 Europe Leg 113 oxygen paleoclimatology palynomorphs Tertiary clastic sediments Ocean Drilling Program ODP Site 689 Paleogene paleoecology sediments Southern Europe Southern Ocean Foraminifera Invertebrata Massignano Italy algae isotopes Italy Weddell Sea Cenozoic Maud Rise nannofossils ooze Plantae Protista upper Eocene Eocene Marches Italy microfossils O-18O-16 isotope ratios marine sediments stable isotopes 