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.