An international team of geologists claimed over the weekend that they have discovered the oldest fossils on record.
The group, lead by the University of Western Australia’s David Wacey and the University of Oxford’s Martin Brasier, say that the fossilized, single-cell organisms are 3.4 billion years old.
If their claim is sustained, the New York Times reports, it would confirm that “life evolved on earth surprisingly soon after” the period known as the "late heavy bombardment," when asteroids smashed incessantly into the earth’s surface, and methane gas in the atmosphere created a greenhouse effect that heated up the oceans substantially.
The team's assertion that the fossils are the oldest ever discovered, however, remains in question, the Times notes. In 1993, paleobiologist J. W. Schopf reported finding fossils that were 3.465 billion years old, a claim that Brasier has disputed for the last decade because he says that the find lacked evidence of living organisms.
Brasier and his team say that their fossils, which were discovered at the base of the Strelley Pool rock formation in Western Australia, contain evidence of bacteria that lived between pebbles on a beach during this period. They also say that chemicals in the fossils they excavated—carbon, sulfur, nitrogen and phosphorus—indicate the presence of life.