Solar neon

Scientists have found three types of neon in meteorites (1) Primordial or planetary neon (called neon A) (2) solar neon (neon B), which consists of solar-wind neon ions implanted in meteorites that happen to have been at the surface of their parent budy and (3) cosiuogeiiie neon (neon 5), formed when cosmic rays passing through the meteorite spall, or shatter, atomic nuclei in their path. Each type has different proportions of the three isotopes of neon. Although the procedure is too detailed for inclusion here, Lewis and Anders explain how, through the use of stepped heating of meteorite materials, the types of neon can be measured. Their ratios to each other provide cities as to what type of star may have been the source of a given meteorite. 

Dixon E. T., Honda M., McDougall 1., Campbell 1. H., and Sigurdsson 1. (2000) Preservation of near-solar neon isotopic ratios in Icelandic basalts. Earth Planet. Sci. Lett. 180, 309 - 324. 

Moreira M., Breddam K., Curtice J., and Kurz M. D. (2001) Solar neon in the Icelandic mantle new evidence for an undegassed lower mantle. Earth Planet. Sci. Lett. 185, 15-23. 

Figure 4 Three-isotope neon plot showing isotopic composition of air and solar neon and the MORB correlation hne plus trajectories for various OIBs (reproduced hy permission of Mineralogical Society of America from Rev.

Evidence for solar neon in the deep Earth and Ne-B in the upper mantle indicates that the... 

As all samples appear to follow linear trajectories in 3-isotope neon space, they must represent binary mixtures between two end-members with distinct neon isotope systematics. One end-member is clearly air reflecting the inevitable contamination of all terrestrial samples with atmospheric neon. The other end-member consists predominantly of mantle neon which is itself composed of a mixture of solar neon (high °Ne/ Ne 13.8) and nucleogenic neon (high Ne/ Ne)—in various proportions. 

In the case of the Lau Basin, Honda et al. (1993b) showed that samples from the Central Spreading Center had measured He/ He ratios (8 1 R ) in agreement with predictions from the solar neon hypothesis and the observed neon isotope values i.e., the trajectory in Figure 3 (slightly steeper than the MORB line) predicts a He/" He ratio of... 

Dixon JE, Stolper EM (1995) An experimental study of water and carbon dioxide solubihties in mid-ocean ridge basaltic liquids. 2. Applications to degassing. J Petrol 36 1633-1646 Dixon ET, Honda M, McDougall I, Campbell IH, Sigurdsson I (2000) Preservation of near-solar neon isotopic ratios in Icelandic basalts. Earth Planet Sci Lett 180 309-324 Doe BR, Zartman RE (1979) Plumbotectonics I. the Phanerozoic. In Geochemistry of hydrothermal ore deposits. Bames HL (ed) Wiley, New York, p 22-70... 

Moreira M, Kunz J, Allegre CJ (1998) Rare gas systematics in popping rock isotopic and elemental compositions in the upper mantle. Science 279 1178-1181 Moreira M, Breddam K, Curtice J, Kurz MD (2001) Solar neon in the Icelandic mantle new evidence for an undegassed lower mantle. Earth Planet Sci Lett 185 15-23 Morrison P, Pine J (1955) Radiogetuc origin of the helium isotopes in rock. Ann NY Acad Sci 62 69-92 Muramatsu YW, Wedepohl KH (1998) The distribution of iodine in the earth s crast. Chem Geol 147 201-216... 

Figure 3 The distribution of neon isotopes in mantle-derived rocks, indicating the presence of an atmospheric component, a radiogenic component adding Ne (produced by neutrons from uranium fission acting on oxygen and magnesium), and a solar component. It is this latter that indicates that gases in the mantle were derived from the capture of solar material in the early history of the Earth. M = MORB (midocean ridge basalts) P = plume or ocean island basalts (OIB) A = atmosphere. Solar neon is represented by the horizontal line at Ne/ Ne = 12.5 MFL is the mass fractionation line. The presence of solar neon in ocean basalts was first identified by Craig and Lupton (Craig H and Lupton JE (1976) Earth and Planetary Science Letters 31 369-385). (Reprinted with permission from Farley and Poreda (1993).

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