Talk:Isotope geochemistry

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article title[edit]

IMHO this article's title should be 'Isotope geology'. Siim 12:45, 10 February 2006 (UTC)

Chemists opinion is that it should be 'Isotope chemistry', thus we call it 'geochemistry'. Feel free to call it as you like, as long as it syncrhronizes with global use of terminolgy. Jclerman 12:52, 10 February 2006 (UTC)
I agree - if you look on google "isotope geochemistry" is about four times more common. It is certainly by far the most common term in use to describe this field amongst geologists in my experience. Actinide 01:06, 12 February 2006 (UTC)

oxygen stable isotopes[edit]

Should there be something here about oxygen stable isotopes and paleoclimatology? Safay 20:48, 6 April 2006 (UTC)

Yes. Here and/or in the stubs: environmental isotopes and in isotope analysis. You can start it with forams. Jclerman 21:16, 6 April 2006 (UTC)
Yeah, that's how I stumbled on it. I'm a foram biologist so I really don't know too much about this subject of isotopes. But I was trying to establish a wikilink from foraminifera to something about stable isotopes and couldn't find anything on oxygen stable isotopes here on this page. I'll check out environmental isotopes, ask some of my colleagues about it, and come back to it.Safay 21:24, 6 April 2006 (UTC)
Yes. I had seen your user page and your mention of forams. I started some of the stubs I mentioned. Also just a few lines in O-18. I was hoping some people would stumble upon them and fill them in ;-) Some colleagues of mine were working in O-18 paleotemps in the early 1970s. With O-18 I mostly looked at precip and groundwater. For sources and links within the wiki look in Cesare Emiliani also and in isotopic signature. Some of the isotope articles should be merged together. Jclerman 21:58, 6 April 2006 (UTC)
The paleoclimate applications could use some fleshing out; I've put in a bit about oxygen, but most of what I deal with is mass-independent fractionation in contemporary stratospheric ozone. Wsmitchell3 (talk) 07:23, 31 January 2009 (UTC)

strontium-neodymium and others[edit]

Strontium-neodymium (Sr-Nd) isotope geochemistry is yielding new information relative to melt sources and new age data on granitoids. See: Millone, et. al. (2000?) "Age and Strontium-Neodymium Isotope Geochemistry of granitoids of the Sierra Norte-Ambargasta Batholith, Central Argentina." Variations in strontium-isotopes proportions incorporated into enamel and dentine of the teeth of horses and other herbivores - and sometimes humans - can detect where it once lived and what it ate. Knowing when, where, and what Tibetan horses, yaks and rhinoceroses ate helps date the Tibetan uplift. See: "Tibetan uplift: looking a gift horse in the mouth." Earth Pages, May 2006.

The plants in the horse's mouth are incorrectly described and treated re their stable carbon isotopes. Jclerman 23:00, 13 September 2006 (UTC)
Plant biology incorrect, arithmetic reversed... in a 30 yrs old field is inacceptable. Jclerman (talk) 06:07, 17 June 2008 (UTC)

Osmium-strontium-neodymium-lead (Os-Sr-Nd-Pb) isotopes for covariation analysis in mid-ocean ridge basalts. See: Allegre et al. (1997) "Osmium-strontium-neodymium-lead isotopic covariations in mid-ocean ridge basalt glasses and the heterogeneity of the upper mantle." Earth and Planetary Science Letters, Vol. 150, No. 3, pp. 363-379(17).

Cerium-lead (Ce-Pb) isotope ratios as an indicator for enrichment in continental crust from volcanic rock. See: Langmuir et al. (1994) "Cerium/lead and lead isotope ratios in arc magmas and the enrichment of lead in the continents." Nature, Volume 368, Issue 6471, pp. 514-520.

Niobium-thorium (Nb-Th) isotope ratios show lithosphere differentiation since ~3.8 bya. See: Collerson and Kamber. (1999) "Evolution of the Continents and the Atmosphere Inferred from Th-U-Nb Systematics." Science, 5 March, pp. 1519-1522.

Niobium-uranium (Nb-U) ratios in greenstone-belts indicating crustal growth. See: Bowyer, et al. (1997) "Niobium/Uranium Evidence for Early Formation of the Continental Crust." Science, 24 January, Vol. 275. no. 5299, pp. 521 - 523.

There's others. I think I should be linking references to articles here that refer to these types of analyses for further clarification, but I don't have enough information to write them. Valich 22:34, 10 September 2006 (UTC)

For clarification, the Re-Os , Rb-Sr, Sm-Nd, and U-Pb isotopic systems are all used frequently by isotope geochemists, as pointed out above. However, the references to Ce-Pb, Nb-Th, and Nb-U "systems", are all cases that are studied from a chemical, not isotopic perspective (i.e., the bulk concentrations of the elements in the rocks and not the isotopic ratios are of interest) and do not belong on this page. The reference to the U-Th system also uses it as a "chemical" system, but in some cases it is used as an "isotopic" system, as in U-series dating.Rickert 23:50, 13 September 2006 (UTC)

natural lead[edit]

Have I minterpreted the comment "Lead is created in the Earth via decay of transuranic elements, primarily uranium and thorium." as meaning that's its only source? Wasn't there some sort of primaeval abundance, aside reom the residues from the decay of heavier elements? —Preceding unsigned comment added by (talk) 01:54, 6 January 2009 (UTC)


I think it would be better to write out the delta notation as the difference between the sample and standard and show how that simplifies to the ratio minus one - that is we can write (Rsam-Rstd)/Rstd = Rsam/Rstd-1. I'm not good at writing out the equations so I don't know how to do that with the code. Alatleephillips (talk) 17:10, 15 April 2016 (UTC)