d. Relict, or remnant from an earlier environment such as a beach or 

 dune. 



e. Detrital material, or presently supplied from rivers, coastal erosion, 

 and eolian or glacial activity. 



Emery (1952) stated that in most coastal environments, the nearshore zone 

 is composed of modern detrital sediments, while the shelf is composed of 

 relict sands. 



Curray (1964) stated that stratigraphy of the continental shelf is a func- 

 tion of the following: 



a. Fluctuations in sea level. 



b. Rate of sediment input to the continental shelf. 



c. Sediment grain size and mineralogy. 



d. Rate of energy input. 



e. Rate of relative sea level change. 



/. Continental shelf slope. 



Curray (1964) found that the onshore (transgression)/offshore (regression) 

 migration of the shoreline, and subsequent sediment dispersal and rate of 

 net deposition/erosion of sediment on the continental shelf are functions 

 of the rate of sea level rise (subsidence of the land) or sea level fall (emer- 

 gence of the land) (Figure 9). Migrations of the shoreline and deposition 

 of sediment on the continental shelf are important in understanding the pa- 

 leogeography, sources, environments, and deposition mechanisms of 

 sediments. 



Examples of Inner Shelf Sedimentary Features 



There exist a wide range of sedimentary features on the inner shelf 

 ranging in scale from linear shoals (also known as ridge and swale topog- 

 raphy) (hundreds of meters) to individual bed forms (centimeters to 

 meters). 



Large-scale sedimentary features 



The large-scale sedimentary morphology of the middle Atlantic Bight 

 was first extensively documented during the Inner Continental Shelf Sedi- 

 ment and Structure Program (ICONS) undertaken by the U.S. Army Corps 



Chapter 4 Sedimentary Features/Stratigraphy of the Inner Shelf 



41 



