Diffusion Kinetics of Samarium and Neodymium in Garnet, and a Method for Determining Cooling Rates of Rocks

Experimental determinations of the diffusion coefficients of samarium and neodymium in almandine garnet and theoretical considerations show that one cannot assign a sufficiently restricted range of closure temperature, T$_C$, to the samarium-neodymium decay system in garnet for the purpose of constraining the cooling rate. However, it is shown that the samarium-neodymium cooling age of garnet can be used to calculate both cooling rate and T$_C$ if the temperature and age at the peak metamorphic conditions are known.