"Sterling K. Webb" wrote: > Footnote: There are anomalous Russian tektites that are not part of the "Big Four" > tektite fields: 1.) three from Novy Urei with 80ppm water content and K-Ar and > fission-track ages of 22-24 million years, and 2.) one from Magnitogorsk in the > Urals with a K-Ar age of 6.3 million years.
Hello Sterling and List, For those who would like to learn more about Sterling's footnote, see: DEUTSCH A. et al. (1997) Geochemistry and neodymium-strontium isotope signature of tektite-like objects from Siberia (urengoites, South -Ural glass) (Meteoritics 32-5, 1997, 679): The authors state that recent FTIR spectrometric investigations yielded H2O contents between 0.008 and 0.024 wt% for three urengoites and K-Ar and fission-track ages of 22-26 million years. According to Koroteev et al. (1994), the H2O content of the South-Ural glass amounts to << 0.09 wt% and a K-Ar age of about 6.2 Ma. The parent crater of the urengoites should be located somewhere in the eastern part of Siberia. References: KOMAROV A.M. et al. (1991) Fission-track dating of the Urengoy tektites using an age standard (Geochem. Intern. 28, 11-17). KOROTEEV V.A. et al. (1994) Tektite from Astaf Evskaja placer deposit, Southern Urals (Zapisky Vseross. Mineral. Obsh. 123, 44-48, in Russian). Best wishes, Bernd ______________________________________________ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
