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Victoria University Antarctic Research Expedition Science and Logistics Reports 2004-05: VUWAE 49

Method

Method

Sampling sites were selected for the occurrence of massive relict ice. At each site, a 1.5 square metre pit was dug into the ice free soil or sediment above the relict ice. In some areas ice cemented sediment was above the relict ice. This was sampled by means of a small gasoline powered hammer drill with a diamond or carbide core bit. Once into the relatively sediment-free relict ice, a sipre auger with carbide cutters was used to core to a depth of about one metre.

Ian Graham and co-workers at GNS, Lower Hutt, will carry out the dating method using atmospheric 10Be. The procedure will be similar to that used in previous studies (Dickinson et al. 2003b; Graham et al. 1995; Graham et al. 2002). To streamline the method, we will only process the >62 micron fraction of sediment which we believe contains most of the Be.

Samples of relict ice taken at 5cm intervals down the sipre auger cores were subsampled and sent to Ron Sletten at the University of Washington for chemical and isotopic analyses (see supporting letter).

Resistivity soundings (one dimensional, vertical profile) were made in selected locations where relic ice was sampled. The results are expected to help characterize the extent and depth of the relict ice. Previous attempts by A. Hubbard (pers. comm. 2001) and H. Conway (pers. comm. 2003) to define the depth of the ice by ground penetrating radar (GPR) have yielded ambiguous results because of salts that have accumulated in the soils and ice. Apart for these two surveys, other geophysical surveys to define the depth of the ice have not been conducted in Beacon Valley.