Creation Moment 1/28/2013 - Dating Discordance in Uranium-Lead

"Behind the confidence of uranium-lead dates hides worry about numbers that don’t match up.
Uranium-lead (U-Pb) dating is a staple of the billions-of-years claims about igneous and metamorphic rocks and meteorites – giving rise to the consensus age of the solar system at 4.55 billion years. The technique has been refined over the last century, but “discordances” (mismatches) remain. That’s because there are two “isotopically distinct yet chemically identical” decay chains, F. Corfu described in the Geological Society of America Bulletin this month: the ²³⁵U to ²⁰⁷Pb pathway, and the ²³⁸U to ²⁰⁶Pb pathway. (The ratios of the products, ²⁰⁷Pb/²⁰⁶Pb, can also be measured.) “These twin decay systems, running at different speeds, allow an immediate verification of the validity of their ages, which must be concordant to be considered valid, although under favorable circumstances, discordant data can be extrapolated to the correct age.” Since uranium is often locked in tightly-bound minerals called zircons, from which parent and daughter product are locked in, the method is thought by modern geologists to provide a reliable clock.

Discordance, however, remains a general problem, the minimization of which still requires work and creative solutions, unless, out of convenience, the historical consciousness of discordance simply disappears from the collective awareness.

In that last sentence, Corfu warns that researchers could simply ignore discordance out of “convenience.” They could pretend that the problems don’t exist or aren’t important, because it’s too much work to get to the one right answer that Tom Krogh said is the only one that’s good enough. If ignoring the problem becomes the choice of the “collective awareness,” credibility of the U-Pb dating method—or any other method—will suffer as a result." CEH

For the wisdom of this world is foolishness with God.

1 Corinthians 3:19

"Where T is the time from starting point,B₀ the original amount of uranium,B_T the amount of uranium at the measurement,A₀ the original amount of lead,A_T the amount of lead at the measurement,R_T the rate uranium changes to lead,Da the average rate of loss and gain in the amount of lead,Db the average rate of loss and gain in the amount of uranium.

For Uranium-Lead dating to work, scientists have to make three assumptions. These assumptions are that the system being dated is a closed system; at the beginning of the time period, there are no daughter isotopes present; and the rate of radioactive decay stays the same through the whole time period. Once all these assumptions are taken, the equation above simplifies to .
Without a closed system, uranium-lead dating, like all other radiometric dating methods, falls apart. Assuming a closed system means that nothing on the outside of the rock affected the sample. This means that none of the parent or daughter isotope leaked in or out. It also implies that none of the factors that might affect the rate of the radioactive decay could not. This is an ideal concept that cannot happen.
All radiometric dating systems depend on the idea that radioactive decay happens at a constant rate. It has been found that the rates fluctuate for an unknown reason. One of the explanations has been found that the rates of decay of some radioactive isotopes change depending on the its proximity to the sun. Two examples of an isotope that exhibits this behavior is silicon-32 and radon-222. Not all radioactive isotopes follow this kind of behavior; others have irregular rate changes that still have no explanation." CreationWiki