Willowtree,
Apologies to those who’ve seen the bulk of this before. It deals with four radiometric dating methods dating K-T tektites that corroborate a 65 m.y. age, & the implications of rationale & reason, with respect to maintaining a YEC 6,000 year old earth world view, based on the odds involved.
http://www.ncseweb.org/.../...radiometeric_dating_does_work...{Shortened display form of URL, to restore page width to normal - AM}
The K-T Tektites
One of the most exciting and important scientific findings in decades was the 1980 discovery that a large asteroid, about 10 kilometers diameter, struck the earth at the end of the Cretaceous Period. The collision threw many tons of debris into the atmosphere and possibly led to the extinction of the dinosaurs and many other life forms. The fallout from this enormous impact, including shocked quartz and high concentrations of the element iridium, has been found in sedimentary rocks at more than 100 locations worldwide at the precise stratigraphic location of the Cretaceous-Tertiary (K-T) boundary (Alvarez and Asaro 1990; Alvarez 1998). We now know that the impact site is located on the Yucatan Peninsula. Measuring the age of this impact event independently of the stratigraphic evidence is an obvious test for radiometric methods, and a number of scientists in laboratories around the world set to work.
In addition to shocked quartz grains and high concentrations of iridium, the K-T impact produced tektites, which are small glass spherules that form from rock that is instantaneously melted by a large impact. The K-T tektites were ejected into the atmosphere and deposited some distance away. Tektites are easily recognizable and form in no other way, so the discovery of a sedimentary bed (the Beloc Formation) in Haiti that contained tektites and that, from fossil evidence, coincided with the K-T boundary provided an obvious candidate for dating. Scientists from the US Geological Survey were the first to obtain radiometric ages for the tektites and laboratories in Berkeley, Stanford, Canada, and France soon followed suit. The results from all of the laboratories were remarkably consistent with the measured ages ranging only from 64.4 to 65.1 Ma (Table 2). Similar tektites were also found in Mexico, and the Berkeley lab found that they were the same age as the Haiti tektites.
But the story doesn’t end there.
The K-T boundary is recorded in numerous sedimentary beds around the world. The Z-coal, the Ferris coal, and the Nevis coal in Montana and Saskatchewan all occur immediately above the K-T boundary. Numerous thin beds of volcanic ash occur within these coals just centimetres above the K-T boundary, and some of these ash beds contain minerals that can be dated radiometrically. Ash beds from each of these coals have been dated by 40Ar/39Ar, K-Ar, Rb-Sr, and U-Pb methods in several laboratories in the US and Canada. Since both the ash beds and the tektites occur either at or very near the K-T boundary, as determined by diagnostic fossils, the tektites and the ash beds should be very nearly the same age, and they are (Table 2).
There are several important things to note about these results. First, the Cretaceous and Tertiary periods were defined by geologists in the early 1800s. The boundary between these periods (the K-T boundary) is marked by an abrupt change in fossils found in sedimentary rocks worldwide. Its exact location in the stratigraphic column at any locality has nothing to do with radiometric dating it is located by careful study of the fossils and the rocks that contain them, and nothing more. Second, the radiometric age measurements, 187 of them, were made on 3 different minerals and on glass by 3 distinctly different dating methods (K-Ar and 40Ar/39Ar are technical variations that use the same parent-daughter decay scheme), each involving different elements with different half-lives. Furthermore, the dating was done in 6 different laboratories and the materials were collected from 5 different locations in the Western Hemisphere. And yet the results are the same within analytical error. If radiometric dating didn’t work then such beautifully consistent results would not be possible.
1/
So the K-T Tektites were dated by no less than four methods that corroborate. 40Ar/39Ar, K-Ar, Rb-Sr, and U-Pb . If that weren't evidence enough, lets take a look at how inaccurate they all must be, to fit a YEC worldview. The lower age given is 64.4 mya. Now, assuming a 6,000 year old YEC earth is what YECs perceive as 100% of available time, then 60 years is 1%. This means that all the above methods, were ALL (1,085,000-100 = ) 1,084,900% inaccurate. Let me reiterate, the YECs requires these FOUR different, corroborating methods to be over ONE MILLION PERCENT INACCURATE all at the same time!!
Now, given that the four methods are different, & are subject to DIFFERENT potential error sources & yet still corroborate closely means that the various potential bugbears of each method have been reasonably accounted for in the date calculations themselves.
2/
The range of dates is from 64.4 mya to 65.1 mya giving a 0.7 my range.
64.4/0.7 = 92 (Not taking the 65.1 m.y. figure to be as favourable as possible to YEC's)
The range of error is 92 times smaller than the minimum given date, giving us usable increments of time. Probabilistically speaking, we basically have four 92 sided dice. What are the odds of all four dice rolling a 92? On the familiar 6 sided die, the chance of rolling two sixes (or any two numbers, for that matter) is 6^2 = 36:1 (Number of sides to the nth power where nth = number of die).
Therefore, the odds of four radiometric dating methods reaching the same date range by chance is..drum roll..
92^4 (92*92*92*92)= 71,639,296:1
Is there any YEC that is prepared to state that the four radiometric dating methods achieve their high level of corroboration by pure chance?
If not, how much of the 65 m.y. old figure do you attribute to chance, & how much to radiometric half lives contributing to the derived date, percentage wise?
Here is your dilemma. The error required by the radiometric methods are 1,084,900% to fit a YEC 6,000 year old view. If they accept that the methods are capable of not being in error by more than 1,084,000%, then they accept a 60,000 year old earth, minimum. So, saying that half lives contribute only 1% to any derived radiometric date, means in this case (1% of 65,000,000 is 650,000 years), so even this small contribution by half lives falsifies a YEC young earth.
3/
The chance of all four methods being off by (chance) 64,400,000 years when the result SHOULD have been 6,000 years is truly staggering.
64,400,000/6,000 = 10,733.33 recurring (following the previous example, we now have four 10,733.33 sided dice)
10,733.33 recurring ^4 = 13,272,064,019,753,086:1
My questions to Willowtree are;
A/ How do you account for four corroborating radiometric dating methods dating the tektites so closely at 65 m.y. old, given the odds of it occurring by pure chance?
B/ IF you don’t accept that radiometric dating is valid as a dating method, how do you account for the four methods being over one million percent inaccurate, relative to a YEC assumed 6,000 year old earth?
C/ If you DO accept that half lives affect the resultant date, even to a small degree, what percentage would you be prepared to accept that radiometric dating is influenced by half lives, the rest being just plain chance? And how do you come by this figure, evidentially?
D/ How do you rationalise the odds of all four radiometric methods being wrong by a factor of 10,733 each, when the odds of such an occurrence is 13,272,064,019,753,086:1 of them being wrong by the same factor?
This is why radiometric dating is deemed as being pretty solid, despite the odd hiccup. The correlation between dating methods shows them to be accurate to within a couple of percent beyond all
reasonable doubt. In order to logically & evidentially contradict the conclusion that the K-T tektites are ~65 myo, you will need to provide 71 million radiometric dating studies that contradict said conclusion. Such is the power of corroborating evidences.
Mark
This message has been edited by mark24, 10-28-2004 09:39 AM
This message has been edited by Adminnemooseus, 10-28-2004 10:57 AM
There are 10 kinds of people in this world; those that understand binary, & those that don't
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