Carrying on from the work initiated over the I.G.Y. period by the United States glaciological parties at Wilkes (cf. Hollin and Cameron, 1961), members of the Australian National Antarctic Research Expeditions have continued accumulation stake measurements to 80 km. inland on the plateau (lat. 66° 31′ S.) and extended them south 480 km. (to lat. 71° S.). These stake measurements, supplemented by pit data and surface observations, supply a comprehensive account of the accumulation in this region; how it builds up during the year, how it varies from year to year and how it is affected by topography.

Ice island ARLIS II, which is adrift in the Arctic Ocean, is a 1.3 km. wide and 3.8 km. long fragment of shelf ice 12–25 m. thick, which preserves several structural features heretofore undescribed in ice. The island is composed of an irregular central block of foliated, locally debris-rich, grey glacial ice bordered in part by extensive areas of stratified bluish sea ice. The central block contains a series of narrow, elongate, sub-parallel dike-like septa of massive fresh-water ice and a large tongue-like body of tightly folded, coarse banded ice. Both the septa and the tongue cut across the foliation and debris zones of the grey ice.

The margins of the central block are penetrated by a series of elongate, crudely wedge-shaped re-entrants occupied by salients of bluish sea ice. Two broad, arch-like plunging anticlines deform the stratified sea ice along one margin of the block.

The foliation and debris zones in the glacial ice are relict features inherited from the source glacier. The septa formed as crevasse and basal fracture fills. Salients represent fills formed in the irregular re-entrants along the margins of the glacial ice mass. The tongue of tightly folded, banded ice represents an earlier generation salient deformed by compressive forces as the fill built up. The broad anticlines are apparently the result of warping in response to differential ablation but the small, tight plunging folds on their noses and limbs are probably the result of compressive forces.

A four-man party representing the Arctic Institute of North America and the Department of Geology, Dartmouth College, went to the Ward Hunt Ice Shelf in 1960 to obtain ice cores for subsequent laboratory analysis. The overall objective of the project was to study the structural and stratigraphic history of the shelf and its relationship to the environment through laboratory analysis of the cores, using stratigraphic. petrologic, chemical, and physical methods.

The four cores obtained were logged, packed, and shipped to Dartmouth College for detailed study. The stratigraphy and structure of the ice were studied under natural and plane polarized light conditions. The results of this initial work showed that the cores were composed of four ice types: glacier ice, lake ice, sea ice, and transition ice. Chlorinity, sulfate, and density profiles complemented megascopic studies and were most useful criteria for plotting stratigraphie changes in ice type.

Results of the investigations thus far have yielded new information about the gross structure and stratigraphy of the ice shelf and re-entrant. They have also shown that the physical and chemical techniques employed will be useful in future ice-core analysis.

Lemon Creek Glacier served as the focus of attention of the Juneau Ice Field Research Project from 1953 through 1958. During the International Geophysical Year, it represented one of the glaciological stations in the North American network. This paper presents some of the results of these studies, its purposes being (1) to discuss the 1953–58 annual hydrological budgets, and (2) to test Nielsen’s equations for the equilibrium glacier using 1957 and 1958 movement and hydrological data.

It is found that each budget year for the period studied shows a deficit, except 1954–55 which registered a pronounced surplus. The net deficit amounts to 10.32×106 m.3 of water. The 1956–57 budget was only slightly negative (0.82×106m.3) but that for 1957–58 was strongly negative (8.96×106 m.3). Surface flow measurements were made along five transverse profiles, two of which were plotted over one full year. It is believed that the one-year measurements provide a more accurate and realistic picture of glacier flow than is normally available from short summer surveys. Thu glacier appears to be close to equilibrium and to behave in the manner predicted by Nielsen’s theory of equilibrium flow.

Lemon Creek Glacier served as the focus of attention of the Juneau Ice Field Research Project from 1953 through 1958, during which period glaciological and related research was accomplished. This paper provides an historical framework for those studies by (1) considering variations of Lemon Creek Glacier in recent centuries and during millennia since the last ice age, and (2) describing certain relationships which appear to exist between these variations and the climatic record.

It is found that Lemon Creek Glacier has been receding intermittently since a maximum c. 1750 and by 1958 had lost c. 25 per cent of the former area. Most rapid recession occurred during the periods 1891–1902 and 1929–58. Behaviour of the glacier since c. 1750 reveals a parallelism with glaciers in most of the regions where temperature trends have been graphed as well as with other glaciers of the Juneau Ice Field. The advances of the 1950’s observed in the Rocky, Cascade and Olympic Mountains do not, however, show up in the Juneau area. Lemon Creek Glacier has not advanced more than 375 m. beyond the 1750 position, if at all, during the last 10,000 yr.

East-west glacial striations and grooves were discovered on the summit ridge of Observation Hill, which parallel the present direction of shelf ice movement to the east and south-east of the Hut Point peninsula. This evidence suggests that Observation Hill may have been glaciated by a thickened McMurdo lobe of the adjacent Ross Ice Shelf, moving west, as it does today.

A comparison of polar ice (several years old) with biennial ice (between one and two years old) was made in the field at lat. 79°N., long. 104° W. Vertical cores were extracted from the ice cover and sectioned. Their ultimate tensile strengths were measured by the ring-tensile method. Supporting measurements were made of the salinity, density, and crystal structure of the ice. Tensile strength values averaged 6 per cent higher for the polar ice and 21 per cent higher for the biennial ice than comparable results for annual sea ice. A few horizontal cores of biennial ice were analysed similarly with inconclusive results.

Young’s modulus E and Poisson’s ratio σ0 were calculated for biennial and polar ice from measurements of the P-wave velocity in small samples and from a study of the resonant frequencies of the saure samples. P- and S-wave velocities in the biennial ice cover were also found by a seismic method. The small-scale tests showed no significant differences between the two types of ice tested. Young’s modulus averaged 3.6 per cent lower than the comparable figure for annual sea ice. The seismic method gave values of E and σ0 about 20 per cent lower than the small-scale tests.

Karst topography may occur on stagnant, drift-covered parts of glaciers such as the Martin River Glacier in south-central Alaska. Glacial karst features there include ice sink-holes, tunnels, caves, sinking streams, blind valleys, large springs, natural bridges, lapiés, hums, and residual “soils” or ablation till. The glacial karst cycle is essentially the same as the limestone karat cycle. Glacial karst is rare today but was widespread on stagnant glaciers in areas such as the northern Great Plains of North America in late Wisconsin time.

In the summer of 1962 a completely portable and relatively simple electrically heated thermal core drill of new design was constructed and used to obtain 16 oriented samples of ice 2.5 cm. in diameter by 120 cm. in length from depths ranging from 12 m. to 137 m. in lower Blue Glacier, Mount Olympus, Washington, U.S.A. The thermal element is a 0.260-in. (0.66-cm.) diameter 300-W. 150-V. tubular heater bent to form an annulus with an external diameter of 5.0 cm. Opposed ratchet-like teeth break off and hold the core inside the tubular core barrel. Orientation is recorded photographically by a commercial inclinometer modified to show azimuth and to be controlled from the surface.