Robust magnetic shielding and the onset of plate tectonics assisted Neoarchean evolution

Plate tectonics is central to the long-term release of heat from Earth’s deep interior, which ultimately maintains habitability, as well as nutrient cycling on the surface important for evolution. A strong magnetic field can further assist evolution by shielding life from harmful cosmic radiation. Paleomagnetic data indicate a strong magnetic field in the Late Paleoarchean through the Proterozoic (Tarduno et al., Nat Sci Rev, 2025), but the onset of plate tectonics has been unclear. Recent paleomagnetic analyses indicate that rocks from the Pilbara craton, once thought to record early plate tectonic motion, have been magnetically reset. Instead, paleomagnetic analyses indicate a Neoarchean start for latitudinal motions similar to modern plate tectonics.  This late start of plate tectonics coincides with the evolution of PMI and PMII photosystems and crown group cyanobacteria. Increased nutrient cycling and sedimentary basin environments associated with a Neoarchean onset of plate tectonics, together with robust magnetic shielding provided by a strong magnetic field, may have aided cyanobacteria evolution, accelerating oxygenation of the atmosphere.