Radiometric dating falsely assumes initial conditions are known (Talk.Origins)

Claim CD002:

Radiometric dating falsely assumes that initial conditions are known, that none of the daughter components are in the mineral initially. Source: Morris, Henry M., 1974. Scientific Creationism, Green Forest, AR: Master Books, p. 139.

CreationWiki response:

It needs to be noted that this book is more than 30 years old and new methods have been developed in that time, some of which are intended to fix this problem.

It needs to be realized that the cited source predates isochron dating, so this is simply a case of the source's being out of date. However, the claim is still valid for most dating methods. At its core, Isochron dating assumes uniformitarian geology; therefore, if the rocks being measured were formed by processes outside that theory, such as the Genesis Flood, the dates derived by it are wrong. So while Isochron dating does not assume that none of the daughter components are present when the rock was formed, it still makes assumptions about the rocks' initial conditions. As such, the first part of this claim is essentially correct.
 * Reference: Isochron dating

The assumed initial conditions are reasonable inside uniformitarian geology, but not necessarily in flood geology or some other model.

So by Talk Origins' own admission the claim is essentially correct for potassium-argon dating. The question is whether or not the assumptions are reasonable. They are only reasonable inside uniformitarian geology. Even the most basic model based on the Genesis Flood would destroy the no-initial-argon assumption. One model that would destroy all three approaches is if the rocks were water-laid sediment rather than laid down in a volcanic eruption. In that case the rock would inherit the isotopic makeup of the source's material and thus make the rock's radiometric date earlier than it really is.

So by Talk Origins' own admission the claim is essentially correct for this method as well. Again, the question is whether the assumption is reasonable or not? It is only reasonable inside uniformitarian geology. According to the creation model these zircons were most probably formed on Day 3 of the creation week. They would have crystallized very quickly, if not instantaneously and therefore there would have been no time for total lead rejection.

This makes carbon-14 accurate to a point, but carbon-14, dendrochronology and other methods are all mutually calibrated to each other. More importantly, they are all calibrated to uniformitarian geology. The results are different when the same data are interpreted by Flood geology.
 * Reference: Carbon-14 dating
 * Reference: Dendrochronology
 * Reference: Carbon 14

Of all assumptions given by Talk Origins, Fission-track dating is the only truly objective one, but it turns out that the calculations of fission-track decay constants are calibrated to other radiometric dating methods, particularly potassium-argon, and as such they are based on the same assumptions as potassium-argon. So it turns out that the original claim is correct once again.
 * Reference: Mythology of Modern Dating Methods