MECHANICAL ANALYSES 



79 



Table 27. Mechanical analyses of certain Carnegie bottom samples by the method of 

 the United States Bureau of Soils 



Sample 

 no. 



Diameter in mm 



1-4 



4-2 2-1 



1-.5 



.5 -.25 



.25 -.12 



.12 -.07 



.07 -.03 



07 - .005 



,03 - .005 



10 



11 



13 



14 



15 



16 



17 



18 



20 top 



20 bottom 



22 



24 



25 



26 



27 



29 



35 



36 



37 



41 



42 



44 



45 



51 



53 



54 



56 



57 



58 



59 



60 



61 



62 



64 



65 



66 



79 



80 



82 



85 



88 



89 



35.0 



42.3 17.8 



9.8 



57.3 

 "3!4 



2.8 0.3 



1.4 



8.6 



tr 



0.3 

 0.1 



0.1 



Percentage in size grades 



5.0 1.6 



11.3 



7.6 



"i'.'e 



3.2 



17 '.6 



35.4 

 19.1 

 27.3 



1.3 



11.8 

 3.3 



7.6 

 48! 6 



4.2 



34.2 

 49.2 



19.6 



32.5 

 28.5 

 76.3 

 22.5 

 10.8 

 13.4 



To 



15.9 . 



57.2 

 26.5 



3.5 



24.1 

 20.6 

 41.8 



26.9 



13.2 



17.4 



19.6 



40.4 



8.7 



2.5 



6.2 



3.3 



3.2 



4.5 



4.1 



5.3 



8.3 



4.7 



<.005 



88.8 



67.9 

 80.1 



47.2 

 34.2 

 58.0 

 34.2 

 22.1 

 44.6 

 22.8 

 46.5 

 29.3 

 13.7 

 5.1 

 82.2 

 49.6 



40.4 



11.1 

 21.9 

 20.0 

 38.5 

 24.3 

 62.9 

 69.0 

 73.4 

 76.8 

 55.6 

 91.0 

 96.5 

 93.6 

 96.7 

 96.8 

 90.5 

 85.7 

 66.2 

 45.3 

 84.6 



the older method for fine-grained samples is well 

 shown in this figure. These analyses, however, do con- 

 firm the conclusions as to the uniform nature and ex- 

 treme fineness of grain of the mechanical composition 

 of north Pacific clays which were stated in the discus- 

 sion of the pipette analyses. 



Histograms for the five detrital muds and red clays 

 of the south Pacific which were analyzed, are shown in 

 figure 34. The double maxima in the size distribution 

 of sample 10 are owing to the presence of coprolitic 

 pellets. The remaining four analyses were made by the 

 pipette method and have been discussed previously. 



Analyses of the five more or less volcanic siliceous 

 muds and oozes collected northeast of Japan, samples 

 56 to 60, which have been shown to be nearly identical 

 in chemical composition, are illustrated in figure 35. 



The progressive decrease in the amount of sand-size 

 material reflects the change in physical composition of 

 these sediments, corresponding to increasing distance 

 from shore, from a deposit with a high content of vol- 

 canic debris such as that of no. 56, to an argillaceous 

 diatom ooze containing very little volcanic material, 

 such as sample 60. 



Three analyses of volcanic sediments and two of 

 near-shore sediments are also shown in figure 35. The 

 large average diameter of the material in sample 11 

 probably indicates that this is a residual deposit from 

 which the fine material has been removed by currents. 

 In samples 51 and 52 the relatively large amounts of 

 material between 1/16 and 1/32 mm diameter are ow- 

 ing to the presence of many small skeletons of radio- 

 laria and frustules of diatoms. 



