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Composite-wedge pseudomorphs in Flanders, Belgium

Composite-wedge pseudomorphs in Flanders, Belgium
Belgium ; Flanders ; Ice wedge ; Palaeo-environment ; Patterned ground ; Periglacial features ; Pleistocene ; Quaternary
of composite-wedge pseudomorphs on the plateau conflicts with the literature suggesting that ice-wedge pseudomorphs are dominant in Flanders. As a consequence, palaeoenvironmental reconstructions may have been biased towards environmental conditions suitable
for ice-wedge formation. Ice wedges probably formed mainly in depressions, whereas composite wedges may have been common on the plateaus.
Wedge structures observed at several sites are interpreted as composite-wedge pseudomorphs, formed by thermal contraction cracking in a permafrost environment. The structures probably formed during the Pleniglacial. The widespread occurrence

Implications of a Middle Pleistocene ice-wedge cast at Trimingham, Norfolk, Eastern England

Implications of a Middle Pleistocene ice-wedge cast at Trimingham, Norfolk, Eastern England
Chronostratigraphy ; England ; Glaciation ; Ice wedge ; Norfolk ; Palaeo-environment ; Permafrost ; Pleistocene ; Quaternary ; United Kingdom
A wedge exposed at Trimingham, northeast Norfolk, in 1998 is interpreted as an ice-wedge pseudomorph indicating that permafrost was present in the surrounding Cromer Foest-bed Formation sediments. The wedge is overlain by North Sea Drift Formation
(NSDF) glacial sediments, demonstrating that the associated ice sheet deposited till in either a terrestrial or an extremely shallow glaciolacustrine/marine environment. This conclusion supports those who believe that this ice sheet was, at least

An analysis of mechanisms of ice-wedge casting based on geotechnical centrifuge simulations

An analysis of mechanisms of ice-wedge casting based on geotechnical centrifuge simulations
Experimentation ; Geotechnics ; Ice wedge ; Model ; Periglacial features ; Permafrost ; Quaternary
The AA. interpret the outcomes of scaled geotechnical centrifuge simulation of ice-wedge casting in terms of the likely significance of Quaternary ice-wedge pseudomorphs observed within different host sediments. In the 6 experiments reported
, permafrost thawing took place continuously from the surface downwards in a single stage, so that the observed wedge casting processes almost certainly represent a major simplification of the natural system.

Ice-wedge casts and relict patterned ground in central Illinois and their environmental significance

Ice-wedge casts and relict patterned ground in central Illinois and their environmental significance
The objectives of this report are to summarize the data and observations on features and forms that the A. interprets to be the result of the formation of ice wedges and ice-wedge polygons during the last glaciation and to discuss

Ice-wedge casts in an early deglaciated area of southern Sweden

Ice-wedge casts in an early deglaciated area of southern Sweden
In the Laholm plain, NW Scania, an area that was the first part of Sweden to emerge from the Weichselian ice-sheet, three types of ice-wedge casts are observed. The wedges are discussed from a morphogenetic, morphostratigraphic and chronological

Age determination of fossil ice-wedge polygons in Nordic areas

Age determination of fossil ice-wedge polygons in Nordic areas
In the Nordic areas there are indications of fossil ice-wedge polygons in the ground surface, e. g. as: (1) a pattern of shallow furrows, (2) crop marks in cultivated areas. The paper intends to give a survey of and to discuss applicable methods
for dating the formation or fossilization of such ice-wedge, polygons (shoreline diagrams, C-14 dating or tephrochronology).

Ice-wedge casts as indicators of paleotemperatures : precise proxy or wishful thinking ?

Ice-wedge casts as indicators of paleotemperatures : precise proxy or wishful thinking ?
Comparative study ; Europe ; Ice wedge ; Palaeo-environment ; Palaeotemperature ; Periglacial features ; Permafrost ; Pleistocene ; Present time ; Quaternary
The main aim of this paper is to stimulate a more critical use of Weichselian ice-wedge casts for paleoclimatic and environmental reconstructions. First, the rationale for estimating palaeotemperatures from ice-wedge casts and its application

Stratigraphic and environmental implications of a large ice-wedge cast at Tjaereborg, Denmark

Stratigraphic and environmental implications of a large ice-wedge cast at Tjaereborg, Denmark
Cryoturbation ; Dating ; Denmark ; Ice wedge ; Jylland ; Palaeo-environment ; Periglacial features ; Permafrost ; Pleistocene ; Stratigraphy ; Thermoluminescence
In this paper, the characteritics of the wedge casts are outlined and an attempt is made to reconstruct their complex environmental history. Optically-Stimulated-Luminescence (OSL) datings of wedge fillings and host sediment are presented along
with an attempt to correlate the events of wedge growth with other parts of northern Europe.

Modelling of ice-wedge networks

Modelling of ice-wedge networks
Ice ; Ice wedge ; Modelling ; Network ; Palaeoclimate ; Patterned ground ; Snow ; Topography

Isotopic composition and thermal regime of ice wedges in northern Victoria Land, East Antarctica

Isotopic composition and thermal regime of ice wedges in northern Victoria Land, East Antarctica
Special Issue : Stable isotopes and geochemistry of ground ice
Antarctica ; Deuterium ; Geochemistry ; Ground ice ; Ice wedge ; Isotope analysis ; Oxygen 18 ; Periglacial features ; Sublimation ; Thermal regime ; Victoria Island
This paper reports the results of oxygen (andO 18) and hydrogen (andD) isotopic analyses of ice wedges and a five-year monitoring programme on the ice-wedge thermal regime at three sites in northern Victoria Land. The purpose of the study
was to characterise isotopically the ice wedges, define the processes leading to the formation of their ice and to determine whether thermal conditions can trigger cracking and hence whether ice wedges are active under present-day climate conditions. The isotopic
values and observations of hoarfrost crystals in ice-wedge cracks during summer field surveys indicate that sublimation processes control the formation of ice in wedges, especially at high elevations within this region.

Palaeoclimate reconstruction on Big Lyakhovsky Island, North Siberia - hydrogen and oxygen isotopes in ice wedges

Palaeoclimate reconstruction on Big Lyakhovsky Island, North Siberia - hydrogen and oxygen isotopes in ice wedges
Asian part of Russia ; Deuterium ; Holocene ; Ice wedge ; Isotope analysis ; Oxygen 18 ; Palaeo-environment ; Palaeoclimate ; Periglacial features ; Pleistocene ; Quaternary ; Siberia
isotope analyses are presented for 6 different generations of ice wedges as well as for recent ice wedges and precipitation. An age of about 200 ka BP was determined for an autochtonous peat layer in ice-rich deposits by U/Th method, containing the oldest
ice wedges ever analysed for hydrogen and oxygen isotopes.

Ice- and soil-wedge dynamics in the Kapp Linné Area, Svalbard, investigated by two- and three-dimensional GPR and ground thermal and acceleration regimes

Ice- and soil-wedge dynamics in the Kapp Linné Area, Svalbard, investigated by two- and three-dimensional GPR and ground thermal and acceleration regimes
Active layer ; Arctic Region ; Cold area ; Geophysics ; Ice wedge ; Periglacial features ; Permafrost ; Snow cover ; Soil temperature ; Spatial distribution ; Svalbard
GPR is applied to image subsurface structures below non-sorted polygons in Kapp Linné, Svalbard, where ice and active-layer soil wedges co-exist within a small area. Two-dimensional GPR images ice wedges as hyperbolic reflections extending down from
the frost table. However, some ice-wedge signals are obscured or masked by similar hyperbolic reflections produced by stones or active-layer soil wedges. Three-dimensional GPR images ice wedges as linear amplitude anomalies, which excludes the possibility
of misinterpretation and offers more reliable results. GPR investigations show that ice wedges are distributed sporadically in lower (younger) beach ridges, but not in higher (older) ones. Inter-site monitoring of ground temperature, soil moisture, slow ground
deformation and cracking during 2004–09 and the determination of near-surface soil texture and stratigraphy suggest that snow cover and soil thermal properties determine the distribution of ice wedges.

Pleistocene ice wedge casts at 34o S eastern Andes piedmont, south-west of South America

Pleistocene ice wedge casts at 34o S eastern Andes piedmont, south-west of South America
This paper deals with cryogenic palaeoenvironmental indicators, ice wedge casts, located at 34o 37' S, 68o 26' W, 825 m a. s. l., 80 km east of the Andes. The interpretation of these ice-wedge casts is based on analysis of fabric diagrams

Observation of rapid drainage system development by thermal erosion of ice wedges on Bylot Island, Canadian Arctic Archipelago

Observation of rapid drainage system development by thermal erosion of ice wedges on Bylot Island, Canadian Arctic Archipelago
Canada ; Cold area ; Drainage ; Gully erosion ; Ice wedge ; Meltwater ; Nunavut ; Permafrost ; Thermokarst
The AA. show the significant impact that hydro-thermal underground erosion can have on the drainage system in a permafrost environment with well-developed ice wedges. They describe the formation of tunnels and the associated gullies

A field perspective on modelling single ridge ice-wedge polygons

A field perspective on modelling single ridge ice-wedge polygons
Climatic variation ; Cold area ; Ice wedge ; Model ; Numerical model ; Palaeo-environment ; Periglacial features ; Polar region
criticisms focus on : the implications of trough evolution for cracking behaviour; the extent to which epigenetic, low-centred polygons represent the population of ice-wedge networks; and the modelled initiation of polygons in drained thaw lakes.

Description and genesis of buried sand-filled soil wedges near Flagstaff, Arizona

Description and genesis of buried sand-filled soil wedges near Flagstaff, Arizona
Arizona ; Cryopedology ; Gelifraction ; Ice wedge ; Palaeosol ; Pedogenesis ; Periglacial features ; Quaternary ; Stratigraphy ; United States of America ; Wisconsinan
or ice-wedge casts formed in continuous permafrost. Their size, spacing, and other characteristics most resemble those of soil wedges formed by seasonal frost craching found near and beyond the southern limit of permafrost in areas where mean annual
Buried, sand-filled soil wedges exposed in stratigraphic sections at 2 sites near Flagstaff, are larger than any observed desiccation cracks or fissures in modern surface soils or sediments but they are smaller than typical periglacial sand wedges
temperatures are about 0°C. Stratigraphic relations and relative degree of development of associated soils suggest the wedges in Flagstaff are of late Wisconsin age whereas.

Characteristics of ice-wedge casts in west central Wales

Characteristics of ice-wedge casts in west central Wales
Most of the wedge casts occur in angular slope gravel, fluvial or fluvio-glacial gravels, the largest reaching a width of 2-3 m and a depth of 3-5 m. Upturning of the host gravel occurs, especially with the larger casts. Slump or sag structures
in the fill are limited to platy gravels| in other gravels, the wedge fill is characterized by very steeply dipping clasts. Though no means of precise dating is available, it is throught that the wedge casts formed in the later part of the last glaciation.

Thermal regime of ice-wedge cracking in Adventdalen, Svalbard

Thermal regime of ice-wedge cracking in Adventdalen, Svalbard
Arctic Region ; Cold area ; Ice wedge ; Ice wedges ; Periglacial features ; Snow ; Snow cover ; Soil temperature ; Soil wedge polygon ; Svalbard ; Thermal regime
One year of monitoring (2002-2003) at a low-centred ice-wedge polygon site on Svalbard is described. Ground temperatures were recorded hourly from the top of an ice wedge through the active layer to the ground surface in the central part of a trough
and in the adjacent rampart. Daily data on snow-cover depth were collected by automatic digital photography. Cracks were mapped in February, April and July. The results show that cracking occurred after ground temperatures at the centre of the ice-wedge top decreased
to below -15°c. Ground cooling in mid-winter occurred mainly through the snow-free ramparts because the ice-wedge troughs were filled by snow to depths of up to 30 cm.

Ice wedges on hillslopes and landform evolution in the late Quaternary, western Arctic coast, Canada

Ice wedges on hillslopes and landform evolution in the late Quaternary, western Arctic coast, Canada
Active layer ; Arctic Region ; Canada ; Coastal environment ; Cold area ; Diapir ; Ice wedge ; Permafrost ; Quaternary ; Slope ; Slope gradient ; Soil erosion
centres, outwards to the throughs and provides survey evidence in support of ice-wedge diapirism. Also it suggests that some discordant hillslope polygon patterns may have developed prior to the evolution of the present topography.
This paper discusses how hilltop epigenetic wedges can evolve into hillslope anti-syngenetic wedges by prolonged slope denudation. It demonstrates the existence, on hillslopes, of thermally induced mass transport of the active layer from polygon

Pseudo-ice-wedge casts of Connecticut, Northeastern United States

Pseudo-ice-wedge casts of Connecticut, Northeastern United States
Since 1965, ice-wedge casts have been reported in deposits of sand and gravel in Connecticut, These are wedge forms up to 1.1 m wide and many meters high. Most are single forms, not in polygonal array. They are found in adjoining states as well

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