Transgressive Holocene sequence recorded in Steinhatchee estuarine sediments: Western peninsular Florida
- Florida Geological Survey, Tallahassee, FL (United States)
- Florida State Univ., Tallahassee, FL (United States). Geology Dept.
The flat regional topography of peninsular Florida's Gulf Coast reflects the shallow dip of the underlying carbonate platform. As a result of this low gradient, wave energy is generally low and sedimentation within the Steinhatchee Estuary is dominated by river- and tidal-hydrodynamics. Carbonate dissolution has caused the Eocene-aged limestone surface to be highly irregular. The transgressive sequence unconformably overlying this karstic surface is comprised of clastics, from upriver and offshore, and organics produced by reefal and salt-marsh communities. Sequences deposited in karstic lows are up to 7 meters (m) thick. More typical sequences are 3 m thick, or less. The oldest unlithified marsh strata include dolosilt or carbonate rubble with clay and wood fragments. This clayey rubble-zone is overlain by subaerially deposited reddish-brown clayey sands and organic sands (including buried trees) which are in turn overlain by black, organic-rich, peaty, wetland deposits. These marsh sequences are primarily sand, which fines upwards. Silt-sized (and smaller) clastics and organic components increase up-sequence at similar rates. Thin sequences (.3--.5 m) of shelly organic-rich sand occur in current submarine environments. Thicker submarine sequences (up to 7 m) of similar material occur in present or relic oyster bars. Although a basal clayey rubble-zone may be present, subaerial and/or wetlands facies are not observed in offshore sediments. Erosion of these facies as sea level rose may have resulted from insufficient sediment supply to maintain the beach profile and/or from down-cutting by tidal currents.
- OSTI ID:
- 7060235
- Report Number(s):
- CONF-9404221-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 26:4; Conference: 43. annual meeting of the Southeastern Section of the Geological Society of America, Blacksburg, VA (United States), 7-8 Apr 1994; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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