Paleotemperature scale, isotopic

The most important part of the anharmonic correction to isotope exchange equilibria is in the zero point energy term. 

The full theory of this correction was developed by Wolfsberg in 1967 (35). We shall outline here the theory for a diatomic molecule 

ACS Symposium Series American Chemical Society Washington, DC, 1975. 

s (19 - 23), Q Is the normal coordinate and the other terms have the usual spectroscopic significance. The Important new term introduced by Wolfsberg is Gq. This correction may be as large as the 1/4 x U) correction in Eq. (20) and may be of the same or opposite ii n. Wolfsberg has extended this method to the water and ammonia molecules. In Fig. II we reproduce the comparison of Bron and Wolfsberg s (36) calculation of exchange equilibrium 

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McCrea, J.M. 1950 On the isotopic chemistry of carbonates and a paleotemperature scale. Journal ofChemical Physics 18(6) 849-857. 

He postulated that the determination of temperatures of the ancient oceans should be possible, in principle, by measuring the 0 content of fossil shell calcite. The first paleotemperature scale was introduced by McCrea (1950). Subsequently, this scale has been refined several times. Through experiments which compare the actual growth temperatures of foraminifera with calculated isotope temperatures Erez and Luz (1983) determined the following temperature equation ... 

Grossman E.L. and Ku T.L. (1981) Aragonite-water isotopic paleotemperature scale based on the benthic foraminifera Hoeglundina elegans. Geol. Soc. America Abstracts with Programs 13, 464. 

Matthews A, Palin, JM, Epstein S, Stolper EM (1994) Experimental study of o/ 0 partitioning between crystalline albite, albitic glass, and CO2 gas. Geochim Cosmochim Acta 58 5255-5266 McCrea JM (1950) On the isotopic chemistiy of carbonates and a paleotemperature scale. J Chem Phys... 

The first carbonate/water paleotemperature scale was based on the fact that the isotopic composition of oxygen from calcium carbonate differs fi-om that of the water and depends on the temperature when the carbonate in question is precipitated under equilibrium conditions. This difference arises from an isotope-exchange reaction that can be represented by the... 

One of the first apphcations of the paleotemperature method was undertaken by Harold Urey et al. (1951), who analyzed incremental sections along the radius of the shell of a fossil belemnite (a type of cephalopod). This bullet-shaped shell, from the Cretaceous PeeDee formation of South Carolina, was the original standard material for 5 C analysis (Table 5.2). The isotopic diary of the PeeDee belemnite (Fig. 5.4) records four cool extremes separated by three warm periods, in what appears to be 3.5 y of life history laid down approximately sixty million years ago. The absolute temperature scale is uncertain, because the 5 0 of the ancient sea where the belemnite lived is unknown. 

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