The carbon (and water, N, noble gas) inventory of the Earth : geochemical and cosmochemical constraints

Abstract

The stable isotopes signatures of terrestrial nitrogen and hydrogen suggest strongly that most volatile elements on Earth originated from a cosmochemical reservoir that also sourced asteroidal bodies. In the Earth's mantle, a minor solar-like volatile component is present and best seen in the Ne (and possibly N and H) isotope composition(s) of mantle-derived rocks. Ne isotopes in minerals from mantle plume provinces discriminate against contribution of dust implanted with solar ions, and instead support trapping of volatile elements directly from the nebular gas. Based on these data as well as Ar/C ratio of bulk Earth, we discuss the carbon (and water, N, noble gas) inventory of the Earth.