In the Earth's crust, there is a deep source of oxygen that has been there since ancient times

An oxygen source discovered by Newcastle University scientists may have contributed to the evolution of life before photosynthesis.

During geological fault movement, Newcastle University's School of Natural and Environmental Sciences found a mechanism that generates hydrogen peroxide from rocks. Their findings are published in Nature Communications today.

Hydrogen peroxide can be harmful to life when high concentrations are present, but microbes also use it for oxygen. Early life on the early Earth might have evolved in hot environments before the evolution of photosynthesis as a result of this additional oxygen source.

Earth's crustal movement produces earthquakes, but it also causes cracks and fractures layering the subsurface with highly reactive rock surfaces containing many imperfections. The newly fractured rock can then be reacted with by water.

Using granite, basalt, and peridotite rock types found in the early Earth's crust, Masters student Jordan Stone mimicked these conditions in the laboratory. Under well-controlled oxygen-free conditions, and at varying temperatures, these were then added to water.

At temperatures close to the boiling point of water, significant amounts of hydrogen peroxide are generated—and potentially oxygen as well. 

It could be important to note that the temperature at which hydrogen peroxide is formed overlaps the growth range of some of Earth's hottest microbes, including ancient oxygen-using bacteria.

According to Jordan Stone, lead author of this study, stressing or crushing rocks in the absence of oxygen can create hydrogen peroxide and other oxidants. This study, however, emphasizes the importance of hot temperatures in maximizing hydrogen peroxide production..'

Dr. Jon Telling, Senior Lecturer and Principal Investigator stated: 'This study shows defects on crushed rock and minerals behave very differently from how they would behave on a more 'perfect' mineral surface. 

Hydroxygen peroxide, and oxygen, must be generated by mechanochemical reactions. The chemistry and microbiology of hot, seismically active areas where life may have first evolved may have been influenced by all of these factors which were present on the early Earth before photosynthesis evolved..'

The UK Space Agency and the Natural Environmental Research Council supported this research. Dr. Jon Telling is currently leading a new NERC-funded project to investigate the significance of this mechanism in supporting life below the surface.