Leg Synthesis: Sea-Level Changes and Fluid Flow on the Great Bahama Bank Slope

During Ocean Drilling Program Leg 166 we drilled 17 holes at seven sites (Sites 1003–1009) on the western flank of the Great hama Bank (GBB), recovering almost 3 km of core and 3.1 km wireline logs ranging in age from late Oligocene to Holocene (Fi 1, 2). Five sites in the Straits of Florida (Sites 1003–1007) comp a transect through prograding carbonate sequences, the Bah Transect. Two boreholes (Clino and Unda) drilled previously on western Great Bahama Bank as part of the Bahamas Drilling Pro represent the shallow-water sites of the transect (Figs. 1, 2; Ebe al., this volume). Leg 166 (Bahamas Transect) had two primary objectives. T first objective was threefold: (1) to document the sedimentary rec of the Neogene −Holocene sea-level changes; (2) to determine t ages of the major unconformities in the sedimentary record; and to compare the sedimentary record with the oxygen isotopic recor glacio-eustasy. Facies variations of the core borings from the c plete transect were expected to document that these variations a sociated with oscillations of sea level, and thereby providing the s imentary response of the carbonate environment to sea-level chan Biostratigraphy was used aboard ship to date unconformities tha thought to be generated by sea-level changes. The correlation tween the two independent records of sea-level changes, seismi quence stratigraphy, and the oxygen isotopic proxy, can potenti help to evaluate rate and amplitude of eustatic vs. relative sea-l changes and to establish a causal link between glacio-eustasy an stratigraphic pattern. The second objective was to investigate the significance of fl flow within the Great Bahama Bank. To achieve this goal, the site the Bahamas Transect were complemented by three additional s low holes on the upper slope: Sites 1004, 1008, and 1009 (Fig The nature and mechanisms of fluid flow through the carbonate b were quantified through in situ temperature measurements through analyses of the composition of the interstitial fluids retain in the sediment. We present in the back-pocket foldout a compilation of the d over the Bahamas Transect (Sites 1003–1007), including the h resolution multichannel seismic section, and the lithostratigraph biostratigraphic, and petrophysical data that compose the basic set for the interpretation of the sequence stratigraphic architectur the Great Bahama Bank margin.