An Alternative Explanation for the Great Oxygenation Event (GOE): Weathering of Rocks Containing Minerals with Peroxy Bonds
Abstract
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).