It wasn't a blue planet by any means." By the end of the Archean Eon
some 2.5 billion year ago, oxygen levels rose quickly, creating an explosion of new life on the planet, he said.
The mantle was so hot from its birth and up until about 2.5 billion years ago - during what is known as the Archean Eon
- because elements like potassium and uranium were decaying and releasing radioactive heat, according to (http://vtnews.vt.edu/articles/2017/05/science-hottestlavas.html) Virginia Tech .
Two researchers from University of Colorado Boulder say all that may have been required to sustain liquid water and primitive life on Earth during the Archean eon
2.8 billion years ago were reasonable atmospheric carbon dioxide amounts believed to be present at the time and perhaps a dash of methane.
Previously scientists have explained the presence of liquid water in that lowlight time, during the Archean Eon
(about 3.8 billion to 2.5 billion years ago), by suggesting that Earth's atmosphere held large amounts of planet-warming greenhouse gases such as carbon dioxide and methane.