Radiometric dating falsely assumes rocks are closed systems (Talk.Origins)

Claim Claim CD001:


 * Radiometric dating falsely assumes that the rocks being dated are closed systems. It inappropriately assumes that no parent or daughter isotopes were added or removed via other processes through the history of the sample.

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 30+ years old and it is recognized that new methods have been developed in that time, some of which are intended to address this problem.

This is exactly the point that Morris is making.

And there are also many rocks with which multiple radiometric dating methods produce radically different dates. The main question is how likely are close dates to occur by chance.

In discussing the assumptions required for computed dates to be accepted as accurate, McDougall states:

"The sample must have remained a closed system since the event being dated. Thus, there should have been no loss or gain of potassium  or 40Ar, other than by radioactive decay of 40K. Departures from this assumption are quite common, particularly in areas of complex geological history, but such departures can provide useful information that is of value in elucidating thermal histories."

"Quite common" likely means more than 50% of the time. Anything less than 50% would not be common. This means that more than half of the time, the computed dates are incorrect, despite their positive twist at the end. And further, the only way it is known that "departures are quite common" is because the results are not what were expected.

An actual list of radiometric dates from Alaska shows that 97% of them were made with only one method and 62% were dated by only one measurement.

If most multiple dates were within 1-3% then Talk.Origins would have a point, but an actual list of  radiometric dates from Alaska shows that among those with multiple dates, but multiple methods, have no statistical tendency for dates to be within 3% of Each other. Another study shows that given enough attempts the odds of finding multiple dates, but multiple methods so close together are actually quite good.

See:
 * Concordance of dates
 * CD010
 * CD020

Isochron dating assumes models for rock formation that do not include the Genesis Flood, so that could throw them off right from the start. False isochrons do occur, so contamination does affect the samples in a way that creates a good looking isochron that is wrong. The main way uniformitarian geologists tell a "good" isochron from a "bad" one is by seeing if it agrees with how old the Geological column says it should be.
 * Reference: Isochron dating

While Concordia dating does not assume a closed system, it does make assumptions about the rock's formation and history. Like all uniformitarian dating methods it does not consider effects of the Genesis Flood and its associated Accelerated decay. Furthermore, according to the creation model, these rocks would have been created on day three so even without Accelerated decay the assumed starting point is different.

No kidding. Contamination is the uniformitarian excuse for ignoring dates that do not fit the Geological column.