Why is carbon dating inaccurate after 50000 years
However, the amount of C-14 has not been rising steadily as Cook maintains; instead, it has fluctuated up and down over the past ten thousand years. From radiocarbon dates taken from bristlecone pines.There are two ways of dating wood from bristlecone pines: one can count rings or one can radiocarbon-date the wood.If we extrapolate as far back as ten thousand years ago, we find the atmosphere would not have had any C-14 in it at all.If they are right, this means all C-14 ages greater than two or three thousand years need to be lowered drastically and that the earth can be no older than ten thousand years. Answer: Yes, Cook is right that C-14 is forming today faster than it's decaying.Question: But don't trees sometimes produce more than one growth ring per year? Answer: If anything, the tree-ring sequence suffers far more from missing rings than from double rings.This means that the tree-ring dates would be slightly too young, not too old.
Such multiple growth rings are extremely rare in bristlecone pines, however, and they are especially infrequent at the elevation and latitude (37� 20' N) of the sites being studied.
Even so, the missing rings are a far more serious problem than any double rings.
Other species of trees corroborate the work that Ferguson did with bristlecone pines.
Of course, species of tree tend to produce two or more growth rings per year.
But other species produce scarcely any extra rings.
Carbon from these sources is very low in C-14 because these sources are so old and have not been mixed with fresh carbon from the air.