Krypton and Xenon Fractionation in North American Tektites
Physics and Astronomy
Elemental and isotopic compositions of the noble gases have been determined in six North American tektites (4 bediasites and 2 georgiaites) and one Ivory Coast tektite. Radiogenically produced 4He may explain the large 4He/36Ar ratios measured relative to air, despite significant diffusive losses. The Ne isotopic composition is enriched in 20Ne consistent with a single stage mass fractionation process. The enormous 20Ne/36Ar enrichments observed in all tektite samples, similar to those reported from other tektites and impact glasses, are attributed to atmospheric diffusion into the samples following solidification. The North American tektites show a systematic increase in 84Kr/36Ar and 132Xe/36Ar relative to air, with enrichments greater than those determined for any other tektite group or terrestrial samples other than shales. These enrichments are inconsistent with existing models of dissolving Kr and Xe in tektite glass without elemental fractionation at atmospheric pressures equivalent to ∼40 km altitude. The Kr and Xe isotopic compositions are indistinguishable from atmospheric within experimental uncertainty.
Meteoritics and Planetary Science
R. L. Palma, M. N. Rao, M. W. Rowe and C. Koeberl, 1997. Krypton and Xenon Fractionation in North American Tektites. Meteoritics and Planetary Science 32(1), 9-14.
Publisher's Copyright and Source
Copyright © 1997 The Meteoritical Society. Article published by John Wiley and Sons in Meteoritics and Planetary Science, volume 32, issue number 1, January 1997, pages 9-14. Available online on February 4, 2010: http://doi.org/10.1111/j.1945-5100.1997.tb01234.x.