200 



ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 32 



thorities, hold that the ocean has had essentially its present salinity 

 from the beginning. Indeed this belief unconsciously tinges the 

 whole philosophy of paleontology in regard to the origin of life as 

 well as the development and evolution of marine invertebrate life. 

 It will be seen that the problem of the amount of salt in the ocean 

 at the beginning of geologic time is highly hypothetical. As, how- 

 ever, it will be shown that the age of the ocean as determined by 

 sodium accumulation can not be used as a check on the far longer 

 span of time indicated by the methods of atomic disintegration, it 

 will be unnecessary to dilate on the question of the j^rimeval content 

 of sodium. 



THE ANNUAL INCREMENT OF SODIUM 



The total quantity of sodium in the ocean is accurately known, 

 far more so than the other factors involved. From the data given 

 by Clarke (1924)* it is computed to be 1.609 X lO^^ metric tons. 



Clarke estimates that the total amount of salts carried annually 

 to the ocean is 2,735 X 10*^ metric tons. This figure is obtained by 

 multiplying the area of the globe that drains to the ocean (40,000,000 

 square miles) by the average amount of dissolved matter supplied 

 by each square mile (G8.4 metric tons). 



> Washington, H. S., Bull. Geol. See. Amer., vol. 33, p. 392, 1922. 



The data for North America are good; for Europe they are less 

 accurate ; and for the other continents hardly more than guesses. Lane 

 (1929) has recently shown that even the data for North America 

 need revision, as the method customarily used in estimating solvent 

 denudation gives results that are probably between 60 and 300 per 

 cent too high. By multiplying the total run-off of a river by the 

 chemical load obtained from one or more analyses of river water 

 during low or medium stages, the fact is neglected that as a rule 

 the great part of the run-off of a river is during the floods, at which 

 time the dissolved load is at a minimum. By taking into account 



■» Clarke uses in hi.s computations the figure 1.413 X 10^° tons, which is based on aii 

 oceanic volume of 302,000,000 cubic miles. He accepts the estimate of 327,700,000 cubic 

 miles by Kossinna as more accurate, but has not changed his computation.s ; the difference, 

 however, does not substantially affect the following arguments. 



