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Early Earth Was A ‘Water World’

GegenWind Photo
After analyzing oxygen isotope data from ancient ocean crust, geologists say the Earth of 3.2 billion years ago was covered in water.

Let’s hop in the time machine, going back, way back, to a time before humans – traveling about three billion years to when Earth was a “water world."

On this edition of River to River, host Ben Kieffer is joined by Ben Johnson to discuss his field work on exposed ancient, ocean crust in a remote part of Western Australia. 

Credit Jana Meixnerova
Ben Johnson in Western Australia.

By analyzing isotope data, Johnson found Earth's continents were once submerged and life on the planet was more of a marine origin story.

“If the hypothesis of the ‘water world’ turns out to be correct, it suggests that all the processes happened early in life’s history,” Johnson said. “Its emergences, the development of certain metabolisms, how cells process food and nutrients all developed in the ocean.”

Johnson is a geologist in Geological and Atmospheric Sciences at Iowa State University. 


  • Ben Johnson, geologist at Geological and Atmospheric Sciences, ISU
Ben Kieffer is the host of IPR's River to River
Matthew was a producer for IPR's River to River and Talk of Iowa