A distinction between ice-pushed and ice-lifted landforms on lacustrine and marine coasts
The distinction between the processes of ice push, and ice lifting and rafting is made in this work from a study of the occurrence of boulder barricades in a small lake, Second Roach Pond, in northern Maine. A classification of shoreline features
Late Devensian ice-sheet in the western Grampians, Scotland
A radial pattern of ice flow of the last ice-sheet in the largest source area of ice in the British Isles is demonstrated by the dispersal of indicator erratics and by patterns of striae, friction cracks and ice-moulded landforms.
Pollen dispersal and deposition on the Quelccaya Ice Cap, Peru
Andes ; Biogeography ; High mountain ; Ice core ; Ice sheet ; Palynology ; Peru ; Tropical zone
This study attempts to utilize 15 surface snow samples, taken on the Quelccaya Ice Cap, southern Peru, in late August of 2000, to help answer some basic questions of pollen dispersal and deposition on tropical Andean ice caps.
This article reviews current knowledge of the principal sea-ice and lake-ice phenomena affecting shore-zone morphology and stability. The AA. emphasize insights developed over the past 100 years or so in Canada and contiguous coastal regions
of the USA, in particular those most relevant to research and engineering practice in Canada. This article builds on a number of recent reviews of coastal ice phenomena, from 1980 to 1992, but this review is necessarily selective.
Jökulhlaup initiation by ice-dam flotation : the significance of glacier debris content
Cold area ; Drainage ; Floating ice ; Glacial lake ; Glacial surge ; Glaciology
Ice-dam flotation is a commonly described mechanism for the initiation of jökulhlaups (catastrophic floods)from ice-dammed lakes, but predictions of the critical lake depth required for flotation often differ from the actual lake depth at which
flotation occurs. Glacier debris content is identifed as an insufficiently recognized variable in ice-dam flotation. It is demonstrated that high debris contents could suppress flotation, and thereby affect the timing, mechanism and magnitude of catastrophic
lake drainage events. The density of the part of the glacier forming the ice dam is the key to predicting ice-dam flotation.
Climatic variation ; Forecast;Prediction ; Glacial features ; Glacier mass balance ; Ice sheets;Ice cap;Inlandsis ; Model ; Scotland ; Topography ; United Kingdom
This paper uses a numerical ice sheet model to investigate the role of topography in influencing ice sheat growth. The model is applied to the maritime, mid-latitutde uplands of Scotland and relies on a series of assumptions about mass balance
, topography, and ice flow. It is driven by an imposed pattern of temperature change. The model is able to predict effectively the extent and thickness of the Loch Lomond ice sheet, using a palaeotemperature curve based on Coleoptera assemblages.
Arctic sea-ice characteristics and associated atmosphere Ice interactions in summer inferred from SMMR data and drifting buoys : 1979-1984
SMMR-derived sea ice concentrations for November 1978-October 1984 in the Canada Basin are examined to determine temporal and spatial scales of variability in ice concentration and extent. Large regions of reduced-concentration ice are observed
. Comparison with buoy-measured surface pressure and winds suggests that reduced ice concentrations are associated with regions of strong winds and divergence beneath low pressure systems.
In this article, the nature, origin and uses of internal Antarctic ice-sheet layering, observed on 60 MHz RES data, are investigated. In doing so an insight into several aspects of modern Antarctic glaciological research is provided : correlating
ice cores; boundary conditions for numerical models to help determine the direction of ice flow; and means of identifying the three-dimensional ice-sheet geometry and architecture.
More on deep glacial erosion by continental ice sheets and their tongues of distributary ice
High latitude intracontinental seaways occupy great troughs carved by broad tongues of inland ice as it debouched to deep marine water. Such troughs occur in glaciated coasts, but not in stable, nonglaciated ones. Where ice flowed across them
, coasts are digitate in low relief. In the northeastern sector of the Laurentide Ice Sheet, large glacial grooves converge toward the Gulf of Boothia - Prince Regent Inlet - Lancaster Sound, suggesting that it was an exit for inland ice which shaped
Advance of part of the margin of the Greenland ice sheet across a proglacial moraine ridge between 1968 and 2002 caused progressive changes in moraine morphology, basal ice formation, debris release, ice-marginal sediment storage, and sediment
Weichselian ice movement in South Norway and adjacent areas
Three main phases of ice-movement pattern in South Norway during the Weichselian are reconstructed. During phaseIII (possibly of Middle/Late Weichselian age) had an easterly situated ice divide. During phaseIV (Preboreal age) the ice divide had
moved back to the West and had partly fragmented into separate domes. The migration of the ice divide from West to East may be due to glacier surges, whilst the ice-divide migration from phaseIII to IV was probably a result of a general reduction in size
Dead-ice features at the maximum extent of the last glaciation in northeastern Poland
Last ice sheet dynamics and deglaciation in the North European Plain
The maximum extent zone of thhe Vistulian Glaciation in northeastern Poland is composed of a complex pattern with alternating dead and active ice features. The former include tripartite fabric of till in morainic plateaux as well as depressions
of varying size, often with numerous secondary forms. Active ice zones represent probable ice streams within the ice sheet, reflected by outwash plains and previous subglacial channels. Different sediments in each zone suggest a coincidence of dead-ice
features with cold ice whereas ice streams corresponded presumably with temperate ice that produced intensive meltwater outflow.
Oxygen-isotope analyses and Pleistocene ice volumes
The oxygen-isotope record from fossil foraminifera in deep-sea sediments is commonly used as a proxy for global ice volume. The linkage between O and ice volume, however, is probably nonlinear. The AA. have developed a simple numerical model
of the isotopic response of the oceans to ice-volume change. They illustrate the response of their model to simple hypothetical ice-volume transitions of ice growth and ice decay. Sensitivity tests are illustrated for all model parameters. The results suggest
that oxygen-isotope records reproduce the general patterns on ice-volume change fairly accurately. The foraminiferal isotope record, however, may misrepresent the true amplitude of the ice-volume signal and lag true ice volume by 1000 to 3000 yr.
Antarctica ; Earth surface processes ; Esker ; Glacial features ; Glacier margin ; Ice sheets;Ice cap;Inlandsis ; Moraines
The eskers described in this paper have formed on the surface of cold ice at the margin of the Antarctic ice sheet. The location, orientation, sedimentary properties and field relationships of the eskers are described and a model of their formation
On the ice age glaciation of the Tibetan Highlands and its transformation into a 3-D model
The AA. present an interdisciplinary study on data and modeling intercomparison, concerning the possible existence of a Tibetan ice sheet and its climatological implications during the ice age.