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Accumulation of bank-top sediment on the western slope of Great Bahama Bank: rapid progradation of a carbonate megabank

R. Jude Wilber·John D. Milliman·Robert B. Halley
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Abstract

High-resolution seismic profiles and submersible observations along the leeward slope of western Great Bahama Bank show large-scale export of bank-top sediment and rapid progradation of the slope during the Holocene. A wedge-shaped sequence, up to 90 m thick, is present along most of the slope and consists of predominantly aragonite mud derived from the bank since flooding of the platform 6-8 ka. Total sediment volume of the slope sequence is 40%-80% that of Holocene sediment currently retained on the bank. Maximum rates of vertical accumulation and lateral progradation are 11-15 m/ka and 80-110 m/ka, respectively: 10 to 100 times greater than previously known for periplatform muds. Slope deposition of exported mud during sea-level highs appears to have been a major mechanism for the westward progradation of Great Bahama Bank throughout the Quaternary; this may provide a critical modern analogue for ancient progradational margins.

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R. Jude Wilber, John D. Milliman, Robert B. Halley. 1990. Accumulation of bank-top sediment on the western slope of Great Bahama Bank: rapid progradation of a carbonate megabank. https://pubs.usgs.gov/publication/70137851

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