The structure of silty ice bands and the formation of their resulting shear moraines are investigated in the light of new evidence provided by two ice tunnels and additional surface investigation in the general Thule area. Previous investigations are examined and discussed; a new interpretation of the phenomena is presented.

The Burroughs Glacier, south-east Alaska, is a slow-moving remnant (14×3km.) of a much more extensive glacier. It is now entirely below the firn line; ablation has revealed ice structures and fabric once 300 m. or more below the glacier surface.

At the present glacier surface three kinds of ice are identified—foliated ice, coarse-grained border ice and very coarse-grained basal ice.

Two systems of fine-grained foliation are present. Differential movement in the glacier has caused recrystallization along closely spaced planes. At the glacier surface this produces a steeply dipping longitudinal foliation. A gently dipping foliation, having a regional trough-like structure, may be associated with former stratification planes or with former spoon-shaped shear surfaces.

The optic orientation of crystals in the coarser layers of the foliated ice shows three weak maxima, and in the finer layers a single weak maximum, corresponding to one of the coarse layer maxima, and normal to the gently dipping foliation plane. The other maxima in the coarse layers are orientated close to the poles of principal fracture planes.

In the coarse ice the fabric shows a pattern with three maxima similar to that obtained in torsion shear experiments. In the glacier the pattern may be formed by shear near the glacier bottom or along gently dipping foliation planes. Grain-size increases towards the glacier terminus, especially in the stagnant ice zone.

Structural evidence suggests that in the early stages of the Little Ice Age the ice flow was from west to east. Later it was to east and west from an ice crest in the upper Burroughs Glacier. Structures produced by present movement have been superimposed on older structures.

An unusual humped formation of floating ice, about 10 m. high, 100 m. wide and 1,200 m. long. was observed on the Ottawa River, Canada. Some characteristics of this formation are described. The cause of the humps was found to be frazil ice deposited in a trench about 90 m. wide, 90 m. deep and 1,200 m. long. The frazil ice was formed in rapids up-stream from the humps.

Previously reported experimental temperature data were used to compute the two components of the heat flux vector in the ice body adjacent to a crevasse in a glacier of the ice sheet of northern Greenland. Graphical differentiation techniques were employed. The computed components were used to synthesize values of the beat flux vector, including magnitude and direction. Improved accuracy was achieved over the previously reported technique of sketching heat flow lines orthogonal to the isotherms.

A drilling operation and core investigations at Base Roi. Baudouin (lat. 70° 25′ 5″ S., long. 24° 18′ 38″ E.) in January 1961 are discussed. The drilling, undertaken with light equipment, attained a depth of 115.72 m. From the start serious difficulties were encountered so that it was decided to use a SIPRE auger driven by the mechanism of the drilling machine. Core recovery was close to 100 per cent. Below a depth of 43.70 m., since the drill had reached the zone of high ice density (0.85 g./cm.3), a 3 m. double core barrel was used with air circulation. A depth of 79.33 m. was reached with a core yield close to 100 per cent. From this level downwards to the final depth of 115.72 in. the core yield was only 55 per cent.

Preliminary observations were made at the site. A stratigraphie profile of the first 43 m. showed an al terna-ion of coarse-grained summer layers with ice formation and fine-grained winter deposits. From the seasonal alternations of the last six years, an average annual accumulation of 38.3 cm. of water was calculated. No coloured or dust layers were observed. Between 9 and 16 m. and between 41 and 44 m. an intense formation of ice was noticed. The depth-density curve is similar to those found by the. Norwegian-British-Swedish Antarctic Expedition at Maudheim and by the Americans at Little America V. If an average annual accumulation of 38 cm. of water is assumed, the whole depth drilled corresponds to approximately 240 yr. Temperature measurements could not he carried out b;rcause of the limited time available.

Detailed stratigraphie and morphological studies of the cores, which are stored at −15°C. in Brussels, are planned, as well as chemical and isotopic investigations.

Specimens of polar snow from the South Pole, Antarctica, were tested to investigate air permeability K (cm.sec.−1), ultimate compressive strength σc (g.cm.−2) and dynamic Young’s modulus E (g.cm.−2) as a function of density. Anisotropy in a single layer of snow (snow between two summer crusts) was found in all three properties. Comparison with data for snow from Site 2, Greenland showed an empirical relation for both areas:

Air permeabilities are different at the two sites because of time and meteorological effects.

Observations in the glaciological pit of Little America III (1939–41), carried out in March 1957 and in January 1958, are discussed. Of particular interest is the analysis of the settling of firn over a period of 17.6 years. The observed data, including those of Wade taken in 1940 and of Howard in 1947, were fitted best by a logarithmic expression, which proved useful as an interpolation formula. From the computed values of the rate of settling, and the observed density-depth relation, the average accumulation is calculated, using Sorge’s law. For the undisturbed period 1947–58 an average annual accumulation of 19 g./cm.2 is found for Little America III (position in 1958 about lat. 78° 26′ S., long. 163° 52′ W.).

Temperature, inclination, and closure have been measured in a 309 m. deep drill hole at Byrd Station, Antarctica. The results of five series of measurements taken yearly since February 1958 show that temperatures below 70 m. have remained constant since December 1958, that the closure rate has accelerated, and that the hole has undergone negligible inclination from the vertical. Anomalous temperatures in the upper levels of the drill hole are attributed to the steel casing that was permanently emplaced to a depth of 36 m. during drilling in 1957–58. A positive temperature gradient was observed in the casing, but negative gradients exist below the casing and a constant gradient profile is developed below 170 m. Both ice motion and climatic changes at Byrd Station are thought to have contributed to the formation of the observed negative temperature gradients. Insignificant bending of the drill hole would imply negligible differential motion in the upper 300 m. of the 2,400 m. thick ice sheet at Byrd Station. The rate of hole closure has accelerated throughout the 4 yr. period of observations, except at the bottom of the drill hole, where the most recent measurements (February 1962) show that some constraint is now developing. Deformation rates throughout the drill hole are not proportional to some constant power of the stress; instead the value of the power has been found to increase with both increasing stress and time of application of stress. This behavior is attributed to some process of continuous deformational recrystallization of ice in the walls of the drill hole. A recoring of the deformed drill hole to investigate such effects is advocated.

An ice surface map of central Marie Byrd Land has been compiled from aero-altimetric data taken on 14,000 km. of flight lines during the Antarctic summer of 1960–61 using standard aircraft equipment. A large depression sloping down towards the Filchner Ice Shelf was determined and earlier known features in the area are shown in greater detail.

The glaciological work of six expeditions from Makerere University College to the Ruwenzori between December 1957 and July 1961 is described and some results are given.

The history of glaciological research in the Ruwenzori mountain range is outlined and the present ice distribution is described. A variety of evidence is presented to illustrate the pattern of change over the last 50 years, and all the glaciers examined are shown to have been drastically reduced in size, with an apparent acceleration in melting since the 1940’s. Six glaciers are known to have disappeared completely, whilst several others have split into smaller units.

A detailed survey of the Speke Glacier on Mount Speke was made, and calculations show that if the present trends continue all the ice below 4,573 in. on Mount Speke can he expected to disappear within the next 40 years.

The Elena and Savoia Glaciers on Mount Stanley and the Moore Glacier on Mount Baker are described, and recessional rates for each glacier are calculated. Measurements of the ice movement of the Elena Glacier demonstrate that it is still a fairly active glacier, although the Moore Glacier is thought to be completely stagnant. Other scientific measurements of glaciological significance include subglacial temperatures for the Elena Glacier, melt-water flow rates from the Speke Glacier and solar radiation measurements for several stations near the Ruwenzori ice margins.

The annual layers in an ice sheet become thinner by plastic deformation, and measurements of annual accumulation by the examination of cores therefore need correction. A simple correction factor is derived.

The Pindari Glacier is situated in the heart of the Kumaon Hills in lat. 30° 17′ N. and long. 80° 0′ E. This glacier was visited by the authors in October 1959 when morphological and other observations were made. On the basis of these observations, it appears that during the last hundred years the rate of retreat of this glacier has been phenomenal, and it may be as much as 132 ft. (40.2 m.)/yr. There is also evidence that in the past the Pindari valley suffered at least two glacial advances.

Mass budget studies on the glaciers of Axel Heiberg Island, Canadian Arctic Archipelago, during the summers of 1959–61, resulted in recognition of five distinct zones in the accumulation area. The 1961 data from these zones of the main glacier investigated are presented. The implication is made that the long-term changes in size, elevation and net accumulation of these zones can be utilized as climatic indicators.