3. Potential Offshore Sand Resources. 



a. General. Delineation of sites within the survey area which appear to be most 

 promising for future detailed investigation as potential borrow areas is accomplished by 

 interpretation of data and comparison with geologically analogous areas. Potential borrow 

 sites are shown in Table 7. 



Suitable borrow sites are considered to be those with clean quartz sand of a size range 

 compatible with that judged to be suitable for fills on nearby beaches and thick enough so 

 that borrowing operations would affect only a small area. 



In general the inshore zone coincident with the surface distribution of type F fine silty 

 sand contains few potential sand sources because of the characteristic fine and frequently 

 silty character of bottom and shallow subbottom sediments in the zone. 



Seaward of the fine silty sand areas, there are extensive but discontinuous deposits of 

 type A quartz sand. The quality of type A sand is more favorable, but deposits are 

 commonly thin and in many areas the sand is too fine to be suitable for beach fill. 



Linear ridge-like shoals occurring on the inner shelf off Fort Pierce and Cape Canaveral 

 were found to be excellent sources of clean, medium to coarse sand (Meisburger and Duane, 

 1971; Field and Duane, 1974). Similar linear shoals occur south of Daytona Beach off the 

 study area. 



In contrast, topographic highs elsewhere in the study area are large, often flat-topped, 

 masses of irregular outline and low reUef. Most of these bank shoals are judged to be largely 

 the product of erosion rather than accretion; however, core data show that accumulations of 

 clean type A sand generally occur atqp these highs and the sand is likely to be several feet 

 thick in places. Additional detailed surveys on these features may serve to precisely define 

 the character and extent of type A sand. 



Very large quantities of fine to coarse quartz sand are believed to be contained in 

 reflection unit B. However, in most places the unit is buried and only readily accessible 

 locally where it outcrops or lies under very shallow overburden. In addition, type M 

 sediment is of doubtful utiUty as beach replenishment because of tlie certain qualitative 

 difficulties with this material as discussed previously. 



Potential sand sources are identified in Figures 40 through 43. Areas designated A are 

 considered to have the best potential for exploitations as offsliore borrow areas. Subareas 

 (within the A areas) that appear to afford the best prospects have also been identified in the 

 figures. 



Areas designated B are judged to be possible sources of suitable sand but available data 

 on these areas are too scant for an assessment. 



In the Figures 40 and 41, M areas show where the top of the type M sediment layer is 

 accessible either in outcrop or under shallow overburden. 



b. Georgia Border through St. Augustine Grid. Fine sediments ranging from clay to 

 clean fine sand cover a zone extending seaward tlirough most of the Fernandina grid and to 



