376 



THE DEEP SEA 



U-238 



(a) 



U-238 -^^^^ ^ lo 



8X10" 



U-238 



7X10 



Ra 



1.6X10' 



1X10 



T 1.6X10 Tl 



lo >-Ra- 



Pb-206 



Pb-206 



U-235 



Pb-208 



Geochemical balance of the nuclides of three radioactive families in the ocean. 

 The contributions are expressed in grams per square centimeter per year (Koczy. 

 1956; Koczy et al., 1957). 



\ Contribution by rivers J, Loss due to precipitation on the floor 



— > Loss due to radioactive | Contribution by dissolution of the ocean 



disintegration floor 



