Carbon dating and reliability melbournedatingguide com
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.Concerning the sequence of rings derived from the bristlecone pine, Ferguson says: In certain species of conifers, especially those at lower elevations or in southern latitudes, one season's growth increment may be composed of two or more flushes of growth, each of which may strongly resemble an annual ring.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.Radiocarbon dating can easily establish that humans have been on the earth for over twenty thousand years, at least twice as long as creationists are willing to allow.Therefore it should come as no surprise that creationists at the Institute for Creation Research (ICR) have been trying desperately to discredit this method for years.
Kieth and Anderson show considerable evidence that the mussels acquired much of their carbon from the limestone of the waters they lived in and from some very old humus as well.
Since the tree ring counts have reliably dated some specimens of wood all the way back to 6200 BC, one can check out the C-14 dates against the tree-ring-count dates.
Admittedly, this old wood comes from trees that have been dead for hundreds of years, but you don't have to have an 8,200-year-old bristlecone pine tree alive today to validly determine that sort of date.
However, in either case, the background beta radiation has to be compensated for, and, in the older objects, the amount of C-14 they have left is less than the margin of error in measuring background radiation. Question: Creationists such as Cook (1966) claim that cosmic radiation is now forming C-14 in the atmosphere about one and one-third times faster than it is decaying.
As Hurley points out: Without rather special developmental work, it is not generally practicable to measure ages in excess of about twenty thousand years, because the radioactivity of the carbon becomes so slight that it is difficult to get an accurate measurement above background radiation. 108) Cosmic rays form beta radiation all the time; this is the radiation that turns N-14 to C-14 in the first place. If we extrapolate backwards in time with the proper equations, we find that the earlier the historical period, the less C-14 the atmosphere had.
Question: A sample that is more than fifty thousand years old shouldn't have any measurable C-14. Radiocarbon dating doesn't work well on objects much older than twenty thousand years, because such objects have so little C-14 left that their beta radiation is swamped out by the background radiation of cosmic rays and potassium-40 (K-40) decay. this isotope [K-40] accounts for a large part of the normal background radiation that can be detected on the earth's surface" (p. This radiation cannot be totally eliminated from the laboratory, so one could probably get a "radiocarbon" date of fifty thousand years from a pure carbon-free piece of tin.