Papers by Dewitt, N.T.

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Brooks, G.R. , Dewitt, N.T. , and Suthard, B. . 1997. Recent sedimentary development of the inner west-central Florida continental shelf.. Geological Society of America, Abstracts with Programs, v.29, p. 7
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Brooks, G.R. , Doyle, L.J. , Suthard, B.C. , and Dewitt, N.T. . 1998. Inner West-central Florida continental shelf: Sedimentary facies and facies associations. Open File Report 98-37, U.S. Geological Survey, Saint Petersburg, FL, p. 177.
Brooks, G.R. , Doyle, L.J. , Davis Jr., R.A. , Dewitt, N.T. , and Suthard, B.C. . 2003. Patterns and controls of surface sediment distribution: west-central Florida inner shelf. Marine Geology, v. 200, p. 307-324
The west-central Florida inner shelf represents a transition between the quartz-dominated barrier-island system and the carbonate-dominated mid-outer shelf. Surface sediments exhibit a complex distribution pattern that can be attributed to multiple sediment sources and the ineffectiveness of physical processes for large-scale sediment redistribution. The west Florida shelf is the submerged extension of the Florida carbonate platform, consisting of a limestone karst surface veneered with a thin unconsolidated sediment cover. A total of 498 surface sediment samples were collected on the inner shelf and analyzed for texture and composition. Results show that sediment consists of a combination of fine quartz sand and coarse, biogenic carbonate sand and gravel, with variable but subordinate amounts of black, phosphorite-rich sand. The carbonate component consists primarily of molluskan fragments. The distribution is patchy and discontinuous with no discernible pattern, and the transition between sediment types is generally abrupt. Quartz-rich sediment dominates the inner 15 km north of the entrance into Tampa Bay, but south of the Bay is common only along the inner 3 km. Elsewhere, carbonate-rich sediment is the predominate sediment type, except where there is little sediment cover, in which cases black, phosphorite-rich sand dominates. Sediment sources are likely within, or around the periphery of the basin. Fine quartz sand is likely reworked from coastal units deposited during Pleistocene sea-level high stands. Carbonate sand and gravel is produced by marine organisms within the depositional basin. The black, phosphorite-rich sand likely originates from the bioerosion and reworking of the underlying strata that irregularly crop out within the study area. The distribution pattern contains elements of both storm- and tide-dominated siliciclastic shelves, but it is dictated primarily by the sediment source, similar to some carbonate systems. Other systems with similar sediment attributes include cool-water carbonate, sediment-starved, and mixed carbonate/siliciclastic systems. This study suggests a possible genetic link among the three systems.
Brooks, G.R. , Doyle, L.J. , and Dewitt, N.T. . n.d. Surface sediment characteristics and distribution patterns: inner west-central Florida continental shelf. U.S. Geological Survey, Open File Report, 177 p.
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