Amery Ice Shelf Glaciology An Overview

(by Max Corry, 2018)

The initial 1963 Amery Ice Shelf glaciological work, of an exploratory nature, consisted of a line of bamboo cane stakes, referred to as accumulation stakes, emplaced on the centreline of the ice shelf. This centreline had stakes at about 2 mile intervals which extended in a south south west direction from some 40-50 miles inland from the ice shelf front, for about 125 miles down the shelf. At the northern end and near the southern end of the centreline, lateral lines of stakes of some 60 miles and 40 miles length respectively, were also emplaced. In 1964 the centreline of stakes was extended a further 20 miles towards the front of the shelf. At specific sites of this scheme being identified as Depot E, site of the last depot on the vehicle route from Mawson, G1, G2, G3, T1, T2, T3 and T4, position line astrofixes and sun azimuths for orientation were observed. At some of these sites additional localised marking and survey work was undertaken to permit more specific ice studies. When revisited and reobserved the stakes provided a measurement of snow accumulation and differences in the astrofix positions at G1, G2 and G3 gave an estimate of the speed of the surface ice movement at that location.

 

This exploratory work prepared the way for a more intensive study of the ice shelf in 1968. Throughout the winter of 1968 a small party was stationed near the 1963 site G1 at 69.5S, 71.5E, about 40 miles from the front of the ice shelf to undertake the work. During the 1968 expedition, and a subsequent resurvey in the 1969/70 summer, 88 ice velocity measurements were made using electronic distance measuring equipment and a geodetic theodolite on a 300 mile network of glaciological survey traverse lines along and across the ice shelf. These repeated measurements gave the actual movement of each survey point on the ice over the intervening period between surveys. The ice shelf surface elevation along these lines was accurately measured using optical differential levelling.

The glaciological survey traverse lines generally followed the routes of the earlier work but as the original bamboo canes were either not available or suitable for survey purposes, 88 new steel poles were emplaced to identify the surveyed positions. So as to connect these glaciological survey traverses to immoveable rock and to known horizontal and vertical survey datums the traverses were extended as follows :

 

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the northern transverse, north east from T1 (now sited further to the east as the original T1 site was never relocated - assumed buried) to Sandefjord Bay to connect to sea level, rock and the geodetic framework;

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the southern transverse, west from T3 to Beaver Lake to connect to rock and sea level as Beaver Lake is tidal, and east from T2 to rock and the geodetic framework;

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the centreline, north east for some 12 miles with a further 9 miles of optical differential levelling which was only terminated when 3 metres from the edge of the ice shelf front.

 

In the extreme south, T4 was connected to rock and the geodetic survey with a repeat of the measurement in 1970. These Tellurometer connections to the Amery Ice Shelf 1968-70 glaciological survey traverse sites from the geodetic traverse, then provided a fixed stable reference for the 88 moving survey points on the Amery Ice Shelf.

 

 

Amery Ice Shelf Glaciology Published Papers

Budd, WF (1965), Glaciological Survey of the Amery Ice Shelf, Australian Antarctic Magazine, September 1965, pp.158-159.

 

Budd, WF (1966), The Dynamics of the Amery Ice Shelf, Journal of Glaciology, Vol.6, No.45, pp.335‑358.

 

Budd, WF, Corry, MJ and Jacka, TH (1982), Results from the Amery Ice Shelf Project, Annals of Glaciology, No.3, pp.36‑41.

 

Budd, WF, Landon‑Smith, IH and Wishart, ER (1966), The Amery Ice Shelf, Proceedings International Conference on Low Temperature Science, Physics of Snow and Ice, Sapporo, Japan, pp.1_447‑467.

 

Janssen, V and Hurd, R (2008), Spatial Sciences on Ice : 50 years of Australian activities on the Amery Ice Shelf, East Antarctica available at : https://eprints.utas.edu.au/8081/