Cosmic ray exposure ages of tektites by the fission-track technique

Tektites exposed to primary cosmic radiation will contain distinctive, readily identifiable, induced-fission tracks, a large fraction of which will survive the heating which occurs as tektites fall to earth. A search for such events in samples from each of the four chronological tektite groups failed to reveal such events and thereby indicates an average cosmic ray exposure age of less than 300 years. By further work a space exposure of 20 years or less could be detected.