This makes them appear older

Carbon 14 dating false

Something like a vapor canopy could affect the atmospheric radiocarbon concentration, but this fact is, once again, irrelevant to the validity of modern tree-ring calibrated radiocarbon dates. So this argon that is being produced will leave some rocks and enter others. Dalrymple goes to great lengths to explain this away, but I think this figure is very telling, and find his explanations unconvincing. The rates of exchange that would mess up the dates are very tiny.

This could cause trouble for Rb-Sr dating. The rate of diffusion is proportional to the gradient of argon concentration, and increases rapidly with temperature. Some recent, though controversial, research has raised the interesting suggestion that c the speed of light has decreased in historical times. It's also possible for other matter to be incorporated into lava as it rises, without being thoroughly melted, and this matter may inherit all of its old correlated radiometric dates. If they contained a hundred times more excess argon, their K-Ar ages would be a hundred times greater, I suppose.

The problems are compounded because many of the parent and daughter substances are mobile, to some extent. One could say that we can detect whether the daughter is embedded in the crystal structure or not. And faster cooling could increase the ages by further large factors. When it is stated that these methods are accurate to one or two percent, it does not mean that the computed age is within one or two percent of the correct age.

Argon from the environment may be trapped in magma by pressure and rapid cooling to give very high erroneous age results. To really understand what's going on you have to sample the recent works of many different authors. Rocks from deeper in the crust would show this to a lesser degree. Henke states that hornblendes retain argon very well, but then later says that they can easily absorb excess argon. Thus it is easy to rationalize any date that is obtained.

In fact the argon in

Thus just by chance, many dates will be considered within the acceptable ranges. The Cambrian period is conventionally assumed to have begun about million years ago. Henke criticized some statements in my article taken from Slusher about the branching ratio for potassium. Plaisted wants to give his readers the impression that argon can readily move in and out of minerals and, therefore, the gas is too volatile for radiometric dating.

Heating of rocks can also release argon. Other flows with wide biostratigraphic limits have weak restrictions on allowable dates. This will cause them to retain argon and appear too old. This will make the sample appear artificially old right away.

Now, some rocks in the crust are believed not to hold their argon, so this argon will enter the spaces between the rocks. In fact, the argon in the magma may well be even higher, as it may concentrate near the top. For example, dates may be accepted even when there is evidence of weathering, and rejected when there is not. This would result in larger K-Ar ages lower down, but lower ages nearer the surface. Argon diffuses from mineral to mineral with great ease.

Now some rocks in the

Heating and deformation of rocks can cause these atoms to migrate, and water percolating through the rocks can transport these substances and redeposit them. These rocks were dated by a variety of different methods.

The issue is not just how well this was known in the past, but which value was actually used, and whether dates published in the past have been computed with the most recent value. Micas exclude strontium, so Rb-Sr dating can be used on micas to determine the length of time since the mica formed. He cites another reference that most igneous bodies have wide biostrategraphic limits. The same question could be asked in general of minerals that are thought to yield good dates.