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Author Topic:   Potassium-Argon Dating
crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 13 of 22 (186303)
02-17-2005 5:02 PM
Reply to: Message 12 by techristian
02-17-2005 4:56 PM


Re: Mount st. Helens lava rock over 300,000 with a/p dating
Did those samples contain xenoliths?
And why do I find your claim that this "just happened" rather suspect, since K-Ar dating hasn't been widely used since the 70's? Did they do 40Ar/39Ar dating to eliminate test errors from nonradiogenic argon? If not, why not? Since that's the most commonly used procedure for dating rocks these days?
Why would they date them at all, come to think of it? I mean, if you wanted to know how old some lava at St. Helens was, why wouldn't you just look up the date of the eruption? Why bother with an expensive procedure that is rarely used nowadays?
There's a lot of obvious questions here that you do not address. Why is that?

This message is a reply to:
 Message 12 by techristian, posted 02-17-2005 4:56 PM techristian has replied

Replies to this message:
 Message 14 by techristian, posted 02-17-2005 5:04 PM crashfrog has replied
 Message 18 by JonF, posted 02-17-2005 5:23 PM crashfrog has replied

  
crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 17 of 22 (186313)
02-17-2005 5:20 PM
Reply to: Message 14 by techristian
02-17-2005 5:04 PM


Re: Mount st. Helens lava rock over 300,000 with a/p dating
Now that I think about it, WHY DO I NEED TO KNOW THE MECHANICS OF THE DATING PROCESS ANYWAY?
Because it's possible, as the group in your example did, to cast fradulent suspicion on a test procedure by tricking them into performing the test on a sample it's not meant to test.
If you send in cat piss for drug testing, and you get funny results, can you use that to overturn your marijuana conviction? Of course not. Human drug tests work on human urine. When you send them samples that they're not designed to test - like rocks with xenoliths, or with known nonradiogenic argon composition - it's no surprise you get wrong results.
But that's not the test's fault.
If I sent a rock sample to the "best" lab for dating, their results should show the date for the sample in question, or mankinds best attempt to date.
Why? Not all tests can be applied to all samples. Your guys applied the wrong test to the sample. What a surprise, since they've been doing that for years in a fraudulent effort to discredit a procedure not used all that often anymore.

This message is a reply to:
 Message 14 by techristian, posted 02-17-2005 5:04 PM techristian has not replied

  
crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 21 of 22 (186317)
02-17-2005 5:27 PM
Reply to: Message 18 by JonF
02-17-2005 5:23 PM


Re: Mount st. Helens lava rock over 300,000 with a/p dating
The most commonly used procedure these days, over 50% of the cases, is U-Pb concordia-discordia dating, for several reasons. Ar-Ar is widely used but may suffer a decline in usage; new regulations for handling irradiated material post-9/11 make it more cumbersome and expensive.
Good to know.

This message is a reply to:
 Message 18 by JonF, posted 02-17-2005 5:23 PM JonF has replied

Replies to this message:
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