One of the riddles which is puzzling geologists all over the world is the continuous retreat of the ice glaciers. Does this phenomenon indicate that the sun is getting hotter as some astronomers believe or is it dependent upon comparatively unimportant changes in the earth’s atmosphere ?
Consideration such as these were discussed by Professor R. Speight, formerly professor of geology at Canterbury College, Christchurch, New Zealand, and now curator of the Canter-
bury Museum. In his presidential address to the geology section of the Science Congress to-day. His subject was “Some Aspects of Glaciation in New Zealand.”
The steady retreat of the glaciers in New Zealand he said had been observed during the last 70 years. Photographs taken in 1896 and 1935 showed that several glaciers had retreated distances varying from 100 yards to half a mile in 40 years.
WORLD-WIDE PHENOMENON
The phenomenon, however, was world-wide. Equally impressive records were obtainable from Switzerland, Scandinavia, Iceland and the United States. Attempts had been made to reconcile these observations with the Bruckner cycle of climate change every 16 years. Professor Speight said, but so many discrepancies occurred that in his opinion precise synchronisation with that period could not be accepted.
In Alaska glaciers had been retreating from 100 to 200 years, the average rate of recession being about 50 feet a year. The Antarctic ice-sheet also showed signs of recent retreat.
“In fact,” said Professor Speight, “no case is recorded of a region of the world in which there are present signs of an advance. This is quite apart from the general retreat since the pleistocene age and may be merely a pacing phase. Its precise significance can only be determined by continued observation.”
