Stratification and Oxygen Isotopes in the Paleozoic: Is Paleotermometry in Hot Water?

Abstract

The oxygen isotope method is probably the most widely used proxy of paleotemperature determination in the fossil record. The relationship as first proposed by Urey (1947) suggests that the ratio of 18O to 16O in the calcitic shells of fossils is proportional to temperature. This was subsequently confirmed by empirical studies (Epstein et al, 1951, Emiliani, 1954; 1955). However, Shackleton (1967), suggested on the basis of co-variance of benthonic and planktonic foraminifera, that the δ18O composition of seawater varied only as a function of glacial ice growth and decay. However, more recent studies have shown that there is still a residual temperature component in the δ18O variability of deep waters.