Jim Kennett found the little microfossil species, I think a diatom, in the first core, that went extinct at 700,000 years ago. The preservation of another type of microfossil, foraminifera, is excellent. That means that later, his gang (well, mostly Karen Thompson and students) will run oxygen isotopes on these cores. Oxygen isotopes track the climate cycles, glacial vs interglacial, very precisely because one of the isotopes gets preferentially evaporated and locked up in ice sheets. Logically it is the lighter one (16) in the ice and the heavier one (18) in the ocean, but I guess I better check unless one of you want to beat me to it.
Chris