New research published in journal Nature Geoscience states that the earth could have been covered by a global ocean 3 billion years ago. The study was conducted by Boswell Wing from the University of Colorado along with former postdoctoral student Benjamin Johnson from Iowa State University. For the study, experts used the “quirk of hypothermal geochemistry,” international media reported.
The research was centred around a geological site called the Panorama district, in Northwestern Australia’s outback where a 3.2 billion-year-old chunk of ocean crust had been turned on its side. For the research, the scientists focussed on different types of oxygen that the seawater had carried into the crust. In particular, they analysed the relative amounts of two isotopes, oxygen-16 and oxygen-18, in more than 100 samples of the ancient stone.
According to the published study, seawater contained more of Oxygen-18, which is a heavier isotope of the Oxygen. From the analysis of the stones, the researchers found that the stones present when the planet’s crust was formed 3.2 billion years ago contained only Oxygen-18 isotope. The explanation they gave was that the earth had no continents at the time crust was formed as the stone contained the ocean’s heavy oxygen isotopes.
Johnson said that the Panorama hill is covered with “rolling hills that are cut through by dry river beds” and described it as a crazy place. He then said that there were no samples of really ancient ocean water lying around, but there were rocks that interacted with that seawater and remembered that interaction. The findings do not mean Earth was entirely landless at the time. The scientists suspect that small “microcontinents” may have poked out of the ocean here and there. But they do not think the planet hosted vast soil-rich continents like those that dominate Earth today, international media reported.