Geologists have unearthed the oldest fossils ever discovered, chunks of quartz that contain tiny tubes and filaments left behind by microorganisms between 3.77 and 4.3 billion years ago. The fossils were discovered in the Nuvvuagittuq Supracrustal Belt (NSB) on the coast of Hudson Bay in the northern reaches of Canada's Quebec province.

The NSB contains some of the oldest layers of sedimentary rock in the world. These deposits of gravel and sand accumulated about four billion years ago around iron-rich hydrothermal vents deep in the ocean, only to be uplifted by geologic processes over time until they emerged from the sea in northern Canada. The layers of quartz contain tubes and tendrils of hematite—a form of iron oxide or rust—likely deposited by bacteria that oxidized iron for energy. Similar tendrils of oxidized iron are formed by bacteria that lives around hydrothermal vents today.

Hematite tubes from the NSB hydrothermal vent deposits that represent the oldest microfossils and evidence for life on Earth. The remains are at least 3,770 million years old. Matthew Dodd

"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," says University College London (UCL) Earth scientist Dominic Papineau, lead researcher on a study published today inNature Paleontology, in a press release. "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."

The finding provides strong evidence that the first life on Earth did in fact form around nutrient-rich hydrothermal vents at the bottom of the ocean. This is one of the leading theories for how life spawned on Earth, as opposed to other theories such as panspermia, which suggests life was deposited here by an asteroid or other rocky body that crashed into our home planet.

"Our discovery supports the idea that life emerged from hot, seafloor vents shortly after planet Earth formed," says Matthew Dodd, first author on the study and a UCL Ph.D. student. "This speedy appearance of life on Earth fits with other evidence of recently discovered [3.7-billion]-year-old sedimentary mounds that were shaped by microorganisms."

Field of microscopic filamentous microfossils inside a rounded concretion from the jasper rock in the Nuvvuagittuq Supracrustal Belt in Québec, Canada. The filaments are composed of hematite (red lines), and are located in a quartz layer (white) surrounded by magnetite (black), where both hematite and magnetite are iron oxide minerals. Matthew Dodd

The oldest known fossils before this NSB find were 3.46-billion-year-old samples discovered in Western Australia. However, many scientists believe the Western Australia microfossils are not fossils at all, but the result non-biological processes of geology such as changes in heat and pressure. (There are also fossilized samples from Greenland known as stromatolites that are 3.7 billion years old, but these are structural mounds thought to be created by microorganisms rather than evidence of the microorganism itself decaying.) The UCL-led team was therefore under significant pressure to provide evidence that the NSB fossils truly formed through biological processes.

Two primary pieces of evidence suggest that ancient bacteria are responsible for the NSB samples. The first is the presence of calcium- and carbon-based minerals such as graphite, apatite, and carbonate. These minerals are found in biologic material such as bones and teeth, and they are widely associated with fossils.

This content is imported from YouTube. You may be able to find the same content in another format, or you may be able to find more information, at their web site.

Perhaps even more convincing evidence that the fossils are in fact remnants of living microorganisms is the fact that the fossils were found within small spheroidal structures in the rock. These egg-shaped structures often contain fossilized remains preserved in this form and embedded in younger rocks. These deposits are believed to be formed by the decay and putrefaction of living organisms.

"We found the filaments and tubes inside centimeter-sized structures called concretions or nodules, as well as other tiny spheroidal structures, called rosettes and granules, all of which we think are the products of putrefaction," says Papineau. "They are mineralogically identical to those in younger rocks from Norway, the Great Lakes area of North America and Western Australia."

Layer-deflecting bright red concretion of hematitic chert (an iron-rich and silica-rich rock), which contains tubular and filamentous microfossils. This so-called 'jasper' is in contact with a dark green volcanic rock in the top right and represents hydrothermal vent precipitates on the seafloor. Nuvvuagittuq Supracrustal Belt, Québec, Canada. Matthew Dodd

As for helping to "identify traces of life elsewhere in the universe," the discovery of fossils this old reveals something remarkable: Life formed on Earth while there was still abundant surface water on Mars. The planet Earth is a little more than 4.5 billion years old, and these fossils are from bacteria that lived 3.8 billion years ago—or perhaps even earlier. It didn't take long for the churning geological and chemical processes on our planet to spark the fire of life, and it may be that the same happened on Mars when it was still a temperate, water-filled world with a protective atmosphere. It might even be that bacterial critters still thrive in the subterranean realms of the Red Planet, something we hope to discover with the upcoming Mars 2020 rover.

"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," says Dodd. "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."

Earth might be a special exception, but stacking evidence—from the geologic history of Mars, to the watery moons of our solar system, out to the widespread planetary systems in our galaxy and down to the ancient rocks that formed at the bottom of our own oceans—suggests that life is not confined merely to our pale blue dot.

Microscopic iron-carbonate (white) rosette with concentric layers of quartz inclusions (grey) and a core of a single quartz crystal with tiny (nanoscopic) inclusions of red hematite from the Nuvvuagittuq Supracrustal Belt in Québec, Canada. These may have formed through the oxidation of organic matter derived from microbes living around vents. Matthew Dodd

This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses. You may be able to find more information about this and similar content at piano.io