Bungar's Oasis is a land of lakes, many of which are 

 entirely ice-free, whereas others contain brash ice and 

 growlers. Some of the lakes occupy glacial gouge basins or 

 are impounded by moraine or ice dams, forming a poorly 

 integrated system. Water from some of the ice-impounded 

 lakes must escape to the coast either through crevasses or 

 through subglacial tunnels. The lakes are deep blue in color 

 except where discolored by inflow of muddy water from fast 

 flowing streams. The blue color suggests a relative paucity 

 of organic matter in the lakes, but simple organisms such as 

 algae are undoubtedly present. The aircraft crew reported 

 that the water in the lakes felt several degrees above freezing; 

 however it is doubtful if thermal springs have played any 

 part in heating the water. The lakes are presumably fed by 

 glacial melt waters by the melting of snow banks accumulated 

 during the winter and by precipitation. 



The sample of brackish water collected from one of the 

 larger lakes, reported to be at an elevation of 200 feet ac- 

 cording to the aircraft altimeter, was analyzed by N. M. 

 Rakestraw. The chlorinity of the sample is 12.01 o/oo (sa- 

 linity 21.71 o/oo, if sea water), which is a little more than 

 half that of sea water. The Ca:Cl is 0.0217 (0.0215 is the 

 average Card of sea water). The S0 4 :C1 is 0.140 (0.140 is 

 the average SO^rCl of sea water). This analysis indicates 

 that the water in this particular lake is composed of sea 

 water diluted with rather pure fresh water. 



The discovery that this reported brackish lake water is 

 diluted sea water is reasonable, because it would be difficult 

 to understand how a saline lake could form in this region 

 where the inflow of the water to the lakes must certainly 

 exceed its evaporation. The reported lake elevation of 200 feet 

 is probably in error because there was a difference in at- 

 mospheric pressure of about minus 0.2 inches of mercury 

 between the point of take-off and the lake; this would make the 

 actual situation of the lake little, if any, above sea level. 

 The lake must be impounded by an ice dam, and the actual 

 coast line (i.e., the zero contour line) must lie close to the 

 oasis. The aircraft crew estimated the shoreline to be 10 or 

 more miles away, but this shoreline is the contact of barrier 

 ice with the open sea. The fact that the salinity of the water 

 is less than 25 parts per thousand is of interest since such 

 water will reach its greatest density above its freezing point 

 and in winter, like a freshwater lake rather than like the 

 ocean, it will freeze only at the surface. A reservoir of 

 water of above-freezing temperature will remain beneath 

 the ice during the winter and will speed up the thawing process 

 with the coming of summer. 



64 



