Pleistocene and Recent sediment source / \ \ 



Abyssal cone '^j.°|"\,* 



Mid-ocean canyon 



Direction of 

 sediment supply 

 (upslope) 



I SMOOTH FLAT TOPOGRAPHY 



(a) Abyssal plain ^^'■'^^^■'^ 



(b) Archipelagic apron .■ ,^._ 



n SMOOTH UNDULATING 

 TOPOGRAPHY 



(a) Continental shelf 



(b) Continental rise 

 (c) Smooth parts 



of oceanic rise 

 (no symbol) 



Inferred but 

 unproven 

 abyssal plain 



IV ROUGH 



TOPOGRAPHY 



OF ABYSSAL 



FLOOR 



(a) Abyssal hills and 



rough part of oceanic 

 rise and outer ridge 



V ROUGH TOPOGRAPHY OF 

 THE MID-OCEANIC RIDGE 



m HIGH 



VERTICAL 

 RELIEF 



(a) Aseismic ridge 

 plateau and 

 seamount-island 

 ine. Relatively 

 smooth locally 

 rough 



(b) Oceanic trench 



locally with trench abyssal plain 



Fig. 2. Distribution of smooth and rough topography in the world ocean. (North Atlantic after Heezen, Tharp and Ewing, 1959 ; South Atlantic after Heezen and Tharp, 1961; Indian Ocean after Heezen and Tharp, in press; Pacific Archipelagic 

 Aprons after Menard, 1956 ; Arctic after Dietz and Shumway, 1961.) 



