Cenozoic climate and ocean chemistry changes are linked to the evolution of deep-water circulation patterns. A project to reconstruct Cenozoic deep-water circulation changes will use benthic foraminiferal . 13C comparisons, supplemented by ongoing faunal (benthic foraminiferal) and sedimentological studies (CaCO3, opal, organic carbon accumulations). An integrated statigraphic framework for synoptic interbasinal and bathymetric (vertical) . 13C comparisons will be constructed. Detailed interbasinal . 13C reconstructions of the Oligocene to Pliocene oceans will delineate various water-type end members (Northern Component, Southern Component, Indian Ocean Water, Pacific Deep Water). Vertical . 13C gradients will be reconstructed in several regions including the North Atlantic and Southern Ocean. These reconstructions will allow evaluation of the role of these critical bottom-water source regions upon the development of long period (106yr) deep-water circulation. The importance of shorter-period (104-105yr) changes across two major climatic transitions (ca. 14-12.5 Ma and 3-2 Ma) will be used to determine if climatic forcing on this bandwidth was linked to deep-water variations as in the Quaternary. %%% This study will involve the use of oxygen and carbon isotopes of foraminifera from sedimentary cores. The history of deep circulation will be inferred for the last 40 million years in order to examine the effects of climate on paleocirculation. The results will provide the opportunity to test models of the interaction of paleoclimate, paleoceanography, and plate tectonic reconstructions on the evolution of the modern ocean.
