Source: News Bharati English07 Mar 2017 10:45:06
Ottawa, March 7: Our planet Earth is supposedly 4.5 billion old; Geologists have discovered the world’s oldest fossil which is 3.7 billion old. Scientists have discovered the world’s oldest fossil- which is microscopic, which have tiny tube like filaments left behind by microorganisms between 3.77 and 4.3 billion years ago.
Researchers reported that these may be the oldest fossils ever discovered, the remains of bacteria thriving on Earth. Martin J. Van Kranendonk, a geologist at the University of New South Wales, called the patterns in the rocks “dubiofossils” — fossil-like structures, perhaps, but without clear proof that they started out as something alive. The signature of the iron-eating bacteria was found encased in a piece of quartz excavated from the Nuvvuagittuq Supracrustal Belt in Quebec, Canada. Scientists described their discovery in the journal Nature.
“Our discovery supports the idea that life emerged from hot, seafloor vents shortly after planet Earth formed,” Matthew Dodd, a PhD student at University College London, said in a news release. “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.” 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.
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 live around hydrothermal vents today.
"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,” said Earth scientist Dominic Papineau who was leading the research.
The oldest known fossils before this NSB find were 3.46-billion-year-old samples discovered in Western Australia. But some scientists suggested the fossil was a non-biological anomaly in the rock.