RARE GASES IN TEKTITES
Tektites from a number of localities were excited for their contents of petassium, atmospheric argon, radiogenic argon, atmospheric neon, and possible cosmogenic neon. At 300 deg K, the coefficient of diffusion for helium in tektite glass from Kalgoorlie, Australia is 4 x lO/sup -10/ cm/sup 2//sec. The activation energy for helium diffusion is 0.27 ev. The helium solubility constant is 0.005. Correspending quantities for neon diffusion are 2 x 10/sup - 15/ cm/sup 2//sec, 0.61 ev and 0.005. The helium diffusion rate is so high that tektites retain no radiogenic or cosmogenic helium. The recent group of tektites should retain a substantial amount of any cosmogenic neon contained at time of fall. In no case was any excess Ne/sup 21/ detected. From the upper limits of original Ne/sup 21/ content, a maximum "flight time" since last melting was computed for each tektite. For a tektite from Kalgoorlie, this is 28,000 years. This result is in apparent disagreement with the finding by Ehmann and Kohman of radioactive Al/sup 26/ in australites. Potassium-- argon ages were computed for each tektite. These range from 0 to 32 m.y. and are usuaily in agreement with the stratigraphic age of the formations on which the tektites lie, according to presently accepted time scales. These data do not support a recent suggestion that the moldavites of Czechoslovakia and the recently discovered tektites from Georgia, U.S.A. are part of the same fall. (auth)
- Research Organization:
- Univ. of California, Berkeley
- NSA Number:
- NSA-15-005213
- OSTI ID:
- 4092983
- Journal Information:
- Geochim. et Cosmochim. Acta, Journal Name: Geochim. et Cosmochim. Acta Vol. Vol: 20
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
POTASSIUM-ARGON AGE OF SOME TEKTITES
GAMMA-SPECTROMETRIC DETERMINATIONS OF THORIUM, URANIUM AND POTASSIUM IN TEKTITES