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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 5. (May)

First Page: 965

Last Page: 965

Title: Faunal Succession Within Deep-Water Coral Mounds North of Little Bahama Bank: ABSTRACT

Author(s): Cathryn R. Newton, Henry T. Mullins

Article Type: Meeting abstract


Deep-water coral mounds of 5 to 40 m relief occur at depths of 1,000 to 1,300 m over a 2,500 sq km area of the lower slope north of Little Bahama Bank. These coral/gorgonian buildups, apparently unlithified, have yielded radiocarbon ages of 860 ± 50 and 940 ± 40 years for the best preserved corals and gorgonians, and preliminary dates of 22,100 years for the most intensively bored corals, the youngest deep-water coral mounds ever reported. Eight genera of deep-water coral represent the highest diversity recorded from a single locality. These ahermatypes are predominantly solitary, although branching and weakly branched forms are also present. The colonial ahermatypes from the mounds possess large-diameter corallites and relatively few corallites per specimen. Se eral of the coral general, most notably Thecopsammia, have significant stereomal deposits in the skeleton, a feature common among deep-water corals. The scleractinians are associated with a diverse fauna. The primary framework builders of the mounds, however, appear to be branching corals and gorgonians.

Based on the relative amounts of boring and Mn-oxide coating on coral specimens recovered from dredge hauls, there appears to be a crude faunal succession within the mounds. Branching colonial corals and gorgonians seem to be the pioneer forms, colonizing hardgrounds. These initial coral thickets form a baffle for sediment as well as substrates for later stages of attached and free-lying ahermatypes such as Desmophyllum, Stephanocyathus, and Deltocyathus. Thus the mounds grow through a combination of sediment trapping and colonization by a greater diversity of coral and other invertebrates. The coarse nature of intermound sediments and the presence of scour and ripple marks in underwater photographs indicate that bottom currents are vital to the development of these deep-water coral s ructures.

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