Remains of microorganisms recently discovered in Canada may be the oldest fossils ever recorded on Earth.
Scientists from University College London (UCL) believe they have landed the find of their lifetimes, with fossils potentially dating back billions of years discovered in Canada.
The estimates at the moment are anywhere between 3.77bn and 4.28bn years ago and, if proven true, these fossils would represent the oldest of any such on Earth.
The fossils are tiny (1cm in size) filaments and tubes, which the research team claims were formed by bacteria that lived on iron. They were found encased in quartz layers in the Nuvvuagittuq Supracrustal Belt in Quebec.
The location is important as Nuvvuagittuq is home to some of the oldest sedimentary rocks ever known, likely part of an iron-rich deep-sea hydrothermal vent system billions of years ago, which helped to create life on the planet.
“Our discovery supports the idea that life emerged from hot, seafloor vents shortly after planet Earth formed,” said Matthew Dodd, first author on the study, which was published in Nature.
“This speedy appearance of life on Earth fits with other evidence of recently discovered 3.7bn-year-old sedimentary mounds that were shaped by microorganisms.”
Prior to the UCL paper, the oldest microfossils were dated at 3.46bn years old, found in Australia.
To establish that the current finds were actually biological, and therefore made naturally by the Earth’s environment billions of years ago, UCL researchers subjected the fossils to a battery of tests.
This was largely a ruling-out exercise, in which Dodd and his team investigated all the unnatural ways that the tubes and filaments, made from haematatie, could have been formed.
Looking at temperature and pressure change possibilities, they were all discounted as “unlikely”.
“We found the filaments and tubes inside centimetre-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,” explained study lead Dr Dominic Papineau.
“They are mineralogically identical to those in younger rocks from Norway, the Great Lakes area of North America and Western Australia.
“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.”
Dodd extrapolated this discovery to the hunt for potential life elsewhere in our solar system, explaining that the date he suspects these fossils are from is the same time period that Mars enjoyed liquid on its surface.
“Therefore, we expect to find evidence for past life on Mars 4,000m years ago or, if not, Earth may have been a special exception,” he said.
Earlier this year, the human species’ earliest ancestor was discovered to be a 540m-year-old sack-like creature.
In a research paper published in Nature, an international team of academics from the UK, China and Germany undertook biological detective work to trace our origins back to a bizarre-looking creature called Saccorhytus coronarius.
Aside from being the most primitive example of a so-called ‘deuterostome’ that encompasses a number of subgroups, including the vertebrates, the creature is also completely new to science, having been discovered in microfossils from China.
At just 1mm in size, the creature likely called grains of sand on the seabed its home and, to the surprise of the team of scientists, does not seem to have any sort of anus whatsoever.
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