Oldest form of life: Fossil of most ancient micro-organisms found
Scientists have discovered remains of microorganisms in Canada that are between 3.8 and 4.3 billion years old, providing direct evidence of one of the oldest life forms on the Earth. Tiny filaments and tubes formed by bacteria that lived on iron were found encased in quartz layers in the Nuvvuagittuq Supracrustal Belt (NSB) in Quebec, Canada.
The NSB contains some of the oldest sedimentary rocks known on the Earth which likely formed part of an ironrich deep-sea hydrothermal vent system that provided a habitat for Earth's first life forms between 3,770 and 4,300 million years ago, researchers said. "Our discovery supports the idea that life emerged from hot, seafloor vents shortly after planet Earth formed. This speedy appearance of life on Earth fits with other evidence of recently discovered 3,700 million year old sedimentary mounds that were shaped by microorganisms," said Matthew Dodd from University College London (UCL) in the UK.
Prior to this discovery, the oldest microfossils reported were found in Western Australia and dated at 3,460 million years old but some scientists think they might be nonbiological artifacts in the rocks. Researchers, including those from University of Ottaw systematically looked at the ways the tubes and filaments, made of haematite - a form of iron oxide or 'rust' – could have been made through non-biological methods such as temperature and pressure changes in the rock during burial of the sediments, but found all of the possibilities unlikely.