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Victoria University Antarctic Research Expedition Science and Logistics Reports 2002-03: VUWAE 47

Method

Method

The following method was used in digging most all of the soil pits: In the area to be excavated (1m × 1m × .5m), the surface material was scrapped off and placed on a 2m square polythene tarpaulin. The underlying soil was then dug out and placed on another 2m square polythene tarpaulin. Loose soil material was dug to a depth of one metre or the top of the ice-cemented soil which ever was the shallowest. After the final pit depth, soil profile and possible permafrost or massive ground ice were described and sampled, all material from the respective polythene tarpaulins was replaced. The ground surface was raked and swept to restore as much as possible of the original appearance. Analyses of the samples will include; OSL (Optically Stimulated Luminescence) of selected dune and pit soil samples, stable oxygen and hydrogen isotopes and 10Be dating for the ice core, and major cation and anion chemistry of soluble salts for the soil samples.

The term "ground ice" refers to all types of ice formed in freezing and frozen ground (Permafrost Subcommittee, 1988 p 46). Permafrost refers to the permanently frozen (<0° C) condition and includes both dry and wet (ice) materials. "Massive ground ice" in this report refers to clear ice with a variable content of sediment >10% of the ice by weight.. Subsurface conditions in the Dry Valleys are generally different from those in arctic and alpine environments in that there is usually 30 to 60 cm of dry frozen sediments above ice cemented sediments. However, because most workers think of permafrost as ice cemented, the term permafrost in this report will include only the ice cemented materials.