Tables 857-858 651 



OCEANOGRAPHY 



(See Nat. Res. Council Bull., 85, 1932.) 

 TABLE 857. — Pacific Ocean Basin. Areas and Depths (Littlehales) 



Depths, km 0-2 2-4 4-6 6-8 Over 8 Total area 



Areas, 1 o e km 2 18.580 31.632 1 15-593 H-4^6 0.521 177-752 



% of whole 10.5 17.8 65.0 6.4 0.3 100 



With much more steeply sloping shores on the E. and W., this ocean, with its Polynesian 

 characteristics, presents a very irregular depth map. Along W. coasts of both N. and S. 

 America steep slopes are remarkable, descending from great heights of Rocky Mts. and 

 the Andes to depths of 4 km or more within short distances; off S. A., between io° and 

 35° S., depths to 8 km near coast. All soundings > 8 km near land, off S. A., Aleutian Is., 

 Kurtle Is., Japan, etc. There are numerous isolated volcanic formations, e. g., Hawaiian 

 chain. The largest and deepest depressions are in the gigantic Pacific basin. Tuscarora 

 deep, 8.513 km; 3 elongated tracts 45 , 38 , 31 lat. > 8 km for 38 km 2 . Manchu deep, 

 31 N., 142 E., 9.435 km for 4 km 2 ; Fleming deep, 23 48' N., 144 6' E., 8.650 km deep; 

 Tonga deep, 23 39' N., 175 4' E., 9.184 km; Aleutian deep > 6 or 7 km near S. A., 

 25° 4 2 ' S., 7i°3i' W., 7.635 km. These deeps are as a rule not associated with the pits 

 of great basins but are nearer land. 



Note : The Arctic basin is about \ of Atlantic Ocean in extent ; greatest depths about 

 4 km. The Antarctic Ocean basin falls steeply from its continent to 2 km. 



TABLE 858. — Physical Properties of Sea Water (Thompson) 



Temperatures. — Tropical, surface up to 28 C, < o° C at bottom. Northern Pacific, 

 extreme variation < 6° throughout. Generally decreases with depth. 



Pressure. — Atmospheric surface pressure generally neglected, called zero. Pressure is 

 f(wt.) =f (temperature, chlorinity, compressibility, latitude). Gravity = f( latitude). 

 Bjerknes (1909) proposed a "bar" as unit of pressure = that due to column of water 

 10 m high. 



Concentration. — Dilute solution of several strong electrolytes. An ionizing medium 

 better than distilled water ; dielectric constant is greater. Composition much the same, 

 varying mainly in dilution. 



Salinity (s) is defined as the total amount of solid material in one kg of sea water when 

 all the carbonates have been converted into oxides, the Br and I replaced by CI and all 

 organic matter completely oxidized. Chlorinity (CI) = total amount chlorine in one kg 

 when all the Br and I have been replaced by CI. S — 0.03 + 1.805 CI. Thus chlorinity 

 may be reduced to salinity (Knudsen, Hydrographical Tables, Copenhagen, 1901). The 

 principal ions, chlorinity 19.374% are (Ditmar, 1884) : 



Cations Na+ Mg++ Ca++ K + Anions .... Ce" S0 4 -- HCCV C0 3 - Br- 



g/kilo 10.722 1.207 0.417 0.382 g/kilo 19.337 2.705 0.097 0.007 0.066 



moles/l 4662 .0533 .0104 .0098 moles/1 ... .5453 -0281 .0016 .0001 .0008 



Totals: 12.818 g/kilo Totals: 22.212 g/kilo 



0.5397 moles/1 0.5759 moles/1 



For fresh water Ca + , HCO3", and COs" predominate. 



Smithsonian Tables 



23 



