Accumulation of bank-top sediment on the western slope of Great Bahama Bank; rapid progradation of a carbonate megabank
Accumulation of bank-top sediment on the western slope of Great Bahama Bank; rapid progradation of a carbonate megabank
Geology (Boulder) (October 1990) 18 (10): 970-974
- Atlantic Ocean
- Bahamas
- banks
- biogenic structures
- bottom features
- carbonate platforms
- Caribbean region
- Cenozoic
- changes of level
- fines
- geophysical methods
- geophysical profiles
- geophysical surveys
- Great Bahama Bank
- lithofacies
- marine environment
- marine sedimentation
- marine sediments
- North American Atlantic
- North Atlantic
- ocean floors
- progradation
- Quaternary
- sedimentary structures
- sedimentation
- sedimentation rates
- sediments
- seismic methods
- seismic profiles
- slope environment
- stratigraphy
- surveys
- West Indies
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.
