In August 1978 “Hazard Lake” released 19.62 × 106 m3 of water through a subglacial tunnel beneath Steele Glacier, Yukon Territory, Canada. The discharge during the outburst flood was measured by recording lake level changes with time, and a peak discharge of approximately 640 m3 s–1 was estimated from the data. We have attempted to model the 1978 flood from “Hazard Lake” using an adaptation of Nye’s (1976) theoretical model for jökulhlaups from Grimsvötn. Our aim has been to calibrate the Nye model as a first step toward using it as a peak discharge estimator for other glacier–dammed basins. The agreement between our measured and simulated hydrographs is good, and we find that creep closure, though included in our analysis, appears to play an insignificant role in limiting the discharge of “Hazard Lake”. Release of thermal energy from the relatively warm lake water is the dominant factor contributing to tunnel enlargement.

The Manning roughness of outlet channels from glacier–dammed lakes is not known a priori and must either be assumed or estimated after the fact from the flood hydrograph. For “Hazard Lake” our fit implies Manning roughness in the range n′ = 0.105 m–1⁄3 s, consistent with Nye’s estimate of n′ = 0.12 ml⁄3s for the 1972 Grimsvötn flood and our estimate of n′ = 0.12 m 1/3 s for the 1967 Summit Lake flood. If the Manning roughness for flood conduits can be shown to lie within a narrow range, this would constrain one of the least certain variables of the Nye model.

By making several simplifying assumptions, we have succeeded in reducing our adapted version of Nye’s model to a simple mathematical description involving dimensionless numbers characterizing reservoir geometry and the relative magnitudes of creep closure and tunnel enlargement by melting. In this simplified form, the influence of lake temperature, reservoir geometry, and creep closure on the character of flood hydrographs can be conveniently studied.

A study of the geomorphology of the Prince Charles Mountains using colour vertical air photographs shows well–preserved old moraines throughout much of the outcrop area. Along Fisher Glacier, lower Lambert Glacier and the Amery Ice Shelf, within the altitude range 50–2 000 m, the old moraines show that the ice level had risen 150–200 m above the present level at least three times. Old moraines elsewhere show that none of the other glaciers had risen significantly in their upper parts; the rise of their lower parts was caused by the rise of lower Lambert Glacier and the Amery Ice Shelf. The changes in ice level are unlikely to be due to climatic change because this would not repeatedly affect only one glacier draining central Antarctica. It is thought that the changes in ice level are caused by repeated surges of Fisher Glacier.

A simple model suggests that the ablation under a debris layer could be estimated from meteorological variables if the surface temperature data of the layer are available. This method was tested by analyzing the data obtained from experiments with artificial debris layers. Fairly good agreement was obtained between the estimated and the experimental data.

A model for the isotopic composition in δD and δ 18O of ice formed by refreezing at the glacier sole is developed. This model predicts relatively well the distribution of points representing samples from basal layers of an Arctic and an Alpine glacier on a δD–δ 18O diagram. The frozen fraction which is the part of the liquid that refreezes can be determined for each basal ice layer. This may have implications on the study of the ice–water system at the ice–rock interface.

As part of the Glaciology of the Antarctic Peninsula (GAP) programme, the snow cover at 25 stations was sampled to 10 m depth for oxygen–isotope and total β-radioactivity analysis. The mean annual oxygen–isotope ratio correlates satisfactorily with 10 m temperature despite the complex topography of the area and suggests on average that climatic trends in the region are fairly systematic. The relationship with temperature is similar to that derived from a simple model in which an air mass initially of maritime subtropical characteristics is progressively cooled as it moves towards the region. The detailed isotope profiles show that for future deep drilling the most easily interpretable climatic information will be found in the more continental areas—on the cast coast and on the plateau in the south of the region. The degree of continentality of particular sites is reflected in the amplitude of the annual wave in the upper portion of the isotope ratio profile as well as in the accumulation rate.

During the 1978 and 1979 field seasons, ice thicknesses on the Quelccaya ice cap were determined using a Worden geodetic gravity meter along a west–east traverse and using a mono–pulse ice radar sounder along a north–south traverse. The maximum ice thickness measured was 180 ± 10 m. Based upon the known thickness of the ice cap and the net accumulation, depth–age calculations indicate that an ice core record covering at least the past 600 years and perhaps 1 300 years could be obtained from this tropical ice cap.

A topographic map of the Qori Kalis glacier (the largest outlet glacier from the Quelccaya ice cap) has been compiled at a scale of 1:6 000 from 1963 aerial photography. Terrestrial photography of the glacier was obtained in 1978 and coordinates of the edge of the glacier were determined photogrammetrically. Comparison of these two shows that over this 15 year period the glacier has thinned with the terminus retreating more than 100 m. The retreat measured for the Qori Kalis glacier is consistent with the behavior of other tropical glaciers.

The small slope magnitude ε. or aspect ratio. of an ice sheet in steady plane motion under gravity user a horizontal plane bed, subject to balancing surface accumulation and ablation. and basal drainage. is determined by the aceunualation magnitude, maximum depth. and the viscous properties of the ice. Horizontal coordinate scaling by a factor ε allows. series expansions in ε for which the leading-order solution is valid ecenschee under some weak restrictions on the ice law and sliding faw. This procedure is now extended to the plane flow problem when the mean bed line is inclined at angle χ to the horizontal and the bed is not flat. The lead order problems for χ of order unity and χ of order t: are distinct. and both are treated, fiir an isothermal sheet. The present analysis is valid only for a maximum bed slope relative to the mean line of order ε or less. The amplitude of it bed profile is ill, wavelength that of’ the ice sheet may therefore be of the same site as the ice sheet depth, which allows treatment of a typical isostatic bed shape.

Surface and core samples of Neh–nar Glacier in the Kashmir Valley have been analysed for the radionuclides 32Si. 210Pb, 40K, and 137Cs. The lateral and vertical profiles (at an altitude of about 4 140 m) reveal:

(1)32Si activity decreasing slowly from the accumulation zone to 4 050 m altitude and then abruptly towards the snout.

(2)Five zones of alternating high and low 210Pb activity in the surface samples.

(3)An horizon at between 2 and 3 m depth containing 210Pb activity above natural levels. This horizon is also associated with 137Cs and a maximum in total ß activity.

The ice samples have been dated on the basis of a simplified two–component model, the “fresh“contribution determined by 2l0Pb and the old component by 32Si. The following conclusions can be drawn from these observations:

(1)The model age of the snout ice is c. 850 years.

(2)The average rate of ice movement in the lower glacier is about 2 m/year, which compares well with the annual movement rate of 2.65 m/year observed since 1974.

The Gor Garung group of glaciers constitute an ice cover of over 4 km2 in a basin of 27 km2 area, lying in the Sutlej River catchment of the north–western Himalaya. This paper, the first record of these glaciers, their moraines and lakes observed in this area, is the result of mapping the glaciers and the pro–glacial field.

An attempt has been made to utilize lichenometry for establishing relative antiquity of various terminal moraine ridges generated by these glaciers, and six groups have been determined.

Ice temperature data collected from the area of continental–type glaciers in China since 1959 are analysed. Formulae for the temperature stratification of the active layer and for annual mean temperature profiles are suggested. The temperature in continental–type glaciers in China is quite low, rising rapidly with depth. A major part of the bottom of most glaciers reaches the pressure–melting point, with basal sliding. The extreme huge valley glacier will change from a cold glacier into a temperate one when it descends to the district where the climate is temperate. The ice temperature of the lower bound of the active layer at the altitude of the equilibrium line is 1.8–3.7 deg higher than the annual mean air temperature at the same level. The western section of Ch’i–licn Shan (Qilian Shan) may be the place where the temperature of alpine glaciers is the lowest of the middle and low latitudes. The infiltration zone is warmed significantly by the infiltration and recongelation process. A scheme showing how the lower bound temperature of the active layer changes with glacial zones is drawn.

Le régime des températures dans les glaciers de type continental en Chine. On analyse les températures de la glace recueillies sur glaciers de type continental en Chine depuis 1959. On a suggéré des formules pour rendre compte de la stratification des températures du niveau actif, et pour le profil de température moyenne annuelle. La température dans les glaciers de type continental en Chine est très basse, s’élevant rapidement en profondeur. La plus grande partie du fond, dans la plupart des glaciers atteint le point de fusion correspondant à la pression, avec glissement sur le fond. Un très grand glacier de vallée se transforme de glacier froid en glacier tempéré lorsqu’il aborde une région où le climat est tempéré. La température de la glace à la limite inférieure du niveau actif, à l’altitude de la ligne d’équilibre est de 1,8 à 3,7 deg supérieure à la température moyenne annuelle de l’air à la même altitude. La section occidentale du Ch’i–lien Shan (Qilian Shan) est peut être l’endroit où la température d’un glacier alpin est la plus basse dans les latitudes moyennes et basses. La zone d’infiltration est, de manière significative, réchauffée par un processus d’infiltration et de regel. On a dressé un schéma montrant les variations de la température de la limite inférieure du niveau actif avec les zones de glaciations.

Über den Wärmehaushalt der kontinentalen Gletscher in China. Die Beobachtungen der Eistemperaturen aus dem Gebiet der kontinentalen Gletscher in China seit 1959 werden analysiert. Formeln fūr die Temperaturschichtung im aktiven Eis und fūr ein Profil der Jahresmitteltemperalur werden vorgelegt. Hie Temperatur in den kontinentalen Gletschern Chinas ist sehr niedrig, steigt jedoch schnell mit der Tiefe. Ein Grossteil der Grundschicht in den meisten Gletschern befindet sich auf dem Druckschmelzpunkt und gleitet am Untergrund. Extrem mächtige Talgletschcr wandeln sich von kalten zu temperierten Gletschern, wenn sie in den Bereich temperierten Klimas herabfliessen. An der unleren Grenze des aktiven Schichts in Höhe der Gleichgewichtslinie ist die Temperatur 1.8-3.7 deg höher als die Jahresmitteltemperatur in derselben Höhe. Der Westteil des Ch’i-lien Shan (QMian Shan) dūrfte der Ort sein, wo alpine Gletscher der mittleren und niedrigen Breiten ihre tiefste Temperatur erreichen. Die Sickerzone wird durch das Sickerwasser und die Wiedergerrierwärme beträchtlich erwärmt. Eine schematisch Darstellung zeigt die Veränderung der Temperatur der Untergrenzc des aktiven Schichts innerhalb der vergletscherten Zonen.

Movement of pack ice in Smith Sound in northern Baffin Bay was observed for April 1975 using the satellite imagery obtained by Landsat. Mean velocity was found to be directed to the south with a magnitude of 4 km d−1. The influence of the wind is discussed and the amount of ice transported from Smith Sound evaluated. The findings show that on a daily average 600 km2 of pack ice was carried out of the area.

Specimens of polycrystalline ice were experimentally deformed in plane strain at a temperature of –1°C, under a constant load and with shortening strains varying from 2 to 27%. The random c-axis orientation of the initial ice aggregates changes continuously with increasing strain towards a steady-state, small-circle containing two maxima lying about the shortening direction. The ice microstructure is sequentially transformed from undeformed grains to smaller, irregular, deformed grains containing recrystallized grains. Grain growth then occurs forming a coarse interlocking-grain aggregate. These microstructural changes are attributed to solid-state processes occurring during deformation. The previously deformed specimens were then annealed without a load at –1°C. Annealing resulted in a substantial grain-size coarsening. However, no c-axis preferred-orientation difference developed between annealed and unannealed samples.

The propensity for crack formation on basal and prismatic planes and twin nucleation on two pyramidal planes in hexagonal ice is examined on the basis of fracture theories and anisotropic elastic theories of dislocations. Calculations show that the ease of crack formation is almost the same in the basal and prismatic planes, whereas it is almost impossible to produce mechanical twinning in ice by stress alone.

Triaxial tests were carried out on randomly oriented, laboratory-made, polycrystalline ice, between strain-rates of 10–7 and 10–1 s–1 and with confining pressures from 0.1 to 85 MN m–2, at –11 ± 1°C. Below strain-rates of about 10–5 s–1 the confining pressure has little effect, but at higher strain-rates the confining pressure prevents cracking which allows the compressive strength to rise to a value greater than the unconfined compressive strength. At 1.4 ×10–2 s–1, the unconfined strength of 12 MN m–2 rises to 26 MN m–2 with a confining pressure of 25 MN m–2, before dropping slowly with greater confining pressures. Above 10–2 s–1 the unconfined strength decreases rapidly with increasing strain-rate, but the confined strength continues to increase. The dependence of strain rate on the maximum compressive stress is discussed.

The Nimbus-6 Satellite’s Scanning Microwave Spectrometer (SCAMS) mapped the terrestrial surface continuously for eleven months at 22.2 and 31.6 GHz. A semi-empirical method was devised to process these observations of Greenland and Antarctica and to infer long-term snow accumulation rates; comparison with in situ data suggests the method is generally successful except in certain locations where re-melting is more likely.

Shear tests performed on natural snow exhibited three kinds of behaviour with increasing shear rate: (1) viscous, without failure, (2) brittle of the first kind (cycles of brittle failure), (3) brittle of the second kind (only one brittle failure, and solid friction). These results can be explained by fast metamorphism of the bond system during the tests. When the shear rate is low, bonds can be regenerated after their destruction, and this regeneration is less active as the shear rate increases.

Diethyl phthalate, dimethyl phthalate, ethyl anisate, and α-tetralone are examples of liquids that can be used to fill the pore space of snow specimens. After the pore space is filled, the specimen is frozen solid. A section plane is microtomed and polished. Photomicrographic contrast of the section plane is improved by gently rubbing on to the plane a water–insoluble powder, such as carbon powder, or by rubbing on a water–soluble stain such as powder of acid fuchsin. Photomicrographic contrast is also improved by adding a water–insoluble dye such as oil blue N or oil red O to the pore–space filler.

A correlation between temperature gradient in snow–pack and material strength is found to exist in laboratory studies on temperature gradient metamorphism of snow. These results are in agreement with earlier field investigations and eliminate diurnal solar and temperature variations as reasons for the existence of the maximum temperature gradient in the zone of minimum strength. Also the laboratory studies have indicated that locally dense layers such as ice crusts tend to enhance weakness directly below the crust due to local alteration of the thermal regimen. Further studies are continuing to describe the thermodynamic process of temperature gradient metamorphism more exactly.

Ice of naled type, in the form of sheets up to 4 m thick and covering areas of 0.5–2.5 km2, is a frequent feature in front of some of the large Spitsbergen glaciers. Observations from the marginal outwash plain of Werenskioldbreen and the extra–marginal outwash plain of Gåsbreen are presented. The morphological role of this type of ice, on which forms similar to glacial eskers and kames may develop, is indicated.

Glace de type “naled” devant quelques glaciers du Spitsbergen. De la glace de type “naled” (glace de regel de l’eau de fusion) en forme de feuilles allant jusqu’à 4 m d’épaisseur, couvrant des surlaces de 0,5 à 2,5 km2, se rencontre assez fréquemment à l’avant de quelques grands glaciers du Spitsbergen. Quelques observations provenant de la plaine de lavage marginale du Werenskioldbreen et de la plaine de lavage extra–marginale du Gåsbreen sont présentées. Le rôle morphologique de ce type de glace, dans lequel peuvent se développer des formes analogues à des “eskers” ou à des “kames” glaciaires, est mis en évidence.

Festeis vor einigen Gletschern Spitsbergens. Festeis in Schollen von bis zu 4 m Dicke und einer Ausdehnung von 0,5 bis 2,5 km2 ist eine häufige Erscheinung vor einigen grossen Gletschern Spitsbergens. Beobachtungen im Gebiet der randlichen Auswaschungsebene des Werenskioldbreen und der Auswaschungsebene ausserhalb des Randes des Gåsbreen werden wiedergegeben. Die morphologische Bedeutung dieser Eisart. auf der sich Formen ähnlich den glazialen Eskern und Kames entwickeln könnten, wird herausgestellt.