centage of sand-sized material increased signif- 

 icantly over the mean for the whole core, as in 

 core E-21, 22 to 36 cm. and 39 to 42 cm. and 

 E-28, 20 to 28 cm., did the percentage of mate- 

 rial finer than 1.0 micron decrease again in 

 subsurface layers. 



Mineralogy 



The chief clay-sized minerals which were 

 found in the samples examined by X-ray dif- 

 fraction consisted of illite, chlorite, kaolinite, 

 and an expandable component which is proba- 

 bly montmorillonite. The percentages of each 

 clay group (table 2) revealed moderate varia- 

 bility with depth in the cores examined, with 

 the greatest differences existing between the 

 surface (0 to 3 cm.) and lower layers. 



The percentages of chlorite-kaolinite ranged 

 from 21 to 32 percent in core E-26 and from 

 13 to 32 percent in core E-21, with the highest 

 percentage occurring in the surface layers of 

 both cores. The percentages of illite ranged 

 from 33 to 50 percent in core E-26 and from 

 32 to 44 percent in core E-21 with the highest 

 percentages in the lowest and surface layers 

 respectively. In core E-26 the surface layer 

 contained the second highest value of illite (48 

 percent). The percentages of montmorillonite 

 ranged from 20 to 42 percent in core E-26 and 

 from 24 to 53 percent in core E-21 with the 

 lowest percentages occurring in the surface 

 samples. 



The peak area ratios (table 2), chlorite- 

 kaolinite /illite and montmorillonite/illite, 

 range from 0.43 to 0.74 and 0.41 to 1.27 respec- 

 tively in core E-26 and from 0.39 to 0.72 and 

 0.53 to 1.55 respectively in core E-21. In core 

 E-26 the montmorillonite/illite ratio shows an 

 increase with depth in the core in the upper 

 brown layers followed by a sharp decrease on 

 entering the upper gray layer. This ratio in- 

 creases again in the secondary brown layer and 

 adjacent layers in core E-26. The peak area 

 ratios for core E-21 support the observation of 

 an increasing montmorillonite/illite ratio with 

 depth in the upper brown layers but reveal no 

 increase in the montmorillonite/illite ratio in 

 secondary brown layers. 



Microscopic examination of the coarse frac- 

 tions from the upper layers of core E-26 re- 

 vealed minor amounts of black crusty material 

 in the layer 3 to 7 cm. from the surface and 



light brown earthy material in the layer 7 to 

 10 cm. from the surface. X-ray diffraction pat- 

 terns (table 10) of these substances revealed a 

 number of peaks which could not be attributed 

 to any of the common detrital minerals and 

 which did not seem to fit any of the published 

 diffraction patterns of iron and manganese 

 minerals. Many of the unidentified peaks were 

 broad and diffuse, suggesting small particle 

 size and/or poor crystallinity. 



Examination of the coarse fractions from 

 other brown layers in core E-26 and in other 

 cores revealed physically similar substances to 

 those X-rayed but never in abundance except 

 for core E-31 which contained abundant co- 

 prolitic matter in a secondary brovsTi layer (20 

 to 23 cm.). X-ray study of this substance 

 (table 11) proved it to be the iron phosphate, 

 vivianite. Andrew (personal communication) 

 also reported an occurrence of vivianite in a 

 secondary brown layer in core N-77 (fig 3). 



Vertical distribution of nondetrital 

 iron and manganese 



The vertical distribution of iron and manga- 

 nese and sediment color in cores E-26 and 

 N-148 is compared in figure 8. Manganese and 

 iron are enriched in separate bands somewhat 

 below the sediment-water interface in dark 

 brown and yellowish-brown or reddish-brown 

 layers respectively. Iron, and to some slight ex- 

 tent manganese, are also concentrated in sub- 

 surface brown layers but the enrichment here 

 of both elements is not nearly so pronounced as 

 in the near-surface layers. The Mn/Fe ratio 

 (tables 12 and 13) is not constant but varies 

 from 5.54 at 3 to 4 cm. to 0.03 at 8 to 9 cm. in 

 core E-26 and from 1.40 at 5 to 6 cm. to 0.01 at 

 43.5 to 44.5 cm. in core N-148. The particu- 

 larly high value for manganese (6.20 percent) 

 at 3 to 4 cm. in core E-26 is notable because 

 the value is higher than is usually observed, 

 even in total sediment analysis. A secondary 

 peak is observed on the shoulder of the major 

 manganese peak in both cores. 



Regional distribution of nondetrital 

 iron and manganese 



In the surface sediments of the Kara Sea the 

 concentration of nondetrital iron varies be- 

 tween 0.43 and 3.04 percent, the concentration 



