RETREAT OF GLACIERS

Dominion, Volume 32, Issue 93, 13 January 1939, Page 3

RETREAT OF GLACIERS

Worldwide Phenomenon

OBSERVATIONS IN NEW ZEALAND

The retreat of glaciers within-recent years apr>eared to be , almost worldwide in its incidence, Professor R. Speight, Christchurch, told delegates to the jubilee congress of the Australian and New Zealand Association for the Advancement of Science in Canberra yesterday. Observations made up to the present indicated a general retreat of New Zealand glaciers within historical times, he added in his paper, ‘‘Some Aspects of Glaciation in New Zealand.” Professor Speight expressed regret, however, that little accurate observation had been carried out in connexion with New Zealand glaciers.

Qualifying his remarks on the worldwide retreat of glaciers, Professor Speight pointed out that of the 160 glaciers in the European Alps, of which there were reasonably complete records from 1911 to 1928, about 75 per cent, showed retreat, whereas for the period 1931 to 1935, of 380 glaciers observed only 10 showed advance, and that only a few metres. There were isolated instances where advances occurred for a particular year, although for the four-year period they showed retreat.

In Scandinavia, of 20 glaciers observed tietween 1912 and 1928, ail showed retreat, and of 43 between 1931 and 1936 all showed retreat, though there appeared to be a period from-1931 to 1936 when advances occurred in some cases for several successive years, but there was a balance in favour of retreat for t'he whole period. During the period 1931-35, all the glaciers of Iceland, 27 in number, with one exception, showed retreat, and the advance of the exceptional glacier was only 56 metres, as compared with a retreat of 250 in the ease of some other glaciers. The glaciers of Greenland and Spirzbergen-also showed retreat. A similar recession occurred also with glaciers of the Sierra Nevada and other high mountains of western United States, though there were a few slight advances. The Antarctic lee-sheet showed signs of recent retreat, though this could not be stated definitely to be analogous to the retreat recorded from other parts of the world during the past few years.

professor Speight said the probable reason for the absence of indieatior.« of glaciation in New Zealand in late Pabi-euzoie times was that the country did not then form.part ut’ an extensive land surface. In the South Island the present glaciers were restricted to the main range of the Southern AJps from the vicinity' of Milford Sound and the head of Lake Wnkfitipu. to Arthur’s Pass, some 150 miles north-east, occurring in. that section of the range with summits exceeding 7500 ft. in height. In the North Island a glacier occupied the erater of Rutipeliti. tint! small overilows therefrom mantled, the upper slopes of the vMctino. Parts of the 'country now no longer glaeierized showed clear traces of the former presence of ice, added Professor Speight. In central ami north-west Nelson, and specially along the Hauks of the Spenser Mountains, at the head of the Wairau Rivers, and in the High country further north, occurred mo“alnes. parched, scoured and scratched surfaces, and also in places on the valley floors, deposits of varied silt. Even the coastal ranges to the west showed signs of being retouched by ice.