Creatures from 4.2bn years ago revealed in ‘oldest-ever’ fossils

A TEAM led by British scientists claims to have discovered the world’s oldest fossils.

The microscopic ‘casts’ – similar to those left by worms – are at least 3.7billion years old, but might date back as far as 4.2billion years ago, the researchers say.

They were produced by bacteria that lived in hydrothermal vents in the Earth’s crust under a sea with a temperature of around 60C. The fossils were found in a Canadian wilderness.

The scientists suggested the find could even be an indicator of life on Mars. They said that at the time the bacteria lived, Earth and Mars were similar hot, rocky worlds with thin atmospheres and oceans bombarded by comets and asteroids.

If life flourished on Earth in such unforgiving conditions, they argued, it may well also have developed on Mars.

The discovery suggests life began to develop on Earth soon after the planet formed around 4.6billion years ago. The earliest micro-fossils previously found were in Western Australia, and around 3.4billion years old, although some scientists believe these might not have been formed by a biological process.

The latest remains are tiny cylinders of haematite – an iron compound – believed to have been formed by bacteria. They were found in rocks discovered in the Nuvvuagittuq belt in Quebec. The study, led by Dr Dominic Papineau of University College London and published in Nature, said the find showed signs of putrefaction – the rotting of biological materials.

However, some scientists are sceptical. Professor Nicola McLoughlin, from Rhodes University in South Africa, said she was not convinced the formations were fossils.