New discovery questions theory that earth was covered by ocean four billion years ago

Fresh water present on Earth ‘500 million years earlier than previously thought’

Nina Massey
2 days ago

Fresh water, which is essential for life, appeared on Earth roughly four billion years ago – 500 million years earlier than previously thought, research suggests.

The findings challenge the existing theory that Earth was completely covered by ocean four billion years ago.

The findings, based on analysis of ancient crystals from the Jack Hills in Western Australia’s Mid West region, push back the timeline for the emergence of fresh water to just a few hundred million years after the planet formed.

Researchers measured the oxygen compositions of zircon, a mineral that formed in some rocks that made up the Earth’s early continental landmasses some 3.2 to 4.2 billion years ago.

They found preserved evidence that the hot, molten rocks they grew in came into contact with water during their formation.

More:
https://www.independent.co.uk/news/science/fresh-water-found-australia-ocean-b2555838.html