Noble gases in the Fayetteville meteorite

Abstract

Noble gases were extracted from the dark portions of Fayetteville by heating the sample to successively higher temperatures up to 1600°C. Analyses of the neon evolved at each temperature indicate that this gas is a mixture of at least three components. It is shown that the isotopic composition of neon observed could be produced from a mixture of primordial neon, cosmogenic neon, and highly mass-fractionated primordial neon. The isotopic composition of helium, neon and argon indicate a primordial component for which He 3: He 4 ≤ 0.00031, Ar 38: Ar 36 ≤ 0.177, Ne 20: Ne 22 ≥ 12.6, and Ne 21: Ne 22 ≥ 0.033. The xenon spectra show an excess of the heavy xenon isotopes with a mass yield curve intermediate between that observed in Pasamonte and that in the earth's atmosphere. It is shown that this atmosphere-like xenon component is not due to contamination but is definitely a component of meteoritic xenon.