BATHYMETRIC MAPS AND GEOMORPHOLOGY OF THE MIDDLE ATLANTIC 



CONTINENTAL SHELF 



BY FRANKLIN STEARNS, RESEARCH OCEANOGRAPHER 



BUREAU OF COMMERCIAL FISHERIES ENVIRONMENTAL OCEANOGRAPHIC RESEARCH PROGRAM 



WASHINGTON, D.C. 20242 



ABSTRACT 



Large-scale bathymetric maps covering the northern 

 two-thirds of the Middle Atlantic Continental Shelf 

 have recently been published. They were compiled at 

 a scale of 1:125,000 from 39 smooth sheets and are 

 contoured in 1-fm. (1.8 m.) intervals on the shelf and 

 in 10-fm. (18.3 m.) intervals on the upper slope. 



Part 1 of this report discusses the construction and 

 reliability of these maps. In addition, a short review 

 of surveys made in the mapped area is given, a few uses 



for the maps are suggested, and the reliability diagrams 

 (which appear on each map) are explained. 



Part 2 discusses the past geologic history, the general 

 distribution of sediments, and the major geomorphic 

 processes at work in the area. In addition, the several 

 physiographic regions and features on the Middle At- 

 lantic Shelf are described in terms of their topography 

 and sediments. 



The Middle Atlantic Continental Shelf is one 

 of the world's most studied shelf areas. The 60,000 

 square nautical miles ^ of drowned coastal low- 

 land making up its surface have long been of in- 

 terest to mariners, commercial fishermen, and 

 scientists. Numerous nautical chart surveys, 

 ooeanographic studies, and geophysical, geolog- 

 ical, and biological investigations have been made 

 in the area (Geyer, 1948; Drake, Ewing, and Sut- 

 ton, 1959 ; Heezen, Tharp, and Ewing, 1959 ; Mur- 

 ray, 1961 ; Drake, Heirtzler, and Hirsliman, 1963 ; 

 Stearns, 1963; Uchupi, 1963; Livingstone, 1965; 

 and Emery, 1966b) . 



The Middle Atlantic Continental Shelf borders 

 one of the world's largest concentrations of hu- 

 man activity. Called Megalopolis by Gottmann 

 (1961), this region contains almost one-fifth of 

 'the population of the United States and is a 

 vast market for marine resources of all kinds. 

 The shelf supplies Megalopolis with commercial 

 and sport fisheries, recreation on the seashores, 



^I use Engllsb fathoms and nautical miles throuKhout the 

 paper because aJl the data -n-cre collected in English rather than 

 metric units. For conversion, 1 fm. equals 1.83 m.. and 1 

 nautical mile equals 1.85 km. 



Published June 1969. 



FISHERY BULLETIN: VOL. 68, NO. 1 



mineral resources, and space for waste disposal. 

 The need for detailed bathymetric maps in the 

 study of Continental Shelf geology, geomorphol- 

 ogy, and mineral resources is well known (Veatch 

 and Smith, 1939; Emery and Schlee, 1963; 

 Emery, 1966b). Less widely appreciated, but 

 equally important, are the uses of such maps in 

 the synthesis and study of physical and biological 

 data. 



The shape of the sea floor can influence the 

 movement of water masses on the shelf, and this 

 movement can affect the distribution of such 

 oceanographic properties as temperature, salin- 

 ity, and nutrient elements (Bigelow, 1931; Hach- 

 ey, Lauzier, and Bailey, 1956; Trites, 1956). Al- 

 though only a few benthonic animals are known to 

 respond directly to the shape of the bottom (e.g., 

 see Yonge, 1962), all marine animals respond to 

 tiie distribution of water-mass properties, which 

 are affected by the bottom. Hence, definite cor- 

 relations exist between the shajje of the Ixjttom 

 and the locations of marine animals (see Parker 

 and Curray, 1956), and detailed studies of en- 

 vironmental relations on the shelf require a de- 

 tailed knowledge of bathymetry. 



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