Earth's birth is all about gases

 It has long been argued about how the earth evolved from a primitive state in which it was covered by ocean of molten rock into the planet we live on today with a solid crust made of moving tectonic plates, oceans and an atmosphere. Now, an international team, led by Dr Mark Kendrick at the University of Melbourne, has shown that atmospheric gases are mixed into the mantle, inside the earth’s interior, during the process called “subduction” when tectonic plates collide and submerge beneath volcanoes in subduction zones.

“This finding is important because it was previously believed that inert gases inside the earth had primordial origins and were trapped during the formation of the solar system,” Dr Kendrick said. Because the composition of neon in the earth’s mantle is very similar to that in meteorites, it was suggested by scientists that most of the earth’s gases were delivered by meteorites during a late meteorite bombardment that also generated visible craters on the earth’s moon. “Our study suggests a more complex history in which gases were also dissolved into the Earth while it was still covered by a molten layer, during the birth of solar system,” he said.