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Author Topic:   Is Radiometric Dating Really that Accurate?
Thunderbird
Inactive Member


Message 21 of 114 (15947)
08-22-2002 7:08 PM


Hi, I am interested in discussing the topic of radiometric dating.

I think that the current potassium-argon radioisotope dating method
for igneous rocks is inaccurate because it has been tested on rocks
that are known to be young since they have been observed to formed
recently by active volcanos, such as at Mount Saint Helens and in
New Zealand.

Applying this dating method to these rocks resulted in very high
numbers for these rocks ranging from 340,000 to 2.8 Million years.


Replies to this message:
 Message 22 by gene90, posted 08-22-2002 8:08 PM Thunderbird has responded
 Message 23 by wj, posted 08-22-2002 9:50 PM Thunderbird has not yet responded

  
Thunderbird
Inactive Member


Message 24 of 114 (15981)
08-23-2002 1:53 AM
Reply to: Message 22 by gene90
08-22-2002 8:08 PM


[QUOTE]Originally posted by gene90:
[B]Who did the analysis and what methodology was used? In lava flows you can find xenoliths--fragments of rock from deep underground that are carried with the lava and so are much older than the flow.
[/QUOTE]

The analysis was done by Dr. Steve Austin. At this point, I
have no reason to believe, he or Snelling are fraudulent, since
I've not read of the reasons this claim is being made.

It was not established that xenoliths were captured by his sample. He took steps to prevent them from being used by manually selecting
rocks that didn't appear to be xenoliths and checking the rocks
under the microscope for microscopic xenoliths.

quote:

YECs can make radiometric dating fail by doing such things as sampling xenoliths and taking only one data point, or discarding several datapoints for one spurious, irreproducible one.


Austin reported on 5 different samples that were sent to the lab
for the Potassium-Argon dating. He didn't say whether other samples
were omitted from his article. The article doesn't state whether
multiple datapoints were provided for each of the samples. Why
wouldn't the lab give produced one number based on the potassium-argon ratios for the entirety of each sample?

I would have no way of knowing if he intentionally selected xenoliths or discarded datapoints. What reason is there to
believe that accusation?

quote:

Another problem with dating such recent flows is that the margin of error commonly is within a couple of million of years. If a flow is 100 million years old, and gives a radiometric age of 102 MY then that error is perfectly reasonable. But if a flow that happened yesterday gives 2 MY, YECs cry foul. It's really a silly argument when taken in the correct context.


I'm not sure if this is a silly argument. The young rocks are exhibiting a very old age because they have argon in them. A small
ratio of argon to potassium would result in a very large age because
of the long half life of potassium. Therefore this method is
susceptible to inaccuracy if small amounts of additional Argon
are present. The error is dependent on the amount or ratio of
additional Argon present.

The young rock should not have a small amount of Argon in it. Instead, it should have next to nil or a trace amount in order for the method to be accurate.

[This message has been edited by gene90, 08-22-2002][/B][/QUOTE]


This message is a reply to:
 Message 22 by gene90, posted 08-22-2002 8:08 PM gene90 has responded

Replies to this message:
 Message 25 by wj, posted 08-23-2002 6:46 AM Thunderbird has not yet responded
 Message 26 by Joe Meert, posted 08-23-2002 7:32 AM Thunderbird has not yet responded
 Message 27 by edge, posted 08-23-2002 4:13 PM Thunderbird has responded
 Message 32 by gene90, posted 08-26-2002 9:26 PM Thunderbird has not yet responded

  
Thunderbird
Inactive Member


Message 28 of 114 (16008)
08-23-2002 10:12 PM
Reply to: Message 27 by edge
08-23-2002 4:13 PM


quote:
Originally posted by edge:
[B]
quote:
Originally posted by Thunderbird:
The analysis was done by Dr. Steve Austin. At this point, I
have no reason to believe, he or Snelling are fraudulent, since
I've not read of the reasons this claim is being made.

Ah, but we do have evidence that Steve Austin has committed fraud. Read this reference, specifically the Introductory Lecture.

http://www.talkorigins.org/faqs/icr-visit/bartelt1.html

[/QUOTE]

I didn't see any evidence of fraud in the lecture. Fraud implies
that he intended to deceive. His interpretation of geological
data may have been disputed, but that doesn't constitute fraud.

quote:

quote:
It was not established that xenoliths were captured by his sample. He took steps to prevent them from being used by manually selecting rocks that didn't appear to be xenoliths and checking the rocks under the microscope for microscopic xenoliths.

But, if someone's agenda is to 'prove' that radiometric dating was invalid, would you trust them to do the sampling? You should learn to critically analyze your sources.


I don't think you can assume that someones viewpoint makes them
untrustworthy or imcomptent and that they would intentionally
decieve people by collecting deceptive samples.

The very purpose of the Austin experiment was to look at the
K-Ar dating method in a critical light and to examine
this question; Is this method accurate?

The method is based on a scientific principle, but also there
are assumptions made so it probably makes since to calibrate
the method to rocks of a known historical age and that was
the reason for testing the young rocks.

Austin also references a 1969 Dalrymple study that shows inaccurate
results for rocks at historically active volcanos.

The method has been shown to inaccurate. If the K-Ar method doesn't work or is unreliable on rocks of a known age, then why go ahead and use it on rocks on a unknown age.

Recently, a new argon method is being used. If scientists are replacing K-Ar method that suggests it is no longer accepted as accurate. What then happens to the all data that resulted from
previous K-Ar calculations? Will it be revised to reflect a newer
method?

[QUOTE]

quote:
The young rock should not have a small amount of Argon in it.

Why not? Should they also not have small amounts of fluorine? Do you really understand geochemistry and radiometric dating?

quote:
Instead, it should have next to nil or a trace amount in order for the method to be accurate.

Not at all. Sometimes it is possible to measure the original content of the sample. In other methods, the actual amount of daughter nuclides does not affect the date. In others, it is a safe assumption that there was no daughter in the sample at the time of formation. [/B]


The point is that Austin was testing a method that makes the assumption that these igneous rocks didn't have any Argon in them.
That is what was assumed in the formula by others who used the
K-Ar method.


This message is a reply to:
 Message 27 by edge, posted 08-23-2002 4:13 PM edge has responded

Replies to this message:
 Message 29 by John, posted 08-24-2002 12:06 AM Thunderbird has not yet responded
 Message 30 by edge, posted 08-24-2002 1:40 AM Thunderbird has not yet responded

  
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