Determination of the spallogenic radionuclides26Al and53Mn in Antarctic meteorites with respect to cosmic ray exposure and terrestrial ages

The spallogenic radionuclides²⁶Al (T=7.18·10⁵ a) and⁵³Mn (T=3.8·10⁶ a) were determined in 11 ordinary chondrites and 7 achondrites from Antarctica by nondestructive coincidence counting techniques and radiochemical neutron activation analysis, respectively. The results are discussed with respect to exposure ages, terrestrial residence times and possible genetic relationships of the meteorites investigated. The high terrestrial ages of some specimens (up to 800 000 years) are of importance for the study of the ice flow in Antarctica.