During the Great Oxygenation Event (GOE) 2.4 - 2.35 Gyrs ago, Earth experienced a notable shift in its oxidation state. This has been widely attributed to cyanobacteria having “invented” oxygenic photosynthesis.  We present a very different view based on the fact that oxygen is released from rocks during weathering. If so, the GOE must have been caused by an influx of abiogenic O2 into Earth’s surface environment. Minerals forming Earth’s crust contain impurity hydroxyls such as O3SiOH. Pairs of those are known to undergo a common redox conversion, ubiquitously forming peroxy defects plus H2: O3SiOH-HOSiO3 ⇌ O3Si/OO\SiO3 + H2 Being diffusively mobile, most H2 will be lost, leaving behind bound O as peroxy. The peroxy defects release O2 during weathering: O3Si/OO\SiO3 + H2O \(\to\) O3SiOH-HOSiO3 + \(\frac{1}{2}\) O2 We suggest that this abiogenically generated O2 was responsible for the progressive oxidation of the early Earth and that this abiotic process drove the Great Oxygenation Event (GOE).