Primordial Noble Gas in the Earth

To resolve the primordial terrestrial noble gas, it would be useful to examine major noble gas reservoirs in the early solar system, which could have supplied noble gases to the Earth. As we discussed in Chapter 3, two major noble gas components occur very widely in the solar system and can be a potential source for the terrestrial noble gas. They are solar noble gas (representative of the sun), which is generally assumed to be best represented by solar wind noble gas implanted on Al-foil target plates on the moon (elemental ratio) and on lunar breccia (isotopic ratio) (e.g., Ozima et al., 1998), and Q phase noble gas (see Wieler, 1994, for a review), which occurs very widely in various chondrites. Next we will compare the bulk Earth noble gas, which we assume to be represented by atmospheric noble gas with these two major noble gas components in the solar system. 

In summary, we may reasonably conclude that except for Ne, and apart from radio-and nucleogenic components, the isotopic composition of atmospheric noble gases well represent the bulk Earth and can be assumed to approximate a primordial terrestrial noble gas component. Thus defined, primordial terrestrial noble gases are 

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Ozima M, Alexander Jr EC (1976) Rare gas fractionation patterns in terrestrial samples and the Earth-atmosphere evolution model. Rev Geophys Space Phys 14 385-390 Ozima M, Igarashi G (2000) The primordial noble gases in the Earth a key constraint on Earth evolution models. Earth Planet Sci Lett 176 219-232... 

Trieloff M., Kunz J., and Allegre C. J. (2002) Noble gas systematics of the Reunion mantle plume source and the origin of primordial noble gases in Earth s mantle. Earth Planet. Sci. Lett. 200, 297-313. 

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