"The mechanism which caused the crust that had been altered by seawater to sink into the mantle functioned over 3.3 billion years ago. This means that a global cycle of matter, which underpins modern plate tectonics, was established within the first billion years of the Earth's existence, and the excess water in the transition zone of the mantle came from the ancient ocean on the planet's surface," said project leader and co-author of the article Alexander Sobolev, a member of the Russian Academy of Sciences (RAS) and Doctor of Geological and Mineralogical Sciences who is a Professor at Vernadsky Institute for Geochemistry and Analytical Chemistry under the Russian Academy of Sciences.
* This article was originally published here
