields are thought to govern the dynamics of protoplanetary disks by mediating inward gas accretion and, possibly, setting up turbulent concentrations of dust to form the first planetary building blocks. A subset of these building blocks then accretes to form rocky planets, which may host a magnetic core dynamo. In the case of Earth, the crust also became partitioned into a system of mobile tectonic plates that gave rise to a biosphere.

Characterizing ancient magnetic fields using rocks surviving from these early times can provide information about protoplanetary disk and dynamo physics while tracking the motion of the first continents. I will present how recent advances in paleomagnetic instrumentation based on the nitrogen vacancy color center have enabled access to complex meteorites and early Earth rocks that record magnetic fields in the protoplanetary disk and document the development of dynamos and plate tectonics on the Earth and Mars. These new techniques hold promise for challenging problems in broad areas of geomagnetism.