So says an international team led by scientists from the University College London. The newly discovered microorganism remains are believed to be at least 3.77 billion years old. Scientists found the ancient fossils in a rock in the Nuvvuagittuq Supracrustal Belt, a remote region of Quebec, Canada.
This rock sample is believed to have once been part of a hydrothermal vent. Today, it sits above the oceans thanks to the slow, but steady work of tectonic plates over millions of years.
Let’s take a closer look.
Those are tiny haematite tubes that show the oldest microfossils and evidence of life on Earth according to scientists. The tubes are believed to be at between 3.77 billion and 4.3 billion years old.
“Our discovery supports the idea that life emerged from hot, seafloor vents shortly after planet Earth formed. This speedy appearance of life on Earth fits with other evidence of recently discovered 3,700 million-year-old sedimentary mounds that were shaped by microorganisms,” explains first author Matthew Dodd.
But how do we know the tubes weren’t formed via some other process like temperature or pressure? This rock’s journey from the bottom of the ocean to above ground might have been slow, but it wasn’t easy. The scientists made a point to look into other ways the haematite tubes could have formed.
There are several factors working in the scientists’ favor. The structure of the haematite tubes in this ancient sample share the same features that we see in iron-oxidizing bacteria found in today’s hydrothermal vents. Plus, graphite, apatite and carbonate were also found alongside the 3.77 billion-year-old fossils. Minerals often seen with fossils.
Scientists can’t say with 100% certainty they’ve found direct evidence of one of Earth’s oldest life forms, but they’re pretty sure.
“The structures are composed of the minerals expected to form from putrefaction, and have been well documented throughout the geological record, from the beginning until today. The fact we unearthed them from one of the oldest known rock formations, suggests we’ve found direct evidence of one of Earth’s oldest life forms. This discovery helps us piece together the history of our planet and the remarkable life on it, and will help to identify traces of life elsewhere in the universe,” says study lead Dr. Dominic Papineau.
Dodd also touched on the notion of extraterrestrial life.
“These discoveries demonstrate life developed on Earth at a time when Mars and Earth had liquid water at their surfaces, posing exciting questions for extraterrestrial life. Therefore, we expect to find evidence for past life on Mars 4,000 million years ago, or if not, Earth may have been a special exception.”
Dodd talks about Mars, but Europa and Enceladus are also exciting possibilities. Mars is a cold, dry wasteland – but we’ve seen evidence of liquid water right now on these two moons. On Enceladus, plumes of liquid vent from the small moon’s south polar region.
Could the bottom of its potential ocean have hydrothermal vents? And life like these ancient fossils? It’s a big ‘could.’ Only one way to find out.