A literal breath of air from the time of Earth’s first animals was recently found, extracted, and analyzed by University of Aberdeen scientists. The discovery of atmospheric gas trapped in a sample of halite shows that a breathable atmosphere was around long before many scientists previously thought.
The study, published in the journal Geology, details the analysis of an 815 million year old sample of halite, or rock salt. Oxygen measurements were taken from the traces of gases found in the material, surprising the researchers with a level of 10.3 to 13.4 percent of the atmosphere (for comparison, Earth’s modern oxygen content is 20.9 percent).
Many studies had pegged the first breathable atmosphere occurring much later, yet the discovery sets the date of the first possible animals breathing Earth’s air back much further. Professor John Parnell of the university said, “What is especially significant in this study is that we actually discovered a real atmosphere sample, where previous estimates have been made using indirect modeling methods.” The finding was made possible through a collaboration between the US, Canada, France, UK, Australia, and China.