that old shell material derived from coquina exposures may represent 

 20 to 60 percent of the carbonate material in east Florida beach sands. 

 The remaining shell material is derived from modem biota and was found 

 to be highest near inlets, where the environment favors large organic 

 populations. 



Using deepwater seismic profiles off northeastern Florida, Emery 

 and Zarudski (1967) made correlations of onshore borings and wells with 

 offshore deep borings at the series level . The deep borings were obtained 

 under the Joint Oceanographic Institutions Deep Earth Sampling (JOIDES) 

 program. However, at the formational level little is knoivn concerning 

 the stratigraphy of the Continental Shelf off either northeastern or 

 southeastern Florida. However, it is probable that beds of Anastasia 

 age underlie the Holocene surface sediments on the shelf throughout much 

 of the study area. South of the Palm Beach- Broward County line the Miami 

 Oolite may crop out on the bottom close inshore. Because of its slight 

 dip and because the base lies only about 20 feet below sea level at the 

 coast, the Miami Formation is not likely to exist in water depths greater 

 than 20 feet. 



The Key Largo Limestone and the Miami Formation are ascribed to the 

 Sangamon interglacial . Coral reefs flourishing during Sangamon time 

 created a shelter behind which the bryzoan facies of the Miami Formation 

 began to form. During the later stages of this period the oolitic facies 

 of the Miami Formation developed as a broad bar along the present-day 

 coastal areas fHoffmeister, et al, 1967). This depositional phase ended 

 with the relative lowering of sea level and the consequent erosion and 

 partial induration of the Miami and Anastasia Formations. The final de- 

 positional event of the Pleistocene in southern Florida occurred with the 

 rise of the Pamlico Sea which inundated the coasta-l area leaving a sheet 

 of quart zose sand covering the eroded surface of both Miami and Anastasia 

 Formations. Subsequent to "Pamlico" time the relative sea level has been 

 near or below its present stand. 



Holocene deposits along the coast consist chiefly of littoral and 

 dune sediments, lagoon fill and shelf facies sands, much of which is 

 probably derived from erosion of Pleistocene deposits and from modem 

 organic production. 



b. Nearshore Shelf Morphology and Surface Sediment 



A generalized plan of the principal morphological elements v 

 on the nearshore shelf off southeastern Florida is shown in Figure 4. 

 This plan is based on USC^GS boat sheets at 1:20,000 scale and bathy- 

 metric profiles obtained in the course of the Florida Sand Inventory 

 Program. A schematic topographic profile across these morphologic ele- 

 ments is illustrated in Figure 6. For the purposes of this report the 

 study area has been subdivided into two sections based on natural differ- 

 ences; and referred to as Section A (25°49' N to 26 "20' N) and Section B 

 (26°20' N to 26°48' N) . 



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