internal bedding features, mostly consisting of high angle to low angle 

 bedding planes inclined seaward. Sandwiched as it is between the blue 

 and yellow reflectors, this unit is probably a distinct stratigraphic 

 unit. 



At a depth of about 140 feet MLW nearshore, and sloping seaward 

 to about 220 feet MLW, is a zone representing an apparent unconformity. 

 Strata below this zone dip more steeply eastward and southward than the 

 overlying strata. The acoustic reflection of the dividing surface is 

 difficult to delineate in detail because it is commonly masked by strong 

 multiple reflections of the bottom-water interface; consequently, this 

 surface can be defined only as a zone separating two sets of strata with 

 generally contrasting inclinations. 



The section below the probable unconformity contains numerous promi- 

 nent reflectors more-or-less parallel to one another and dipping eastward 

 and southward. A map of a reflector in this series, called the "orange" 

 reflector (Figure 11) illustrates the structural configuration of the 

 deeper strata, at least to the 500- foot depth of penetration of geo- 

 physical records of the ICONS program. Dip of the orange reflector and 

 associated strata is about 7 feet per mile (1 on 750) . Beyond the point 

 at which the reflector dips below the range of the records, similar dip- 

 ping reflectors overlap one another to the seaward limit of the records 

 (see Appendix A profiles). 



A somewhat deeper reflector is visible in the northwest corner of 

 the Fort Pierce grid. Although it dips below the record margin a short 

 distance southward, it has been tentatively mapped northward as far as 

 Femandina. This reflector is believed to lie ajt or near the Eocene - 

 post-Eocene boundary (Meisburger and Duane, 1969). 



c. Reconnaissance Areas 



(1) General - From Fort Pierce grid north to Canaveral Bight and 

 south to Palm Beach, the field survey consists only of "zigzag" seismic 

 reconnaissance lines intended to serve as a link between detailed survey 

 areas (Figures 2 b and c) . These lines extend no more than 3.5 miles sea- 

 ward of the shoreline and cover a limited shelf zone everywhere but on the 

 narrowed shelf south of St. Lucie Inlet. Thirteen cores in the section 

 between Fort Pierce grid and Canaveral Bight provide some data on the com- 

 position of the inshore bottom and near subbottom of the area. Only two 

 cores were taken from the reconnaissance area south of Fort Pierce grid, 

 an area also deficient in other sources of sediment data, e.g., hydro- 

 graphic charts and literature. Because data are sparse for the recon- 

 naissance areas, the following discussion is necessarily in broad terms. 



(2) Fort Pierce to Cocoa Beach - The blue reflector in the Fort 

 Pierce grid can be identified on the reconnaissance lines for about 10.5 

 miles north of grid line A. At this point the reflector surface apparently 

 feathers out against the rising yellow reflector of 'the Fort Pierce grid 

 area. Consequently, sediment below the blue reflector is interpreted 



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