scholarly journals Studies of Englacial Profiles in the Lake Hazen Area of Northern Ellesmere Island

1960 ◽  
Vol 3 (27) ◽  
pp. 610-625
Author(s):  
G. Hattersley-Smith
Keyword(s):  
Crystal Structure ◽  
Budget Deficit ◽  
Ice Core ◽  
Ellesmere Island ◽  
Equilibrium Line ◽  
Mean Annual Temperature ◽  
The Past ◽  
Ice Cap ◽  
The North ◽  
The Mean

AbstractGlaciological research on the ice cap to the north of Lake Hazen in northern Ellesmere Island was one of the main objectives of the Canadian I.G.Y. expedition to this area in 1957–1958. The method of nourishment of this ice cap and of Gilman Glacier, one of its southward-flowing outlets, was studied in pit and bore hole profiles above and below the equilibrium line, which was found at an elevation of about 1,200 m. Between an elevation of about 1,450 and 2,000 m. accumulation is by firn formation, while between about 1,280 and 1,450 m. interfingering of firn and superimposed ice occurs. At 1,800 m. the mean annual accumulation over the past twenty years is estimated as 12.8 g. cm.–2. On Gilman Glacier below the equilibrium line variations in density and crystal structure in an ice core to a depth of 25 m. are seen to depend on the proportion of firn to superimposed ice formed during accumulation. These variations correspond to past changes in the position of the equilibrium line. Englacial temperature measurements indicate a mean annual temperature of about –18.5° C. at an elevation of 1 ,040 m. A budget deficit for Gilman Glacier during two years of observations may be related to the increased summer melting of the last 20 years, deduced from pit studies at 1,800 m.

scholarly journals Studies of Englacial Profiles in the Lake Hazen Area of Northern Ellesmere Island

1960 ◽  
Vol 3 (27) ◽  
pp. 610-625 ◽  
Author(s):  
G. Hattersley-Smith
Keyword(s):  
Crystal Structure ◽  
Budget Deficit ◽  
Ice Core ◽  
Ellesmere Island ◽  
Equilibrium Line ◽  
Mean Annual Temperature ◽  
The Past ◽  
Ice Cap ◽  
The North ◽  
The Mean

AbstractGlaciological research on the ice cap to the north of Lake Hazen in northern Ellesmere Island was one of the main objectives of the Canadian I.G.Y. expedition to this area in 1957–1958. The method of nourishment of this ice cap and of Gilman Glacier, one of its southward-flowing outlets, was studied in pit and bore hole profiles above and below the equilibrium line, which was found at an elevation of about 1,200 m. Between an elevation of about 1,450 and 2,000 m. accumulation is by firn formation, while between about 1,280 and 1,450 m. interfingering of firn and superimposed ice occurs. At 1,800 m. the mean annual accumulation over the past twenty years is estimated as 12.8 g. cm.–2. On Gilman Glacier below the equilibrium line variations in density and crystal structure in an ice core to a depth of 25 m. are seen to depend on the proportion of firn to superimposed ice formed during accumulation. These variations correspond to past changes in the position of the equilibrium line. Englacial temperature measurements indicate a mean annual temperature of about –18.5° C. at an elevation of 1 ,040 m. A budget deficit for Gilman Glacier during two years of observations may be related to the increased summer melting of the last 20 years, deduced from pit studies at 1,800 m.

scholarly journals Climatic and Chemical Studies in James Ross Island Snow (Antarctic Peninsula) (Abstract only)

1982 ◽  
Vol 3 ◽  
pp. 347-347
Author(s):  
A Aristarain ◽  
M Briat ◽  
R Delmas ◽  
M Pourchet ◽  
J Jouzel
Keyword(s):  
Antarctic Peninsula ◽  
Seasonal Variations ◽  
Ice Core ◽  
Sea Salt ◽  
Eastern Coast ◽  
Mean Annual Temperature ◽  
Ice Cap ◽  
James Ross Island ◽  
The Mean ◽  
The Antarctic

James Ross Island (mean diameter 50 km) is located near the north-eastern coast of the Antarctic Peninsula. An ice cap, covering nearly the entire island, rises to a height of ~1 600 m. Three summer expeditions with glaciological purposes were recently achieved on this ice cap by the Instituto Antártico Argentino, two of them with the scientific participation of the Laboratoire de Glaciologie et Geophysique de I'Environnement, Grenoble.We present results of climatic and chemical investigations performed on recent snow layers dating back about 25 a. The studied samples were collected at different sites on the upper part of the ice dome. Detailed measurements (deuterium, oxygen 18 and total β activity) were performed on more than 1000 selected samples. The relationship between stable isotope and mean annual temperature fits very well with the one previously obtained in the Antarctic Peninsula.An ice core 22 m deep drilled on Dome Dalinqer (elevation 1600 m, mean annual temperature -15˚C) showed well-preserved seasonal variations in deuterium all along the profile, thus providing a yearly dating of the samples which was confirmed by β activity reference levels. The mean annual accumulation thus deduced is 500 kg m−2 between 1955 and 1979, with values significantly lower (30%) in the 1955–65 decade than in 1965–79. The same trend earlier observed in east and central parts of Antarctica thus appears to have a very large geographical extent.This well-dated core allows us to undertake a year-to-year comparison between isotopic and climatological data over the 1953–78 period. The mean annual values of the deuterium content are well correlated with the average surface temperature taken over the whole Antarctic Peninsula (δD = (3.4±2.0)T - (98±32))These data and the experimentally derived δD/δ180 relationship obtained on James Ross Island allow us to deduce a δ180 temperature gradient of 0.44‰°C−1. This low value is discussed in view of a new isotopic model taking into account the partial removal of precipitation and the possible variation of the oceanic source. James Ross Island thus appears suitable as a potential site for reconstructing past climatic changes of the Antarctic Peninsula beyond existing data.Contamination-free techniques were used for sampling and analysing the snow samples. Na, K, Ca, and Al (by atomic absorption), H+ (by titrimetric measurements), SO42- and NO3− (by ion chromatography), and conductivity were determined on more than 100 samples collected in a 4.3 m deep pit. Some of these parameters were also measured on ice-core samples or additional pit samples.Snow impurities are contributed by different aerosol sources: sea salt, continental particles and the small-size particles produced by the conversion of various atmospheric gases. The relative importance of these sources has been estimated.James Ross snow was found always to be slightly acid (1 to 10 μEquiv. l−1 of H+, mainly as sulphuric acid). Nitrate concentrations are much smaller (0.4 μEquiv. l−1). Strong seasonal variations are observed for H2SO4 deposition, probably in relation to its formation in the Antarctic atmosphere.Sea-salt deposition exhibits also seasonal variations which can be correlated with storm frequency in the Weddell Sea area. The continental aerosol contribution is weak as indicated by very low Al values.The influence of Deception Island volcanism on the regional aerosol chemistry is examined. A marked increase of snow acidity was detected after the 1967 eruption of this volcano, but no ash layers were observed.The strong variations of the conductivity of melt water are interpreted: it is shown that this parameter is not representative of the extent of sea ice

scholarly journals The Mass Balance of the Devon Island Ice Cap, Northwest Territories, Canada, 1961-66

1970 ◽  
Vol 9 (57) ◽  
pp. 325-336 ◽  
Author(s):  
R.M. Koerner
Keyword(s):  
Mass Balance ◽  
Equilibrium Line ◽  
Accumulation Pattern ◽  
North West ◽  
Average Value ◽  
Devon Island ◽  
Ice Cap ◽  
The North ◽  
West Part ◽  
The Mean

Methods used in measuring the mass balance of the Devon Island ice cap are described. The use of dyes and melt trays is recommended in the superimposed-ice and firn zones of sub-polar glaciers. The north-west part of the ice cap was studied in most detail and has had a slightly negative net balance for the period 1961-66. An inverse relationship between mean net balance(bn)and elevation of the equilibrium line in the north-west part of the ice cap indicates that the mean net balance there would be zero with an equilibrium line at 920 m (±80 m) elevation. Accumulation on the ice cap is greatest in the south-east but the measurements suggest that the mean net balance there is similar to the mean net balance on the rest of the ice cap. It is concluded that the present accumulation pattern must have existed for several hundreds, and possibly thousands of years. A study of firn stratigraphy and of variations in the elevation of the firn and equilibrium lines indicates that between 1961 and 1966 only 1962 had a more negative mean net balance than the average value for the period 1934-60. During the same 26 year period the net balance at 1 787 m elevation has varied, but summer conditions do not appear to have changed significantly.

scholarly journals The Mass Balance of the Devon Island Ice Cap, Northwest Territories, Canada, 1961-66

1970 ◽  
Vol 9 (57) ◽  
pp. 325-336 ◽  
Author(s):  
R.M. Koerner
Keyword(s):  
Mass Balance ◽  
Equilibrium Line ◽  
Accumulation Pattern ◽  
North West ◽  
Average Value ◽  
Devon Island ◽  
Ice Cap ◽  
The North ◽  
West Part ◽  
The Mean

Methods used in measuring the mass balance of the Devon Island ice cap are described. The use of dyes and melt trays is recommended in the superimposed-ice and firn zones of sub-polar glaciers. The north-west part of the ice cap was studied in most detail and has had a slightly negative net balance for the period 1961-66. An inverse relationship between mean net balance (bn) and elevation of the equilibrium line in the north-west part of the ice cap indicates that the mean net balance there would be zero with an equilibrium line at 920 m (±80 m) elevation. Accumulation on the ice cap is greatest in the south-east but the measurements suggest that the mean net balance there is similar to the mean net balance on the rest of the ice cap. It is concluded that the present accumulation pattern must have existed for several hundreds, and possibly thousands of years. A study of firn stratigraphy and of variations in the elevation of the firn and equilibrium lines indicates that between 1961 and 1966 only 1962 had a more negative mean net balance than the average value for the period 1934-60. During the same 26 year period the net balance at 1 787 m elevation has varied, but summer conditions do not appear to have changed significantly.

scholarly journals Glaciological Reconnaissance of an Ice Core Drilling Site, Penny Ice Cap, Baffin Island

1984 ◽  
Vol 30 (104) ◽  
pp. 3-15 ◽  
Author(s):  
G. Holdsworth
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Surface Air Temperature ◽  
Tritium Concentration ◽  
Mean Annual Temperature ◽  
Climatic Data ◽  
Baffin Island ◽  
The Core ◽  
Ice Cap ◽  
The Mean

AbstractA site situated close to the main divide of the Penny Ice Cap, Baffin Island was occupied in 1979 for the purpose of determining the suitability of this ice cap for providing proxy climatic data and other environmental time series for a span of 104a. A 20 m core was extracted and analysed for stable oxygen isotopes, tritium concentration, pH, electrolytic conductivity, major ion concentrations, and particulate concentration. An adjacent dedicated shallow core was analysed for pollen content to determine if a significant seasonal variation in the pollen rain existed. From these measurements, and from the observations made on the stratigraphic character of the core, the mean net accumulation rate over the approximately 30 year period covered by the core is found to be about 0.43 m water equivalent per year. This is in agreement with a single value determined 26 years earlier at a nearby site (Ward and Baird, 1954). The mean annual temperature in the bore hole was found to be close to −14.4° C, possibly some 2–5 deg warmer than the expected mean annual surface air temperature at the site. This difference is due to the expulsion of latent heat upon freezing of melt water at depth in the snow-pack which gives rise to the many ice layers observed in the core. The percentage thickness of ice layers per year may be correlated with summer temperatures.Total ice depths were measured using a 620 MHz radar echo-sounder. In the vicinity of the divide, over an area of 1 km2, the ice depths vary from about 460 to 515 m. These values compare favourably with values determined from an airborne radar depth-sounding flight carried out over the ice cap by a joint U.S.–Danish mission operating out of Søndre Strømfjord, Greenland. The data suggest that the ice-cap divide would be a worthwhile location to deep core drill with an expected useful coverage of at least the Holocene period.

scholarly journals Climatic and Chemical Studies in James Ross Island Snow (Antarctic Peninsula) (Abstract only)

1982 ◽  
Vol 3 ◽  
pp. 347
Author(s):  
A Aristarain ◽  
M Briat ◽  
R Delmas ◽  
M Pourchet ◽  
J Jouzel
Keyword(s):  
Antarctic Peninsula ◽  
Seasonal Variations ◽  
Ice Core ◽  
Sea Salt ◽  
Eastern Coast ◽  
Mean Annual Temperature ◽  
Ice Cap ◽  
James Ross Island ◽  
The Mean ◽  
The Antarctic

James Ross Island (mean diameter 50 km) is located near the north-eastern coast of the Antarctic Peninsula. An ice cap, covering nearly the entire island, rises to a height of ~1 600 m. Three summer expeditions with glaciological purposes were recently achieved on this ice cap by the Instituto Antártico Argentino, two of them with the scientific participation of the Laboratoire de Glaciologie et Geophysique de I'Environnement, Grenoble. We present results of climatic and chemical investigations performed on recent snow layers dating back about 25 a. The studied samples were collected at different sites on the upper part of the ice dome. Detailed measurements (deuterium, oxygen 18 and total β activity) were performed on more than 1000 selected samples. The relationship between stable isotope and mean annual temperature fits very well with the one previously obtained in the Antarctic Peninsula. An ice core 22 m deep drilled on Dome Dalinqer (elevation 1600 m, mean annual temperature -15˚C) showed well-preserved seasonal variations in deuterium all along the profile, thus providing a yearly dating of the samples which was confirmed by β activity reference levels. The mean annual accumulation thus deduced is 500 kg m−2 between 1955 and 1979, with values significantly lower (30%) in the 1955–65 decade than in 1965–79. The same trend earlier observed in east and central parts of Antarctica thus appears to have a very large geographical extent. This well-dated core allows us to undertake a year-to-year comparison between isotopic and climatological data over the 1953–78 period. The mean annual values of the deuterium content are well correlated with the average surface temperature taken over the whole Antarctic Peninsula (δD = (3.4±2.0)T - (98±32)) These data and the experimentally derived δD/δ180 relationship obtained on James Ross Island allow us to deduce a δ180 temperature gradient of 0.44‰°C−1. This low value is discussed in view of a new isotopic model taking into account the partial removal of precipitation and the possible variation of the oceanic source. James Ross Island thus appears suitable as a potential site for reconstructing past climatic changes of the Antarctic Peninsula beyond existing data. Contamination-free techniques were used for sampling and analysing the snow samples. Na, K, Ca, and Al (by atomic absorption), H+ (by titrimetric measurements), SO4 2- and NO3 − (by ion chromatography), and conductivity were determined on more than 100 samples collected in a 4.3 m deep pit. Some of these parameters were also measured on ice-core samples or additional pit samples. Snow impurities are contributed by different aerosol sources: sea salt, continental particles and the small-size particles produced by the conversion of various atmospheric gases. The relative importance of these sources has been estimated. James Ross snow was found always to be slightly acid (1 to 10 μEquiv. l−1 of H+, mainly as sulphuric acid). Nitrate concentrations are much smaller (0.4 μEquiv. l−1 ). Strong seasonal variations are observed for H2SO4 deposition, probably in relation to its formation in the Antarctic atmosphere. Sea-salt deposition exhibits also seasonal variations which can be correlated with storm frequency in the Weddell Sea area. The continental aerosol contribution is weak as indicated by very low Al values. The influence of Deception Island volcanism on the regional aerosol chemistry is examined. A marked increase of snow acidity was detected after the 1967 eruption of this volcano, but no ash layers were observed. The strong variations of the conductivity of melt water are interpreted: it is shown that this parameter is not representative of the extent of sea ice

scholarly journals Glaciological studies on the King George Island ice cap, South Shetland Islands, Antarctica

1998 ◽  
Vol 27 ◽  
pp. 105-109 ◽  
Author(s):  
Wen Jiahong ◽  
Kang Jiancheng ◽  
Han Jiankang ◽  
Xie Zichu ◽  
Liu Leibao ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Stable State ◽  
Equilibrium Line ◽  
South Shetland Islands ◽  
Mean Annual Temperature ◽  
King George Island ◽  
Equilibrium Line Altitude ◽  
Shetland Islands ◽  
Ice Cap ◽  
The Mean

The King George Island ice cap, South Shetland Islands, Antarctica, was studied between 1985 and 1992. At the steady-state equilibrium-line altitude of the ice cap, the mean annual temperature is -3.6°C, the mean summer (December-February) temperature is 0°C and annual precipitation is 800 mm w.e. Precipitation increases rapidly with elevation, and annual accumulation rate at the Main Dome summit reaches 2480 mm a−1. Between 1985 and 1991 the equilibrium-line elevation averaged 140-150 m a.s.l. The ice cap has been in an overall stable state for the past 20 years, going from a weak negative to a small positive mass imbalance as increased precipitation outweighs the effects of rising temperatures. Temperatures at the bottom of the active layer over most of the accumulation area are close to 0°C, with colder temperatures down to -1.9°C in the ablation zone. Soluble impurities in the ice cap are mainly from marine sources, while undissolved mineral material amounts to only 15-54% of the total microparticle content.

scholarly journals Glaciological Reconnaissance of an Ice Core Drilling Site, Penny Ice Cap, Baffin Island

1984 ◽  
Vol 30 (104) ◽  
pp. 3-15 ◽  
Author(s):  
G. Holdsworth
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Surface Air Temperature ◽  
Tritium Concentration ◽  
Mean Annual Temperature ◽  
Climatic Data ◽  
Baffin Island ◽  
The Core ◽  
Ice Cap ◽  
The Mean

AbstractA site situated close to the main divide of the Penny Ice Cap, Baffin Island was occupied in 1979 for the purpose of determining the suitability of this ice cap for providing proxy climatic data and other environmental time series for a span of 104 a. A 20 m core was extracted and analysed for stable oxygen isotopes, tritium concentration, pH, electrolytic conductivity, major ion concentrations, and particulate concentration. An adjacent dedicated shallow core was analysed for pollen content to determine if a significant seasonal variation in the pollen rain existed. From these measurements, and from the observations made on the stratigraphic character of the core, the mean net accumulation rate over the approximately 30 year period covered by the core is found to be about 0.43 m water equivalent per year. This is in agreement with a single value determined 26 years earlier at a nearby site (Ward and Baird, 1954). The mean annual temperature in the bore hole was found to be close to −14.4° C, possibly some 2–5 deg warmer than the expected mean annual surface air temperature at the site. This difference is due to the expulsion of latent heat upon freezing of melt water at depth in the snow-pack which gives rise to the many ice layers observed in the core. The percentage thickness of ice layers per year may be correlated with summer temperatures.Total ice depths were measured using a 620 MHz radar echo-sounder. In the vicinity of the divide, over an area of 1 km2, the ice depths vary from about 460 to 515 m. These values compare favourably with values determined from an airborne radar depth-sounding flight carried out over the ice cap by a joint U.S.–Danish mission operating out of Søndre Strømfjord, Greenland. The data suggest that the ice-cap divide would be a worthwhile location to deep core drill with an expected useful coverage of at least the Holocene period.

scholarly journals Climatic Records from the Dunde Ice Cap, China

1988 ◽  
Vol 10 ◽  
pp. 178-182 ◽  
Author(s):  
Lonnie G. Thompson ◽  
Wu Xiaoling ◽  
Ellen Mosley-Thompson ◽  
Xie Zichu
Keyword(s):  
Accumulation Rate ◽  
Ice Core ◽  
Average Thickness ◽  
The Past ◽  
Bedrock Topography ◽  
Ice Cap ◽  
Pulse Radar ◽  
Oxygen Isotope Ratios ◽  
Ice Core Record ◽  
Climatic Record

Results from the first glaciological investigation of the Dunde ice cap demonstrate that a long, highly temporally resolvable climatic ice-core record is preserved in this ice cap. Measurements of stratigraphy, microparticle concentrations, liquid conductivity, and oxygen-isotope ratios from three snow pits in 1984 suggest that the annual accumulation is approximately 200 mm (water equivalent). Measurement of microparticle concentrations and conductivities of pit samples collected in 1986 confirm the existence of annual dust layers and an annual accumulation rate of ∼200 mm/year over the past 5 years. Bore-hole temperatures of –5.4°C at 30 m indicate that the ice cap is polar. Mono-pulse radar depth determinations yield an average thickness of 140 m, which (coupled with the smooth bedrock topography and the current accumulation rate) suggest that the Dunde ice cap should contain at least a 3000 year climatic record. A drilling program to recover that record from this subtropical location is planned for 1987.

Radiogenic Isotope Signatures of Holocene Sediments from Kane Basin: Linkage with the Re-opening and Evolution of Nares Strait

2021 ◽  
Author(s):  
Lina Madaj ◽  
Friedrich Lucassen ◽  
Claude Hillaire-Marcel ◽  
Simone A. Kasemann
Keyword(s):  
Ellesmere Island ◽  
The Arctic ◽  
Baffin Bay ◽  
Low Salinity ◽  
The Core ◽  
The Past ◽  
Nares Strait ◽  
The North ◽  
Sediment Input ◽  
Detrital Sediment

<p>The re-opening of the Arctic Ocean-Baffin Bay gateway through Nares Strait, following the Last Glacial Maximum, has been partly documented, discussed and revised in the past decades. The Nares Strait opening has led to the inception of the modern fast circulation pattern carrying low-salinity Arctic water towards Baffin Bay and further towards the Labrador Sea. This low-salinity water impacts thermohaline conditions in the North Atlantic, thus the Atlantic Meridional Overturning Circulation. Available land-based and marine records set the complete opening between 9 and 7.5 ka BP [1-2], although the precise timing and intensification of the southward flowing currents is still open to debate. A recent study of a marine deglacial sedimentary record from Kane Basin, central Nares Strait, adds information about subsequent paleoceanographic conditions in this widened sector of the strait and proposed the complete opening at ~8.3 ka BP [3].</p><p>We present complementary radiogenic strontium, neodymium and lead isotope data of the siliciclastic detrital sediment fraction of this very record [3] further documenting the timing and pattern of Nares Strait opening from a sediment provenance approach. The data permit to distinguish detrital material from northern Greenland and Ellesmere Island, transported to the core location from both sides of Nares Strait. Throughout the Holocene, the evolution of contributions of these two sources hint to the timing of the ice break-up in Kennedy Channel, north of Kane Basin, which led to the complete opening of Nares Strait [3]. The newly established gateway of material transported to the core location from the north via Kennedy Channel is recorded by increased contribution of northern Ellesmere Island detrital sediment input. This shift from a Greenland (Inglefield Land) dominated sediment input to a northern Ellesmere Island dominated sediment input supports the hypothesis of the newly proposed timing of the complete opening of Nares Strait at 8.3 ka BP [3] and highlights a progressive trend towards modern-like conditions, reached at about 4 ka BP.</p><p>References:</p><p>[1] England (1999) Quaternary Science Reviews, 18(3), 421–456. [2] Jennings et al. (2011) Oceanography, 24(3), 26-41. [3] Georgiadis et al. (2018) Climate of the Past, 14 (12), 1991-2010.</p>

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