Record Search Query:[Parameters: Topic='LAND SURFACE', Term='FROZEN GROUND', Variable_Level_1='PERMAFROST']
Soil pit description and analysis (thin sections, cation and anion chemistry of soluble salts) from Beacon, Arena and Pearce Valley to determine the origin of ground ice at high elevations in the Dry Valleys
The origin of ground ice at high elevations (>1000m) throughout the Dry Valleys of Antarctica was investigated as the origin is unclear because there is no obvious comtemporary source of water. A model to explain the occurrence of ground ice in glacial sediments and bedrock was developed from previous work at Table Mountain. The model is based on mineralogical, chemical and isotopic analyses of ... ground ice and frozen sediments that come from cores of Sirius Group sediments at Table Mountain. The model indicates that ground ice and diagenetic minerals accumulated over long periods of time from atmospheric water vapour and brine films formed on the surface of the ground. This model was tested at three other geologically different locations in the Dry Valleys including Beacon Valley for its polygonal ground, glacial sediments and old ice, Arena Valley for its potentially old, non-glacial soils, and Pearce Valley for its abundance of young glacial sediments at a low elevation. A total of 21 soil pits were generally dug in the centers of polygons to control the comparison between different sites and areas. Loose soil material was dug to a depth of 1m or the top of the ice cemented soil, which ever was the shallowest. The soil and permafrost were described and sampled. Samples were analysed for thin section of soil clods as well as major cation and anion chemistry of soluble salts in the soils and ice from the permafrost to determine (a) if a chemical and mineralogical relationship exists between the soils and ice cemented sediments, (b) if there are differences in the chemistry and mineralogy of the soils and ice cemented sediments between the different areas and (c) the relationship of relative soil age, chemistry and ice content to polygonal ground.