bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temperature Gradients in the Antarctic Ice Sheet
Authors: Mellor Malcolm 
Published: September 2017

AbstractMeasurements of ice temperature to depths of 30–40 m. are given for a number of points on the ice sheet in MacRobertson Land. Variations of mean surface temperature with elevation and with latitude, and the temperature gradients below a depth of 15 m. are compared with results from other parts of Antarctica and from Greenland. Explanations of negative temperature gradients near the surface of ice sheets are reviewed, and an equation derived by Robin is checked against the measurements following its recent justification from conduction theory. Surface ice velocities necessary for development of the observed temperature gradients are computed, and these values are then compared with ice velocities estimated independently from flow measurements at the coast and continuity considerations. It is found that, if negative gradients are attributed solely to the Robin effect, improbably high ice velocities are called for, and so climatic change is reconsidered. Some evidence of secular warming in Antarctica is mentioned and a recent numerical solution of the conduction equation for the surface-warming case is described. It is concluded that the measured temperature profiles can be explained reasonably by climatic amelioration.
The United States Glaciological Researches during the International Geophysical Year
Authors: Crary A. P. , Field W. O. , Meier M. F. 
Published: September 2017

AbstractThe U.S. IGY program in glaciology is reviewed in two parts: Antarctica and northern latitudes. The objectives of the program are outlined and the results of each investigation are briefly summarized. A separate discussion of observations related to changes in the Earth’s ice cover is included.
Tensile Strength of NaCl Ice
Authors: Weeks W. F. 
Published: September 2017

AbstractTo resolve some of the factors causing strength variation in natural sea ice, fresh water and five different NaCl–H2O solutions were frozen in a tank designed to simulate the one-dimensional cooling of natural bodies of water. The resulting ice was structurally similar to lake and sea ice. The salinity of the salt ice varied from 1‰ to 22‰. Tables of brine volumes and densities were computed for these salinities in the temperature range 0° to −35° C. The ring-tensile strength σ of fresh-water ice was found to be essentially temperature independent from −10° to −30°C., with an average value of 29.6±8.5 kg./cm.2at −10° C. The strength of salt ice at temperatures above the eutectic point (–21.2° C.) significantly decreases with brine volumev;. The σ–axis intercept of this line is comparable to the a values determined for fresh ice indicating that there is little, if any, difference in stress concentration between sea and lake ice as a result of the presence of brine pockets. The strength of ice containing NaCl.2H2O is slightly less than the strength of freshwater ice and is independent of the volume of solid salt and the ice temperature. No evidence was found for the existence of either phase or geometric hysteresis in NaCl ice. The strength of ice at sub-eutectic temperatures, however, is decreased appreciably if the ice has been subjected to temperatures above the eutectic point; this is the result of the redistribution of brine during the warm-temperature period. Short-term cooling produces an appreciable (20 per cent) decrease in strength, in fresh-water and NaCl.2H2O ice. The present results are compared with tests on natural sea ice and it is suggested that the strength of freshwater ice is a limit which is approached but not exceeded by cold sea ice and that the reinforcement of brine pockets by Na2SO4.10H2O is either lacking or much less than previously assumed.
Antarctic Interglacial Features
Authors: Nichols Robert L. 
Published: September 2017

AbstractThe upper 180 ft. (55 m.) of Lake Vanda in Wright Valley, south Victoria Land, is essentially potable, whereas that part below 200 ft. (61 m.) is more than three times as saline as sea-water. The salinity below 200 ft. (61 in.) resulted from the evaporation and freezing, mainly during interglacial (Loop-Trilogy) time, of a larger, less saline body of water.An alluvial fan in Wright Valley has been dated as interglacial on the basis of (1) ice-marginal channels formed in Loop time that cut across it, and (2) the fjord-like longitudinal cross-section of the valley formed by the ice of the oldest glaciation or glaciations.Fossils found in till and glacio-fluvial deposits in the McMurdo Sound region, south Victoria Land, date from both early and late Pleistocene interglacial time.An ocean-bottom core sample obtained in the Ross Sea contained interglacial material. The presence in the sample of glacial marine sediments deposited in interglacial time suggests that the Antarctic Ice Sheet maintained itself throughout the Pleistocene.Sub-surface efflorescences consisting of a layer of pure salts as much as 3 in, (7.6 cm.) thick are found 2−5 in. (5−13 cm.) below the surface in Loop deposits in Wright Valley. The absence of similar thick occurrences in Trilogy deposits indicates that the efflorescences are, in part at least, interglacial.Interglacial cinder cones and lava flows are found in the McMurdo Sound area, and some of the widespread scoria present in moraines, glacio-fluvial deposits and beaches dates from interglacial time.
Instruments and Methods: A Steam-Operated Ice Drill for the Installation of Ablation Stakes on Glaciers
Authors: Howorka F. 
Published: September 2017

AbstractAn easily portably thermal ice drill was designed and constructed, with water vapour being used for melting the ice. A lore hole, 8 m. deep, can be drilled within about 30 min., depending on the ice properties. The energy for boiling the water is supplied by butane cartridges similar to those used for camping purposes. One cartridge lasts for drilling about three holes 8 m. deep. The weight of the whole equipment is 12.5 kg.
Instruments and Methods: An Effective Pressure Room Seal in Ice
Authors: Ballard G. E. H. , Ramseier R. O. 
Published: September 2017

AbstractSeveral methods were tried to seal a room in ice which could be pressurized to the overburden pressure of the ice. We found that a keyed bulkhead consisting of two ice walls with an in-place frozen mixture of water, clay and styrofoam pellets between them produced an effective seal.
The Distribution of 10 Meter snow Temperatures on the Greenland Ice Sheet
Authors: Mock S. J. , Weeks W. F. 
Published: September 2017

AbstractAll available 10 m. snow temperatures from the Greenland Ice Sheet have been analyzed using multiple regression techniques to develop equations capable of accurately predicting these temperatures. The analysis was carried out for all Greenland and for various sub-areas. The resulting equations show that 10 m. snow temperatures can be accurately predicted from the parameters latitude and elevation. Longitude was found to be a further significant parameter in south Greenland.Gradients of 10 m. snow temperatures versus elevation for north Greenland are close to the dry adiabatic lapse rate indicating adiabatic warming of katabatic winds as the controlling mechanism in their altitudinal distribution. In both south Greenland and the Thule peninsula, gradients of 10 m. snow temperatures versus elevation are markedly greater than the dry adiabatic lapse rate and are highly dependent upon elevation, indicating downward transfer of latent heat in the snow, largely as a result of percolating melt water.An isotherm map, showing the distribution of 10 m. snow temperatures on the Greenland Ice Sheet calculated from the prediction equations, was prepared. The map is based upon a revised contour map of the ice sheet made from a compilation of all known elevations.
The Regime of the Western Part of the Ross Ice Shelf Drainage System
Authors: Giovinetto M. , Robinson Edwin S. , Swithinbank C. W. M. 
Published: September 2017

AbstractThe net mass budget is estimated for the western part of the Ross Ice Shelf drainage system. The area of the system is (1.75±0.26) × 106 km.2, and the drainage periphery extends along the eastern flank of the Trans-Antarctic Mountains between lat. 77° 58′ S., long. 164° 37′ E. and lat. 85° 27′ S., long. 147°50′ discharge is estimated from vertical cross-sections and corresponding ice-movement data for eight outlet glaciers. Free-air gravity anomalies, corrected for the effect of terrain above the glacier surface, are used to determine cross-sections of valleys by comparison with theoretical gravity profiles for several two-dimensional valley models. These data provide a basis for estimating the rate of ice discharge from the plateau, which is compared with the estimated rate of net accumulation at the surface, to determine the net budget of the ice sheet in the region. Representative mean rates of ice discharge measured in different types of glaciers are approximately 0.25 × 1015 g. km.−1 yr.−1 in outlet glaciers with large basins, and 0.05 × 1015 g. km.−1 yr.−1 in outlet glaciers with small basins. Taking into account the snowshcd area and the rate of accumulation, the rate of ice discharge in cirque and piedmont glaciers is estimated at about 0.02 × 1015 g. km.−1 yr.−1 The difference ((48±29) × 1015 g. yr.−1) between mass input ((96±25) × 1015 g. yr.−1) and mass output ((48±15) × 1015 g. yr.−1) is large enough relative to the estimated standard error to indicate a probable positive net budget.
Ice-Flow and Thickness Measurements in the Sør-Rondane, Dronning Maud Land, Antarctica
Authors: Van Autenboer T. , Blaiklock K. V. 
Published: September 2017

AbstractVelocity and ice-thickness profiles were measured un the western glaciers of the Sør-Rondane during the Expéditions Antarctiques Belges of 1959 and 1960 Some of the stations were re-occupied for velocity measurements during the Expédition Antarctique Belgo-Néerlandaise, Campagne d’Été 1964–65.The profiles, with stations at 1 mile. (1.6 km.) intervals, were generally east-west and at right-angles to the direction of flow of the plateau outlet glaciers. The movement was measured by resection of each station from the main triangulation points over periods ranging from 256 to 1,501 days. Double ties with a Worden geodetic-type gravity meter were measured between the stations. An additional gravity station was occupied on rock at each end of the profile. The ice thickness and the subglacial topography are calculated from the gravity profiles. Combined with the surface velocity, they allow an estimate of the discharge of the glacier. The results indicate a close relationship between the glacier flow and the supply from the Antarctic Ice Sheet, as demonstrated by a study of the aerial photographs.
Certain Effects of Glacial Events in the Vale of Glamorgan, South Wales
Authors: Crampton C. B. 
Published: September 2017

AbstractIn South Wales there is evidence for two phases of intense glaciation and an interglacial phase during the Pleistocene. During the closing stages of the earlier glaciation in the west of the Vale of Glamorgan two overflow channels were cut by melt water from an ice lobe off the Glamorgan upland, abutting against ice from the Irish Sea. During retreat, ice from the Irish Sea and local ice deposited material on the Lower Lias outcrop on which two contrasting soils developed. Soils normally associated with a Mediterranean climate developed locally on the outcrop of the Carboniferous Limestone during the interglacial phase.
Creep-Velocity Bounds and Glacier-Flow Problems
Authors: Palmer Andrew C. 
Published: September 2017

AbstractA general result due to Martin can be used to find upper and lower bounds on velocities in steady-creep problems. This method can be applied to glacier flow if ice can be assumed to satisfy a powerlaw stress–strain-rate relation. Bounds on the mean velocity over the glacier cross-section and on the mean velocity on the surface are determined for a particular example (a uniform parabolic channel, with powerlaw exponent 3) and they are shown to bound quite closely the exact solutions due to Nye. Bounds can be found rapidly by hand calculation. The method can be applied to real glacier cross-sections measured in the field.
Metamorphism of Air Bubbles in a Snow Crystal
Authors: Maeno Norikazu , Kuroiwa Daisuke 
Published: September 2017

RésuméObservations have been made of the modification produced by a temperature gradient in the shape of air bubbles in natural snow crystals, and also of the shrinkage of the bubbles with time. The rate of shrinkage is governed by a constant which is strongly temperature dependent with an activation energy of about 15.1 kcal./mole, a value sufficiently similar to the activation energy for diffusion of tritium, dielectric relaxation and mechanical relaxation to suggest that atomic diffusion processes may be responsible for all of these phenomena.
Glaciological Notes From Sukkertoppen, West Greenland
Authors: Gribbon P. W. F. 
Published: September 2017

AbstractThe 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.
Recent Glacial History of an Alpine Area in the Colorado Front Range, U.S.A.: II. Dating the Glacial Deposits
Authors: Benedict James B. 
Published: September 2017

AbstractRecent glacial deposits in the Indian Peaks area of the Colorado Front Range have been dated lichenometricaily, using a growth curve developed locally for Rhizocarpon geographicum. Radiocarbon dates, where available, tend to support the lichen chronology. Three distinct intervals of glaciation, each consisting of several minor pulsations, have occurred in the area during the past 4500 years. The earliest advance (Temple Lake Stade) is dated at 2500–700 b.c. A later advance (Arikaree Stade) began in about a.d. 100 and ended in a.d. 1000. The most recent advance (Gannett Peak Stade) is dated at a.d. 1650–1850. It remains to be seen whether the Arikaree Stade was purely a local development or whether glaciers were advancing elsewhere in the cordilleran region during this interval. Alluviation on the plains east of the Colorado Front Range seems to have occurred during the waning stages of mountain glaciation.
Short Note: Steady Profile of a Finite-Amplitude Kinematic Wave on a Glacier
Authors: Johnson James N. 
Published: September 2017

AbstractThe steady profile of a finite-amplitude kinematic wave on a glacier is calculated with the assumption that the wave velocity varies linearly with h1, the departure of the ice thickness from the datum state. If the flow of ice is due mainly to sliding of the glacier on its bed, the width of the calculated steady profile is several hundred times the datum state ice thickness. The width of an observed kinematic wave front on Nisqually Glacier, Mt. Rainier, Washington is at least an order of magnitude smaller than the calculated steady profile. This indicates that the observed steepening of the wave may be due to effects other than variation of wave velocity with ice thickness.
A Supraglacial Extension of an Ice-Dammed Lake, Tunsbergdalsbreen, Norway
Authors: Howarth Philip J. 
Published: September 2017

AbstractObservations on Tunsbergdalsbreen show that an ice-dammed lake, Store Brimkjelen, overflowed on to the surface of the glacier. The lake lifted a section of the glacier and formed a long irregular crevasse along the line of dislocation.
Fabric Analysis of a Core from the Meighen Ice cap, Northwest Territories, Canada
Authors: Koerner R. M. 
Published: September 2017

AbstractIce samples from a 121 m core, representing the total thickness of the Meighen Ice Cap near its highest point, were studied for ice fabric, firn- and dirt-layer distribution. The absence of a strongly preferred fabric between the surface and the base of the ice cap at the core site suggests an absence of past or present ice movement at this point. From the variations of ice texture, am- and dirt-layer distribution with depth it is concluded that the ice cap post-dates the climatic optimum and has never been much thicker than it is at present. There is a possible relic ablation surface at a depth of 50 m which is estimated to be at least 500–600 years old.
Slip in Single Crystals of Ice
Authors: Readings C. J. , Bartlett J. T. 
Published: September 2017

AbstractRectangular specimens of ice (c. 5 cm × 2 cm × 0.5 cm) were cut from large single crystals (c, 10 cm × 5 cm2) grown from pure water by a modified Bridgman technique. When these specimens were deformed under controlled conditions, slip lines which were predominantly parallel to the basal plane became visible. In some cases short. perpendicular segments were also seen which can be interpreted as evidence for cross-slip in ice. Measurements of slip-band spacings were made on silvered “formvar” replicas of some deformed crystals. These measurements showed that “coarse” slip occurred when the resolved shear stress on the basal plane. σ, was greater than about 0.2 bars, and that the average thickness of the slip lamellae, d (cm) was approximately given by Wakahama’s relationship. (σ−0.2) d = 0.45 × 10−3. At lower stresses “fine” slip occurred, and the relationship between the average thickness of the lamellae and the resolved shear stress was more adequately described by Taylor’s formula, σd = 7.2 × 10−5. It is. however, possible that both coarse and fine slip occurred at higher stresses, but that the fine slip was then below the limit of resolution.
Regime of an Afghan Glacier
Authors: Gilbert O. , Jamieson D. , Lister H. , Pendlington A. 
Published: September 2017

The climatic snow line is a little above the highest peaks in this region (Mir Samir, 5 809 m, lat. 35° 35′ N., long. 70° 10′ E.) but steep north-facing slopes provide a topographie reason for small glaciers persisting, with a snow line a little below 4 900 in (16 000 ft). Snow accumulation at this height averages 1 300 kg m−2, most of this falling in late winter and spring. Gross ablation reaches 40 kg m−2 d−1. Net ablation (July–August), measured as stream discharge, averages 3 600 m3 d−1 = 9 kg m−2 d−1. Slow recession is the average condition. Halt stages at 4 800, 4 600 and 4 000 m are interpreted from the topography. Dating of moraines by lichen distribution indicates for the highest of these a minimum age of 400 years.The vertical flux of heat and of water vapour were calculated through an air layer 30–100 cm over a melting firn surface for 24 h. The source of heat available at the surface expressed as a percentage of the total was: net radiation 87, condensation 5, forced convection 1, conduction through snow 6 and unexplained 1. The heat sink was: long-wave radiation 4, evaporation 6, forced convection 6, conduction into snow 2 and melting 82%.
Errors in Short-Term Ablation Measurements on Melting Ice Surfaces
Authors: Müller Fritz , Keeler Charles M. 
Published: September 2017

Rapid changes in time and space in the micro-relief of an ablating glacier surface and radiation-induced melt within the uppermost ice layer, termed the “weathering crust”, seriously affect the accuracy of the short-term ablation measurements. The various measuring techniques commonly used (stakes, ablatometers, ablatographs) and some new methods (measurement of discharge from a small supra-glacial drainage basin, and mass loss directly measured on core samples) are critically reviewed and assessed in the light of these phenomena. The implications for studies of heat and mass balance are discussed.It appears that the direct measurement of mass flux is the most accurate means of assessing short-terni ablation rates. The errors in short-term ablation measurements by any method are largely compensatory and consequently do not influence long-period mass-balance estimates.
Geometry and Dynamics of a Surge-type Glacier
Authors: Bindschadler R. , Harrison W. D. , Raymond C. F. , Crosson R. 
Published: September 2017

AbstractMeasurement of geometry, motion, and mass balance from Variegated Glacier, Alaska portray conditions in this surge-type glacier close to the mid-point of its 20 year surge cycle. Comparison of longitudinal profiles of ice depth, surface slope, and surface speed indicate that the motion occurs largely by internal deformation assuming the ice deforms according to the experimental law of Glen. Surface speed is not noticeably affected by local surface slope on the scale of the ice thickness or smaller, but correlates well with slope determined on a longitudinal averaging scale about one order of magnitude larger than the ice depth. The rate of motion on Variegated Glacier agrees well with rates on non-surge type temperate glaciers which have similar depth and slope. Although the (low regime at the time of the measurements is apparently typical of temperate glaciers, a large discrepancy between the balance flux needed for steady state and the actual flux is indicative of a rapidly changing surface elevation profile and internal stress distribution.
The Distribution of Glaciers in the Rocky Mountains of the United States
Authors: Graf W. L. 
Published: September 2017

AbstractEvidence from aerial photographs, maps, and field checks indicates that 319 glaciers lie in cirques of the Rocky Mountains, south of the United States-Canadian border. On a subcontinental scale, the distribution of glaciers is highly clustered, with larger and denser clusters located in the northern Rocky Mountains. Lesser concentrations of small glaciers occur in the southern Rocky Mountains. The total area of glaciers in the Rocky Mountains of the U.S.A. is 78.9 km2.
Stress in an Elastic Bedrock Hump Due to Glacier Flow
Authors: Morland L. W. , Morris E. M. 
Published: September 2017

AbstractThe stress field in an isotropic elastic hump representing a typical bedrock feature is obtained for plane strain conditions. Gravity effects are included and the applied load is a normal pressure distribution deduced from an idealized model of glacier flow. A Coulomb failure criterion is applied, including the effective stress change due to pore-water pressure, and stresses on the predicted failure planes determined for different pressure amplitudes and relative gravity contributions. The latter make little difference to the maximum “failure stress" but influence the regions where such stress levels occur. Levels of cohesive stress required to inhibit Coulomb failure are obtained, and are low in general, implying that coherent rock in the adopted hump profile, subject to the model pressure, would not fail. That is, this profile is stable unless jointing introduces an easier failure mechanism.
A Snow-bank Push Mechanism for the Formation of Some “Annual” Moraine Ridges
Authors: Birnie Richard V. 
Published: September 2017

AbstractIce-marginal features in South Georgia include minor moraine ridges running approximately parallel to the ice margin and developed as superficial forms in various depths of till. It is suggested that these developed as ice-contact landforms, some being created by the interaction of the ice edge and abutting marginal snow bank, whilst the glacier is advancing. This advance is essentially short-term, being part of a seasonal variation in the position of the ice margin. “Snow-bank push” is the term proposed to describe this mechanism of ridge formation.