Table 1. Summary of Test Sites Investigated 



Site 



Approximate 

 Longitude 



Approximate 

 Latitude 



Water 

 Depth 



Sediment 

 Type 



In- 

 Place 

 Vane 

 Tests 



Box 



Cores 



Piston 

 Cores 



Other 



General Comments 



Feet 



Meters 



I 



III 



IV 



66°15'W 

 77°12'W 

 65°54'W 



21°N 

 28°N 



17°53'N 



17,900 

 3,700 

 6,500 



5,460 

 1,100 

 2,000 



pelagic clay 

 foram ooze 

 turbidites 



3 



2 



1 

 1 

 1 



1 

 2 



1 hydro- 

 plastic 

 core 



1 boomer- 

 ang 



Numerous manganese 

 nodules; typical 

 "red clay" 



Sediment is highly sen- 

 sitive with laboratory 

 strength less than 1/10 

 field strength 



Alternating sand-silt 

 clay layers; relatively 

 dense and competent 



IN-PLACE TEST RESULTS 



In-place vane shear tests were conducted at Sites III and IV. Site 

 I was too deep for the ONR vane tower. 



The results of these tests are given in Figures 1 and 2 in the form 

 of original vane strength and sensitivity versus subbottom depth. At 

 several points (usually in sand layers) insufficient torque was available 

 to rotate the vane. At these points an arrow is drawn indicating the 

 maximum shearing resistance developed. The actual strength would be 

 higher. 



In the sand layers at Site IV, some drainage must have occurred 

 during vane rotation. The strength given, therefore, is not a true 

 undrained shearing strength, but rather a strength index property. The 

 strengths in the Site III oozes and the Site IV silts are probably true 

 undrained shearing strengths. 



Table 1 lists the number of cores that were obtained at each site. 

 Table 2 gives the CEL identification for each core and its exact geo- 

 graphic coordinates. 



The CEL piston corer was lost during lowering at Site I. It evi- 

 dently pre-triggered 5,000 feet (1,500 m) below the ship and fell to the 

 end of the coring cable, causing the cable to part. Apparently, reso- 

 nance in the coring cable was set up by a series of consistent, large 

 swells passing through the area. The resulting large motions of the 

 corer could easily have caused pre- triggering. Future coring operations 

 will be conducted with a pressure-activated triggering device, thereby 

 reducing problems with pre-triggering. 



To conduct the coring operations at Site IV, a similar Benthos 

 corer was borrowed from NAVFAC (FP0-1) in Washington. 



