Non-destructive measurements of cosmogenic 26Al, natural 40K and fallout 137Cs in Antarctic meteorites

Non-destructive γ-ray measurements have been made to determine cosmogenic ^(Al), natural ^K and fallout ^(Cs) activities in 15 Antarctic meteorites (14 from Yamato Mountains and 1 from Allan Hills). The ^(Al) activities range from 72 to 29 dpm/kg. If we assume that the saturation activity of ^(Al) in chondrites is 60,about 1/3 of the measured meteorites show the contents close to this value; however, the rest show lower values. A simple graphical method was applied to estimate the exposure and terrestrial ages based on ^(Al) and ^(Mn) data, and these ages are compared with exposure ages obtained by ^(Ne) measurements. The results are generally consistent with the ^(Ne) data. It must be noted that the Antarctic meteorites are highly contaminated with fallout ^(Cs) derived from nuclear test explosions