I want to revisit radiocarbon years.
If articles written for laypeople indescriminately mix radiocarbon and calendar years without making clear which is which, then rampant confusion can result, and according to Scientific American, this occasionally happens:
The distinction between radiocarbon years and calendar years is important. A report earlier this year described a 13,000-year-old skeleton found in California and compared it to 12,500-year-old Monte Verde, without mentioning that the former date was in calendar years and the latter, radiocarbon years. Some readers understandably thought that the California skeleton was older than the campsite at Monte Verde. But in calendar years, Monte Verde is 14,700 years old. (Scientific American, September, 2000, Error – Scientific American - it includes a conversion table)
When writing your book I assume you didn't just throw up your hands and say, "Radiocarbon years, calendar years, who knows?" You took the time to investigate and you compared calendar years to calendar years or radiocarbon years to radiocarbon years, and you therefore know that by the most recent estimates you have a gap of some thousands of years between the end of the ice age and the estimate for the Black Sea flood postulated by Ryan and Pitman.
wmscott writes:
Dates from scientific dating methods are approximate, frequently given with a error range of plus or minus so many years with a 90% estimate that the time the event actually occurred at falls inside of that range. This is why the month or the day of the week that the event happened on is not also given, the dating systems are not that precise. Even with a good date with a 90% reliability, it is still acknowledged there is an estimated 10% chance that the date is in error, and that is not even allowing for other errors such as contamination.
Experimental error is understood, but three points. First, radiocarbon researchers have not been sitting on their hands since Gwen Schultz wrote
Ice Age Lost in 1974, which seems to be where your impressions of the efficacy of radiocarbon dating originates. If you visit
The Oxford Radiocarbon Accelerator Unit website and click on
Radiocarbon in the sidebar you'll read about the tight calibration back 11,000 years that's been achieved using tree ring data.
Second, radiocarbon error is coming to be reported in the manner you describe, ie, a range with a confidence factor, though the Oxford unit provides a 95% value, not 90%. But you would be wrong to conclude that there's a 5% chance dates are off by the thousands of years required for your theory that the Black Sea flood was caused by the end of the Wisconsian ice age.
Three, the confidence factor increases dramatically as you make more measurements, and the number of dated samples relevant to the end of the last ice age must be very large by now. While researching this post I found no mention of a trend toward lower dates.
Your Gwen Shultz quote is an honest assessment of the uncertainty of dating techniques in 1974, but while it's a caution to be conservative she's optimistic about the future because she goes on to say, "It can be foreseen, though, that as absolute-dating techniques are perfected they will reveal enlightening and startling results."
And this is just what has happened.
You also cut her short with your quote, "Will the trend someday change, shrinking the tape measure, requiring us to shorten our time scale?" While she bemoans the search for antiquity being reduced to a contest to find the oldest, she balances her comments by continuing, "Or are we in for still more staggering surprises about the antiquity of our world and the age of its people?"
--Percy
[This message has been edited by Percipient, 01-12-2002]
™ Version 4.2