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Originally posted by blitz77:
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As proof of the unreliability of the radiometric methods consider the fact that in nearly every case dates from recent lava flows have come back excessively large. One example is the rocks from the Kaupelehu Flow, Hualalai Volcano in Hawaii which was known to have erupted in 1800-1801. These rocks were dated by a variety of different methods. Of 12 dates reported the youngest was 140 million years and the oldest was 2.96 billion years. The dates average 1.41 billion years.
--John G. Funkhouser and John J. Naughton, "Radiogenic Helium and Argon in Ultramafic Inclusions from Hawaii," Journal of Geophysical Research
This quote is a bit old, and some later datings give correct dates
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Thus the large majority of historic lava flows that have been studied either give correct ages, as expected, or have quantities of excess radiogenic 40Ar that would be insignificant in all but the youngest rocks. The 40Ar/39Ar technique, which is now used instead of K-Ar methods in most studies, has the capability of automatically detecting, and in many instances correcting for, the presence of excess 40Ar, should it be present.
--G. Brent Dalrymple
but it does illustrate the problems of radiometric dating.
Rubbish. Blitz, either you are being deceptive and misrepresentative or you are the victim of such actions. The Funkhousen and Naughton paper was published in 1968. Typical up-to-date creationist research! The purpose of the paper was to test the limitations of the K-Ar method and xenolyths were tested. These were expected to give dates much older than the solidified lava matrix and this is what was seen. So, the purpose of the paper has been misrepresented by creationists!
The inclusion of the Dalrymple quote is presumably from The Age of the Earth published in 1991. Surely it should be acknowledged that it provides a more recent, more comprehensive assessment of the issue than a single 1969 paper. Typical creationist tactic. Actually the quotes indicate that certain potential problems with radiometric dating need to be recognised and avoided. As with any testing method, if you don't know what you are doing then you can't trust your results. This is illustrated by the dating results which creationists produce.
[QUOTE][B]Situations for which we have both the carbon-14 and potassium-argon ages for the same event usually indicate that the potassium-argon `clock’ did not get set back to zero. Trees buried in an eruption of Mount Rangotito in the Auckland Bay area of New Zealand provide a prime example. The carbon-14 age of the buried trees is only 225 years, but some of the overlying volcanic material has a 465,000-year potassium-argon age.
[Harold Coffin, Origin by Design, page 400.]
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Not a lot of information in this quote. No reference to published research; could it be a creationist urban myth? Did Coffin do this research and publish it? He apparently is a geologist.
[QUOTE][B]A few years ago I took a course in the "Evolution of Desert Environments". We were standing on the Simi Volcanic flow, about 80 miles south of the south end of Death Valley. The instructor was a well known geologist and evolutionist from Cal. State Long Beach. He told us that the upper end of the flow was dated at 100,000 years, the middle of the flow was dated at 50,000 years, and the toe of the flow was dated at 20,000 years. He then noted that the whole flow probably occured and solidified (the surface at least) within weeks. He then said, based on his observation of the rates of evolution of desert environments he thought the flow was less than 10,000 years of age. He then said "radiometric dating is the cornerstone of modern historical geology and we get this kind of variation?" Clearly he was not happy with the published dates on the Simi flow.
He was also not happy with the published dates on the flows in the Nevada Atomic Bomb Test site where one of the volcanic flows showed a reversal of isotope ratios and gave a value of 20,000 years in the future! These data were, in fact, published in Science magazine in about November of 1988. Please note, these were not MY ideas but the statements of a convinced, tenured, evolutionary geologist who apparently really wanted to beleive in the credibility of radiometric dating. I am just reporting what HE said![/QUOTE]
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So this is a story from an unnamed friend of Plaisted (a Professor of Computer Science) about comments by an unnamed geologist. Well, that's convincing evidence! The anolomolous dates all look very young for radiometric dating. Could it be that they all fall within the experimental error range of the method employed?
I'm afraid the above examples of "problems" with radiometric dating are only convincing to those who want to believe in a young earth for fundamentalist religious reasons. Maybe this illustrates the point best:
During the Arkansas trial, Harold Coffin, a Creation Research Society member from Loma Linda University, was asked about the Burgess Shale fossil site, which has been dated to the early Cambrian period:
"Q: The Burgess Shale is said to be 500 million years old, but you think it is only 5,000 years old, don't you?
COFFIN: Yes.
Q: You say that because of information from the Scriptures, don't you?
COFFIN: Correct.
Q: If you didn't have the Bible, you could believe the age of the earth to be many millions of years, couldn't you?
COFFIN: Yes, without the Bible." (Trial transcript, McLean v Arkansas, cited in Berra, 1990, p. 135)
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