Magnitude of the CaCO₃ dissolution events marking the onset of times of glaciation

Abstract

The availability of CaCO 3 and ³He content results for core TT 13‐72 from 4.3 km depth in the equatorial Pacific [ Marcantonio et al., 1996] allows the magnitude of the excess (i.e., over ambient) CaCO 3 dissolution at the onset of marine glacial stages 10, 8, and 6 to be estimated. These three events are remarkably similar; during each an integrated loss of about 28 g CaCO 3 per cm² occurred. While the magnitude of this loss is consistent with that expected from the interglacial to glacial p H shifts reconstructed based on boron isotope measurements on benthic foraminifera [ Sanyal et al., 1995], measurements at a number of other locations and water depths will be required before this approach can be used to evaluate the global toll of these dissolution events.