340 



HKEZEN AND liAUGHTON 



[chap. 14 



2800 FATHOMS 



1000 



2800 FATHOMS 



100 



200 300 



NAUTICAL MILES 



AQO 



500 



600 



Fig. 21. Eight east-west profiles across the Northwest Atlantic Mifl-Oeean Canyon. 

 (After Heezen et al., 1959.) 



places exceeds the gradient of the canyon. The gradient west to east is about 

 1 : 1500 while the gradient of the cany6n from north to south is about 1 : 2250. 

 The canyon forms gentle meanders and, as its gradient decreases, it changes its 

 cross-sectional shape from a narrow deep canyon to a broad shallow one. 



A second mid-ocean canyon of similar form and shape has been traced for 

 350 mi in the northwest arm of the Sohm Abyssal Plain. It is possible that this 



