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Victoria University Antarctic Research Expedition Science and Logistics Reports 1964-65: VUWAE 9

INVESTIGATIONS ON THE GLACIAL AND PERIGLACIAL GEOLOGY OF THE MIERS AND TAYLOR VALLEYS

page 10

INVESTIGATIONS ON THE GLACIAL AND PERIGLACIAL GEOLOGY OF THE MIERS AND TAYLOR VALLEYS,

Special interests of the tiers and Taylor Valleys lie in their ice covered lakes end in the problematic bonches which run around the valleys. Our team began research with the ridges of rock dotritus, commonly and erroneously called ice-cored moraine, which lie on the ice and run inside the margin of Lake Miers. Drilling proved the ridges to be only superficially covered with rock debris and to be essentially of rure ice. Observation showed that they are probably now rising from the lake at the rate of about one [unclear: on] a day. It appears that during freezing end thawing that accompanies weather changes ice melts then water freezes along vertical fissures in the ice. The resultant expansion of the ice is camulative towards the shore and causes thrusting in that direction. In the centre of the lake low domes and basins are formed and at the lake edge the ice is warped into sharp folds. Where the lake shallows gently the ice meets the bottom 50 yds out and ridges are formed there but where the bottom is steep ridges thrust on to land. Ice pushes up ridges of gravel and boulders to form ridges and benches on land, under the ice and on the ice. The resultant bonches differ from familiar lake terraces but now they are understood they can be recognised at levels up to 1500 ft. above sea level.

In view of the general topography this indicates that ice covered water once occupied the Taylor and liters Valleys and probably many similar valleys and that all of those valleys were fiords or arms of the Ross Sea. In turn this Bonus that the region has probably all been uplifted by above 1500 ft in petit glacial time. That is borne out by studios of the sediments of the liters and Taylor valleys. These are not the normal deposits of valley glaciers but include fine sediments and salt deposits probably laid down under a floating ice shelf like the present Ross Barrier. Ice from the Ross Sea flowed up the valleys and as it melted any contained rock sank to the bottom. At the heads of valleys glaciers flowed into waters of the fiords and on melting also laid [unclear: down] characteristic sediments.

This general explanation satisfies many of the anomalous features of the glaciation of the region. The concept of uplift is consistent with ideas on the- structure of Antarctica and the Ross Sea and the finding is generally important.

Further and related studies concerned the unusual nature of rock erosion in a frigid and arid environment. Frost and wind cause erosion on a scale not previously thought possible, end have produced remarkable land forms which will probably be described during the coming year.

The region is still of surpassing interest. It has provided an excellent and unequalled field of research in this as in poet years and remains a profitable venue for future explorations.

J. Bradley.