Abstract
Biogenic calcium carbonates (e.g. coral skeleton, foraminifera and bivalve shell) have been widely used as proxies for past changes in sea water temperature because elemental composition (Sr/Ca and Mg/Ca ratio) of their skeletons are believed to vary quantitatively as a function of the ambient seawater temperature. However, recent studies using micro-analytical technique have revealed that there is a large chemical heterogeneity in their skeleton, which cannot be explained by the temperature variation. To reconstruct the past climate accurately, it is essential to understand the mechanism of elemental fractionation in biogenic calcium carbonate.
