Talk:Uranium-uranium dating

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A Wikipedian removed Uranium-uranium dating from the good article list. There are suggestions below for improving areas to satisfy the good article criteria. Once the objections are addressed, renominate the article as a good article. If you disagree with the objections, you can seek a review.
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1 Delisted GA
2 Use of common-Pb in U-series dating
3 U238/U235 ratio cannot be used for dating
4 Request for Mediation

[edit] Delisted GA

There are no images. slambo 16:55, 23 October 2005 (UTC)

Geez. Is this something you'd want? Rolinator 11:20, 19 February 2006 (UTC)

The mushroom cloud of the Atom bombs use uranium. Hyuck!

[edit] Use of common-Pb in U-series dating

Hi all. The last line seems out of place. Common-Pb measurements are not necessary for ²³⁴U/²³⁸U dating and it is my understanding (although I could be wrong!) that it is not routine to measure Pb during U-Th series measurments. At least it is the case in the older alpha counting methods and on single-collector MS's. Can anyone comment on this or make it jive a little bit better with the rest of the text (which is quite good)? I understand that common-Pb measurements in, for example, corals that are well dated may provide a secular seawater Pb isotopic record, but I don't know if anyone does that. Does anyone have an interest in the Pb isotopic history of seawater (does anyone have a ref for it?).

Additionally, I would like to change the way that the mass-numbers are written in the text. In particular I would like to put the mass-numbers in superscript to the top left of the element ( e.g., U-234 would be changed to a ²³⁴U). It makes the text a little bit easier to read and is consistent with general scientific usage. Again, if no one takes offence to this I will go ahead and make the changes. Cheers, Rickert 17:25, 3 February 2006 (UTC)

Do it. I prefer leading superscripts and that last line just seems to have been added to plug the Isotope geochemistry article. Vsmith 17:48, 3 February 2006 (UTC)

Rickert, it sounds like you are a true-blue expert! Please make any changes you think are appropriate. I was the principal author of the original text, and I depended almost exclusively on the references listed, as I have no outside knowledge of this subject. Indeed, I'm quite flattered that you think the article is good overall, coming from someone with your qualifications. So, change away! The only thing, and it seems that you are aware of this already, is to please try to reference any material you add if you can -- or in fact, switch out the references that are there now for better ones if you're able (perhaps you're aware of a text covering this topic?). Thanks, and I look forward to seeing the changes you make. - Bantman 17:53, 3 February 2006 (UTC)

Lol, hardly an expert (and my qualifications are embarassingly small). I know what I know and thats about it. I will try and add to the references, but it seems to me that the type of people that use the Wikipedia are more inclined to find hyperlinks more useful than references to textbooks, so what is there is probably fine for now. For example, the MSA volume on U-series isotopesis great, but who the heck is going to look it up? Since I (still) mostly use paper I don't have a lot of useful stuff to add. I'll do what I can. Cheers Rickert 18:28, 3 February 2006 (UTC)

[edit] U238/U235 ratio cannot be used for dating

A user keeps trying to link to a page (his/her own?) that attempts to use 235U/238U to determine the age of the earth on the basis of an entirely arbitray initial state assumption. This cannot work for the simple reason that the only way we can determine the 235/238 ratio at the time the earth formed is by back-calculating using a known age for this event as already determined by other means (i.e. by U-Pb dating). With one or two very notable exceptions, the 238/235 ratio is constant throughout the earth (currently at 137.88; the number of significant figures given here reflects the accuracy with which we can measure this ratio in absolute terms). Some types of U-Pb dating (there are several) utilise the change in U238/U235 ratio over time but do not do so by measuring the ratio as it is now (we know this already as it is the same everywhere).

In most U-series analytical techniques we actually use the known 238/235 ratio to aid in the measurement of unknown U and Th (sometimes Pb) isotope ratios, as in isotope mass spectrometry the best way to measure an unknown ratio is by normalising its apparent value to the apparent value of a known ratio. Actinide 00:51, 12 February 2006 (UTC)

Ah - I now see this had already been done to death on age of the earth and elsewhere. Sorry! Actinide 02:48, 14 February 2006 (UTC)

Yes, it was a rather disheartening introduction to editing a Wikipedia article. Having my arithmatic rudely and wrongly questioned was less than pleasent. Oh well, c'est la vie. In a couple of months I hope to have time to get other radiogenic isotope pages up to the quality that you have achieved for the U-series methods. BTW, I quite like how you wrote those pages up: Concise, precise, and accurate. Some of these articles have a way of becoming too long and detailed (however accurate and thorough) for a proper lay-persons encyclopaedia. Rickert 04:39, 14 February 2006 (UTC)