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Victoria University Antarctic Research Expedition Science and Logistics Reports 1999-2000: VUWAE 44
1 Aims
1 Aims
VUW
This project is a detailed study of ancient glacial deposits termed the Sinus Group at Allan Hills, Southern Victoria Land, Antarctica. The Sirius Group is a collection of Neogene deposits that crop out at high elevations (mostly >1500 m) throughout the Transantarctic Mountains (TAM). Allan Hills occupies a low point in the TAM, making the site more susceptible to overriding by the EAIS during minor ice volume fluctuations. The aim of this project is to show whether the Sirius Group was deposited by valley glacier or continental ice sheet, by wet- or dry-based glacial ice, by a single depositional event or several overriding events and to determine paleoflow direction.
This past field season ran from mid-November 1999 to mid-January 2000 at Allan Hills during which time field mapping of early glacial deposits was continued from last season. The Sirius Group takes the form of seven patches of thin debris with a total area of 2 km2. From these, eight outcrops were selected for detailed description and sampling. The collected data include: orientations of 300 stones, 270 linear glacial abrasions and 90 planar deformational structures. In addition, 37 rock samples were collected for laboratory analysis. Sample processing has not yet begun but evidence indicates wet-based glacial deposition. Although the number of advances is not yet known, the work thus far suggests flow from the southwest and west. The presence of a cirque incised into a surface capped with Sirius deposits on the south side of Trudge Valley reveals a later phase of local temperate ice before the present cold ice sheet formed.
Univ. of Amsterdam
| 1) | Build upon research carried out by Hiemstra and van der Meer (1999) in their field report for the Netherlands Centre for Geo-ecological research titled: Neogene Glacial History of the Allan Hills, South Victoria Land, Antarctica. This would include quantification of Sirius related glacio-tectonic bedrock deformation structures and further descriptions and sketches. |
| 2) | Collect spatially and stratigraphically variable Sirius diamict samples for analyses by micromorphology. Wherever these micromorphology samples are taken, a small sample will also be taken for bulk texture analysis. Determine whether this is possible with a University of Amsterdam hand held drill or by simply removing a block of diamict using a chisel and geological hammer. |
| 3) | Describe, sketch and quantify glacio-tectonic deformation of bedrock related to a recent advance of the Manhaul glacier. Collect spatially variable samples of Manhaul glacial diamict associated with the glacio-tectonic deformed bedrock for analysis by micromorphology. Wherever these micromorphology samples are taken, a small sample will also be taken for bulk texture analysis. |
| 4) | Collect samples of 'sublimation till' from the snout of Taylor glacier and Suess glacier, Taylor Valley for analysis by micromorphology. |
| 5) | Collect samples from the debris-laden basal layer of Taylor glacier itself for micromorphology analysis. |
| 6) | Determine the practicality of undertaking pre-impregnation of unconsolidated sediments in the Antarctic field, with daily temperatures considerably below zero. |