Three CaCO3 dissolution events have been documented in the western equatorial Atlantic, one associated with marine isotope stage 5d, one with stage 5b, and one with early stage 4. The intensity of these events appears to require a greatly expanded invasion of waters with a low carbonate ion concentration akin to that characterizing today's deep Pacific (and also the Antarctic Bottom Water). While evident in a core from a depth of 3.4 km, these three events appear to be much less intense in the western equatorial Pacific than in the western Atlantic. The Atlantic results appear to be telling us that the density difference between Southern Ocean and North Atlantic deep waters has been modulated by insolation changes associated with the 23,000-year precession cycle.