W 90' 60° 30° 0° 30° E 



E 30" 60" 90" 120" 150° E 



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I 150°180°150°1ZO° 90° 60° W 



PLJ^■re 1. World-map of ocean depth. 

 Isobalhs for 1000 and 2000 m and from Ihcre on for each 2000 m-mlcrval. The isohalh are denoted on the maps by 100 



Colouring: 0- 1000 m light yellow; 1000 - 4000 m light green; 4000 - 6000 m blue; 0000 m red. 



W 60" 30° 0" 30" E 



(for example 4000 m = 400). 



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