The signature of inner-core nucleation on the geodynamo

- Dynamo simulations with core evolution to identify footprints of inner-core nucleation in the palaeomagnetic field.
- Geocentric axial dipole before and after inner-core nucleation is most likely (uniformitarian scenario).
- No footprint of inner-core nucleation on geomagnetic surface field intensity.
- Axial octupole increases with age due to smaller inner core.
- A weak-field dynamo prior to ICN (catastrophic scenario) is possible but less probable.