This is always being improved upon and multiple dates from different methods are sought whenever possible so there are tens of thousands of comparisons. They also provide a good example study (under the title a good example) which compares several methods for dating the K-T boundary and yields an error of about ~1 million years between them .Beware of older studies (1970's or older) which can have much larger error bars.Of the 26 lava flows that were sampled and analyzed, 18 of them gave expected results. Eight rocks yielded unrealistic dates, which were either too old because of the presence of excess 40Ar (5 of them) or too young (negative ages) because of the presence of excess 36Ar (3 of them). The details on the 8 anomalous samples are listed in Table 2 of Dalrymple (1969, p. The one case that would have produced a significant error, the Hualalai flow in Hawaii, was expected (see the previous essay). Naughton, 1968, 'Radiogenic Helium and Argon in Ultramafic Inclusions from Hawaii,' J. Even that significant error is only 1.19 million years (and not the 1.60 million years that Snelling claimed). Harrison, 1999, Geochronology and Thermochronology by the 40Ar/39Ar Method, Oxford University Press, New York."For the time will come when they will not endure sound doctrine; but after their own lusts shall they heap to themselves teachers, having itching ears; And they shall turn away their ears from the truth, and shall be turned unto fables." 2 Timothy 4:3-4 In "The Carbon Dating Game," we covered flaws, assumptions, and cherry-picking in dating methods that are said to be used for up to 50,000 years, which many evolutionists still use to say the dates of the Bible incorrect.
Indeed, if Dalrymple’s data is representative, 3 times out of 26 the K-Ar method will give a too young date (though by only an extremely trivial amount for a rock that is really millions of years old). Rather than checking the accuracy and relevancy of Austin's quotations from Dalrymple (1969), Snelling and Swenson simply uncritically parroted and perpetuated Austin's mistakes in their later web essays. This is truly a case of the blind leading the blind!! B., 1969, '40Ar/36Ar Analyses of Historic Lava Flows,' Earth Planet. As further discussed in Dalrymple and Lanphere (1969, p. 91-92), Dalrymple concludes that excess argon is rare in volcanic rocks. B., 1991, The Age of the Earth, Stanford University Press, Stanford, California, USA. In addition, excess argon is even less of a problem with Ar-Ar dating, where excess argon can often be distinguished from radiogenic argon and its effects eliminated (Mc Dougall and Harrison, 1999, p. , Snelling failed to properly quote the 'apparent K-Ar dates' from Table 2 in Dalrymple (1969, p. That is, Snelling mistakenly listed the concentrations of 40Ar (in 10 to the -12 moles/gram) for the Hualalai, Mt. Lassen, and Sunset Crater samples as their apparent K-Ar dates!! A good general rule for modern studies is expect a date to vary by ±5%.