are present in slielf sands beyond the 60-foot contour (Terlecky, 1967). At Cape Canaveral 

 tliesc ooids are present in both shelf and beach deposits, suggesting that an exchange of 

 material has taken place between the two environments (Pilkey and Field, 1972). 

 4. Inner Shelf History. 



Certain events in the Cenozoic history and evolution of the inner shelf are indicated by 

 data collected for this study. Reflection records yield good evidence of several episodes of 

 erosion and fragmentary evidence of the sedimentary processes and environment controlhng 

 deposition of some units. Sediment cores contain much hthologic and faunal data relating to 

 tlie history and origin of the late Tertiary, Pleistocene, and Holocene section. 



Seismic reflection data throughout the area show no evidence of structural deforma,tion 

 or faulting sufficient to reverse stratal positions. Therefore, it is assumed that superposition 

 is valid in estabUshing tlie relative ages of reflection and sediment units. 



The earliest event recorded in the ICONS survey is erosion of the Ocala Group limestone 

 before deposition of overling Miocene strata. The erosional interval is inferred from the 

 locally irregular nature of the green reflector in the area where it correlates with the top of 

 the Eocene in onshore wells. Tliis erosional episode probably correlates with the 

 post-Oligocene, pre-Tampa Stage (Miocene) erosion of rocks underlying the Florida 

 peninsula (Puri and Vernon, 1964). 



Evidence of probable erosion of unit E can be seen throughout the penetration range of 

 tlie seismic reflection profiles; thus, assuming that erosion took place in a subaerial or 

 littoral setting, relative subsidence of more than 450 feet has occurred off northeastern 

 Florida since late Oligocene or early Miocene time (about 26 million years B.P.). 



Following erosion of E unit, sea level rose and D unit was deposited on the eroded 

 surface. Internal reflection in D unit can be seen only in a small part of the study. Where 

 visible, the secondary reflectors suggest that the unit consists of thin parallel beds of a 

 homogeneous sediment. Such a deposit is usually associated with nonturbulent depositional 

 conditions occurring in deep or protected waters. 



The evidence at hand indicates that the D unit was in place before the uplift resulting in 

 the high off Daytona Beach. 



Whether the surface of D unit was eroded before deposition of C unit is not known 

 because the contact between these two units is obscure. Later erosion of high standing parts 

 of the unit did apparently occur and is discussed later. The internal bedding pattern 

 of C unit suggests that this deposit may have formed as either a river mouth delta or a tidal 

 platform at the entrance to a large estuary. Subsequently, the unit was planed off by 

 erosion. This erosion surface (wliite reflector) also transgresses the top of the older D unit 

 where it supplants C unit in the area south of Jacksonville (Fig. 14). 



The general smoothness of the white reflector surface and apparent lack of channels 

 incised in underlying units suggest that the surface may have been eroded in a shallow 



79 



