@Setanta,
Oh that, i know about radioisotope dating ( potassium-40 decays to argon-40; uranium-238 decays to lead-206 via other elements like radium; uranium-235 decays to lead-207; rubidium-87 decays to strontium-87; etc.).
I mentioned this in my first comment. radioisotope dating cannot be used the date rocks or anything because it is based on again, assumptions that the preconditions have been met for the sample being dated
http://en.wikipedia.org/wiki/Radiometric_dating#Preconditions
These preconditions are unprovable. For example, the basic equation of radiometric dating requires that neither the parent nuclide nor the daughter product can enter or leave the material after its formation.
If i gave you a rock sample how would you prove that this condition has been met before radioisotope dating the sample? There is no way to prove this so scientists assume before dating the rock that neither the parent nuclide nor the daughter product entered or left the material after its formation.
I know they take multiple rock samples from different locations to enhance precision, but even this is based on the assumption that these rocks were formed by the same event.
Show me a way to prove from a rock fossil that after its formations along time ago this condition was met and i will apologize to you and admit my ignorance gladly.
To use radioisotope dating one has to also assume that the rates of decay are consistent. This is unprovable because our life span is too short to observe this.
At this moment please feel free to bring up HALF LIFE.