University of California - Riverside sedimentary geologist Andrey Bekker along with his colleagues investigated how oxygen content rose in our home planet. They conducted new dating of ancient volcanic rock in southern Africa.
According to Science News, previous studies suggested that the first instance of abundant oxygen in Earth's atmosphere, which is known as the Great Oxidation Event (GOE), happened about 2.3 billion years ago. However, new dating of ancient volcanic rocks claimed that oxygen levels had an upsurge between 2,460 billion and 2,426 billion years ago.
The study, entitled "Timing and Tempo of the Great Oxidation Event," was published in the journal "Proceedings of the National Academy of Sciences." It was conducted by, Ashley Gumsley, a geologist of Lund University in Sweden, Bekker, from UC - Riverside, as well as their colleagues: Kevin R. Chamberlain, Wouter Bleeker, Ulf Söderlund, Michiel O. de Kock and Emilie R. Larsson.
Bekker explained that the time difference is a "big deal." The new date has shaken up previous understanding of the environmental conditions that led to the GOE, which resulted to the evolution of oxygen-dependent life-forms named eukaryotes.
At the time, massive volcanic eruptions sent fresh rock over a supercontinent near the equator. This resulted to a dip in the planet's temperature, leading to a frigid period known as a Snowball Earth.
The same series of geologic events about 700 million years ago matched with a second rise of oxygen to near-modern levels. Some eukaryotes were claimed to have evolved into the first animals during that period. Bekker noted that both oxygen surges led to complex life and, eventually, to the development of humans.
In a report by Science Daily, the study found that the emergence of oxygen happened when most of the Earth's landmasses were grouped in a single supercontinent named Kenorland. This continent was said to have extended at the equator and was mostly covered by volcanic lava rocks.
It was also noted that the increase in oxygen was not a steady process but, rather, featured significant fluctuations. Researchers believe that this was linked to a very unstable climate, which may have been a result of the volcanic activity on the large supercontinent.
