Talk:Lead–lead dating
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Basic Wikification
editThe article was a mess of raw HTML, and it looks to have been that way from the beginning. A bot came through recently and removed the paragraph tags which is what made the need for wiki markup evident. It still could use some refinement, but it's better. Yock (talk) 18:27, 9 April 2008 (UTC)
huh?
editEvery kind of 'dating' measures how long ago... something... happened. For C14, it's how long ago the carbon was alive, cuz the c14 is generated in the upper atmosphere at a known rate, and is therefore incorporated into living things. For Archaeomagnetic dating, it's how long ago the iron was liquid and then solidified, capturing the global magnetic field at that time.
So what is it with Lead-Lead dating? I get the impression it was the age of the (assumed) supernova explosion that created all our heavy elements, is that right? Cuz LeadLead is only used for dating the earth (one supernova date) and for metorites (from other places from other supernovas, potentially). And other rocks in the world will just give you the same answer for the earth, yawn. Is that right?
Could someone please specify this in the article, and write up what the mechanism is? thanks. OsamaBinLogin (talk) 20:52, 6 June 2009 (UTC)
I agree it's unclear as written. I get the impression that it measures the time since the rock solidified, since that's when the initial Pb/U ratio would be fixed, Vilhelm.s (talk) 21:24, 14 September 2011 (UTC)
"Assuming X is Y" replaces "X is Y therefore" when no citation is given
editUnder The Formation of the Geochron, first paragraph,
Changed "The process of isotopic differentiation is identical on Earth as it is on other planets, therefore the core of these planetesimals would be..."
To "Assuming the process of isotopic differentiation is identical on Earth as it is on other planets, the core of these planetesimals would be..."
No reference is given for "The process... is identical..." This should be treated as an assumption. mr.svensson@gmail.com 2012-01-06 — Preceding unsigned comment added by 63.146.67.200 (talk) 19:02, 6 January 2012 (UTC)
no difference in ages
editThe section on meteorite dating left me disappointed. It started with "Samples of iron meteorite from Canyon Diablo (Meteor Crater) Arizona were found to have the least radiogenic composition of any material in the solar system. The U/Pb ratio was so low that no radiogenic decay was detected ... Therefore, [it] represents the primeval lead isotope composition of the solar system, dating back to 4.55 +/- 0.07 Byr." So that sounds super old. Then the next paragraph starts "Stony meteorites however, exhibited very high 207Pb/204Pb versus 206Pb/204Pb ratios". This is setting us up to expect a big difference, but it concludes with "gives the age of meteorites as 4.55 Byr.". So despite the large ratio difference they actually have the exact same age??? Nerfer (talk) 22:23, 10 January 2019 (UTC)