Age of Meteorites by theA40—K40Method

Abstract

The ages of two stony meteorites were determined by measuring the ${\mathrm{A}}^{40}$/${\mathrm{K}}^{40}$ ratio using an isotopic dilution technique. With a branching ratio $\frac{{\lambda }_e}{{\lambda }_{\beta }}=0.085\mathrm{}$ and a decay constant $\lambda =0.55\mathrm{}\times {10}^{-9\mathrm{}}$ ${\mathrm{yr}}^{-1\mathrm{}}$, the ages obtained were (4.82±0.20)×${10}^9$ and (4.58±0.20)×${10}^9$ years.