Rb sr dating example
In order to make this determination, Papanastassiou et al.
3.3), the points move up straight lines with a slope of Sr by the same amount. Such determinations are called model ages because the initial ratio is predicted by a model rather than measured directly.Sr method was extended to less exotic rock-forming minerals such as biotite, muscovite and K-feldspar, with lower Rb/Sr ratios.3.11) by assuming a homogeneous Rb/Sr ratio in the solar nebula (Papanastassiou et al., 1969). However, basaltic achondrites and ADOR are themselves products of planetary differentiation.
The results are only model ages because they depend on an assumed composition for the source reservoir (solar nebula), and they would be rendered invalid if it did not evolve as a homogeneous reservoir. Therefore, a better interpretation (Tilton, 1988) is that the entire model chronology really indicates times of differentiation and metamorphism, rather than condensation. However, they may not have participated in the full planetary differentiation process which generated iron meteorites.