Scientists in Canada have found fossils that are thought to be the remnants of the earliest trace of life on earth.
According to the new study, published in the journal Nature, the straw-shaped microfossils are believed to come from ancient microbes.
The study said the fossils, narrower than the width of a human hair and invisible to the naked eye, were discovered in rocks from the Nuvvuagittuq belt in northeastern Canada. Scientists are debating their age, although they say the youngest estimate could be about 3.77 billion years.
Beside the fossils, the rocks also contain a cocktail of chemical compounds that is almost certainly the result of biological processes. A method called Raman analysis, which uses laser to find the type of molecules a material contains, has shown that the rocks contain carbonate, apatite and magnetite, all of them minerals that often form in the presence of organic matter. They also contain graphite, another mineral which could prove life. According to the study, the graphite contain the isotope carbon-12, a form of carbon which is preferred for biological processes, and many call it an isotopic signature of life.
If the findings are confirmed, they could prove the notion that life arose very early in the history of earth. Experts have challenged the age of the materials as rocks as old as the ones in the study could rarely survive the weathering, erosion, subduction and deformation.
Elaborating on the age, the study says the area the fossils have been found, now an iron-rich jasper cutting across the eastern shore of Hudson Bay, was once a hydrothermal vent on the ocean floor.
Scientists say ancient microbes flourished around those vents billions of years ago and took advantage of the chaotic chemistry to generate fuel. Then the microbes died and iron in the water was deposited on their decaying bodies, replacing cellular structures with stone. The rocks that contained the structures then were buried, heated, squashed, and then forced upward to form the part of North America through the ages. They say the material could be as old as 3.77 billion years, or even as ancient as 4.28 billion years, according to the dating method.