bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Motion of Ice Sheets and Glaciers
Authors: Nye J. F. 
Published: September 2017

AbstractThe distribution of velocity along a vertical line in Greenland is calculated. Almost all the relative shear motion is concentrated at and very near to the bottom, and this result is thought to apply generally in Greenland and Antarctica. It is due to the relatively high temperature of the lowest layers and the strong dependence of creep rate on temperature. The outward velocity being thus almost constant with depth, it is assumed proportional to themth power of the shear stress on the bed; the results previously obtained by the approximation of perfect plasticity then correspond tom→∞. Steady-state solutions for finitemare derived, and non-steady states are discussed by use of Weertman’s perturbation method. The steady-state height of an ice sheet is found to be very insensitive to the rate of accumulation. Surface waves in Antarctica are attributed to mountains buried beneath the ice, and it is shown how the height and form of a buried mountain ridge may be calculated from the associated surface disturbance.The application of a law of sliding to glaciers leads to an expression for the longitudinal strain-rate, hitherto an undetermined parameter.
Particle-Size Distribution of Pulverized Snow
Authors: Jellinek H. H. G. , Schlueter Warren A. 
Published: September 2017

AbstractA microscopic method for the determination of particle-size distribution of pulverized snow was worked out. The method gives satisfactory distribution curves, presenting the number of particles as a function of their cross-sectional “areas”. The measurements were made by means of a filar micrometer eyepiece, the snow particles being placed on a ruled glass slide, which was submerged in silicone oil to prevent evaporation. The time for the determination of a distribution can be appreciably shortened by estimating the size of the particles instead of measuring them, though the accuracy is not so high in this case.
Temperature Distribution Near a Crevasse
Authors: Pings C. J. 
Published: September 2017

AbstractDuring the summer of 1955, 53 thermocouples were installed in the ice mass near a crevasse in a glacier in the ice sheet of northern Greenland. Temperatures were observed in 1955 and 1956. The accumulated data were sufficient to prepare a description of the transient thermal behavior of the ice body adjacent to the crevasse. The isotherm maps have provided a base for the computation of heat flux vectors.
Glacier Problems in South Georgia
Authors: Smith Jeremy 
Published: September 2017

AbstractThis paper is a synopsis of Falkland Islands Dependencies Survey Scientific Report No. 29. Glaciological and climatic investigations carried out in South Georgia during the International Geophysical Year are described. The budgets of the Hodges and Hamberg Glaciers for 1957–58 are given and discussed in relation to climatic factors. Temperature measurements indicate that the Hodges Glacier, and probably all ice in South Georgia below an altitude of 1,000 m., is geophysically temperate. The fluctuations of South Georgian glaciers during relatively recent times are briefly discussed.
Snow Depth and Snow Density at Resolute, Northwest Territories
Authors: Longley Richmond W. 
Published: September 2017

AbstractObservations of the snow depth at 21 sites at Resolute were made twice weekly during the winter of 1957–58. As a result of these observations, and of other observations on snow made for the National Research Council, it is shown that the snow depth and the water content of the snow did not continue to increase during the winter as the snow fell. Rather the strong winds eroded the snow surface and the increase in depth was irregular and relatively slow. Furthermore, the observations on the density of the snow cover lead to the conclusion that attempts to measure the density in similar regions with an accuracy greater than ± 0.05 g. cm.−3 are not warranted.
Some Observations on the Snowfall of Ruwenzori
Authors: Whittow John B. 
Published: September 2017

AbstractThe seasonal precipitation of Ruwenzori is examined and the height of the climatic snowline determined. Two distinct periods of surplus accumulation and two ablation seasons can be recognized and give rise to a somewhat complex stratification. Precipitation diminishes with altitude above about 10,000 feet (3,050 m.). The water equivalent of the annual accumulation on the highest peak is thought to lie between 25 and 30 inches (635–762 mm.). Twelve months’ synoptic charts have been analysed and an attempt is made to relate the seasonal variations of accumulation and ablation to the meteorological factors accompanying the oscillations of the Inter-Tropical Convergence Zone.
Age of Moraines in Victoria Land, Antarctica
Authors: Péwé Troy L. 
Published: September 2017

Abstract“Fresh-looking” moraines lying within a mile of glaciers in the lowlands of the McMurdo Sound area, Victoria Land, Antarctica have been interpreted by some to be only 50 or 100 yr. old and to have been left by recent glacier retreats. The present author believes that these moraines are considerably older because a comparison of the position of existing glacier fronts in the area with positions on photographs of 50 yr. ago shows no movement of the front or appreciable thickening or thinning of the glaciers during the last 50 yr.Radiocarbon dating of mummified seal carcasses lying near glacier fronts indicates that the glaciers have not been more extensive for at least 1,000 yr. The youngest moraines in the area are ice-cored moraines to the existing glaciers. Radiocarbon dates of algae from extinct ephemeral ponds in the ice-cored moraines indicate the moraines to be at least 6,000 yr. old.Additional evidence for the antiquity of the near-glacier moraines is the presence of a rather uniformly well-developed micro-relief pattern of sand-wedge polygons on both the end moraines and the ground moraines extending up to the existing glacier front. Studies show that it requires hundreds if not thousands of years for such well-developed polygonal patterns to form.
Ice Surface Elevation of Central Marie Byrd Land
Authors: Behrendt J. C. , Wold R. J. , Dowling F. L. 
Published: September 2017

AbstractAn 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.
Pleistocene Geology of the South-West Yukon Territory, Canada
Authors: Krinsley Daniel B. 
Published: September 2017

AbstractA morainal sequence in south-west Yukon Territory, Canada, records at least four major, successively less extensive glaciations from ice fields in the St. Elias Mountains south of the glaciated area.The Nisling Moraine flanks the Klondike Plateau in a belt t km. wide to an altitude of 1,040 m., 12 km. north-east of Snag. The northernmost lobe of this moraine terminates at the junction of the Donjek and White Rivers, 120 km, from the nearest source of ice, Klutlan Glacier. 11 km. north-east of Snag, the prominent front of the Donjek Moraine lies 180 m. below the front of the Nisling Moraine. The northernmost lobe of the Donjek Moraine terminates 106 km. north of Klutlan Glacier and occupies the lower courses of canyons cut into the Nisling Moraine. The front of the Snag Moraine crosses the White River valley 210 m. below the front of the Donjek Moraine and 96 km. north of Klutlan Glacier. The Tchawsahmon Moraine, 38 km. north-west of Klutlan Glacier. consists of a series of concentric ridges, the oldest of which impounded Tchawsahmon Lake.Provisional correlations suggest that the Nisling Moraine is pre-Illinoian; the Donjek, Illinoian; the Snag, pre-classical Wisconsin; and the Tchawsahmon, classical Wisconsin.
Comparative Glacier Photographs from Northern Alaska
Authors: Hamilton Thomas D. 
Published: September 2017

AbstractEarly photographs of a cirque glacier complex in the Arrigetch Peaks of the south-central Brooks Range date from 1911, and are the second oldest known set of glacier photographs from northern Alaska. Matching photographs and supplementary observations made in 1962 indicate that changes over the past 51 yr. in this area include general glacial recession and thinning, the emergence of pronounced trimlines and partial melting of ice cores beneath recent moraines.Renewed post-hypsithermal glacial activity in the Arrigetch Peaks area attained two maxima in the recent past. The younger moraines lie close to glacier positions shown in the 1911 photographs, contain ice cores which extend practically to their surfaces and were probably formed in the latter part of the nineteenth century. More weathered deposits, underlain by ice cores at relatively greater depths, were formed at some unknown earlier date. The moraines are correlated with the two-substage recent Fan Mountain advance of northern Alaska and may correspond to dated mid-eighteenth century and middle to late nineteenth century advances of alpine glaciers in the north Pacific coastal mountains of North America.
On the Relationship of Ice-Surface Topography to Bed Topography on the South Polar Plateau
Authors: Robinson Edwin S. 
Published: September 2017

AbstractIce-surface and isopachous maps, and rock-elevation maps, were prepared for the area between the South Pole and the Horlick Mountains from seismic and gravimetric measurements. Basal shear-stress was calculated from these data and surface-slope measurements at 25 sites. The mean is 0.8 bar with an areal standard deviation of 0.5 bar. Forty-five values of average basal shear stress were computed from consecutive 30 km. segments along flow lines. The mean is 0.4 bar with an areal standard deviation of 0.1 bar. These variations are too large for accurate estimates of ice-thickness variations to be made from surface-slope data alone, following Nye’s suggestion that basal shear-stress be treated as constant. From theoretical considerations Nye demonstrated that surface features of wave-length less than 40 km. should disappear within a few months unless related to bed topography. Ice and rock profiles along a 220 km. line do not show an expected theoretical relationship. Surface-elevation measurements, repeated after a 2 yr. interval. showed the surface features with wave-lengths between 5 and 40 km. to be essentially unchanged in amplitude and position. Hence these features are not adequately explained by existing theory.
An Ablation Rate for Lake Fryxell, Victoria Land, Antarctica
Authors: Henderson R. A. , Prebble W. M. , Hoare R. A. , Popplewell K. B. , House D. A. , Wilson A. T. 
Published: September 2017

AbstractThe average yearly net ablation rate on permanently ice-covered Lake Fryxell, Victoria Land, Antarctica, is 30 to 40 cm. This figure was calculated by a novel method utilizing a record of ablation which is incorporated in the ice cover of the lake. These values are higher than those measured on Ross Island 80 km. to the east; the difference in ablation rates for the two areas is attributed to the prevalence of katabatic winds in the climate of Taylor Valley. The Lake Fryxell ablation figure is applied to nearby Canada and Commonwealth Glaciers in the calculation of their ice budgets.
Experiments on a Snow-Patch in the Mountains of Sweden
Authors: Ashwell I. Y. , Hannell F. G. 
Published: September 2017

AbstractInvestigations into the mechanism of dirt-cone formation, and snow patterning, are described. In each case the changes in patches of various materials arranged on a snow surface, were observed over a period of three weeks in the summer, under varying weather conditions. The effects of fine rock flour on the formation of dirt cones are analysed. Two main weather types are recognized as having different, but important, effects on the surface features of the snow; föhn-type winds, and calm, sunny conditions.
Pollen-Analysis Investigation of a 20 m. Firn Pit on the Kesselwandferner (Ötztal Alps)
Authors: Ambach W. , Bortenschlager S. , Eisner H. 
Published: September 2017

AbstractFirn samples from a 20 m. deep pit were examined by pollen analysis methods in order to confirm the stratigraphy of the annual net accumulation back to 1949. The late summer horizon separates the overlying winter layer with a small pollen content from a firn layer with a large pollen content. There are also differences in the spectra of the species which enable a seasonal separation of the layers. In addition, the mineral dust content was examined.
The Origin of Morainic Deposits and the Characteristics of Glacial Erosion in the Western Sør-Rondane, Antarctica
Authors: Souchez R. A. 
Published: September 2017

AbstractTwo types of morainic deposits can be found in western Sør-Rondane mountains: the super-glacial morainic ridge the material of which comes from slope evolution, and the hillocky moraine whose origin is related to shear planes in the glacier and therefore subglacial. A hypothesis of the formation of the hillocky moraine is given and the lithological composition of this deposit allows us to deduce the importance of glacial erosion at the level of the ice falls which frequently exist at the beginning of outlet glaciers where they leave the polar ice sheet. On this step, the role of glacier fluctuations is of importance in relation to a special periglacial process: greenhouse frost shattering.
Re-Evaluation of the Rammsonde Hardness Equation
Authors: Waterhouse R. W. 
Published: September 2017

Penetration tests in snow show that the Rammsonde number R as a measure of force resisting penetration may be in error by a factor of two depending on the ratio of hammer to probe weight and the coefficient of restitution. It is suggested that the Hiley pile driving formula is applicable to the problem and gives more accurate values for the force of penetration. This formula accounts for the influence of different hammer weights, is in agreement with the conservation laws to the first approximation, and has been in general use for some time as one of the best simple equations for determining the dynamic resistance of piles.The Rammsonde equation is notable for its simplicity. The Hiley equation, using the same factors does not detract from this virtue. Further research is suggested to find ways of replacing the coefficient of restitution with more fundamental parameters in impact problems.
Internal Structure of Sandy Glacier, Southern Victoria Land, Antarctica
Authors: Dort Wakefield 
Published: September 2017

AbstractThis narrow, 600 m. long cirque glacier is apparently composed throughout of alternating layers of ice and sand that strike parallel to the edge of the glacier and dip into the glacier at an angle of 82°. The thickness of the sand layers averages 10 cm., and that of the ice layers 20 cm. The sand layers are generally composed of thin parallel laminations but micro-cross-bedding is present locally. The layers have been broken into angular blocks 0.5 to 3.0 m. long, separated by ice columns connecting adjacent ice layers. The ice layers show thinner zones of contrasting bubble content which bend into the columns separating the sand blocks.The sand was probably blown into this cirque from the floor of Wright Valley 6 km. south-west and 1,100 m. below. Each pair of sand and ice layers may record accumulation during one year. The steeply dipping yet otherwise undeformed layers clearly prove that rotational movement has taken place. The breaking of the sand layers into blocks is the result of plastic extension within the glacier.
Water Expulsion and Pingo Formation in a Region Affected by Subsidence
Authors: Bostrom R. C. 
Published: September 2017

AbstractGeophysical evidence indicates that the delta area of the Mackenzie River, Northwest Territories, is affected by tectonic subsidence. Pingos are of sparse occurrence in the Arctic as a whole but they occur in hundreds in the Mackenzie River delta.In a region of subsidence, as recent sediments pass through the base of permafrost, compaction becomes possible. The resulting water expulsion produces an artesian head responsible for building pingos.
General Theory of Subglacial Cavitation and Sliding of Temperate Glaciers
Authors: Lliboutry L. 
Published: September 2017

AbstractEarlier theories of Weertman and the present author are reviewed and compared; both are insufficient to account for the facts observed at the tongue of the Allalingletscher.A calculation of the stresses and heat flow at the bed of a glacier with a sinusoidal profile is given which takes account of any degree of subglacial cavitation. The sliding due to plasticity and that due to pressure melting are related to this degree of cavitation and it is shown that these two terms are additive. There results an expression for the friction fω in terms of the total sliding velocity u and the height of the bumps a. For a given and large enough value of u, fω(a) exhibits two maxima which are equal and independent of u.The paper then considers a more realistic model of the bed consisting of a superposition of sine waves all having the same roughness r, and a decreasing in a geometrical progression. The biggest a may be inferred from the overall profile of the bedrock; the resulting frictional force can be regarded either as part of the total frictional force f in an overall view for which f = ρgh sin α holds, or else as a correction to such a value on the small scale (the best point of view for crevasse studies). To a first approximation Coulomb’s law of friction holds provided one takes account of the interstitial water pressure at the ice-rock interface.This interstitial pressure p is next related to the thickness of the glacier h. If the subglacial hydraulic system is at atmospheric pressure, p is proportional to h. Next, if the sliding velocity is not too large, the surface slope approaches 1.6r ≈ 0.12 and kinematic waves (which move four times as fast as the ice) disappear rapidly. If the hydraulic system is not at atmospheric pressure the surface slope is smaller and flow instabilities can occur.
Field Measurements of Dielectric Absorption in Antarctic Ice and Snow at Very High Frequencies
Authors: Walford M. E. R. 
Published: September 2017

AbstractField measurements are presented of dielectric absorption in Antarctic snow and ice at frequencies of a few hundred megahertz. They are compared with measurements by other authors at very high frequencies. The dielectric absorption in ice at these frequencies is accounted for in terms of absorption bands both at radio frequencies and in the infrared. Bands at radio frequencies are caused by a relaxation mechanism which depends upon the temperature and the impurity content of the ice. These two factors are therefore included in an account of the dielectric absorption in ice at very high frequencies.
The Formation and Shape of Drumlins and their Distribution and Orientation in Drumlin Fields
Authors: Smalley Ian J. , Unwin David J. 
Published: September 2017

AbstractIf glacial till contains more than a certain minimum boulder content, it is dilatant and requires a much larger stress to initiate shear deformation than to sustain it. If the stress level at the glacier–terrain interface drops below a certain critical level, or the till reaches its critical boulder-content density, then the till beneath the glacier packs into stable obstructions. These are shaped into streamlined forms by the glacier and are found distributed at random in drumlin fields. Due to drumlin coalescence there is a normal distribution of drumlin axes about the direction of ice movement.
Instruments and Methods: A Buoyancy-Stabilized Hot-Point Drill for Glacier Studies
Authors: Aamot Haldor W. C. 
Published: September 2017

AbstractHot-point drills are practical for producing holes in glaciers for ice-thickness and temperature measurements, as well as other glaciological studies. Buoyancy stabilization assures a vertical attitude of the drill and a plumb hole. This is achieved by designing a drill with a heavy hot point and a light upper section which is buoyant in the surrounding melt water. The buoyant force is less than the weight of the drill in air but its rectifying moment about the fulcrum (the tip) is greater than the tilting moment of the drill weight. Two methods to prevent refreezing of the melt water are proposed in order to permit drilling in cold ice and to assure continued access to the hole.
Short Notes: Directions of Ice Movement in the Southern Irish Sea Basin During the Last Major Glaciation: An Hypothesis
Authors: John B. S. 
Published: September 2017

AbstractThe movement of the Irish Sea glacier is discussed for the St George’s Channel sector during the last major glaciation. It is considered that the ice was already diverging when it crossed Pembrokeshire, after passing through a constriction farther north. This constriction was probably caused by local Irish ice in the west and local Welsh ice in the east. In view of this, it is suggested that the Cardigan Bay coasts could not have been ice-free during the last glaciation.
Sub-Surface Melt Pools in the McMurdo Ice Shelf, Antarctica
Authors: Paige R. A. 
Published: September 2017

AbstractSub-surface melt pools were discovered during construction of an airfield located on glacier ice in the western part of the McMurdo Ice Shelf, Antarctica. The melt pools occur beneath areas of blue glacier ice and they are impossible to detect by visual examination. They vary in size and shape but are usually 1.0 to 1.5 m deep and span circular areas 10 to 15 m in diameter. Sub-surface melting starts in mid-December at depths of 40 cm or more and it progresses until late January when refreezing begins. The ice cover over melt pools may thin to as little as 7 cm and this creates a serious hazard to aircraft operations.The melt pools are caused by the greenhouse effect of intense solar radiation, low albedo of the blue glacier ice and heat absorption by rock particles and dust. The high-albedo layer of chipped ice and powdered ice that was produced during runway construction was completely successful in preventing sub-surface melting. The thickness of this protective layer appeared to be of little importance, providing it exceeded 3 cm.
Geodetic Results of the Ross Ice Shelf Survey Expeditions, 1962–63 and 1965–66
Authors: Dorrer Egon , Hofmann Walther , Seufert Wilfried 
Published: September 2017

By means of modern geodetic observation techniques the ice movement along an east-west and a north-south profile across the Ross Ice Shelf, Antarctica, was measured during the two Antarctic summers, 1962–63 and 1965–66. 103 markers were placed on the 910 km long traverse. Distances were measured by tellurometer, and traverse angles by a precision theodolite between all consecutive markers, normally 8 to 9 km apart. For this type of observation method, six men distributed into three groups of two men each were necessary.The main part of the paper deals with data processing and with the computation of the ice movement. As the ice moves, the geometrical configuration of the traverse changes during the epoch of observation. For this “reduction to epoch” problem two methods are described in detail: (1) time reduction of observations, and (2) time reduction of positions. Between the two field journeys, only linear ice movement can be assumed. It is possible, however, to determine acceleration and curvature of the ice flow at all traverse points where the traverse angles differ considerably from 180°.The result of all computations is the field of velocity vectors along the traverse. Obvious characteristics are the rapid increase of velocity between the McMurdo Ice Shelf and Ross Ice Shelf, the uniform and nearly parallel movement in the middle of the ice shelf (maximum velocity 935 m year−1), the decrease of velocity along the north-south profile, and the systematic increase of divergence of the flow lines towards the ice margins. Careful study of the velocity vector field shows some deviations from an entirely uniform distribution.