Fig. 1: Core and field. | Nature Geoscience

Fig. 1: Core and field.

From: Geodynamo recharged

Fig. 1

Roberto Molar Candanosa and Peter Driscoll

As the liquid core (orange) of the Earth cooled, thermal convection — and hence the geodynamo — weakened, which led to a weak, multipolar and unstable geomagnetic field (left). Crystallization of iron in the inner core (red) and the associated compositional convection could have reinvigorated the dying geodynamo (right). Bono and colleagues2 present geomagnetic measurements that place the transition between these two states sometime after 565 Ma, and thereby suggest that the inner core is younger than previously thought.