to the transgression; e.g., subtle hills, ridges, and depressions. These 

 processes are not detailed enough on available bathymetric charts to be 

 outlined but can be detected on fathometer and seismic reflection records. 



c. Surficial Sediment Distribution and Origin . 



(1) Previous Studies . Surficial sediment characteristics of the 

 south Atlantic shelf have been covered in regional studies by Gorsline 

 (1963), Pilkey (1963, 1964), Goodell (1967), Terlecky (1967), Doyle, 

 Cleary, and Pilkey (1968), Pilkey, et al. (1969), Field and Pilkey (1969), 

 and Judd, Smith, and Pilkey (1970). These studies, though general in 

 nature, provide valuable information on the inner shelf between Cape 

 Lookout and the South Carolina border. More localized studies concerning 

 the North Carolina shelf have been made by Roberts and Pierce (1967), 

 Latemauer and Pilkey (1967), Cleary and Pilkey (1967), Cleary (1968), 

 Milliman, Pilkey, and Blackwelder (1968), Pratt (1970), and Mill iman, 

 Pilkey, and Ross (1972). 



Within the Cape Fear ICONS study boundaries, the most common surface 

 sediment has been described as pale-olive or yellowish-gray, fine quartz 

 sand. Calcium carbonate content is commonly less than 20 percent but 

 may be larger locally. Heavy minerals usually constitute less than 1.3 

 percent of the total. Pratt (1970) found that on the inner shelf of 

 Long Bay, opaques comprised 30 to 45 percent of the heavy mineral frac- 

 tion and that nonopaque heavy minerals are dominated by staurolite 

 (comprising 15 to more than 32 percent of the total heavy mineral frac- 

 tion) , followed by epidote (5 to 14 percent) , and the pyroxcene-amphibole 

 group (0 to 10 percent). Garnet, zircon, rutile, sillimanite, kyanite, 

 and tourmaline were also present but comprised less than 5 percent of the 

 heavy fraction. 



On the inner shelf of Onslow Bay, Cleary (1968) found that heavy 

 minerals increase in abundance from a low of to 0.5 percent near Cape 

 Fear" to more than 2 percent near Cape Lookout. Opaques comprise more 

 than 40 percent of the heavies in this region (Gorsline, 1963; Goodell, 

 1967) . Pilkey (1963) reported significantly higher percentages of zircon 

 and garnet north of Cape Fear than to the south (Long Bay) ; epidote was 

 higher to the south of Cape Fear. Staurolite was the dominant heavy 

 mineral species with a frequency ranging from 5 to more than 15 percent 

 of the heavy mineral fraction. Other heavy minerals found by Pilkey 

 (1963) in Onslow Bay include kyanite, pyroxcenes and amphiboles, rutile, 

 and tourmaline, all apparently with a frequency of less than 10 percent. 

 Gorsline (1963) found that staurolite comprised 10 to as high as 60 per- 

 cent of the heavy mineral fraction in Onslow Bay inner shelf sediments, 

 with an average frequency of 40 percent or more south of about Bogue 

 Inlet. In Long Bay staurolite was less than 32 percent (Pratt, 1970), 

 suggesting a further minerological division between the two bay areas. 



Doyle, Cleary, and Pilkey (1968) reported that sand-size detrital 

 mica on the southeastern Atlantic shelf is deficient in the central and 



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