Published: Thu, March 02, 2017
Science | By Boyd Webster

Scientists Dig Up Earth's Oldest Fossil

Scientists Dig Up Earth's Oldest Fossil

Study co-author Johnathan O'Neil, of the University of Ottawa, says the fossilized remains are the "oldest record of life on Earth", and could offer clues about the emergence of life on our planet and others. One of the biggest questions in science is whether life is an inevitable and common outcome of the laws of chemistry, or a lucky one-off confined to Earth alone.

Dodd ventured to one of Earth's oldest rock formations, Canada's Nuvvuagittuq Supracrustal Belt, in hopes of findings these early signs of life.

Part of the interest in ancient life is in the implication it has for organisms elsewhere in the Solar System.

These are the world's oldest fossils and were found in Quebec, Canada.

"They are mineralogically identical to those in younger rocks from Norway, the Great Lakes area of North America and Western Australia", said study lead author Dr. Dominic Papineau, also from the University College London.

In a remote region of northern Quebec, scientists have found the remains of microorganisms at least 3.77 billion years old.

The team sliced the rocks into sections about 30 microns in width - thin enough to see light shining through them.

Any claim for the earliest life on Earth attracts scepticism. For hundreds of millions of years after the planets were formed, they would've been regularly bombarded with asteroids and comets much bigger than the one we believe destroyed the dinosaurs on Earth. Inside, researchers found the fossils of what they say are long-gone bacteria left behind during Earth's tumultuous early days. Some of that carbon is inside crystals of phosphorus-rich minerals, which also hints at early biology. If confirmed, the find will open new avenues to the search for life on Mars and other planets.

The paper's evidence that the rock features were caused by living organisms falls short, he said. Instead, it stated that the objects are "best explained" as being hydrothermal vent microbes that may represent "the oldest life forms recognized on Earth".

"These discoveries demonstrate life developed on Earth at a time when Mars and Earth had liquid water at their surfaces, posing exciting questions for extra-terrestrial life", Dodd said, in the statement.

During an expedition there, Papineau helped find an especially old-looking lump of rusty rock called jasper, or haematitic chert (haematite is an iron-containing mineral). The rock's composition was consistent with a deep-sea vent environment. Intriguingly, the sort of life that Dr Papineau and his colleagues think they have found is very different from the sort that built the stromatolites.

Boswell Wing, a University of Colorado geobiologist who has also studied the Nuvvuagittuq belt, was less convinced.

Dodd says the rocks around the fossil-containing layers contain chemical signatures of a hydrothermal vent.

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. Emerson has spent many years investigating the biology of modern microbial mats. And if they're right, the find is staggering indeed. "But the evidence could equally be interpreted as non-biological". The filaments might simply be a curious by-product of those reactions and have nothing to do with biological activity, she says. He says it "beggars belief" that fragile, microscopic structures could survive in rocks that have been subjected to high temperatures and pressures deep underground. However, some scientists are casting doubt on what the findings truly mean.

The claims by Dodd's team can not be summarily dismissed on first impressions, though.

"Within the last 15, 20 years, we have more and more evidence that that's not the case", he said. "It may be many years before a consensus is reached", he says. The planet is 4.55 billion years old, but thanks to plate tectonics and the constant recycling of Earth's crust, only a handful of rock outcrops remain that are older than 3 billion years, including 3.7-billion-year-old formations in Greenland's Isua Greenstone Belt.

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