Figure 42. Paleocrystic ice. 



the average power of the paleocrystic fields at 30-and-more meters, noting at this time that even in 

 the frontier seas of the Siberian shoreline, where the ice is weaker, separate grounded hummocks 

 attained greater dimensions . 



LITERATURE: 67, 77, 



171. 



Section 50. Glacier Ice 



In the North Arctic Ocean, along the shores of antarctica, and also in some areas of the mid- 

 dle latitudes of the world ocean, aside from the ice formed of sea water, glacier ice is found, which 

 differs from sea ice both in its forms and in its properties. In high mountain passes and in the low 

 latitudes, and especially in the polar regions, where during the course of the summer a smaller 

 amount of snow melts than has been precipitated during the winter, a constant accumulation of snow 

 occurs in depressions. In addition, the snow which had fallen on neighboring, more elevated points 

 of the locale, is carried into the same depressions by the wind and by the weight of the snow itself. 

 It is clear that an accumulation of a great amount of snow is aided by high latitudes, the great ele- 

 vations above the level of the sea, and marine climate which is characterized by the frequency and 

 intensity of winds off the sea, which carry with them moisture and abundant precipitation. 



Gradually, with the increase in the amount of snow cover, the lower layers of the snow under- 

 go important changes. First of all, due to the pressure of the upper layers, they become more 

 solid. Secondly, due to the effect of the same pressure, which lowers the temperature of freezing, 

 they are gradually transformed. 



The first phase in the transformation of snow is "fim ice," which consists of a conglomera- 

 tion of separate ice grains, white in color, and the size of peas. The next stage is a "bubble ice, " 

 which forms from the seeds of the fim frozen together and which includes within itself great 

 amounts of air bubbles. 



In time, the air bubbles are pressed out through cracks by pressure of the upper layers, and 

 the last stage is obtained — "blue glacier ice. " 



120 



