PRESENT INVESTIGATION 



Field Procedure 



Seventy -three sediment cores, 6 grab samples, and 4 deep sea camera lowerings 

 were made from aboard USS SAN PABLO (AGS -30) during September 1961 and 

 February 1962, The cores were collected at depths varying from 430 to 2,800 meters, 

 and the average length of each core collected was 99 centimeters. Fifteen of the 

 sediment samples were obtained with a Hydro-plastic piston corer and the remainder 

 with a Kullenberg gravity corer. Cores obtained with the Kullenberg apparatus were 

 coated with a microcrystalline wax a few hours after collection to inhibit loss of 

 moisture. In a few instances the hydrogen ion (pH) concentration at the top of the 

 core was measured with a Beckman pH meter. A small portion from the top and 

 bottom of each core was removed as soon as the core was brought aboard and stored 

 under refrigeration while awaiting organic carbon analyses. 



Sampling stations were positioned by Decca Hi-Fix navigational aids in the 

 area of the TOTO north of Green Cay, and visual and radar fixes were used in the 

 cul-de-sac. Locations of sampling stations are presented in Figure 4, and coordinates 

 of sampling station, length of core, and water depth are listed in Appendix I. 



Photographs of the bottom were taken with an underwater camera system con- 

 sisting of two 35 mm cameras and two 100 watt -seconds strobe light sources. A sonar 

 pinger, mounted on the camera frame and used in conjunction with the ship's trans- 

 ducer, and a Precision Graphic Recorder provided monitoring of the comera-to-bottom 

 distance. A compass direction vane was suspended below the cameras to Indicate 

 direction of camera movement and orientation of the photographs. 



The camera system was held within 5 feet of the desired 15 feet from the bottom 

 distance during the photographing sequence. Between 276 and 572 meters was trav- 

 ersed during the 2-hour period of each lowering. Along these tracks, photographs 

 of the bottom were taken every 14 seconds. Subsequent to the field operations, 

 relief from selected photographs was measured and contoured. Camera lowering 

 positions are shown on Figure 5, 



Laboratory Analyses 



Utilizing facilities provided by the Marine Laboratory, University of Miami, 

 all cores were analyzed within two weeks from the date of collection. Subsequent 

 to lithological examination and engineering properties analyses, subsamples from the 

 cores were forwarded to the Oceanographic Office for further analyses. The following 

 is a tabulation of the analyses performed and description of the terms employed in the 

 data summation tables and the text: 



Constituents: A visual estimate, based on microscopic examination, of the 

 constituents constituting the sand size and larger material present in selected 

 core subsamples. 



