Volatile accretion and evolution in the terrestrial planets

Planetary habitability is tied to the history of volatile accretion, volatile loss, and the evolution of surficial environments. Habitability is particularly related to the record of the life essential volatile elements such as hydrogen, carbon, nitrogen and sulfur. Noble gases are another set of volatile elements, but given their inert nature, are neither relevant for pre-biotic chemistry, or for life itself. And yet, the noble gases are intricately linked to the question associated with the planetary habitability and the origin of life through the remarkable portrait that they paint of the processes associated with the formation and evolution of a habitable planet. For example, the noble gas isotopes record processes associated with volatile delivery, how volatile sources changed through time, volatile loss, the evolution of the early atmosphere, and volatile exchange between the surface and the interior of a planet. It is this process-based framework provided by the noble gases…