Manganese-53 in the trenton iron meteorite

The cosmic-ray produced 53Mn was determined in two fractions of the Trenton iron meteorite. The chemical separation and purification of manganese was performed by solvent extraction and anion and cation exchanges. In the extracted manganese fraction, the isotopic ratio of 53Mn to 55Mn was measured by mass spectrometry and the total amount of manganese was determined by flame photometry using the recovery of 54Mn tracer. The 53Mn observed were 1.74+-0.18(x1012) atoms 53Mn/g meteorite for the fraction of AII -6+2 and 1.82+-0.14(x1012) atoms 53Mn/g meteorite for AII -22+2. These values obtained were compared with those in other iron meteorites. From the result of it, this iron meteorite seems to have at least>=1x107 years of exposure age and <=1x106 years of terrestrial age. (auth.)