on the isopachous map (Fig. 10) correspond to shoal locations and the plano-convex nature 

 of the shoals. Thicknesses greater than 20 feet are beneath Chester Shoal, Southeast Shoal, 

 Ohio Shoal, Hetzel Shoal, and a small area in the northeast corner of the grid where the 

 subbottom slope exceeds the sea-floor slope. 



Locations of cores containing samples of the blue material are plotted in Figure 10. The 

 recovered material (Type E) is a partially cemented skeletal sand which was judged 

 deposited during the Pleistocene, and later subaerially exposed and cemented. (See Sections 

 III, a. 5, and IV, a.) 



The blue horizon is a continuous surface over most of the south and central Florida 

 Atlantic Inner Continental Shelf. Meisburger and Duane (1971) have traced the surface from 

 Fort Pierce to Cape Canaveral and characteristics of the blue are similar off Cape Canaveral; 

 the surface is generally flat and uniform or gently dipping with only minor fluctuations, and 

 internal seaward dipping reflectors are common on the outer edge of the study area. At Fort 

 Pierce the blue horizon lies between —50 and —100 feet MLW and strikes nearly 

 north-south. Northwest and up dip from Fort Pierce, the blue horizon features out against 

 the yellow horizon and does not reappear until just south of Cape Canaveral. 



m. SURFACE AND SUBBOTTOM SEDIMENT CHARACTERISTICS 

 1. Cape Canaveral Grid. 



a. General. Sediment data are based on macroscopic and microscopic examination of 91 

 vibratory cores of 3-inch diameter and averaging 10 feet in length. Numbered core locations 

 are plotted in Figure 2. Sediment samples were collected at 1-foot intervals from each core; 

 selective cores were split and samples collected at closer intervals for examination. 



In general, sediments of the Cape Canaveral Inner Continental Shelf are highly variable in 

 grain size, sorting, composition, and lateral continuity. Although similar sediment types are 

 correlative between individual cores and over small areas, the relation between major 

 lithologies is more complex and diverse than that of inner shelf sediments along 

 reconnaissance lines to the south or north. 



Sands off Fort Pierce display a relatively simple surface and stratigraphic distribution. 

 (Meisburger and Duane, 1971.) In that region Hthologic differences are distinct and relative 

 position in the sediment column is clear cut (i.e., Type B sediment is always overlain ]3y 

 Type A.) In contrast. Cape Canaveral sediment types are interbedded and interfingered. 

 Some transitions in sediment character are gradual vertical changes while others are marked 

 by abrupt contacts between sediments representing distinctly different environments of 

 deposition. 



Major sediment categories in the grid area are: 1) Type A— well -sorted, fine to coarse 

 quartzose— calcareous sands; 2) Type C— muddy coarse shell sands and gravels; 

 3) Type H— very fine silty sands and muds; and 4) Type E— semiconsohdated, quartz-rich 

 calcarenites. Letters assigned to hthologics are arbitrary and established for this program to 

 simpUfy correlation and associations of sediment in one area to another. Therefore, 

 Types A, C, and E are similar in character to sediments designated by those letters in the 

 Fort Pierce area; Type H is not present in the Fort Pierce area. In both areas Type E is the 

 lowest sediment stratigraphicaUy and Types C and H are variable in their position. Of these 

 four classes, only Type E is restricted in distribution, occurring in a few locaHties, generally 

 the deeper parts of the grid. Except for calcarenite (Type E), these sediment categories are 



26 



