Scientists could have been forgiven for thinking when, six years ago, paleontologists examining rocks in Greenland found what they believed to be the oldest fossils on Earth. The remnants of life dated back to a time when scientists believe Earth’s skies were orange and the seas green, when massive tectonic plates splt apart in giant seas of molten lava.
That changed earlier this week with University College London’s revelation that an international team of researchers in Quebec unearthed the fossilized remains of a creature that lived some 3,7 million years ago. The remains could even be as old as 4.3 million years, researchers say.
One link between the two finds is climate change. The 2012 fossils were found in a newly melted part of Greenland, where a team of researchers examined terrain that had been unexposed to open air for tens of thousands of years.
The new findings were made in a northern clime as well: the Nuvvuagittuq Supracrustal Belt in Quebec, on the eastern shores of Hudson Bay. There may well be more, similar finds as the polar ice caps melt and recede.
The newly discovered fossils aren’t easy to spot. These aren’t woolly mammoth tusks or the skeletal remains of one of humankind’s early ancestors, but rather microbes, microrganisms individually too small to be seen with the unaided eye. The Nuvvuagittuq fossils are tiny fialments and tubes formed by bacteria that live on iron. The researchers would have had to know what they were looking for, and some idea where to find them.
The fossils may be small, but they’re meaningful — especially in a time when global news events are most depressing than enlightening.
UCL PhD student Matthew Dodd, author of the study published in the journal Nature, said the fossils support the idea that life emerged from hot, sea-floor vents shortly after the Earth formed. The evidence fits with other evidence — the Greenland findings, for one — of microorganisms believed to have formed the foundation for early life forms.
The Nuvvuagittuq Belt, much like Africa’s Great Rift Valley, has proved a boon for paleontologists studying the originis of life. This part of Quebec is home to some of Earth’s oldest rock formations, dating back some 4.28 billion years. Earth is believed to have formed some 4.6 billion years ago. What are towering rock formations today once lay on the sea floor, when Earth and Mars would both have been covered by water.
Dodd said the find suggests there may have been life on Mars as well, some 4,000 million years ago.
If not, he wrote in Nature, it would suggest Earth was unique — an exception amond exceptions.
Dodd’s research for University College London was supported by NASA, Carnegie Canada and the UK Engineering and Physical Sciences Research Council. The findings have since been reported by BBC and in the Washington Post, Wired and Chicago Tribune, among others.
Why does it matter? For one, the discovery shows life may have formed more quickly than once thought. Scientists originally believed it would take life nearly a billion years to gain a toehold once the molten Earth cooled enough to sustain life.
Now it appears life may have formed virtually overnight, in geological terms.
The study is likely to be contentious. Claims about early life often are. Either way, though, it’s one more potential piece in the puzzle of life on Earth.
“This discovery answers the biggest questions mankind has asked itself,” Dodd told the BBC. “It’s very humbling to have the oldest known lifefroms and your hands and be able to look at them and analyze them.”