Another problem that calls into question the credibility of radiometric dating is heat contamination.
For example, In 1973, in Alberta, Canada (near the town of Grand Prairie) a high voltage line fell which caused nearby tree roots to fossilize almost instantly.
To do this they have selected a certain meteorite, which contained various types of lead (including lead 204, 206, 207 and 208) but no uranium, and they have assumed that this ratio is equivalent to the earth's original lead ratio.
They did this because it is almost certain that these lead isotopes were all present in large quantities when the earth was created.
The only dating methods discussed (over and over) by evolution-believing scientists and the mass media are those that supposedly "prove" that the earth is billions of years old.