Talk:Oxygen isotope ratio cycle

Mv proposal
This article is about d-o-18 as a proxy; there is no need to make the "cycles" important, its the variations (which don't have to be, and often aren't at all cyclic) that are of interest. So I'd like to move it to just Oxygen isotope ratio.

Also, it should cover the proxy in general, not just in calcite.

Also, there is a lot of overlap with Proxy (climate).

William M. Connolley (talk) 20:50, 25 January 2008 (UTC)


 * I'd agree with moving to oxygen isotope ratio, the more general article needs to be written before this more specific subject is covered. Tim Vickers (talk) 17:13, 4 May 2008 (UTC)

This article should be deleted
Why? All the issues discussed in the previous comments and more. E.g.: it contains incorrect definitions and/or descriptions. like that a molecule contains the three isotopes. This article should be deleted and the article oxygen-18 corrected and expanded. That is, if you think that the this wiki should be regarded as a serious reference source. Jclerman (talk) 01:03, 7 April 2008 (UTC)


 * The "molecule" bit is just a misstatement, and I've corrected it. But I agree this probably needs merging, whether with O18 or elsewhere William M. Connolley (talk) 07:20, 7 April 2008 (UTC)
 * It needs rewriting. See below for unclear and deficient sections. Also, the prominent use of cycle when there are not really cyclical variations as implied by the harmonics reference, is confusing because there is a chemical oxygen cycle. Jclerman (talk) 17:20, 4 June 2008 (UTC)

Connection between temperature and climate
The 18O/16O ratio provides a record of ancient water temperature. Water 10 to 15 degrees Celsius (18 to 27 degrees Fahrenheit) cooler than present represents glaciation. Precipitation and therefore glacial ice contain water with a low 18O content. Since large amounts of 16O water are being stored as glacial ice, the 18O content of oceanic water is high. Water up to 5 degrees Celsius (9 °F) warmer than today represents an interglacial, when the 18O content is lower. A plot of ancient water temperature over time indicates that climate has varied cyclically, with large cycles and harmonics, or smaller cycles, superimposed on the large ones. This technique has been especially valuable for identifying glacial maxima and minima in the Pleistocene.

Jclerman (talk) 17:12, 4 June 2008 (UTC)
 * The situation is complicated by the presence of at least three influences on the O18 of microfossil calcite: a temperature relationship with isotope ratio incorporation, the effect of depletion of light isotopes in the ocean during glacials by differential evaporation and precipitation, and the presence of "vital effects" (biological fractionation effects) which vary between microfossil species and (inconveniently) over time as well. see Hoogakker et al Paleoceanography, Vol. 25, PA4229, 11 PP., 2010 for a discussion of vital effects; Sosdian and Rosenthal Science Vol. 325, pp. 306 - 310, 17 July 2009 for a discussion of temperature effects on benthic Oxygen isotope ratios, also discussed in Elderfield and Ganssen Nature 405, 442-445 (25 May 2000); for an attempt to deconvolve the elements of the signal see Shackleton Science 15 September 2000; Vol. 289 no. 5486 pp.  1897-1902; for an insightful (but perhaps incorrect) critique of Shackleton's procedure see Ruddiman 2003, Climatic Change, Vol. 61, pp. 261–293. The relationship between temperature and ice volume is not exactly straightforward, although it is certainly true that in general glacials were colder and had more ice than interglacials!  Orbitalforam (talk) 17:07, 22 September 2011 (UTC)

This section tautologic and unclear
Oxygen isotope ratio cycles are cyclical variations in the ratio of the mass of oxygen with an atomic weight of 18 to the mass of oxygen with an atomic weight of 16 present in some substance, such as polar ice or calcite in ocean core samples. The ratio is linked to water temperature of ancient oceans, which in turn reflects ancient climates. Cycles in the ratio mirror climate changes in geologic history.

Jclerman (talk) 17:15, 4 June 2008 (UTC)

Extremely unclear
I understand the concept and yet found myself confused after reading the article. It really needs a cleanup. —Preceding unsigned comment added by 67.176.78.164 (talk) 21:41, 10 April 2010 (UTC)

Statement Conflicts with Physics
''Because H216O requires less energy to vaporize, and is more likely to diffuse to the liquid phase, the first water vapor formed during evaporation of liquid water is enriched in H216O, and the residual liquid is enriched in H218O. When water vapor condenses into liquid, H218O preferentially enters the liquid, while H216O is concentrated in the remaining vapor.''

Latent Heat of vapourization is increased by the presence of the heavier Oxygen-18 isotopes in that it makes the Water molecule ~ 10% heavier (Molecular Weight 18 increased to 20). The predominant forces that set the melting point and boiling point of water arise from Hydrogen Bonding which are unrelated to molecular mass. Therefore melting point and boiling point is unaffected by the different isotopes of oxygen.

While it is true that water containing O-16 will vapourise more quickly, this water will also condense more quickley because it needs to give up less heat to do so. The statement, "When water vapor condenses into liquid, H218O preferentially enters the liquid," is not true. — Preceding unsigned comment added by Murray Peterson (talk • contribs) 13:18, 15 July 2020 (UTC)