The three geochemical stages of a planet: accretion; evolution; and exploitation

Noble gas isotopic compositions of natural gases provide a non-traditional sample resource that have played a significant role in our understanding of the Terrestrial mantle's accretionary volatile sources and processes. This data underpins the construction of models that simulate the isotopic evolution of the mantle within the fluid dynamical constraints imposed by mantle rheology and thermodynamics - with some success in recreating mantle radiogenic isotope systems and mantle volatile recycling/degassing, but yet to fully account for 3He. Within the continental crust noble gas isotopes have helped our understanding of crustal hydrogen sources and sinks, biome preservation on planetary timescales and the mechanisms that form societal helium and hydrogen resources.