occurrence of plant debris and hydrotroilite (an amorphous monosulfide of Iron 

 FeS.HoO) in ungraded beds within cores from the North Atlantic. However, it can 

 be shown that no evidence of organic entrapment is present in the graded portions of 

 axial sediments, and organic carbon values from turbidites in this area follow the 

 general decrease in organic matter with depth found throughout the sediment. 



Mass Physical Properties : Axial cores display relationships between physical 

 properties with depth in the sediment which are similar to the near-flank group. 

 Sediment density generally increases with depth; conversely, water content, void 

 ratio, and porosity values generally decrease with depth. 



Table IV shows the sediment from this area to be slightly denser and considerably 

 lower in water content, void ratio, and porosity than near-flank sediments. In addi- 

 tion, the axial group shows less magnitude of variation of these values around the 

 mean. 



Below are the maximum, minimum, and average values of the properties tabulated 

 in Table IV: 



Property 



Maximum 



Minimum 



Average 



Wet Unit Weight 



1.76 



1.53 



1.66 



Water Content 



89.1 



44.5 



66.9 



Void Ratio 



2.58 



1.35 



1.75 



Porosity 



72.1 



56.3 



63.0 



Cul-de-sac Sediments 



Bottom samples representing cul-de-sac sediments are from the flat, central area 

 of the cul-de-sac and the flanks bounding the northern and northeastern portion of this 

 area (Fig 6). Cores from the central portion of the cul-de-sac are differentiated from 

 near-flank and axial cores by more frequent turbidites, poorer sorting, lower density, 

 higher water and organic carbon content, a high void ratio, and a higher porosity. 



Cores included in this group are: 



62-40 62-45 62-56 



62-41 62-46 62-59 



62-42 62-53 61-11 



62-43 62-54 61-12 



62-44 62-55 61-16 



Cores 62-45, 62-46, 62-44, 62-53, and 62-55 are arbitrarily included in the 

 cul-de-sac group because of variations in color and the presence of a few recogniz- 

 able turbidites; however, these cores are very similar to near-flank cores and the 

 difference between the two is slight. 



33 



