Modern plate tectonic motions commenced after formation of voluminous Paleoarchean to Mesoarchean TTG crust

Plate tectonics is central to the long-term release of heat from Earth’s deep interior, which ultimately maintains habitability, but its time of onset is highly debated. Early Archean granitic domes surrounded by greenstones provide evidence for gravitational reorganization of the crust and dominance of vertical tectonics distinct from plate tectonics. However, because plate tectonics is a kinematic framework, a measure of motion such as that provided by paleomagnetism is needed for direct tests. The East Pilbara craton (Western Australia) preserves classic Paleoarchean to Mesoarchean granite-greenstone geology, but paleomagnetic data from these rocks have been interpreted as tracing modern plate tectonic velocities. Herein, we report new paleomagnetic data from granite, basalt and dacite ranging in age from 3.49 to 3.2 Ga from the East Pilbara craton and find that these carry a 2.7 Ga reset magnetization, a pattern seen in data throughout the craton. The recognition of this resetting resolves the conflict with the geological record, and together with other paleomagnetic results from the Kaapvaal (South Africa) and the Yilgarn (Western Australia) cratons define a 600 myr-long transition between stagnant lid tectonics and modern plate tectonic motions, the latter beginning ca. 3.0 to 2.7 billion years ago.