HNrT.A.S.g;TFTFn 



SECURITY CLASSIFICATION OF THIS PAOE(irh«a Data SnlarMQ 



20. Abstract (Continued) 



Analysis shows the shallow subbottom is characterized by two continuous 

 mappable acoustic horizons which lie nearly parallel to the present surface. 

 The lower one lies at about 40 to 80 feet subsurface and is mid-Pleistocene 

 in age. The upper sonic reflector lies between 10 and 40 feet below bottom, 

 and correlates well with a marked lithologic change from overlying unconsoli- 

 dated sediments to deposits partially lithified by blocky, mosiac, calcite 

 cement. Radiocarbon dates of intertidal shells and of overlying peats indi- 

 cate this horizon is a pre-Holocene regressive surface. Slightly oolitic 

 sediments comprising the layer are interpreted to represent a coastal complex 

 deposited during a late Pleistocene (mid-Wisconsin) high sea level. Tertiary 

 strata are truncated by a Pleistocene erosion surface lying at between -120 

 and -160 feet MSL. Overlying Quaternary sediments average about 80 feet in 

 thickness. 



Surficial sediments adjacent to Cape Canaveral are medium to coarse, well- 

 sorted quartzose-mollusk sand. Areal distribution and thickness (up to 40 

 feet) of this modern sand is directly related to topography: deposits are 

 thickest beneath topographic highs, generally less than 5 feet thick on flat 

 areas, and absent in depressions. Late Pleistocene regressive sediments, which 

 locally crop out, and overlying mid-Holocene, transgressive coastal (lagoon, 

 barrier) sediments, have been reworked and reshaped to form an undulatory 

 surface of active sediments. Late Quaternary and modern deposition has 

 centered around the large, south trending, cape-associated shoals. The large 

 plano-convex isolated shoals lying seaward of cape shoals, particularly The 

 Bull Shoal, represent remnants of earlier cape-associated shoals segmented and 

 stranded during late Holocene sea-level rise. 



Studies of area beach sediments show them to be derived from: erosion of 

 the shoreface; onshore transport from adjacent shoal regions; and southerly 

 longshore transport into the area. Petrology, faunal assemblages, and textural 

 characteristics indicate that local coastal and shelf sources have been more 

 important in the genesis of modem areal beach sands than southerly longshore 

 drift. 



Nearly all of the surficial sand deposits are suitable for beach restora- 

 tion, and the thick deposits associated with topographic highs are the most 

 suitable. Extensive deposits of sand suitable as a borrow source comprise The 

 Bull, Ohio-Hetzel, Chester and Southeast Shoals, which have minimum volumes of 

 32, 76, 9, and 15 (xlO^) cubic yards, respectively. Volumes of suitable sand 

 in unsurveyed portions of Chester Shoal and Southeast Shoal are likely an 

 order of magnitude larger. Total volume of surficial medium-grained sands withii 

 the confines of the study area is over 2 x 10^ cubic yards. 



UNCLASSIFIED 



SECURITY CLASSIFICATION OF THIS PAGEfHTien Datm Enterarf; 



