> This process of conversion and decay will, after time, reach
> equilibrium. There is very good evidence that we have been in
> this equilibrium position for at least several thousand years (10
> to 20,000 years at least), and probably much longer.
My understanding of the empirical data is that the 14C reservoir
is NOT in equilibrium. The problem of non-equilibrium was noted by
Libby in his book on 14C dating, and subsequent research has
confirmed the discrepancy is real. The definitive study was
undertaken by Ramart, R. and Lingenfelter, R.E. in 1970.
"Astrophysical and geophysical variations in C-14 production" in
*Radiocarbon variations and absolute chronology* (ed Olsson, I.U.).
John Wiley and Sons, pp. 513-537.
The most promising explanation of non-equilibrium seemed to be
the irretrievable loss of carbon by sedimentation on to the ocean
floors. However, this appears to be too small by a factor of 10 to
explain the observations.
To my knowledge, this research has not developed, because more
emphasis has been given to the calibration of radiocarbon dates using
archaeological samples and, even more important, dendrochronological
samples. 'If the dates can be calibrated, what does it matter about
the generation and decay rates of 14C?'
So, I am suggesting that, to the best of our knowledge, the 14C
system is NOT in equilibrium, but the ability to calibrate dates
against samples of known age means that people do not need to explain
the situation. If this assessment is incorrect, I would appreciate
an update from Steve.
> I am sad to say that I have not yet
> found any evidence at all that the earth is young, and I have
> looked. Kurt Wise and I once had a rather heated debate about
> 14C right here within this group and in the end I think that it
> was found that there was no evidence that 14C could be used to
> set a limit on the age the creation.
Non-equilibrium does not allow an estimate to be put on the age
of the earth - but it does suggest that something rather drastic has
happened to the earth in the not too distant past. This is the kind
of evidence that can be developed by catastrophists. Of necessity
though, it does require an alternative approach to calibration -
which means revision of the chronology of the ancient world and of
the dendrochronological data.
Best wishes,
*** From David J. Tyler, CDT Department, Hollings Faculty,
Manchester Metropolitan University, UK.
Telephone: 0161-247-2636 ***