Can radioactive dating used metamorphic rocks
The third assumption is that the sample has remained in a closed system.
And since the only rocks which yield ages in excess of 100,000 years are of volcanic origin, this method of dating the earth is not based on science, but rather speculation and subjecting reasoning. * "Allende" is the name given to the meteorite that was used to "date" the age of the earth. It is the site where the famous 1470 skull was found.
For Uranium/Lead dating this means that some of the uranium that was initially present would be "leached" out of the rock.
Leaching can also cause uranium to be leached into rocks that have little or no uranium in them. Note: As for the few cases where scientists do know what the "original" condition (or date of eruption) was, they still have not been able to come up with the correct "date" for the age of the rock without all sorts of fancy footwork and massaging of data.
Although there is no way to prove whether or not this has been the case, scientists have attempted to alter the rate of decay of radioactive materials and have found that they are almost immune to change.
Most creationists have few qualms in accepting this first assumption.