42,000-year-old trees allow more accurate analysis of last Earth’s magnetic field reversal

The last complete reversal of the Earth’s magnetic field, the so-called Laschamps event, took place 42,000 years ago. Radiocarbon analyses of the remains of kauri trees from New Zealand now make it possible for the first time to precisely time and analyse this event and its associated effects, as well as to calibrate geological archives such as sediment and ice cores from this period. Simulations based on this show that the strong reduction of the magnetic field had considerable effects in the Earth’s atmosphere. This is shown by an international team in a study that appears in the journal Science. Credit: Nelson Parker