Lead could easily reside in impurities and imperfections in the crystal structure. Anyway, to me it seems unlikely that this chain of events would occur. So this implies some kind of chemical fractionation. If P1 is increased, it will make the age smaller. It is possible that the reason is that uranium-lead dates so rarely agree with the correct dates. This can happen by mixing scenarios as indicated above. An error has occurred.
It is very likely that some of this melt will be squeezed from the mixture into the cracks which develop in the surrounding rock.
ERRORS ARE FEARED IN CARBON DATING
The relative concentrations of lead isotopes are measured in the vicinity of a rock. The electric charge distribution would create an attraction between the uranium compound and a crystallizing mineral, enabling uranium to be incorporated. We will examine some of these mechanisms at the end of the next chapter. Cortini, in an article appearing in the Journal of Volcanology and Geothermal Research also suggests this possibility. The uncertainty of fossil dates in the Middle Stone Age is just the tip of the iceberg.