SECT. 2] 



TOPOGRAPHY OF THE DEEP-SEA FLOOR 



239 



100 



SCALE IN NAUTICAL MILES 

 400 _ 500 600 



0- 



2- 

 4- 

 6 



8- 

 10- 

 12- 

 I4-- 

 16- 

 18- 



I 

 I 



margin ^ -^Abys.sal floor — 



Abyssal plain' Abyssal 



■^ tills-' ■ 



o 



-1000 



-2000 



-3000 



-4 000 



-5000 



6000 



7000 



8000 



9000 



-10.000 



UNCONSOLIDATED" SEDIMENTS ANO^ 

 SEDIMENTARY ROCK 



CONSOLIDATED" SEDIMENTARY ROCK 



VERTICAL EXAGGERATION 40 I 



0- 



-I 000 

 -2000 

 -3000 

 -1 000 

 5 000 

 6000 

 -7000 

 8000 

 ■9 000 

 -10.000 



300 200 



CRYSTAL 



100 100 200 300 400 500 



STRUCTLHE AND CONTINKNTAI. MARGIN PKONINCKS 



Fig. 8. Crustal structure and continental margin provinces. The three profiles represent 

 typical areas of the continental margin of North America. They may represent 

 a genetic sequence, starting with an unfilled trench, such as Puerto Rico, and ending 

 with a filled marginal trench, as illustrated by the Newfoundland profile. (After 

 Heezen et al., 1959.) 



