ICE-FREE AREAS IN ANTARCTICA 



Aircraft from the USS CURRITUCK photographed two 

 extensive ice-free areas on the Indian Ocean sector of Ant- 

 arctica. These "oases" are unusual because nearly all of 

 the other known ice-free antarctic areas are nunataks (i.e., 

 mountain peaks projecting through the polar ice plateau). 

 An expedition was organized to fly into the first discovered 

 area (Bungar's Oasis) to make a scientific reconnaisance, 

 but unfavorable weather and lack of time prevented execution 

 of this plan. However, some information about this area 

 was obtained from aerial photos and from the sample of lake 

 water obtained by the crew of Commander Bungar's aircraft. 



Bungar's "Oasis" (approximate latitude 66°15'S and 

 longitude 100°15'W) is a physiographically youthful region 

 with rugged topography and nonintegrated drainage (see 

 figs. 33 and 34). It is completely enclosed by an ice plateau 

 which, in a few localities, tends to spill into the oasis. Judging 

 from the flow lines, along the south and east boundary there 

 are rapidly flowing streams of ice; along the west boundary 

 there is a slowly moving, or possibly a stagnant, mass of ice; 

 and along the north or coastal boundary there is a mass of 

 relatively stagnant ice. Although the terrain is rugged, the 

 hills, with an elevation of only a few hundred feet, rise to a 

 concordant summit level which has the appearance of an old 

 peneplain surface. 



Scour lines indicate that, in the recent geological past, 

 the oasis must have been overridden by ice that moved first 

 in one direction and later in another. The area is covered 

 with glacial rubble, and moraines and glacial erratics are 

 present everywhere. However, the effect of the moving ice 

 in this region has been mainly erosional. The ice has rounded 

 the hills and produced roches moutonnees; it has grooved 

 the terrain and gouged out the basins that are now occupied 

 by lakes. The present physiography of the area is obviously 

 largely the result of intense glaciation of massive rock. 



The bed rock is well exposed, but it is difficult to deter- 

 mine the nature of the rock from aerial photographs. In the 

 color photos examined, the reddish brown rock appears to be 

 of a massive metamorphic type. The complexly contorted 

 nature of the rock suggestive of metamorphism can be seen 

 in figure 33.. Two large black basic dikes that intrude the 

 country rock are clearly discernible in figure 34. As there 

 is no evidence of recent volcanism or thermal activity, there 

 is little basis for the widely publicized speculation that this 

 area is heated by hot springs. The rocks of Bungar's Oasis 

 are probably a portion of a vast shield of the pre-Cambrian(?) 

 rocks that apparently forms the Indian Ocean sector of Ant- 

 arctica. 



63 



