Dating Question For Members

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:

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Archaeologists Assume Superposition

Gets me strange looks sometimes...

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.

My supposition was that that was what you meant.

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Anyone so limited that they can only spell a word one way is severely handicapped!

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 dinosaursFrom the article.

quote:

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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.

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

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.

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BUZSAW B 4 U 2 C Y BUZ SAW.
The Immeasurable Present Eternally Extends the Infinite Past And Infinitely Consumes The Eternal Future.

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.

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Anyone so limited that they can only spell a word one way is severely handicapped!

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

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

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BUZSAW B 4 U 2 C Y BUZ SAW.
The Immeasurable Present Eternally Extends the Infinite Past And Infinitely Consumes The Eternal Future.

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?

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Anyone so limited that they can only spell a word one way is severely handicapped!

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

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

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

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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

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...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

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.

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?

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BUZSAW B 4 U 2 C Y BUZ SAW.
The Immeasurable Present Eternally Extends the Infinite Past And Infinitely Consumes The Eternal Future.

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.

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Anyone so limited that they can only spell a word one way is severely handicapped!

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: 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: 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