Modern deep-water coral mounds north of Little Bahama Bank: criteria for recognition of deep-water coral bioherms in the rock record.

Deep-water, ahermatypic coral mounds are present at water depths of 1000-1300m on the lower slope of Little Bahama Bank. The mounds display 5-40m of relief above the sea bottom. A diverse benthic community exists, including 11 genera and 16 species of ahermatypic coral. Conspicuously absent from the coral fauna are Lophelia and Dendrophyllia. Radiocarbon dates on fresh coral and gorgonian fragments indicate the mounds are at least in part Recent. The mounds probably developed on sea-floor perturbations in areas where strong bottom currents provide needed oxygen and nutrients. If found in the rock record, the mounds would be considered bioherms, ie. bioherms are not uniquely shallow-water in origin. The distinction between ancient deep- and shallow-water coral buildups involves using multiple recognition criteria which are discussed here and include presence of algae, coral morphology and trace element geochemistry. -from Author