palm updating databases - Radioactive dating problems and answers
Jim Mason made no reference to the Concordia line and I could not find any reference to the Concordia line on any articles on the CMI website, even though it is well known (e.g. Jim raised the issue of Helium concentrations in Zircon.
Furthermore, the same method can produce different ages on different parts of the same rock.
Sometimes these are close but other times they are very different.
Some rocks dated older than the 4.5 billion year evolutionary age for Earth. Isochron dating can also produce negative ages, by producing a negative slope.
K-Ar and Ar-Ar can result in negative ages when atmospheric argon is considered.
For allegedly older samples K-Ar is used to "date" the standard and as such it still has the same problems as K-Ar dating.