>Well, if the data form an isochron, it's assumed that the system has been
>closed since isotopic resetting.
However, Davis Young points out in "Christianity and the age of the earth"
that there are some physical inspections that can be made to help ensure
that the rocks being dated have not been contaminated in some way. They
involved things like looking for cracks and signs of seepage into the rock
being dated.
Bill Hamilton | Chassis & Vehicle Systems
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