It will be noted from the above description of the characteristics 

 of the sediment contained in this short core, that conditions were 

 markedly different at the time when the center portion of the core 

 was being deposited than at either the present time or earlier. It 

 would be interesting to speculate upon how long ago conditions occurred 

 which permitted such excellent sorting as was observed in the particles 

 deposited in the midportion of the core taken at Admiral Byrd Bay, Such 

 conditions wovild have involved retreat of the ice shelf sxofficiently so 

 that water runoff from the bare land occurred, or the existence of a 

 strong submarine current having the same power of causing well sorted 

 sediments after their deposition. 



6, Conclusions 



It is evident from the descriptions of cores taken in the Ross Sea 

 area apd in the Weddell Sea area, that there are marked differences in 

 the two areas. The continental shelf is raujch narrower on the Atlantic 

 side of the Antarctic Continent, the layer of sediment appears to be 

 much thinner, and the substratum harder. The sediments are of a more 

 grayish color on this side, but tend toward the yellow-brown shade 

 observed on the Pacific side. The only place where any degree of 

 sorting was observed was at Admiral Byrd Bay on the Atlantic side. 

 Magnetic grains vrere most evident in the Bellingshausen Sea and 

 Bransfield S trait j however, they were not abundant in the Antarctic 

 area as present inadequate sampling indicates. Radioactivity appears 

 to be nonexistent if the few tests that were made on cores can be 

 used as a criterion in the areas investigated. 



In general, organic carbon was low. This is especially notable 

 when one considers the amoimts reported from shelf areas in lower 

 latitudes, v:here organic carbon usually runs between 2 and 3 percent 

 and may, under special environmental conditions, reach as high as 6 

 to 10 percent. The Gulf of Mexico averages about 2 percent. Wien 

 one compares these figures with averages obtained in the Ross Sea 

 (0,[!6 percent), Peter I Island (0„3li percent), Atka Bay (0,37 percent), 

 and Admiral Byrd Pay (0.17 percept.), it is apparent i.hat Antarctic 

 bottom sediments are low in orgpr-ic carbon. This agrees well with 

 •some 'studies of organic carbon made in the Arctic where consistent 

 figures of less than 1 percent were reported, Bransfie3.d Strait 

 showed the highest percentages, of organic carbon, largely because 

 of the greater supply from pelagic diatoms which were most numerous 

 here. There can be little terrircnous so\irce of organic matter in 

 the Antarctic, and most or all organic matter musl come from organisms 

 of the sea, Lov: temperatures aid in retaining organic matter in the 

 bottom se^^iments but it appears doubtful if variations in oxygen con- 

 tent can have much effect. 



^'S 



