movement of the icehole hut, so that not enough sample was obtained 

 for analysis. In general, the bottom over the area sampled was 

 very hard and was apparently uneven with pockets and ridges. Since 

 most of the ice-deposited sediment is not dropped from the shelf ice 

 until it reaches a more northerly latitude, as pointed out by Lisitsyn 

 (1960), sediment was found in the pockets (the large Peterson grab 

 would often be completely filled); on the ridges, it was impossible 

 to obtain any sediment. Color was variable with grayish olive and 

 medium olive brown being dominant. Other colors noted were light olive 

 brown and dusky brown. None of the samples had any odor, whatsoever. 

 This contrasted sharply with the sediments taken in Newcomb Bay at 

 Wilkes Station, where many of the samples had a strong fishy or sul- 

 phurous smell (Tressler, 1960). Grain size was too large for any 

 plasticity to be evidenced. The greater portion of all samples con- 

 sisted of pebbles and sand; the amount of silt and clay was small. 

 About one-half of most samples consisted of particles larger than 

 sand size. With one exception, the sediments were poorly sorted. A 

 sample taken on 27 July 1960 showed a Phi Deviation Measure of 0.18 

 with a Phi 84% figure of 1.28. Bottom currents apparently account 

 for the well sorted condition of this sample. It will be noted that 

 magnetic content of the samples was rather low. Those samples show- 

 ing only traces of magnetic minerals were composed primarily of 

 biological detritus (silicious sponge spicules, etc.) rather than 

 sediments. This probably accounts for their unusually low percent 

 of magnetic minerals. The magnetic materials found in the samples 

 are tn the form of weathered basic rock fragments probably contain- 

 ing mud and magnetite. Only a few samples showed siliceous sponge 

 spicules in any great amount. The often encountered mat of sponge 

 spicules of the outer areas of McMurdo Sound, was not found at the 

 icehole. The greater depth of water apparently accounts for this 

 fact as was earlier mentioned by Beliaevand Dshakov (1957) and 

 reported on in Lisitsyn's account of the bottom sediments of the 

 Eastern Antarctic and southern Indian Ocean (Lisitsyn, 1960). Beliaev 

 and TJshakov found siliceous sponges dominant at depths of less than 

 400 meters. Evidently, the large sponges from which the spicules were 

 derived do not live in the deeper water adjacent to the icehole, and 

 the presence, of scattered spicules indicates current activity. 



Field inspection notes and bottom sediment analysis sheets are 

 presented as Appendix B. 



85 



