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An Anonymous Coward writes:

Scientists at Newcastle University have uncovered a source of oxygen that may have influenced the evolution of life before the advent of photosynthesis:

In tectonically active regions, the movement of the Earth's crust not only generates earthquakes but riddles the subsurface with cracks and fractures lined with highly reactive rock surfaces containing many imperfections, or defects. Water can then filter down and react with these defects on the newly fractured rock.

In the laboratory, Masters student Jordan Stone simulated these conditions by crushing granite, basalt and peridotite—rock types that would have been present in the early Earth's crust. These were then added to water under well controlled oxygen-free conditions at varying temperatures.

The experiments demonstrated that substantial amounts of hydrogen peroxide—and as a result, potentially oxygen—was only generated at temperatures close to the boiling point of water. Importantly, the temperature of hydrogen peroxide formation overlaps the growth ranges of some of the most heat-loving microbes on Earth called hyperthermophiles, including evolutionary ancient oxygen-using microbes near the root of the Universal Tree of Life.

[...] Principal Investigator Dr. Jon Telling, Senior Lecturer, added: "This research shows that defects on crushed rock and minerals can behave very differently to how you would expect more 'perfect' mineral surfaces to react. All these mechanochemical reactions need to generate hydrogen peroxide, and therefore oxygen, is water, crushed rocks, and high temperatures, which were all present on the early Earth before the evolution of photosynthesis and which could have influenced the chemistry and microbiology in hot, seismically active regions where life may have first evolved."

Journal Reference:
Stone, J., Edgar, J.O., Gould, J.A. et al. Tectonically-driven oxidant production in the hot biosphere. Nat Commun 13, 4529 (2022). DOI: 10.1038/s41467-022-32129-y

Original Submission