In an interview with the discoverers, Meagan Campbell of MacLean’s explores how fossils 3.8 billion years old were found in a rock formation in northern Québec.
The oldest proof we have of life on Earth is in Quebec, according to a team of international researchers. On the edge of the Hudson Bay, geologists and biologists from England, Australia, the United States and Canada collected fossils of microscopic lifeforms. On March 1, they published an article in the journal Nature, suggesting that these lifeforms existed 3.7 to 4.3 billion years ago, before the planet had oxygen or oceans—meaning life could begin in other barren parts of the universe, too. For a look behind the scenes of the discovery, Maclean’s spoke with Jonathan O’Neil, a geologist at the University of Ottawa who dated the fossils.
Q: Can you describe the moment of discovery?
A: I was with some of my colleagues at the Carnegie Institution for Science in Washington. The first moment, you don’t even believe it. You say, “that can’t be.” So you reanalyze it, and you get the same result. You redo it again, redo it again, redo it again, and you start coming back with the same data, same results, same numbers, and you start to believe it. It’s a weird feeling. It pushes everything back.
Q. Why is the finding controversial?
A: Rocks are always dated with radioactivity. We use that as a timer. The golden standard for us is we’re trying to date a certain mineral, a Zircon. We’re excellent at it. We can get super nice and precise and robust dates. The only drawback is you need Zircons to do it. These rocks from northern Quebec, they don’t have them. We used a different clock. It’s only good for rocks that are 4 billion years old. We’ve done it for some rocks from the moon, but it’s the first time we’ve done it on Earth.