d. Modern Mud Layers and Sand Bodies on the Inner Shelf. Large volumes of Type H 

 sediment (very fine sands and silts) are restricted in distribution to the surface and 

 subsurface of Canaveral Bight and the area adjacent to the shoreface north of Cape 

 Canaveral. (Figure 21.) Layers of Type H material are at shallow sediment depths near the 

 seaward edge of the grid, but their origin is different from either small single shell and tests, 

 thin angular shell fragments, or a small percentage of carbonate silt. 



Type H material mostly represents both Holocene and modern deposition of fine-grained 

 sediments in protected areas where littoral processes are less active compared to the shoaler 

 open coast. Large swells approach Cape Canaveral from the east and northeast and 

 hurricanes passing within a 150-mile radius occur once every 3 years. (U.S. Army, Corps of 

 Engineers, 1967.) The area between the two shore -connected shoals is partly protected from 

 these rigorous forces and is the site of deposition of fine and very fine sands selectively 

 sorted from the shoals and upcoast beaches. Canaveral Bight is protected from northeast 

 swell by the projection of the cape and associated shoals. Surficial muds and very fine sands 

 are derived by bottom erosion, shore erosion south of Canaveral Harbor, winnowing of fines 

 from the shoal areas near the cape, and perhaps a small fraction from turbid sediment-laden 

 water from Canaveral Harbor. 



Definitive studies required to assess the source most influential in terms of volume input 

 to the bight area are beyond the scope of this report. However, it seems probable that 

 deposition is minimal. The peat layer in core 100 (Fig. 16) at a subsurface depth of 6.5 feet 

 was deposited about 7,320 B.P. No well defined breaks in the sediment character indicate a 

 hiatus, but deposition has probably been discontinuous since the formation of the peat in a 

 lagoon or swamp environment. The rate of deposition of Type H sediment in the bight, 

 based on the age and depth of the peat deposit is approximately 0.1 -foot per 100 years. 



Type A sediments mantle most of the Cape Canaveral survey area, and specific sediment 

 characteristics vary with location. All of the sands are well sorted, medium to coarse and of 

 nearly equal fractions of terrigenous and calcareous grains. The thickest accumulations of 

 Type A sediment are in the shoals region and the seaward edge of the grid. Figure 21 is a 

 map of Type A thicknesses as determined from core sample data; it shows the influence of 

 the shoals, and the nearly continuous surface extent of the sand. Shore -connected and 

 isolated shoals are plano-convex features on a flat or nearly flat surface. (Figures 6 and 10.) 

 It cannot be determined from available data if Type A sediments extend from the shoal 

 crests down to the blue horizon, but 14-foot -long cores from the shoals indicate they extend 

 to at least that depth. 



Type A sand is the result of older sediments being actively reworked, sorted and 

 redistributed by bottom currents, storm waves and organisms. This sediment which has 

 petrographic criteria of being remnant from a earlier depositional environment, but is 

 actively reworked can be described as palimpsest. (Swift, Stanley and Curray, 1971.) 

 Evidence for this recent activity is the wide surficial cover, the consistent medium-to-coarse 

 grain size, and distinct lack of fine-grained sediments in the sorting values. The abraded 

 polished nature of the calcareous fraction and the near absence of easily abraded biogenic 

 grains strongly suggests continual transport of this sediment. Samples from 14 feet beneath 

 the shoal have textural and grain characteristics identical to those from the surface, 

 indicating the shoal sediment at that depth may have been recently in motion. 



48 



