Sediment distribution patterns and the development of the marsh system rimming a shallow-water shelf embayment: Waccasassa Bay, Levy Co. , FL
- Univ. of South Florida, St. Petersburg, FL (United States). Dept. Marine Science
- Geological Survey, St. Petersburg, FL (United States). Center for Coastal Geology
Waccasassa Bay is a wide-mouthed, open basin located at the head of a 35 km wide coastal reentrant along Florida's west-central marsh coast. It is an ideal shallow-water shelf embayment, being characterized as a microtidal, low-wave energy, freshwater-influenced, shallow-water depositional basin. The embayment is rimmed by a contiguous, open-marine Juncus roemerianus marsh, typical of the wetlands along this coast. A series of large, relict, subtidal oyster bioherms traverse the central channel of the embayment, a site at which there are also submarine freshwater springs. Approximately 100 km of high resolution seismic reflection data and side scan sonar data were collected across the embayment. Ground-truthing was performed using probe rod transects and surface sediment grab samples. These data show a high diversity and zonal distribution of bottom sediments, ranging from coarse, shelly sands to detrital coralline algae. However, unlike the nearshore zones north and south of Waccasassa Bay, sediment cover over 90% of the basin is less than 1 m in thickness, and exposed bedrock is common. The Waccasassa Bay basin is largely an exposed shallow limestone shelf. This contrasts with Crystal Bay, a shelf embayment to the south, which contains several distinct coastal facies averaging 3 m in thickness. Initial research onshore shows that the sediment veneer of the coastal marshes along the embayment is thin, on the order of 1-2 m, suggesting long term instability of the system. The marsh sediments also appear to have little siliciclastic content. Vibracore and probe rod transects provide a stratigraphic framework from which to reconstruct the geologic history of these wetlands. The results will allow the Waccasassa Bay marsh/shelf embayment system to be compared with other systems along this coast and elsewhere.
- OSTI ID:
- 6112481
- Report Number(s):
- CONF-9304188-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 25:4; Conference: 42. annual Geological Society of America (GSA) Southeastern Section meeting, Tallahassee, FL (United States), 1-2 Apr 1993; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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BAYS
SEDIMENTATION
CONTINENTAL SHELF
STRATIGRAPHY
FLORIDA
ALGAE
DEPOSITION
MARSHES
SEDIMENTS
SEISMIC SURVEYS
SONAR
THICKNESS
AQUATIC ECOSYSTEMS
COASTAL WATERS
CONTINENTAL MARGIN
DEVELOPED COUNTRIES
DIMENSIONS
ECOSYSTEMS
GEOLOGY
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NORTH AMERICA
PLANTS
RANGE FINDERS
SURFACE WATERS
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WETLANDS
580000* - Geosciences