Re: [coCBanned] Re: Radiometric dating
- DW here,
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>>David:What this data fails to show is what is the RANGE of dates obtained/reported (which SHOULD contain all the "bad" dates too!). For instance if Allende got dates from 8 samples and they had a range of 2by to 16by, but they averaged to 4.5by, then that isn't much testimony for the accuracy/consistency of the radio dates they got.
What I presented was a summary of the data, as I stated. David should have gone to the link.
The last number provided for each of the samples IS the range. For example, the Allende meteorite had 8 samples tested by Ar-Ar. The youngest age was 4.48 billion years and the oldest was 4.57. Guarena had 14 samples using Ar-Ar and Rb-Sr with the youngest being 4.44 billion years and the oldest 4.46.... and so on. The link to T-O provides the individual ages of many of these tests. For example, each of the 8 Allende reports is listed.
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I DID go to the T-O site. My point is that another source (which footnoted the primary source...which I could not check) indicated that OTHER methods besides Ar-Ar were used on Allende and those other sources had a WIDE range. It is totally BOGUS to use just one method (Ar-Ar) and imply that there is a narrow range from radiometric dating, when the OTHER methods disagree so much!
So you have nothing specific.
Let me help. Go to scirus.com and search for "allende meteorite age." I got nearly 1200 hits. Better, here's a link:
Discusses problems with the Ar-Ar dating.
The second hit ( http://geosci.uchicago.edu/~grossman/G80AR.pdf ) is a 51 page paper (of which 7 pages are bibliography). In that source, there is a likely answer to your problem. Allende is a carbonaceous chrondite. This means it's structured like a sedimentary rock composed of particles from a variety of sources. It's entirely possible, even likely, the particulate would have a wide variety of ages.
The paper also lists results of various other radioisotopes beginning on page 41. The commentary about Rb-Sr doesn't indicate an age, but states the material tests "identifies the inclusions as the oldest known solids in the solar system." There are 11 dates all in the neighborhood of 4.5 billion years mentioned in the section on U-Th-Pb. There is also a discussion of "extinct" isotopes such as Al26, Sm146, Pu244, and I129.
States: "The initial 182Hf/180Hf of CAIs corresponds to an absolute age of 4568.3 ± 0.7 Ma, which may be defined as the age of the solar system. This age is 0.5–2 Myr older than the most precise 207Pb–206Pb age of Efremovka CAI 60"
Mentions substantial uncertainties in the ages that were previously determined by lead-lead dating.
That should be enough......
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>>David:A source I have indicates that is exactly the case. And that doesn't even count any "bad" dates they tossed out.
Good... then I'm sure you won't mind presenting the information. I'd be especially interested in the information about the "bad" dates. Things like who reported them, what the reported age was, and why it was rejected.
My first bet is we know about them because they were reported by the researchers. Even my 9th graders are instructed to report what they see and they can deal with the unexpected observations in the analysis and conclusions part of their lab reports.>>
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I didn't mean that I saw "bad" dates in the data. I meant that it is likely (based on what some non-YE's have said about how they handle "anomolous" results) that even WORSE discordant data was returned but NOT reported...but the reported ones have very WIDE ranges.
Hearsay. Notice, of the first four references I found, two were discussing dating problems. So, it's not like there's some kind of big cover-up going on.
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>>David:That source also indicates Allende was dated by several other methods besides Ar-Ar.
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Then why did you (or T-O) present only the Ar-Ar method...and ignore the others?
You'll need to ask T-O. I ignored nothing.
IF radiometric dating is SOOOOO great...such that it causes you to dismiss SOOOOO many other YE arguments....then the methods all should be very close in agreement almost all the time.
Well, we now have an additional dozen or more tests using another 3 isotopes all in the range of 4.5 billion years.... and I haven't even looked hard.
Further, I remind you radiometric dating isn't the reason I dismiss SOOOOOOO many YEC arguments.... it's astronomy.
Ad hoc attempts to explain away the discordant data when there is no basis to do so should NOT be accepted as a substitute for data that is in agreement.
I absolutely agree. Let me know when you have something more than innuendo, rumor, and hearsay to substantiate your claim.
##### Pi (previously) #####
>>I never said it was an exhaustive list of all the tests that were done on any of these meteorites There are a LOT of articles out there on each of these objects.David:
Fine. Then address the problem I've brought up.
Done. I've found more tests using different isotopes and they still are in the same range. I've also found articles discussing problems with the dates obtained.
The various methods which measure the SAME rock unit (or meteorite) SHOULD agree, but they don't.
Unsupported assertion. The documentation shows the ages for various methods DO agree.
If all they do is say "these rocks are really OLD" but the range is all over the map, then that is NOT good grounds to say that YE is disproved by radiometric dating.
Seems all someone is doing is saying "the range is all over the map" .... but he doesn't seem to have anything more substantive than rumor, innuendo, hearsay, and (unsupported) assertions.
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