University of Edinburgh, United Kingdom

The development of the Bahamas is characterised by a series of sedimentologic changes, which correlate with distinct paleoceanographic events. The cores taken on the leeward side of Great Bahama Bank (ODP Leg 166, Bahama Transect) clearly display these events. Within the lowermost Pliocene a sharp transition can be observed from cyclic wacke-packstones to poorly differentiated mud-wackestones. The paleoceanographic data shows that the Pliocene was remarkably warmer than the pre-existing Miocene. This change is probably related to the closure of the Panama Isthmus. During the Early Pliocene (4.6 Ma) erosional horizons can be found within the seismics. These events can be attributed to the intensification of the Gulf Stream, an increased productivity of Upper NADW and a change in the deep-water circulation. The Gulf Stream and the Upper and Lower NADW stream reach their maximum strength during the Late Pliocene (3.4 Ma). An erosive boundary marks this event in the slope sediments of the Bahama Transect. The major phase of Northern Hemisphere ice growth took place between 3.1 and 2.5 Ma. The transition from a skeletal- to a non-skeletal dominated system falls within this period. Intensification of continental glaciations resulting in stronger sea-level changes shape the Pleistocene platform development.