Earth’s crust ‘500m years older’ than it was believed

EARTH’S crust is 500million years older than previously thought – which could change what we believe about how life evolved.

It formed 3.7billion years ago, scientists say, meaning our world became ready to host life significantly earlier.

The new discovery may also be significant in the search for alien organisms on other planets and moons.

Study author Prof Desiree Roerdink, from Bergen university in Norway, said: ‘That is a huge time period. It essentially has implications for the way we think about how life evolved.’

Life is usually thought to have started in deep sea hydrothermal vents. But the biosphere – where all ecosystems exist, including land and sea – is complex.

Prof Roerdink said: ‘We don’t really know if it is possible that life could have developed at the same time on land.’

Once the crust becomes established through processes such as plate tectonics, it begins to weather and crucial minerals and nutrients are added to the seas. The first emergence of continental crust showed when Earth cooled and became habitable.

Earlier analyses relied on the silvery metal strontium in rare marine carbonate which is altered in sediments older than 3billion years.

But the latest study, by an international team, is based on barite, made through sulphate mixing with barium in ocean water. Calculations revealed chemical weathering in the ocean began about 3.7billion years ago.

Previously, it was believed Earth’s crust was 3.2billion years old.

‘The composition is exactly the same as it was when it precipitated,’ Prof Roerdink said. ‘So, in essence, it is really a great recorder to look at processes on the early Earth.’ The study was presented at a virtual meeting of the European Geosciences Union.