THE GREAT ICE AGE.

Manawatu Herald, Volume XLIII, Issue 2342, 15 October 1921, Page 4

THE GREAT ICE AGE.

FORMATION OF GLACIERS,

TRACES IN NEW ZEALAND.

“Glaciers of the Past and Present,” was the title of an interesting lecture delivered by Mr J. A. Bartram, M.Sc., before the Auckland Institute recently.

After dealing with the types and nature, of glaciers, the speaker referred to the en •rmous size of glaciers during the great ice-age. It

was estimated that during that age, :) e Ross Barrier, which most British Antarctic expeditions encountered during the voyage south, must have been 800 ft. thick, and instead of floating, as it does to-day, must have touched the bottom of the ocean, thus being solid ground. The same thing applied to the main plateau, which instead of being 000 ft. deep in ice as at present, Sir Ernest Shackleton estimated, must have been 2,000 to 3,000 feet deeper during the ice-age. These facts were in accordance with data obtained in New Zealand, America, and Europe, all of which went to show that within moderately recent geological times-all glaciers were greatly extended. In the Cambrian and Archaean ages glaciers covered enormous areas, in one case an area of 800 miles by 250 miles. Traces of these huge glaciers were now to be found in the Flinders Range and round Lake Eyre, in South Australia, in China, South Africa, India, and other countries. Of great interest was the fact that these beds lay within 30 deg. of the Equator. Another kind of glacier, the permocarboniferous, had left its traces in Brazil, India, South Africa (where one had existed 1,000 square miles in extent), and in Australia, where they had extended 000 miles up the east and west coasts, These glaciers were said to have occurred on the surface of an enormous lost • continent named Gondwahaland, which had stretched from the South Atlantic to India, and had included South Africa and Australia.

The great ice-age, said Mr Bartrum, was characterised by the repeated iiltervention of warm periods, as tlm invasion of warmth-lov-ing animals from Asia showed. Thus lions had invaded England at one period, whereas reindeer and other Arctic fauna came in at another.

Evidence of the extention of glaciers in the ice-age was found, in New Zealand in Central Otago —in the numerous lakes there, and in those of Canterbury and Nelson. Professor Park had supposed that an ice sheet had covered the centre of the North Island at one period of this age, and he had described traces found near Hautapu and Mount Ruapehu. The only certain evidence obtainable, however, said the speaker, was in the Tararua Ranges, where a comparatively insignificant glacier had existed. Various attempts had been made to account for the existence of the ice-age. The theory most generally held accounted for the world-pre-vailing cold by a reduction of the carbonic acid content of the earth’s atmosphere. This extraordinary reduction was due to a great uplift of the land in the ice-age, the consequent exposure of an immensely larger surface of the earth and the uncovering of the oceans leading to the absorption of a greater amount of carbonic acid gas through rock weathering. The absorption of such a proportion of this gas would remove to a large extent the blanketing effect of the atmosphere, and would thus lead to the comparatively unhindered radiation of heat from the earth’s surface.