Isotope characterisation of ground ice in northern Canada
Special Issue : Stable isotopes and geochemistry of ground ice
Arctic Region ; C 14 dating ; Canada ; Cold area ; Geochemistry ; Ground ice ; Ice wedge ; Isotope analysis ; Oxygen 18 ; Permafrost ; Pingo ; Polar region
This paper reviews isotopic research on the characterisation and identification of various types of ground ice throughout the Canadian Arctic, including buried glacier ice, massive segregated ice, segregated ice lenses and offshore ice-rich
permafrost, as well as ice related to other cold-region phenomena such as ice wedges, icings (aufeis), frost blisters and pingos. The formational age of ground ice bodies ranges from recent (seasonal ice in the active layer) to tens of thousands of years
, when the region experienced widespread continental-scale glaciation. The ratios O 18/O 16 are analysed. Placing the ice bodies into a time frame can be accomplished either through age dating of the enclosing sediments and encased organics, or by direct
dating of the ice utilising tritium (3H) for relatively young ice and radiocarbon (14C) analysis of contained gas bubbles for older ice.
Origin and characteristics of massive ground ice on Herschel Island (western Canadian Arctic) as revealed by stable water isotope and Hydrochemical signatures
Special Issue : Stable isotopes and geochemistry of ground ice
Arctic Region ; Canada ; Cold area ; Deuterium ; Geochemistry ; Ground ice ; Hydrochemistry ; Inland ice ; Isotope analysis ; Oxygen 18 ; Periglacial features ; Permafrost ; Polar region
Herschel Island in the southern Beaufort Sea is a push moraine at the northwestern-most limit of the Laurentide Ice Sheet. Stable water isotope (δ18 O, δD) and hydrochemical studies were applied to two tabular massive ground ice bodies to unravel
their genetic origin. Buried glacier ice or basal regelation ice was encountered beneath an ice-rich diamicton with strong glaciotectonic deformation structures. Both massive ground ice bodies exhibited a mixed ion composition suggestive of terrestrial waters
with a marine influence. Hydrochemical signatures resemble the Herschel Island sediments that are derived from near-shore marine deposits upthrust by the Laurentide ice. A prolonged contact between water feeding the ice bodies and the surrounding sediment
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.
Sulfur and carbon isotopes within atmospheric, surface and ground water, snow and ice as indicators of the origin of tabular ground ice in the Russian Arctic
Special Issue : Stable isotopes and geochemistry of ground ice
Arctic Region ; Coastal environment ; Geochemistry ; Ground ice ; Ice ; Isotope analysis ; Moisture ; Periglacial features ; Russia
Field sampling of tabular ground ice (TGI) was undertaken at a number of geological sections along the Russian Arctic coast. S 34 in sulfate ion and C 13 in organic matter were analysed in ground ice and enclosing deposits, and in reference samples
structure between TGI and atmospheric and continental moisture. TGI and its enclosing deposits have a heavier isotopic composition of sulfur and carbon than buried snow and glacial ice. This is considered to be evidence of an essential contribution of marine
Investigation of ice-wedge infilling processes using stable oxygen and hydrogen isotopes, crystallography and occluded gases (O2, N2, Ar)
Special Issue : Stable isotopes and geochemistry of ground ice
Alaska ; Arctic Region ; Canada ; Cold area ; Geochemistry ; Holocene ; Ice wedge ; Isotope analysis ; Micro-organism ; Periglacial features ; Pleistocene ; Yukon
The AA. investigated the infilling process in ice wedges of various ages (modern to Pleistocene) preserved in the Old Crow region (Yukon), dating from the Late Holocene, and Vault Creek tunnel (Alaska), dating from the Late Pleistocene. A variety
of techniques are used, including ice crystallography, the determination of andO 18 (ice) and andD (ice), the molar ratios of occluded gases (and(O2/Ar) and and(N2/Ar)), and the stable isotope composition of O2 (andO 18) and N2 (andN 15) gases. The results
indicate that climatic and site-specific conditions may influence the source of infilling during ice-wedge growth, so that wedge ice in wet and dry environments exhibits different characteristics. In both ice-wedge types, the δ(O2/Ar) values are much lower
than both dissolved and atmospheric values, which may be due to the respiration of microorganisms living within ice bubbles or interstitial water at the grain boundaries.
Isotopic composition of syngenetic ice wedges and palaeoclimatic reconstruction, western Taymyr, Russian Arctic
Special Issue : Stable isotopes and geochemistry of ground ice
Arctic Region ; Asian part of Russia ; Deuterium ; Geochemistry ; Holocene ; Ice wedge ; Isotope analysis ; Oxygen 18 ; Palaeo-environment ; Palaeoclimate ; Pleistocene
This paper reports the results of oxygen (andO 18) and hydrogen (andD) isotopic analyses of ice wedges of different generations at 3 sites on the western Taymyr coast. Palaeotemperature reconstruction based on the data shows that winter temperatures
during the formation of older generation ice wedges were lower than Holocene winter temperatures, indicating that they developed in the Late Weichselian. The presence of syngenetic ice wedges strongly suggests that the coast of western Taymir was not ice
Palaeoclimatic information from stable water isotopes of Holocene ice wedges on the Dmitrii Laptev Strait, northeast Siberia, Russia
Special Issue : Stable isotopes and geochemistry of ground ice
Arctic Region ; Asian part of Russia ; Deuterium ; Geochemistry ; Holocene ; Ice wedge ; Isotope analysis ; Oxygen 18 ; Palaeo-environment ; Palaeoclimate ; Permafrost ; Siberia
The stable isotopic composition (andO 18, andD, d) of 3 Holocene-age ice wedges at the Dmitrii Laptev Strait was studied at high resolution in order to develop palaeoclimatic records. AMS C 14 ages of organic matter in the ice prove the Late
Holocene age of the studied horizontal ice-wedge profiles and indicate syngenetic growth associated with sediment accumulation. A general Late Holocene winter warming trend is inferred from andO 18 data with periods of marked variability superimposed
to infer the origin of subsurface ice. However, d values do not provide much information on the origin of subsurface ice, as d is dependent on freezing conditions. To make proper use of d, its relation with D needs to be investigated, with no relation