MARCH OF THE GLACIERS.

Auckland Star, Volume LXV, Issue 45, 22 February 1934, Page 6

MARCH OF THE GLACIERS.

NEW ZEALAND INVESTIGATIONS. (By J.C.) The news that the 1 ,- ranz Jutef and l''ox Glaciers in South Westland are steadily advancing down their valleys need not bo taken as an indication that the great ice age is returning in New Zealand. Our weather iin winter time may sometimes create the I impression that the icy regions are impinging 'rather too closely on us, but we have to Look I farther south than our West Coast glacier land for conditions really severe. West land's climate is. mild despite the fact that the glaciers descend almost to the settlers' wire I fences. There are grassy lields and even 'gardens and orchards within a short distance of the terminal face of the l'Yanz Josef, and the tongues of the two glaciers almost brush the rata bush on the lower slopes of the gorges through which they descend. I'rofessor Speight, of Cliristchurch, who reports the advance of the terminal face of the glacier, explains it as being due to a very severe snowfall in the alpine collecting basins which feed the ice streams; this snowfall of many years ago is only now making itself evident. The fact is that these glaciers are subject to )>eriodical waves of advance and retreat. Measurements such as Professor Speight has just taken to determine the movements of the glaciers have not been taken systematically in New Zealand, but it is fairly evident from such observations as have been made that periods of advance follow abnormally heavy accumulations of enow and ice in the high heart of the Alps, nine or ten thousand feet above sea level. Forty years ago Mr. A. I'. Harper and the lote Mr. Charles Douglas, of Westland, when carrying out Government exploration work on the glaciated section of Westland, took a series of measurements to ascertain the rate of movement of the Franz Josef, and found that the ice in some plaits moved as much as fifteen feet in a day, a very high rate of travel indeed for glaciers. Mr. Harper later ! came to the conclusion that a great or exceptional push forward and downward which began on the high Alps would make itself manifest at the face approximately thirty years later.

All parts of a glacier do not move at the Willie rate. The maximum rate of movement of the Franz Josef would be two or three miles up the glacier, where the ice masses, broken into pinnacles, are tossed up in wild forms like rapids in a river. On the eastern elope .of the Alps, Mr. Broderick, of tiie Survey Department, found in 185)0 that the Tasman glacier s movement was very slow at the terminal face, only two or three inches per day, and that the fastest rates were from nine to eighteen inches per day at various places near the foot of the Ball glacier. As for the Mueller glacier, he calculated that its ice moved at the rate of a mile in twenty-six years. The terminal faces of these and other glaciers visited from the Mount Cook Hermitage remain practically unaltered as to situation; the normal melting of the ice keeps pace with the downflow of accumulations from the alpine feeders. The great variations in the glaciers on the opposite and steeper side of the range are due to the more restricted character of the valleys through which the ice must find its way to the plain, and to the enormous size of the snow catchment area for which they are the outlet. That they were a great deal larger once is shown by the smoothed icecarved sides of the gorges and by such wonderful monuments as the Cone Rock, near the face of the Fox, a great rock with ice-polished sides high above the present level of the glacier.

Hie alternative phases of advance and retreat of the ice are peculiarly interesting subjects for study by alpinists and geologists. Students who seek fields of research untouched by others might also consider a branch of exploration so far neglected in New Zealand, the measurement of glacier depths, the thickness of the ice. I have been reading an account of the operations of modern glaciologists in Europe. Not only do the scientists study exactly the advance and retreat of the glaciers in the Swiss Alps and elsewhere, but they use rotary drills, sometimes working at the rate of 300 feet a day, to penetrate the ice, and they are now applying the principle of echo-sounding, which has yielded such remarkable results in marine hydrography. Explosives are set off and the echoes sent back from the bed of the glacier are recorded by means of seismographs. Such experiments are always full of interest, for everyone who has "been on a glacier wants to know how thick the ice is. The Franz Josef ice is about a hundred feet 'deep at the face, but it must be a great deal more than that up the valley. It°has been surmised that the Tasinan glacier at the point opposite the Malto Brim hut, which is nearly half-way up the valley, must be a thousand feet in depth. In the North Island we have Ruapehu's frozen cap to experiment with. Will any of our bands of young mountaineers pet busy with a drill and tell us how thick is Ruapehu's basinful of ice?