A group of scientists from the University College London recently discovered one of the earliest lifeforms ever found on the earth. The remains of microorganisms are at least 3770 million years old.
The conclusion was reached after examining rock found along the eastern shore of Hudson Bay in northern Quebec, Canada. Carbon dating techniques indicate that these rocks are at least 3.77 billion years old and might even be 4.28 billion years old.
The discovery was published in the first week of March 2017 in the journal called Nature.
Key highlights of the discovery
• The microscopic filaments and tubes formed by bacteria that lived on iron were found encased in quartz layers in the Nuvvuagittuq Supracrustal Belt (NSB).
• The researchers systematically looked at the ways the tubes and filaments, made of haematite, could have been made through non-biological methods. The methods could be temperature and pressure changes in the rock during burial of the sediments.
• The haematite structures have the same characteristic branching of iron-oxidising bacteria found near other hydrothermal vents today. These structures were also found alongside graphite and minerals like apatite and carbonate, which are found in biological matter including bones and teeth. The size and arrangement of the structures indicates that these microbes were breathing oxygen at a time when oxygen is thought to have been scarce.
• During the examination of the rocks, it was found that the mineralised fossils are associated with spheroidal structures that usually contain fossils in younger rocks. It suggests that the haematite most likely formed when bacteria that oxidised iron for energy were fossilised in the rock.
• The scientists estimate that the filaments and tubes inside centimetre-sized structures called concretions or nodules, as well as other tiny spheroidal structures, called rosettes and granules, are the products of putrefaction.
Significance of the discovery
• The recent discoveries made the scientists demonstrate that life developed on Earth at a time when Mars and Earth had liquid water at their surfaces.
• The Nuvvuagittuq Supracrustal Belt contains some of the oldest sedimentary rocks known on Earth. It is most likely that these rocks formed part of an iron-rich deep-sea hydrothermal vent system that provided a habitat for Earth's first life forms between 3770 and 4300 million years ago.
• The discovery supports the idea that life emerged from hot, seafloor vents shortly after planet Earth formed.
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