There and again once more: Mantle xenon has a narrative to inform

Volatiles — similar to water, carbon dioxide and the noble gases — come out of the earth’s inside by way of volcanism and could also be injected into the mantle from the ambiance, a pair of processes referred to as mantle degassing and regassing. The change controls the habitability of the planet. This transport couldn’t have begun a lot earlier than 2.5 billion years in the past, in keeping with new analysis that additionally establishes a spread of dates throughout which the Earth shifted to a internet regassing regime.
Geology News — ScienceDaily