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The Geology of Early Earth: New Evidence Show Planet was a Flat ‘Waterworld’

May 09, 2017 09:12 AM EDT
Earth Viewed From Apollo 17
Light reflected over water could be easy to explain as sunlight reflecting over a smooth part of a sea or lake. However, the flashes captured by NASA’s camera weren’t just seen over water bodies.
(Photo : NASA/Newsmakers via Getty Images)

The landscape of early Earth was a far different picture than the one we know now, more of a water world than the complex formations present in the present planet. Researchers from the Australian National University (ANU) found that during the planet's first 700 million years or so, the Earth was likely barren, mountainless and nearly completely underwater with just a few tiny isles.

According to an official report from ANU, the team analyzed tiny zircon mineral grains that were found preserved in sandstone rocks in the Jack Hills of Western Australia. These mineral grains are the oldest fragments of the Earth ever found, dating to be 4.4 billion years old.

"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," lead researcher Dr. Antony Burnham of the ANU Research School of Earth Sciences explained.

The first 700 million years of the planet's existence was a quiet and dull landscape with no mountains or continental collisions at all. He added, "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."

Meanwhile, the first known form of life developed a little later at about 3.8 billion years ago. Zircon is created with melting older igneous rocks instead of 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," Burnham said.

The study has been published in the journal Nature Geoscience.

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