Hadean isotopic fractionation of xenon retained in deep silicates.

Our understanding of atmosphere formation essentially relies on noble gases and their isotopes, with xenon (Xe) being a key tracer of the early planetary stages. A long-standing issue, however, is the origin of atmospheric depletion in Xe and its light isotopes for the Earth and Mars. Here we report that feldspar and olivine samples confined at high pressures and high temperature with diluted Xe and krypton (Kr) in air or nitrogen are enriched in heavy Xe isotopes by +0.