A few cores recovered atypical sediment of the various unclassified sediments (Type U). 

 Characteristics and fauna of these sediments indicate deposition in a wide variety of 

 environments ranging from marginal marine to mid-shelf. Many may represent remnants of 

 previously extensive PUocene-Pleistocene deposits largely removed by erosion during low 

 eustatic sea level stands. In some cores the deposits from the area over the Daytona Beach 

 high may be of Miocene age. Since such remnant deposits rarely occur together in the same 

 core, there is little information about relative stratigrapliic relationships or history. 



Although the Pliocene-Pleistocene history of the inner shelf from ICONS data is 

 fragmentary, some meaningful generalizations can be made. Pleistocene deposits are 

 locaUzed and thin and in many places absent from the inner shelf of north Florida. This 

 contrasts sharply with the thick late Pleistocene sands mapped from Cape Canaveral (Field 

 and Duane, 1974) and farther south (Meisburger and Duane, 1971). The paucity of fluvial 

 and coastal sands south of the large Piedmont-draining Georgia river system has two possible 

 explanations— either the area was one of nondeposition, or original deposits were stripped 

 off by subsequent erosion. Because of the preservation of thick subsurface Pleistocene sands 

 south of the study area (Field and Duane, 1974) and in other parts of the east coast, the 

 latter explanation seems unlikely. It seems more probable that each time the sea 

 transgressed the shelf, the deep stream channels that were cut into the shelf became 

 embayed and began to trap sediment, thereby reducing the detritus supphed to the coastline 

 when the shorehne was farther seaward. This lack of new material resulted in ^ very thin 

 sediment cover derived principally from erosion of exposed strata. 



The most recent event apparent from the north Florida ICONS data is the Holocene 

 transgression beginning about 15,000 years (B.P.) following the termination of the last 

 Pleistocene glacial stage. As the shorehne migrated landward. Pleistocene and Tertiary 

 substrata were reworked to generate thin surficial type A sediment deposits. During the last 

 several thousand years finer type F sediments in the littoral system have been transported 

 seaward mantUng the shoreface and the innermost shelf floor. Outside of the littoral and 

 shoreface zones there seems to be little modern sedimentation taking place. Reworking of 

 surface sands of the inner shelf by waves and currents in continuing and possibly significant 

 transportation and redeposition of winnowed fines is occurring. 



V. SAND RESOURCES ON THE NORTH FLORIDA INNER SHELF 

 1. Sand Requirements for the North Florida Coast. 



The National Shoreline Study (U.S. Army, Corps of Engineers, 1971) Hsts the northeast 

 coast of Florida as one of four areas within the State where shore erosion problems are 

 serious. Specific areas covered in this study and undergoing sufficient erosion to warrant 

 engineering protective measures are shown in Figure 38. Quantities required for initial 

 restoration and annual nourishment of those areas are cited in Table 5. According to a 

 Beach Erosion Control Study (BEC) for Duval County (U.S. Congress, 1965) the shorehne 

 south of St. Johns River to tlie county Une, a distance of about 10 miles, will require 



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