New research on the state of the earth 2.5 billion years ago:
Just 2% to 3% of the Earth’s surface would have been dry land, compared with 28% today. Back then life consisted of nothing more complex than algae and bacteria. The Australian scientists who produced the new computer simulation believe that billions of years ago the Earth’s deep mantle was 200C hotter than it is today. A hotter mantle would have thickened and buoyed up the Earth’s crust beneath the oceans, creating shallower basins and leading to the flooding of what is now land. The continental crust would also have spread, making it lower and flatter and more vulnerable to floods. New Scientist magazine reported: “As the mantle cooled, land would have gradually appeared as the oceans became deeper and regions of high relief on the continental crust formed.” The transition may help explain why oxygen levels in the atmosphere rose at this time in the Earth’s history, say the researchers led by Dr Nicolas Flament from the University of Sydney.
Tags: ocean
