A diabase dike of the Mackenzie swarm has been sampled at two localities where it intrudes basic volcanics and granite respectively. The portion of the dike intruding the granite has statistically significant higher contents of K, Rb, Li, and Tl, as a result of in situ, residence, contamination from the country rock. Ion transfer from the granite toward the diabase took place mainly before the magma crystallized, therefore a process of differentiation was superimposed to that of diffusion.