GLACIER WONDERS

Otago Daily Times, Issue 22609, 28 June 1935, Page 7

GLACIER WONDERS

FORMATION AND PROGRESS It is one of Nature's greatest miracles that ice, which itself is so easily broken or crushed, should have in it a tremendous amount of power which manifests itself sometimes in phenomena which man cannot resist. In houses the formation of ice in cold weather is capable of cracking pipes and radiators; a comparatively thin coating of ice is capable of supporting the weight of many hundreds of people when floating on the surface of a lake, and, mightiest wonder of all, a solid river of ice can carve its way relentlessly from a mountain valley to the sea or to lower Jevels. , The ice of the glacier originates from the mountain snowfall. In the depressions and valleys of mountains high up above the snow line vast masses of snow accumulate. The pressure of layer after layer of enow eventually causes it to be compressed and consolidated and the basi9 of a glacier is formed. More snow falls and gradually the mass of ice grows larger and larger until finally it begins to make its way slowly down the mountain side. To a great extent the glacier will take the path of least resistance, but it is irresistible and will break or wear off large pieces of the rock face as it grinds its way slowly downward. Tbe pace is slow, of course, but somewhat faster in summer than in winter, as is to be expected. Here and there huge cracks occur in the river of ice when it is forced to turn some, difficult corner and strained in.some other way. These crevasses, often hidden by the snow, make the crossing of the glacier a dangerous adventure to the unskilled or the unwary. As the glacier slides slowly down the slope masses of debris are collected on its surface. Some of these larger rocks are the cause of ice tables. The sun melts the surrounding snow and ice, but the small area around and underneath the rock is sheltered and stands up in the form of a table. Finally, When the glacier melts, all the debris which it lias brought down .is.. piled, .up to form a "terminal moraine." It is these terminal moraines and also the marks and wearing of rocks which enab'e geologists to determine the course of ancient glaciers and to gain information about glacial activity of past centuries.