Earth 4.4 billion years ago was flat and almost entirely covered in water with just a few small islands, new research suggests.
Scientists came to the conclusion after analysing tiny zircon mineral grains from a region of Western Australia containing the oldest rocks ever found.
Lead researcher Dr Antony Burnham, from The Australian National University, said: ‘The history of the Earth is like a book with its first chapter ripped out with no surviving rocks from the very early period, but we’ve used these trace elements of zircon to build a profile of the world at that time.
‘Our research indicates there were no mountains and continental collisions during Earth’s first 700 million years or more of existence – it was a much more quiet and dull place.
‘Our findings also showed that there are strong similarities with zircon from the types of rocks that predominated for the following 1.5 billion years, suggesting that it took the Earth a long time to evolve into the planet that we know today.’
Researcher Dr Antony Burnham said earth was a much more quiet and dull place for the first 700 million years
Sandstone from the Jack Hills date back to when earth was just 160,000,000 years old
The team, whose findings are reported in the journal Nature Geoscience, conducted a forensic study of the grains looking for clues to their formation.
They found that the zircon was created by melting old igneous rocks rather than sediments.
The new research fits in with the ‘Cool Early Earth’ theory that suggests a cool, quiet period followed the extreme conditions of Earth’s earliest history.
It pre-dated the Late Heavy Bombardment 4.1 to 3.8 billion years ago when the Earth was pummelled by comets and asteroids.
Bacterial life is thought to have emerged on Earth at the end of the Bombardment around 3.8 billion years ago.
By Richard Hartley-Parkinson, Metro.co.uk
Scientists came to the conclusion after analysing tiny zircon mineral grains from a region of Western Australia containing the oldest rocks ever found.
‘Our research indicates there were no mountains and continental collisions during Earth’s first 700 million years or more of existence – it was a much more quiet and dull place.
‘Our findings also showed that there are strong similarities with zircon from the types of rocks that predominated for the following 1.5 billion years, suggesting that it took the Earth a long time to evolve into the planet that we know today.’
The team, whose findings are reported in the journal Nature Geoscience, conducted a forensic study of the grains looking for clues to their formation.
They found that the zircon was created by melting old igneous rocks rather than sediments.
‘Sediment melting is characteristic of major continental collisions, such as the Himalayas, so it appears that such events did not occur during these early stages of Earth’s history,’ said Dr Burnham.The zircon grains, preserved in sandstone rocks in the Jack Hills, date back to when the Earth was only 160 million years old.
The new research fits in with the ‘Cool Early Earth’ theory that suggests a cool, quiet period followed the extreme conditions of Earth’s earliest history.
It pre-dated the Late Heavy Bombardment 4.1 to 3.8 billion years ago when the Earth was pummelled by comets and asteroids.
Bacterial life is thought to have emerged on Earth at the end of the Bombardment around 3.8 billion years ago.
By Richard Hartley-Parkinson, Metro.co.uk