IV. GEOMAGNETISM 
A. Summary of Operations 
The program of geomagnetic measurements aboard STATEN ISLAND during DEEP 
FREEZE 61 was the first extensive shipborne investigation of the earth's magnetic field 
made in Antarctic waters by the United States. Approximately 22,000 miles of con- 
tinuous total magnetic intensity profiles were recorded for the entire cruise. Of these, 
approximately 11,500 track miles were recorded south of New Zealand. Ship positions 
were determined by celestial navigation and dead reckoning. Errors in position were 
estimated to range from approximately 5 nautical miles to perhaps as much as 50 nauti- 
cal miles under the most adverse conditions. A brief discussion of significant findings 
from the Antarctic portion of the cruise is presented in this report. Data from other 
portions of the cruise are presented in profile or tabular form. 
B. Compilation of Data 
Total intensity data were scaled and converted to values in gammas (1 gamma = 
1079 oersted); no corrections for diurnal variation were made. Profiles of data south 
of 45°S, corrected for regional gradient, were plotted along the ship's track as shown 
in Figures 30 and 31. Figure 32 presents comparative profiles of magnetic and bathy- 
metric data measured simultaneously during a crossing of the Pacific - Antarctic Ridge. 
Total intensity values obtained on the cruise south of 45°S are compared in Figure 33 
with total intensity values taken from H. O. Chart 1703S for the year 1955, 
Measurements made while the ship was hove to at oceanographic stations, and 
short profiles recorded while in open channels in the ice are presented in Figures 34 
through 39. Continuous measurements made during the transits north of 45°S are 
depicted as sections along the ship's tracks in Figure 40. Profiles were prepared for 
each section and are presented in Figures 41 through 53. 
C. Discussion of Data 
The objective of the geomagnetic program aboard STATEN ISLAND was to inves- 
tigate the character of the earth's magnetic field in this largely unexplored region. 
It was anticipated that the magnetic data collected would yield new information con- 
cerning the composition and possible structure of upper layers of the earth's crust. 
As anticipated, examination of the data collected has revealed several quite signifi- 
cant characteristics. In addition, several new problems requiring further investigation 
have been found. 
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