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Author Topic:   Dating Question For Members
dwise1
Member
Posts: 2049
Joined: 05-02-2006
Member Rating: 3.3


Message 16 of 77 (610177)
03-27-2011 11:39 AM
Reply to: Message 13 by Percy
03-27-2011 7:17 AM


OK, Law of Superposition. It was late and I had had a glass of wine. I've posted much worse before.
This message is a reply to:
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Replies to this message:
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Coyote
Member
Posts: 4530
Joined: 01-12-2008
Member Rating: 3.9


Message 17 of 77 (610178)
03-27-2011 11:42 AM
Reply to: Message 16 by dwise1
03-27-2011 11:39 AM


dwise1 writes:

OK, Law of Superposition. It was late and I had had a glass of wine. I've posted much worse before.

Have a bumper sticker on my truck:

Archaeologists Assume Superposition

Gets me strange looks sometimes...


This message is a reply to:
 Message 16 by dwise1, posted 03-27-2011 11:39 AM dwise1 has not yet responded

  
Coragyps
Member
Posts: 5050
From: Snyder, Texas, USA
Joined: 11-12-2002
Member Rating: 5.1


Message 18 of 77 (610179)
03-27-2011 11:44 AM
Reply to: Message 14 by Buzsaw
03-27-2011 9:46 AM


Re: Related Dating Questions
Over the millennia the leaf ceased to be and the sediment formed the fossil.

No, it didn't. Ground water containing dissolved minerals might have formed the fossil, if it was a replacement sort of fossilization event. Or surrounding sediments might have made a mold that preserved the shape of the leaf. But the anthill grains themselves didn't "form the fossil."

And in answer to your topic title: no, Buz, I won't go out with you. I'm a happily married man.


This message is a reply to:
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jar
Member
Posts: 24504
From: Texas!!
Joined: 04-20-2004


Message 19 of 77 (610181)
03-27-2011 11:51 AM
Reply to: Message 16 by dwise1
03-27-2011 11:39 AM


dwise1 writes:

OK, Law of Superposition. It was late and I had had a glass of wine. I've posted much worse before.

My supposition was that that was what you meant.


Anyone so limited that they can only spell a word one way is severely handicapped!
This message is a reply to:
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bluegenes
Member
Posts: 2800
From: U.K.
Joined: 01-24-2007


Message 20 of 77 (610182)
03-27-2011 12:11 PM
Reply to: Message 15 by JonF
03-27-2011 11:32 AM


Re: Related Dating Questions
JonF writes:

There are lots of scenarios and variations, but the bottom line is that most fossils are dated by radiometric dating of associated igneous layers, the association being established by various means.

You can probably tell us something about this, Jon. Apparently, there's a new way of using U-Pb dating directly on fossils themselves, which sounds very interesting to me.

Dating very late dinosaurs

From the article.

quote:

A laser beam unseats minute particles of the fossil, which then undergo isotopic analysis. This new technique not only allows the age of fossil bone to be determined but potentially can distinguish the type of food a dinosaur eats. Living bone contains very low levels of uranium but during fossilization (typically less than 1000 years after death) bone is enriched in elements like uranium. The uranium atoms in bone decay spontaneously to lead over time and once fossilization is complete the uranium-lead clock starts ticking. The isotopic composition of lead determined in the hadrosaur's femur bone is therefore a measure of its absolute age.

Could this improve accuracy all round from 1 Mya right back to the oldest fossils?


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 Message 15 by JonF, posted 03-27-2011 11:32 AM JonF has responded

Replies to this message:
 Message 27 by JonF, posted 03-27-2011 4:18 PM bluegenes has acknowledged this reply

  
Buzsaw
Member (Idle past 216 days)
Posts: 9158
From: new york usa
Joined: 03-14-2003


Message 21 of 77 (610184)
03-27-2011 1:26 PM
Reply to: Message 18 by Coragyps
03-27-2011 11:44 AM


Re: Related Dating Questions
Coragyps writes:

Over the millennia the leaf ceased to be and the sediment formed the fossil.

No, it didn't. Ground water containing dissolved minerals might have formed the fossil, if it was a replacement sort of fossilization event. Or surrounding sediments might have made a mold that preserved the shape of the leaf. But the anthill grains themselves didn't "form the fossil."

And in answer to your topic title: no, Buz, I won't go out with you. I'm a happily married man.

I'll rephrase my statement for clarification. After the leaf formed the sediment leaf mold, over the millennia the leaf mold fossilized so as to form the fossil,

I would assume that minerals or surrounding sediments would have dated older than the organism forming the fossil.

The question remains, why would the old minerals, sediment rock or whatever makes up the sediment date the time of the deposit of the leaf forming the fossil any more than the time of a present ant hill calculation by modern calculation for dating old rocks date the time the ant hill was made/deposited by the ants?

ABE: As to your title comment, the title date had nothing to do with either kind of dates one might eat.

Edited by Buzsaw, : No reason given.


BUZSAW B 4 U 2 C Y BUZ SAW.
The Immeasurable Present Eternally Extends the Infinite Past And Infinitely Consumes The Eternal Future.
This message is a reply to:
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Replies to this message:
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jar
Member
Posts: 24504
From: Texas!!
Joined: 04-20-2004


Message 22 of 77 (610185)
03-27-2011 1:54 PM
Reply to: Message 21 by Buzsaw
03-27-2011 1:26 PM


Re: Related Dating Questions
Buzsaw writes:

I would assume that minerals or surrounding sediments would have dated older than the organism forming the fossil.

Not quite.

You need to understand some basics.

First, in general, unless a formation has been disturbed, material above something is younger than material below something.


Anyone so limited that they can only spell a word one way is severely handicapped!
This message is a reply to:
 Message 21 by Buzsaw, posted 03-27-2011 1:26 PM Buzsaw has responded

Replies to this message:
 Message 23 by Percy, posted 03-27-2011 3:27 PM jar has acknowledged this reply
 Message 24 by Buzsaw, posted 03-27-2011 3:37 PM jar has responded

  
Percy
Member
Posts: 12821
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.3


Message 23 of 77 (610189)
03-27-2011 3:27 PM
Reply to: Message 22 by jar
03-27-2011 1:54 PM


Re: Related Dating Questions
I think that by "minerals or surrounding sediments" that Buz was referring to sediment deposited contemporaneously with the organism. He understands that the sedimentary material is particles broken down from older rock, so he's asking how you can date the organism if the sediments containing it are made up of much older material.

Of course, this question has already been answered at least several times in nearly identical ways by you and others. At one point JonF mentioned a method by which one might extract the date of sedimentation from the layer itself, see Message 15, but Buz didn't respond so that may not be the source of his confusion.

The trick in this thread won't be answering the question - that's already been done. The trick will be getting Buz to understand the answer.

--Percy


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Buzsaw
Member (Idle past 216 days)
Posts: 9158
From: new york usa
Joined: 03-14-2003


Message 24 of 77 (610190)
03-27-2011 3:37 PM
Reply to: Message 22 by jar
03-27-2011 1:54 PM


Re: Related Dating Questions
jar writes:

First, in general, unless a formation has been disturbed, material above something is younger than material below something.

That would, of course, be true assuming a relative uniformitarion hypothesis, but not necessarily from a catastrophic hypothesis.


BUZSAW B 4 U 2 C Y BUZ SAW.
The Immeasurable Present Eternally Extends the Infinite Past And Infinitely Consumes The Eternal Future.
This message is a reply to:
 Message 22 by jar, posted 03-27-2011 1:54 PM jar has responded

Replies to this message:
 Message 25 by jar, posted 03-27-2011 3:42 PM Buzsaw has responded
 Message 26 by subbie, posted 03-27-2011 3:43 PM Buzsaw has acknowledged this reply

  
jar
Member
Posts: 24504
From: Texas!!
Joined: 04-20-2004


Message 25 of 77 (610191)
03-27-2011 3:42 PM
Reply to: Message 24 by Buzsaw
03-27-2011 3:37 PM


Re: Related Dating Questions
Buzsaw writes:

jar writes:

First, in general, unless a formation has been disturbed, material above something is younger than material below something.

That would, of course, be true assuming a relative uniformitarion hypothesis, but not necessarily from a catastrophic hypothesis.

Did you read what I wrote?

We'll go slowly until you understand the basics.

Not quite.

You need to understand some basics.

First, in general, unless a formation has been disturbed, material above something is younger than material below something.

Is that clear?


Anyone so limited that they can only spell a word one way is severely handicapped!
This message is a reply to:
 Message 24 by Buzsaw, posted 03-27-2011 3:37 PM Buzsaw has responded

Replies to this message:
 Message 28 by Buzsaw, posted 03-27-2011 7:54 PM jar has responded

  
subbie
Member
Posts: 3316
Joined: 02-26-2006
Member Rating: 6.4


Message 26 of 77 (610192)
03-27-2011 3:43 PM
Reply to: Message 24 by Buzsaw
03-27-2011 3:37 PM


Re: Related Dating Questions
That would, of course, be true assuming a relative uniformitarion hypothesis, but not necessarily from a catastrophic hypothesis.

So under a "catastrophic hypothesis," something or someone is coming along and sliding newer material underneath already existing material?


Ridicule is the only weapon which can be used against unintelligible propositions. -- Thomas Jefferson

We see monsters where science shows us windmills. -- Phat

It has always struck me as odd that fundies devote so much time and effort into trying to find a naturalistic explanation for their mythical flood, while looking for magical explanations for things that actually happened. -- Dr. Adequate

...creationists have a great way to detect fraud and it doesn't take 8 or 40 years or even a scientific degree to spot the fraud--'if it disagrees with the bible then it is wrong'.... -- archaeologist


This message is a reply to:
 Message 24 by Buzsaw, posted 03-27-2011 3:37 PM Buzsaw has acknowledged this reply

  
JonF
Member
Posts: 2602
Joined: 06-23-2003
Member Rating: 3.7


Message 27 of 77 (610195)
03-27-2011 4:18 PM
Reply to: Message 20 by bluegenes
03-27-2011 12:11 PM


Re: Related Dating Questions
You can probably tell us something about this, Jon.

I'm not familiar with that particular technique, but it makes sense. Except for the "kind of food a dinosaur eats" bit. I don't see any way for that kind of information to be extracted.

There is all sorts of interesting work with U-Th disequilibrium dating. Uranium is somewhat soluble in water (deposition from groundwater is probably how the uranium gets into the dinosaur bones you mentioned). But thorium is very insoluble in water. So when the decay chain from uranium hits thorium, the thorium drops out of solution. But when the uranium starts building up in a solid such as a bone or coral or a stalactite or stalagmite, the thorium is trapped and starts building up. Since the half-life of the uranium is much much longer than thorium, eventually the thorium concentration reaches "secular equilibrium", in which the number of thorium atoms formed per unit time equals the number of thorium atoms decaying per unit time and the thorium concentration is constant. But you can date things that haven't reached that point yet by measuring how far away the thorium concentration is from secular equilibrium.

That was how they dated the Siloam tunnel in Jerusalem, getting a U-Th disequilibrium date for a stalactite and a 14C date for a leaf trapped in the plaster, which obviously bracketed the construction date.

But that's only good for about a million years at most.

Edited by Admin, : Fix superscript.


This message is a reply to:
 Message 20 by bluegenes, posted 03-27-2011 12:11 PM bluegenes has acknowledged this reply

  
Buzsaw
Member (Idle past 216 days)
Posts: 9158
From: new york usa
Joined: 03-14-2003


Message 28 of 77 (610196)
03-27-2011 7:54 PM
Reply to: Message 25 by jar
03-27-2011 3:42 PM


Re: Related Dating Questions
jar writes:

Buzsaw writes:

jar writes:

First, in general, unless a formation has been disturbed, material above something is younger than material below something.

That would, of course, be true assuming a relative uniformitarion hypothesis, but not necessarily from a catastrophic hypothesis.

Did you read what I wrote?

We'll go slowly until you understand the basics.

Not quite.

You need to understand some basics.

First, in general, unless a formation has been disturbed, material above something is younger than material below something.

Is that clear?

I understand this fully, Jar, but you seem to be ignoring what I wrote. Catastrophes disturb formations. No? Formations which are relatively suddenly created by catastrophes are disturbed formations. No?


BUZSAW B 4 U 2 C Y BUZ SAW.
The Immeasurable Present Eternally Extends the Infinite Past And Infinitely Consumes The Eternal Future.
This message is a reply to:
 Message 25 by jar, posted 03-27-2011 3:42 PM jar has responded

Replies to this message:
 Message 29 by jar, posted 03-27-2011 8:00 PM Buzsaw has responded
 Message 30 by Percy, posted 03-27-2011 8:35 PM Buzsaw has not yet responded

  
jar
Member
Posts: 24504
From: Texas!!
Joined: 04-20-2004


Message 29 of 77 (610197)
03-27-2011 8:00 PM
Reply to: Message 28 by Buzsaw
03-27-2011 7:54 PM


Re: Related Dating Questions
A catastrophe can disturb formations, and guess what, it also leaves evidence of the disturbance.

It can for example, overturn a formation, or tilt a formation, but those things are also taken into consideration.

BUT in the end, younger things are above older things.

Even when a catastrophe creates such a formation, it is the younger material on top of older material.


Anyone so limited that they can only spell a word one way is severely handicapped!
This message is a reply to:
 Message 28 by Buzsaw, posted 03-27-2011 7:54 PM Buzsaw has responded

Replies to this message:
 Message 31 by Buzsaw, posted 03-27-2011 9:13 PM jar has responded

  
Percy
Member
Posts: 12821
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.3


Message 30 of 77 (610198)
03-27-2011 8:35 PM
Reply to: Message 28 by Buzsaw
03-27-2011 7:54 PM


Re: Related Dating Questions
Buzsaw writes:

I understand this fully, Jar, but you seem to be ignoring what I wrote. Catastrophes disturb formations. No? Formations which are relatively suddenly created by catastrophes are disturbed formations. No?

Obviously as sedimentary layers form, the newest layers are always on top. This is how things always start, with newer layers atop older layers. The layers start out like this:

Layer 5
Layer 4
Layer 3
Layer 2
Layer 1

Now you're proposing that some catastrophe might come along and leave the layers in some other order. For the sake of discussion I'll assume inverted order, like this:

Layer 1
Layer 2
Layer 3
Layer 4
Layer 5

Though the majority of geological formations have not experienced this kind of topsy-turvy past, we do find inverted formations like this in many places around the world, but turning trillions of tons of rock upside down leaves a lot of evidence behind. What kind of tectonic process or even catastrophe are you imagining that could do this without leaving any evidence behind?

And more importantly, what has this got to do with your original question?

--Percy


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