Influence of the Suwannee River on sediment patterns along the marsh coast, north east Gulf of Mexico
- Univ. of South Florida, St. Petersburg, FL (United States). Dept. of Marine Science
- Center for Coastal Geology, St. Petersburg, FL (United States)
The central, west Florida, open-marine marsh system overlies a thin sediment veneer on top of limestone. Large embayments, like Wacassassa and Deadmans Bays, form where spring-fed rivers discharge into the Gulf of Mexico. The only major point source of sediment along the coast is the Suwannee River (SR). It forms a small river-dominated delta at its mouth and the large fresh water supply and relict topography have formed a series of shore-normal oyster reefs projecting seaward of the coast. Limestone bedrock outcropping on the river bed, as revealed by side-scan sonar collected from the mouth of the 3 main passes to a point 8 km upriver, is jointed and may be similar to the regional jointing pattern reported to the south. The limestone becomes more prevalent upriver and is exposed along much of the southern pass. The thalweg of the main river is floored by large sand-waves, approximately 1 m in height and 50 m in length, which diminish in size as the river shallows towards its delta. Seaward of the oyster bioherms, side-scan sonagraphs show topographic highs mantled with small bedforms. High-resolution seismic and vibracores confirm that the sediment cover remains a thin veneer to 6 m depth (10 km offshore). Seaward of 6 m depth, limestone becomes exposed, with a series of alternating shore-normal sediment highs and limestone exposed lows occurring at 10 m depth (15 km offshore). Surface samples collected along the coast as well as in the river show higher percent organic values found at the mouth of the river and in the estuary to the south. The SR is a primary source of sediment for the section of coast from Cedar Key to Horseshoe Point. It controls morphology of the coast and distinguishes it from the sediment starved marshes to the south. The marsh coast is only now being intensively studied and an understanding of the SR's influence on sedimentation will aid future investigations of the marsh system.
- OSTI ID:
- 6077305
- 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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Related Subjects
ALLUVIAL DEPOSITS
GEOMORPHOLOGY
GULF OF MEXICO
COASTAL REGIONS
FLORIDA
MARSHES
RIVERS
SEDIMENTATION
SEDIMENTS
SEISMIC SURVEYS
SONAR
AQUATIC ECOSYSTEMS
ATLANTIC OCEAN
CARIBBEAN SEA
DEVELOPED COUNTRIES
ECOSYSTEMS
GEOLOGIC DEPOSITS
GEOLOGY
GEOPHYSICAL SURVEYS
MEASURING INSTRUMENTS
NORTH AMERICA
RANGE FINDERS
SEAS
STREAMS
SURFACE WATERS
SURVEYS
USA
WETLANDS
580000* - Geosciences