The establishment of an oxygen-rich atmosphere dramatically altered the evolution of life on Earth. Most of the recent discussion of the topic has been focused on the timing of the event rather than on its mechanism. Here we draw upon recent developments in the understanding of Earth's interior to propose that the rise of oxygen followed a geologically abrupt period of mantle overturn and/or intense plume activity near the Archean-Proterozoic transition, 2470-2450 million years ago. The magmatic event has already been linked to the widespread deposition of oxide-facies banded iron formation, and the rise of oxygen has been implicated as the trigger for iron deposition and Earth's first major glaciation. We argue that these events are all related to a change in redox state of volcanic gases brought about by deep-seated Late Archean and earliest Paleoproterozoic magmatism.