Posted by Wendel Swan on June 23, 1999 at 06:34:48:
In Reply to: Re: Sources of error in Carbon-14 dating? posted by Steve Price on June 22, 1999 at 20:22:39:
Dear Steve,
Nearly all living organisms absorb C-14 from the atmosphere in such a manner that there is a direct correlation between atmospheric C-14 and the amount in the organism. Radiocarbon dating measures the decay of C-14 following the death of the organism.
One difficulty in the calibration of the rate of decay is that atmospheric C-14 has not, and does not, remain absolutely constant. Hence, a line illustrating the decay will appear as a slope with irregular spikes - particularly for relatively recent periods.
During the testing process, measurement of beta radiation from the organism is within certain tolerances. If you visualize those tolerances as two parallel, horizontal lines which intersect the jagged slope of the decay, you will find that there could be several points of intersection - depending on whether the organism lived during a period when atmospheric C-14 remained constant or during a period of these spikes.
The various dates and variables which you read are verbalizations of the graph of the measurement and the decay. It isn't easy to understand. In April, Jurg Rageth spent about 2 hours explaining it to me.
Regards,
Wendel