Natural Thermoluminescence and Terrestrial Ages of Meteorites from a Variety of Temperature Regimes

• Main Authors: Benoit, P.H., Sears, D.W.G., McKeever, S.W.S.
• Format: Text
• Language: English
• Published: Oxford University Press 1993
• Subjects: Article; antartic*
• Online Access: http://rpd.oxfordjournals.org/cgi/content/short/47/1-4/669

The natural thermoluminescence of meteorites from Antartica, the Prairie and western States of the US and the Sahara Desert has been determined and compared with estimates of terrestrial age (time since fall) obtained by isotropic measurements. After fall on Earth, the natural TL of meteorites decays from the high values caused by high cosmic ray dose rates and low temperatures of space. The decay is temperature dependent, but can be theoretically modelled. The present data show good agreement between theory and observation. It is therefore possible to determine terrestrial ages from the natural TL data and theoretical TL decay curves, selecting appropriate temperatures from meteorological data. About 20% of the meteorites have low natural TL values which result in unrealistically long terrestrial age estimates. These meteorites are readily distinguished from the others and usually have cosmic ray produced isotope activities which suggest atypical radiation histories in space. The low TL signal, and perhaps the unusual isotopic data, is readily understood in terms of passing close to the Sun.