A brief description of the resistivity method is given, stressing the points which are of particular importance when working on glaciers. The literature is briefly reviewed.

D.C. resistivity soundings have been carried out on Unteraargletscher at three places for comparison with earlier seismic reflection results. While in two cases a fair agreement was obtained, the third sounding indicated a strong inhomogeneity of the ice, making a reliable interpretation impossible. Using the seismic depths in the interpretation, more reliable values of ice resistivities were obtained. Additional apparent resistivities were measured on ice and firn on Grosser Aletschgietscher, which are discussed together with similar results from the literature. The resistivity values of temperate glaciers observed so far fall in the range from 25 to 120 MΩ.m. and are thus significantly higher than the experimentally determined ultimate value of 5 MΩ.m. reported for extremely pure ice at 0°C. by Eigen and others (1964). The necessary conditions fur successful resistivity soundings are discussed.

The electrical resistivity of firn and ice of ice sheets is a function of the “base” resistivity, the contact resistance between the grains, and the temperature. At greater depths temperature is the predominant influence, and observed resistivity curves can be explained by temperature variations which agree partly with the theories of heat conduction in ice sheets.

Ice thickness and resistivity of an Arctic glacier have been systematically investigated by the geoelectrical method. Further measurements were carried out on the ice cap. Favourable conditions for soundings were encountered, since the ice masses proved to be generally homogeneous, and there was a sufficient difference between the resistivities of ice and bedrock, while the surface layer differed only very little from the ice mass. A higher resistivity was found for bedrock than for the ice.

An attempt has been made to measure the D.C. resistivity of ice directly by placing plane–parallel samples between two electrodes with guard rings. Very strong polarization effects were observed which were most pronounced in ice from an ice–cored moraine, lesser in glacier ice, and the least in artificially frozen ice.

The growth modes of ice crystals in supercooled water and various aqueous solutions were studied at different supercoolings by a motion-picture technique. ln pure water contained in plastic capillary tubes, ice dendrites formed which at supercoolings between 1 and 4°C. grew parallel to the tube axis. At supercoolings larger than 4°C. the direction of growth was inclined to the tube axis such that the dendrites hit the tube wall and afterwards proceeded growing in a new direction. As a result it appeared that the ice crystals grew in a zig-zag or screw fashion. This growth mode became enhanced when the supercooling was increased or salts were dissolved in the water. In large water drops, ice dendrites formed which at supercoolings smaller than 1°C. were co-planar with the seed crystal and between 1° and 5°C. split into two dendritic segments. At supercoolings larger than 5°C. multiple splitting of the seed crystal was observed and this became strongly enhanced when salts were dissolved in the water. Tentative explanations for these results are given.

Dendritic aggregates of ice and brine formed upon freezing of aqueous solutions have been studied. Chlorides of sodium, potassium, lithium and hydrogen were used as solutes; structures produced on freezing of binary, ternary and quaternary solutions were examined. Effects of freezing rate, solute concentration, solute diffusivity, mixing of solutions and magnetic fields are reported.

The spacing between ice platelets or dendrites was found experimentally to be proportional to the square root of the freezing time when the freezing rate was constant from beginning to end of solidification. During unidirectional freezing from a constant temperature chill, the solution at each location is subjected to a spectrum of freezing rates; dendrite spacing increases linearly with distance from the chill surface and it is inversely proportional to the square root of the maximum freezing rate.

In binary solutions dendrite spacing increases linearly with solute concentration; above a critical solute concentration ice platelets develop side branches. Application of an external magnetic field has an effect similar to increasing concentration. At a given solute concentration, spacing between ice dendrites increases linearly with solute diffusivity.

In ternary and quaternary solutions dendrite spacing is a function of the concentrations and diffusivities of each of the constituent solutes.

When a surface layer of the soil freezes, both heat and water diffuse from the unfrozen soil beneath to the frozen region. Often the soil does not freeze homogeneously but distinct ice lenses form. An analysis of the diffusion and ice nucleation processes suggests conditions under which ice lensing can be expected; in particular, it is shown that multiple ice lenses cannot form unless the soil thermal diffusivity is greater than the water diffusion coefficient. Analysis of a simple one-dimensional case (a semi-infinite mass of homogeneous soil whose surface temperature is suddenly lowered) gives the temperature and water-content fields as functions of time; these agree with those observed in an experimental study of freezing clay.

The flow near the end of a glacier in a steady state is investigated by using a theoretical model: a plastic–rigid material with a constant flow stress resting on a rough horizontal bed. Starting from an appropriately chosen slip-line far from the end, the slip-line field is constructed numerically and continued to the end of the glacier. The field rapidly settles down to a form independent of the precise starting conditions. In the region of small surface slope it agrees with the approximate analytical solution reported earlier (Nye, 1951). To avoid a breakdown in the method it is found necessary to modify the bed by a trivial amount over the final 3 m. In practice the ice can lose contact with the bed very near the end, and the effect of this on the solution is discussed.

The velocity field is computed for a uniform ablation-rate. Other distributions of ablation-rate could be accommodated, but there appears to be a critical gradient of ablation-rate beyond which the slip-line field fails.

A series of concentric debris bands crop out on the frontal stagnant zone of Sørbreen, Ny Friesland, Vestspitsbergen. The contained debris, which is dominantly sand and silt with some clay and gravel, is well sorted and banded, and it is thought to be derived from subglacial fluvial deposits. These debris bands give rise to a complex series of bedded moraine ridges, and bedded and unbedded sediment sheets on the glacier surface.

The development of a supraglacial hummocky moraine is traced and it is composed of several elements: supraglacial ridges, kettle-holes, and flowed sediment sheets, which are derived from debris bands; supra-glacial fluvial deposits and clay-silt ablation tills; and englacial fluvial deposits. It is also suggested that large areas of the outwash plain are underlain by dead glacier ice.

From the present work there are several possible implications for the interpretation of Pleistocene deposits:

• i. Certain types of “controlled disintegration features” may have formed supraglacially from debris bands. Some bedded features hitherto interpreted as Huvioglacial in origin may be supraglacial moraines.

• ii. Certain types of “kame-and-kettle“moraine may be mainly supraglacial in origin.

• iii. Complex sequences of tills and bedded sediments may have been formed during a single glacier retreat phase rather than by multiple advance and retreat.

Young moraines and rock glaciers in the central part of the Ben Ohau Range, about 42 km. south of the highest peaks of the Southern Alps, are briefly described. A new formation, the Ben Ohau Formation, consisting of the Ferintosh, Jacks Stream and Dun Fiunary Members, is proposed for moraines and rock glaciers believed to have been built since the climatic optimum by three minor glacial advances. Moraines, and outwash and fan gravels, deposited during a more extensive pre-climatic optimum advance which was contemporaneous with the Cockburn Glacial Phase (Cochrane) in North America are assigned to the Birch Hill Formation. The sequence of glacial advances recorded in the Ben Ohau Range is compared with that found in western North America.

Morainic deposits associated with boulder spreads and outwash sands in the High Andes of the Atacama Desert are described and provide evidence of a Pleistocene glaciation. Widespread, locally folded gravel sheets of a similar age may provide a datum for correlating movements resulting in the uplift of the Andes.

The retreat of a glacier front at Sukkertoppen, West Greenland, has been related by lichen size measurements to the lowering of the snow level in the accumulation region of the glacier. The altitudes of two Quaternary marine shell beds near Sukkertoppen have been measured and the shell fauna contained in them has been identified. The behaviour of two adjacent ice-dammed lakes is also discussed.