>Since there are no trees that have 10,000 continuous rings, I would be
>willing to bet that there is some tautological analysis involved in that
>extrapolation. Although the picture of tree ring variation appears to be
>pretty well closed for about 4000 years, I wouldn't stake my life on dates
>older than that. Brown has done some interesting analysis on trends older
>than 4000 years that is revealing.
But there are more than 10,000 successive varves each with organic material
which can be dated. The comparison of varve count vs C14 age is pretty good.
"The good agreement between both counts indicates an error of
only a few percent in the varve counting. The varve C14 ages
generally agree within about 100 years with the varve counts when
corrected for atmospheric C14deviations known from the tree ring
chronolgoy. Evidently the varves are annual over at least a
7400-year interval."~Minze Stuiver, "Evidence for the Variation
of Atmospheric C14 Content in the Late Quaternary," in Karl K.
Turekian, editor, The Late Cenozoic Glacial Ages, (New Haven:
Yale University Press, 1971), p. 62.
Lake of the clouds Minnesota varve record
count C14
842 1120+/-90
1479 1750 +/-70
2298 2660+/-100
2942 3270+/-80
3525 3570+/-70
4232 4250+/-80
4960 4730+/-70
5515 5300+/-70
5877 5650+/-100
6283 6080+/-70
6658 6490+/-70
7001 6640+/-80
7150 6850+/-90
7290 7020+/-80
7464 7280+/-80
7696 7570+/-80
7924 7720+/-80
8269 8240+/-80
8430 8260+/-80
8577 8420+/-70
8735 8530+/-100
8894 8600+/-80
9040 8750+/-100
9180 8960+/-80
9270 9100+/-100
9471 9080+/-100
9671 9070+/-100
9867 9430+/-100
10034 9600+/-100
10200 9830+/-110
glenn
Adam, Apes, and Anthropology: Finding the Soul of Fossil Man
and
Foundation, Fall and Flood
http://www.isource.net/~grmorton/dmd.htm