68 



MARINE BOTTOM SAMPLES OF LAST CRUISE OF CARNEGIE 



Sixty-seven samples were analyzed for barium and 

 in forty-four of these barium was present in quantities 

 greater than 0.05 per cent; in eight others it was present 

 in amounts less than 0.05 and possibly greater than 0.02 

 per cent; in fifteen samples barium was not present in 

 detectable quantities. Clarke and Steiger (1914) record 

 0.086 per cent as the average amount of barium found in 

 793 analyses of igneous rocks of the United States. 

 Orton (1924) obtained 0.2 mg barium per liter of sea 

 water. It may be seen from table 18 thatthere is no ob- 

 vious correlation between barium content and depth, but 

 on the other hand charts 8 and 9 show that there is a re- 

 lation between the amount of calcium carbonate in a deep- 

 sea sample and the barium content, and that the distri- 

 bution of barium is almost the opposite of that of boron, 

 at least as far as the Carnegie samples are concerned. 

 Nearly all the Globigerina oozes tested for barium 

 showed more than approximately 0.05 per cent whereas 

 only about half of the red clays showed the presence of 

 this element in corresponding amounts. It appears pos- 

 sible that barium is precipitated, in part at least, as the 

 carbonate in pelagic deep-sea sediments rather than as 

 the sulphate as in the case of the nodules described by 

 Jones (1887, 1888) from off Colombo and by Andr6e 

 (1918) from the East Indies. As pointed out by Steiger, 

 one of the striking facts about the distribution of barium 

 is that it is concentrated in the northeast and southeast 

 Pacific off the west coast of North and South America, 

 even at considerable distance from shore. 



Of the fifty -two samples analyzed for boron, twenty- 

 four definitely contain this element and in six others it is 

 possibly or doubtfully present. Only seven of the twenty - 

 one Globigerina oozes analyzed contain boron, whereas 

 twenty-three of the twenty-nine noncalcareous sediments 

 contain it. Three possible explanations present them- 

 selves for the concentration of boron in the deeper non- 

 calcareous samples: 



1. The samples were sent to Mr. Steiger in their 

 original condition without being washed. It is possible 

 that the boron was present in the sea salt remaining in 

 the samples and that the more clayey samples which, as 

 Trask (1932) has shown, would be expected to have a high 

 initial water content and hence to be high in salt, had a 

 correspondingly higher percentage of boron. Investiga- 

 tions of the boron content of sea water by Buch (1933), 

 Wattenburg (1933), and Harding and Moberg (1934), show 

 that boron is present to the extent of about 4.5 mg per 

 liter, and bears a fairly constant ratio to the salinity, 

 namely BS0.00013S when both quantities are expressed 

 in parts per thousand. Gebbing s (1909) analyses of red 

 clay show that the maximum sea salt content of unwashed 

 samples is about 8 per cent. Thus, if all the boron were 

 present as part of the residual sea salts, it would only 

 amount to about 0.001 per cent, a quantity much too small 

 to be detected. 



2. The concentration of boron in deeper sediments 

 may be owing to the solution of non-boron-containing 

 material during the process of settling or on the bottom. 



3. It is possible that boron atoms take the place of 

 a small amount of aluminium atoms or are otherwise 

 present in the crystal lattices of the clay minerals which 

 make up a large part of the finer fractions of the sedi- 

 ments. If this were the case, one woxild expect the red 

 clays, which consist largely of noncalcareous colloidal 

 material, to contain more boron than the Globigerina 

 oozes, which contain much smaller amounts of clay min- 

 erals. 



It may be seen from the accompanying table 17 that, 

 as pointed out by Mr. Steiger, none of the sixty-seven 

 samples contain enough beryllium or germanium to be 

 detected with the methods used. Only one of the samples 

 contains even doubtfully detectable quantities of bismuth, 

 namely sample 46, which, as will be recalled from the 

 synoptic descriptions of the samples, consists almost 



