328 



HEEZEN AND LAUGHTON 



G. Abyssal Plains of Adjacent Seas 



[chap. 14 



Although geiieraUy smaller in size than the great abyssal i^lains of the oceans, 

 abyssal plains are also found in the adjacent seas. 



a. Mediterranean Sea 



The ^Mediterranean Sea is divided into three deep basins, the Western 

 Mediterranean, the Tyrrhenian Sea and the Eastern Mediterranean. The floor 

 of the Western Mediterranean is nearly completely filled by the Balearic 



98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 



98 97 



96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 



Fig. 1 1 . Chart of the physiographic provinces of the Gulf of Mexico showing the location 

 of the Sigsbee Abyssal Plain. The floor of the eastern Gulf of Mexico is dominated by 

 the Mississippi Cone. Turbidity currents originating at the mouth of the Mississippi 

 have built the large Mississippi Cone and the Sigsbee Abyssal Plain. (After Ewing, 

 Ericson and Heezen, 1958.) 



Abyssal Plain. The Balearic Abyssal Plain seems to be fed predominantly from 

 the north. It apparently spreads out from the foot of the Rhone Abyssal Cone. 

 However, the plain is probably also fed from the south, as indicated by the 

 numerous submarine canyons of the Algerian continental slope and by 

 the events associated with the Orleansville earthcjuake (Heezen and Ewing, 

 1955). The area of the Balearic Abyssal Plain probably exceeds 30,000 mi^. A 

 small abyssal plain is found in the center of the nearly circular Tyrrhenian Sea. 

 Many small abyssal hills ])rotrude from this abyssal plain. In the eastern 



