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Immediate report on the Victoria University of Wellington Antarctic Expedition 1959-60: VUWAE 3

Physiography and Glaciology

Physiography and Glaciology

Owing to the restricted time that was available, no long-term glacial projects were attempted, but field observations were made whenever possible.

The Victoria Valley, formerly ice-filled is now free of ice for most of its 40-mile length. Remnants of the glacier system are now: The Lower Victoria Glacier, an invading tongue of the Wilson Piedmont, to the east; The Upper Victoria Glacier, flowing from a large ice-field to the north-west; and the Webb Glacier to the west. Bordering ranges reach an average height of 4500 feet and on these, hanging cirques and valleys show a general accordance of floor levels, These cirques often have remnants of ice on thier backwalls which commonly show small terminal moraines as evidence of recent wasting and retreat. No such evidence was seen at the snouts of major glaciers.

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The valley floors are mantled by thick moraine which rarely shows any glacial structures, but is invariably patterned by frost polygons. Although the moraine varies greatly in size and rock composition, no glacial striations were seen. Large areas of sand occur and well developed sand dunes are found to the north and east of Lake Vida. The effect of wind erosion was shown by a differential polishing on the faces of larger rocks, and quite frequently by fields of well-developed faceted pebbles.

The form and setting of Lake Vashka suggests it originated as a kettle- a deep remnant of ice left in the moraine by irregular glacial retreat. Large boulders and fine sandy bands now exposed on the surface of the lake ice support this theory. It is possible that the majority of the lakes on the valley floors originated in this way, and many may never have been entirely melted. Certainly the small lake at the head of Balham Valley and the empty depression at the junction of Balham and Barwick Valleys are of this form.

Stream beds leading into these lakes differ greatly, depending on the type of moraine on which they develop. The streams flowing westward from the Packard and Lower Victoria Glaciers over flat sandy floors have a braided course up to 100 yds. Wide. In contrast the western stream flowing into Lake Vashka is often 20 feet wide out cut 10 feet deep in coarse moraine. A great quantity of water would be required to develop a bed like this, although this summer only a trickle was running here and there. Along these streams in Barwick, Balham and Upper Victoria Valleys, well developed strings of paternoster lakes were found.