Radioactive dating problems and answers
Sr-86 diffuses more quickly than Sr-87, and that has never been taken into account when isochrons are analyzed. Perhaps, but it’s rather tricky, because the rate of diffusion depends on the specific chemical and physical environment of each individual rock.
If the effects of diffusion can be taken into account, it will require an elaborate model that will most certainly require elaborate assumptions. Hayes suggests a couple of other approaches that might work, but its not clear how well. If you believe the earth is very old, then most likely, all of the radioactive dates based on isochrons are probably overestimates. I have no idea, and I don’t think anyone else does, either. Hayes’s model indicates it could add as much as 29 billion years to ages determined with rubidium and strontium, although his model is rather simplistic.
As I have stated previously, we just don’t know a lot about radioactive decay.
Certainly not enough to justify the incredibly unscientific extrapolation necessary in an old-earth framework.
If some process brought Sr-87 into the rock, it probably brought different amounts of the atom into different parts of the rock, so the ratio of Sr-87 to Sr-86 won’t stay consistent from one part of the rock to another. He says that there is one process that has been overlooked in all these isochron analyses: diffusion.
If a consistent isochron is generated, however, we can be “certain” that no process interfered with the relative amounts of Rb-87 and Sr-87, so the radioactive date is a good one. Atoms and molecules naturally move around, and they do so in such as way as to even out their concentrations.
One way this is done in many radioactive dating techniques is to use an isochron. To understand the problem, let’s start with an example of how radioactive dating works. Sr-87 is not radioactive, so the change is permanent.
The elements rubidium and strontium are found in many rocks. As illustrated above, a neutron in a Rb-87 atom can eject an electron (often called a beta particle), which has a negative charge. We know how long it takes Rb-87 to turn into Sr-87, so in principle, if we analyze the amount of Rb-87 and Sr-87 in a rock, we should be able to tell how long the decay has been occurring.
This false notion is often promoted when radioactive dates are listed with utterly unrealistic error bars.
The amount of Sr-87 that was already in the rock when it formed, for example, should be proportional to the amount of Sr-86 that is currently there.
Since the data are divided by the amount of Sr-86, the initial amount of Sr-87 is cancelled out in the analysis.
It refers to one specific source of error – the uncertainty in the measurement of the amounts of various atoms used in the analysis.
Most likely, that is the least important source of error.