ABSTRACT 



Results of oceanographic operations during the U.S. Navy Antarctic Survey Operations in 

 support of DEEP FREEZE II, 1956-1957 are presented. 



In the Little America Area the surface layer temperatures varied greatly, depending on 

 currents, winds, and shelf-ice melting. A temperature minimum was likely at about the 200- 

 meter depth close to the Ross Ice Shelf. Low salinities (34.00 °/;,o or less) were evident in 

 the surface layers near the ice shelf. 



In the McMurdo Sound Area water mass characteristics were nearly identical for any given 

 time; changes were brought about by seasonal variation. 



The Antarctic Convergence is not well delineated. Vertical temperature and salinity meas- 

 urements taken north of, in, and south of the convergence in the Atlantic, Pacific, and Indian 

 Oceans depict the water dissimilarities; surface positions are shown. 



The Antarctic bottom sediments coincide closely with the continental shelf. They are of 

 marine glacial type, for the most part unsorted, and primarily of terrigenous origin. The 

 dominant mineral of the sediments appears to be feldspar, while quartz and a wide variety 

 of rock fragments are of secondary importance. Organic remains include Foraminifera, Radio- 

 laria, sponge spicules and many other forms. These sediments generally range in color from 

 olive grey to yellowish brown, possess low to medium sphericity, and vary in degree of round- 

 ness from subrounded to angular. Sediments are predominantly volcanic, in the MclVIurdo 

 Sound-Cape Adare region, primarily rock fragments in the Weddell Sea, and primarily organic 

 in the Wilkes coast region. 



Occurrence and depth of the deep scattering layer (DSL) were observed and reported 

 throughout the cruise. 



Ice observations and reconnaissance by the USS GLACIER, USS ATKA, USS STATEN 

 ISLAND, and USCGC NORTHWIND are presented and discussed. 



