THE CENOZOIC OCEAN CIRCULATION BASED ON OCEAN GENERAL-CIRCULATION MODEL RESULTS

A series of ocean General Circulation Model (GCM) experiments for Paleocene, Eocene, Miocene and present-day continental geography with atmospheric forcing prescribed from atmospheric GCM experiments is utilized to investigate the changes in surface and deep-water ocean circulation through the Cenozoic. The experiments illustrate a number of similarities with previous observation-based reconstructions, although the timing of the development of particular gyre systems and the nature of the high southern latitude circulation are generally different than previous interpretations. In addition, the model results suggest substantial changes in the sites of deep water formation, including a middle Eocene subtropical source. Because of a number of experimental limitations, the experiments should be considered largely as a sensitivity analysis of the role of changing geography in modifying the ocean circulation.