Talk:Δ18O

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Untitled[edit]

So is the abundance d18O positively or negatively correlated with temperature.

negatively; low ocean surface temp will give you a high delO18 --Boris Wawrik 21:03, 24 January 2010 (UTC)

Isn't this calculated as (sample-standard)/standard ? --Boris Wawrik 21:03, 24 January 2010 (UTC)

(sample-standard)/standard is the same as (sample/standard) - 1 --Thilo Kübler

THE FORMULA IS WRONG!!! I EDITED IT YESTERDAY AND IT WASNT ACCEPTED! BUT IM RIGHT I REEDIT IT AGAIN.

Explaination: If its cold delta18O is positive. if its cold theres less 18O in the sample. Therefore the formula must be (16O/18O)/(16O/18O)SMOW - 1. I saw that the wrong formula is also in the other wikipedia article about 18O. I edit it there as well. a right source (german) would be http://de.wikipedia.org/wiki/Sauerstoff (chapter "Indirekte Temperaturmessung") --Thilo Kübler —Preceding unsigned comment added by 95.117.202.122 (talk) 23:30, 24 January 2011 (UTC)[reply]

Which is the name of d18O and how is it pronounced?[edit]

Could anyone with knowledge of the topic write in the main article what is the name in English of the d18O parameter and how is it pronounced in English. I suppose that the pronounciation could be something like "delta-eighteen-ou", or "di-eighteen-ou". I have no idea what its name is. Thank you for the interesting article.

Pmronchi (talk) 14:28, 5 December 2013 (UTC)[reply]

Yeah, that's a delta, so delta-eighteen-o

Cheers, Thouny (talk)

References[edit]

You would think that this topic is obscure enough, and straightforwardly scientific enough, that people could just cite their sources. But... they don't. So we get this equation,[1]

T({\text{deg C}})=16.9-4.0\times \mathrm {\delta ^{18}O_{calcite}} -\mathrm {\delta ^{18}O_{seawater}}

without even a pretense of citing a source, or even explaining what the "calcite" or "seawater" difference is about. The formula doesn't even make sense, unit-wise, unless you imagine brackets around the two delta values. However, the formula seems to be somewhat related to the one found in Epstein et al. (1953), p. 1324,[2]

t=16.5-4.3\mathrm {\delta } +0.14\mathrm {\delta ^{2}}

This is the result of least-square fit, with a stated standard deviation of 0.6 °C (based on data of temperature values between 9°C and 29°C). Now, it may not be the worst idea to cite a study from 1953, certainly a time when science was still taken seriously, but it does seem a little dated nevertheless. The formula we have in the 2015 Wikipedia article seems to be very roughly compatible, except we have gotten rid of the quadratic term, the standard deviation, and any kind of context or reference. --dab (𒁳) 10:47, 14 December 2015 (UTC)[reply]

Sources and Citations[edit]

The intro gives a good general understanding of delta18O, and its practical applications. However, the strengths and weaknesses of delta18O as a proxy are not addressed in the article. Could that be added to expand upon the intro, or into the mechanism section? Also, the references for this article could be expanded upon and updated. There are not any citations in the mechanism section, and all of the sources are from 1953-2005. Maybe this link (https://dspace.mit.edu/handle/1721.1/65936) could be cited to update the information since it was published in 2010. (http://www.ajsonline.org/content/298/4/324.short) This source is not as current, but could help expand upon the information in the article. FuSha (talk) 02:44, 23 February 2017 (UTC)FuShaFuSha (talk) 02:44, 23 February 2017 (UTC)[reply]

Dubious chart[edit]

That chart has a 150+kyr period labeled as a 41kyr cycle... — Preceding unsigned comment added by 24.56.246.116 (talk) 02:14, 5 July 2020 (UTC)[reply]

Seems fine to me. Further information and primary references regarding the 41 kyr orbital cycle period are found here. +mt 10:29, 5 July 2020 (UTC)[reply]