Abstract:
The process of ice accretion at the base of dry polar glaciers in the Dry Valleys of southern Victoria Land was examined. The Suess, Canada, LaCroix and Taylor glacier in the Taylor Valley, the Lower Wright and the Clark glaciers in the Wright Valley and the Upper Victoria glacier in the Victoria Valley were all sampled. Five glaciers terminated in or near lakes, and the other two terminated high
... on the valley side but were investigated as examples of glaciers that have not interacted with lakes.
There were five main objectives of the study including:
1) to determine the base cation and chloride concentration of white glacier ice, basal ice and lake ice from glacier margins,
2) to determine the ion exchange capacity of sediment samples from the terminus of glaciers,
3) to determine the origin of basal ice in dry based alpine glaciers,
4) to determine whether lake ice/water is accreted to the base of dry based glaciers and
5) to determine whether lake ice occurs in thrust block moraines which form at the glacier terminus.
At each glacier margin basal zone ice and white glacier ice was sampled at the glacier terminus with sampling sites sketched and photographed. Ice was also sampled from ice-cored thrust block moraines with the area sketch and photographed. Samples of lake ice and water were taken near the terminus of each glacier. Water samples from below the frozen surface and moat water were sampled from lakes including Lake Popplewell, Lake Chad, Lake Fryxell, Lake Hoare, Lake Bonny, Lake Brownworth and Upper Victoria Lake. Conductivity was measured from basal ice, apron ice and lake moat water as an indicator of ion concentration. Sediment was sampled to investigate the rate and influence of ion exchange on glacier melt water. Base cation and chloride concentration and ion exchange analyses were conducted on melt water samples.