Striated ground was found above 3 600 m elevation in the Páramo de La Culata, Pico Espejo and Pico Bolívar areas of the central Venezuelan Andes. This ground, formed by nocturnal freezing and diurnal thawing of the contained water, consisted of aligned lumps of fine to coarse sand, separated by small discontinuous channels (1–3 cm wide). Sorting was observed in the form of pebble-rich and pebble-poor zones. Striated ground in the process of formation showed that needle ice filled the channels before thawing. Lack of sorting is an indication of very recent formation, probably the previous night. The orientation of the striae is compared with the wind direction. This indicates that the formation of needle ice in the ground reflects the direction of the freezing wind, producing striae orientated in that direction, thus supporting Troll’s (1944) original observations.

A new extraction system has been designed and constructed which allows the extraction of gases from air bubbles in ice without melting it. The ice sample of about 500 g is crushed an evacuated container by a milling cutter, and the gas escaping from the opened bubbles is collected by condensation at 15K. Results of CO2 analyses of extracted gases are discussed with respect to possible contamination risks by the system.

The drill hole at “Byrd” station, which was completed in January 1968 to a vertical gerpth of 7 063 ft (2 153 m) below the top of the hole casing, was resurveyed in January 1975 to a vertical gerpth of 4 835 ft (1 474 m)· Inclination and azimuth measurements were mager with a Parsons multiple shoe inclinometer and compared with the earlier measurements mager during drilling. The results indicate a progressively increasing displacement with gerpth to a value of 51.2 ft (15.6 m) or about 7.3 ft/year (2.23 m/year) at the 4 835 ft (1 474 m) level. The direction of movement relative to the surface varies freom south-west at 300 ft (91.5 m) to north-east at 1 100 ft (335 m) to east at 3 368 ft (1 027 m) to north-east at 4835 ft (l 474 m), indicative of a complex twisting motion. An increase in accessible gerpth along the hole axis of 18 ft (549 m) beyond the 1969 gerpth was noted. No attempt was mager to measure hole diameter or vertical strain. It is recommengerd that the hole be resurveyed in 3-5 years if it is still logistically feasible, using a more up-dated inclinometer.

For flat external ice shelves, expanding freely in all directions, the problem of thermodynamics is one-dimensional. In the affine dimensionless system of coordinates, equations of the dynamics together with the rheological equation lead to the non-linear integro-differential equation involving the reduced temperature. In the quasi-steady case the boundary problem for this equation is solved by means of the method of combining asymptotic expansions. It is shown that if ice is coming from the upper and lower surfaces in the opposite directions the regime is unsteady because of the internal heat accumulation.

The integro-differential equation for the temperature in the case of thinning internal ice shelves is more complicated, but it can be solved by a method analogous to the one mentioned above.

Evidence is brought together concerning the deglaciation of a small valley and the subsequent development in it of periodic glacier-dammed lakes. The respective volumes and drainage dates of the lakes are evaluated, and an attempt is made to relate these to the down-wastage of the impounding glacier.

We present a new map of bed topography and ice thickness together with a corresponding ice volume estimate representative of the years ~2010 for all Scandinavian ice caps and glaciers. Starting from surface observations, we invert for ice thickness by iteratively running an innovative ice dynamics model on a distributed grid and updating bed topography until modelled and observed glacier dynamics as represented by their rate of surface elevation change (dh/dt) fields align. The ice flow model used is the instructed glacier model (Jouvet and Cordonnier, 2023, Journal of Glaciology 1–15), a generic physics-informed deep-learning emulator that models higher-order ice flow with high-computational efficiency. We calibrate the modelled thicknesses against >11 000 ice thickness observations, resulting in a final ice volume estimate of 302.7 km3 for Norway, 18.4 km3 for Sweden and 321.1 km3 for the whole of Scandinavia with an error estimate of ~$\pm 11\%$. The validation statistics computed indicate good agreement between modelled and observed thicknesses (RMSE = 55 m, Pearson's r = 0.87, bias = 0.8 m), outperforming all other ice thickness maps available for the region. The modelled bed shapes thus provide unprecedented detail in the subglacial topography, especially for ice caps where we produce the first maps that show ice-dynamically realistic flow features.

Observations have been made in one of several deep holes drilled in Salmon Glacier in the course of mining development. Surveys, particularly of the displacement of a 481.5 m. length of pipe in this hole over a 94 day period, show movement diminishing downward from a maximum value of 0.225 m./day at the surface, through a slightly lower value at mid depth to 45 per cent of this value at the bottom of the pipe. By extrapolation movement on the glacier floor, 490 m. below the surface, is believed to be about 44 per cent of the surface rate. The data closely approximate Nye’s (1952) theoretical formula for laminar flow:

in which u0=78 m./yr., α=2°00′, n=2.8 and K=1.25×10−4. Maximum shear stress at the glacier floor is calculated to be about 1.42 bars.

The existing theory of kinematic waves on glaciers does not account for self-induced instability of the flow, or for surges which are not the result of external disturbances. Surges do however have much in common with kinematic waves. Unstable behaviour of glaciers can be explained by a straightforward modification of kinematic wave theory. In this modification the relation between the ice flow and the ice depth is not the same when the ice is accelerating as when it is slowing down. A similar effect has previously been shown to explain observed instabilities in the flow of highway traffic, a phenomenon which is otherwise adequately described by a simple kinematic wave theory.

Using frequency-modulated continuous wave radar data from the 32nd Chinese Antarctic Research Expedition in 2015/16, subsurface profiles were obtained along an East Antarctic inland traverse from Zhongshan station to Dome A, and four distinct regions were selected to analyze the spatiotemporal variability in historical surface mass balance (SMB). Based on depth, density, and age data from ice cores along the traverse, the radar data were calibrated to yield average SMB data. The zone 49–195 km from the coast has the highest SMB (235 kg m−2 a−1). The 780–892 km zone was most affected by the Medieval Warm Period and the Little Ice Age, and the SMB during ad 1454–1836 (71 kg m−2 a−1) was only one-quarter of that in the 20th century. The SMB in the 1080–1157 km zone fluctuates the most, possibly due to erosion or irregular deposition of snow by katabatic winds in low SMB areas with surface elevation fluctuations. Dome A (1157–1236 km) has the lowest SMB (29 kg m−2 a−1) and did not decrease during Little Ice Age. Understanding the spatiotemporal variability of SMB in a larger space can help us understand the complex climate history of Antarctica.

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.

Most non-linear fluids for which the appropriate measurements have been made exhibit non-zero and unequal normal stress differences in shearing flows. Power-law models such as Glen’s law cannot represent this phenomenon. The simplest constitutive equation that does embody normal stress effects defines the second-order fluid. An exact analytical solution for biaxial creep of such a fluid is fit to data from four tests on polycrystalline ice. The model gives an excellent representation of both primary and secondary creep. The fits provide values for the three material constants. These coefficients indicate positive first and second normal stress differences. One consequence is the prediction that a steady open-channel flow will exhibit a longitudinal free-surface depression of up to several meters for sufficiently thick ice on steep slopes. In addition, the compressive principal stress at the channel margin is decreased and the tensile principal stress is increased in magnitude over those predicted by models without normal stresses. The normal stresses thus favor the formation of crevasses. Furthermore, the angle these crevasses form with the channel margin is decreased.

Motion produced by ice expansion and by wind-blown ice cakes has modified the shores of lakes in northern New England, U.S.A. Twenty-six lakes have been studied, the processes observed, and measurements made of the rate and extent of ice action. Conclusions as to the effectiveness of the two processes are brought out.

A lattice Boltzmann technique for modeling Navier–Stokes fluid flow is extended to allow steady-state simulations of glaciers and other slow-flowing solids. The technique is based on a statistical mechanical representation of flowing ice as a set of particles (populations) which translate and collide on a face-centered cubic lattice. The average trajectories of the populations give the velocities of the ice at any point in the glacier. The method has considerable advantages over other techniques, including its ability to handle complex realistic geometries without additional complications to the code Examples are presented for two-dimensional simulations.

The Antarctic ice sheet has been reconstructed at 18000 years b.p. by Hughes and others (in press) using an ice-flow model. The volume of the portion of this reconstruction which contributed to a rise of post-glacial eustatic sea-level has been calculated and found to be (9.8±1.5) × 106 km3. This volume is equivalent to 25±4 m of eustatic sea-level rise, defined as the volume of water added to the ocean divided by ocean area. The total volume of the reconstructed Antarctic ice sheet was found to be (37±6) × 106 km3. If the results of Hughes and others are correct, Antarctica was the second largest contributor to post-glacial eustatic sea-level rise after the Laurentide ice sheet. The Farrell and Clark (1976) model for computation of the relative sea-level changes caused by changes in ice and water loading on a visco-elastic Earth has been applied to the ice-sheet reconstruction, and the results have been combined with the changes in relative sea-level caused by Northern Hemisphere deglaciation as previously calculated by Clark and others (1978). Three families of curves have been compiled, showing calculated relative sea-level change at different times near the margin of the possibly unstable West Antarctic ice sheet in the Ross Sea, Pine Island Bay, and the Weddell Sea. The curves suggest that the West Antarctic ice sheet remained grounded to the edge of the continental shelf until c. 13000 years b.p., when the rate of sea-level rise due to northern ice disintegration became sufficient to dominate emergence near the margin predicted otherwise to have been caused by shrinkage of the Antarctic ice mass. In addition, the curves suggest that falling relative sea-levels played a significant role in slowing and, perhaps, reversing retreat when grounding lines approached their present positions in the Ross and Weddell Seas. A predicted fall of relative sea-level beneath the central Ross Ice Shelf of as much as 23 m during the past 2000 years is found to be compatible with recent field evidence that the ice shelf is thickening in the south-east quadrant.

The thermodynamics of phase equilibrium control the temperature distribution around the ice particles in wet snow. When the snow is stressed, pressure melting occurs at the inter-particle contacts and the snow densifies. Densification is described by a physical model which simulates the heat flow, meltwater flow, and particle geometry. The effects of ionic impurities, liquid saturation, and particle size are demonstrated. Typical values of the temperature difference, inter-particle film size, and density are calculated as functions of time. The calculated rates of compaction are too large, hence, at some later time, the effects of simultaneous grain growth must be added to the model.