Wisconsinan and pre-Wisconsinan ice thicknesses on Ellesmere Island, Canada: inferences from ice cores

1987 ◽  
Vol 24 (2) ◽  
pp. 296-301 ◽  
Author(s):  
R. M. Koerner ◽  
D. A. Fisher ◽  
W. S. B. Paterson
Keyword(s):  
Ice Cores ◽  
Ellesmere Island ◽  
Climatic Warming ◽  
Ice Cap ◽  
Basal Melting

Study of two cores through an ice cap on northern Ellesmere Island suggests (1) during the Wisconsin Glaciation the ice near the crest was never more than about 200 m thicker than at present; (2) in a preceding glaciation, the ice was thicker than this, and the local ice divide near the boreholes was eliminated; (3) early in the Sangamon Interglacial, basal melting occurred in a deep bedrock valley south of the borehole site; and (4) the change in δ18O at the Wisconsinan–Holocene transition is 11‰, of which at least 8‰ results from climatic warming.

Global transport rates and future prediction of hazardous materials: Pu and Cs – from Nagasaki to Canadian Arctic

2000 ◽  
Vol 42 (7-8) ◽  
pp. 163-169 ◽  
Author(s):  
A. Kudo ◽  
J. Zheng ◽  
R. Yamada ◽  
G. Tao ◽  
T. Sasaki ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Atomic Bomb ◽  
Canadian Arctic ◽  
Ice Cores ◽  
Hazardous Materials ◽  
Ellesmere Island ◽  
The Arctic ◽  
Ice Cap ◽  
Global Transport ◽  
Analytical Technology

A historical man-made global pollution of hazardous materials occurred at Nagasaki, Japan on August 9, 1945 detonation of a plutonium (10–15 kg) atomic bomb. Recent advancements in analytical technology made it possible for artificial radionuclides released from the nuclear explosion to be detected in the Arctic ice core layer of 1945. The fission product, 137Cs (23.4 g or 7.44×1013 Bq), and unexpended fission material, 239+240Pu (8.8–13.8 kg or 2.22–3.49×1013 Bq), originating from the Nagasaki A-bomb were measured by collecting 10 ice cores on the Agassiz ice cap, Ellesmere Island, Canada. The deposition rates were 20 mBq/cm2 for 137Cs and 0.16 mBq/cm2 for 239+240Pu, originating from Nagasaki. Assuming the radionuclides, excluding the amount deposited as local fallout, are deposited evenly throughout the northern hemisphere, a rate of 67% of the expected amount of 137Cs arrived at the Arctic while 1.1% of 239+240Pu reached the Arctic. The results suggest that different transport mechanisms exist for these two hazardous contaminants in the global transport system. A non-reactive rare gas, such as neon and argon, can spread evenly throughout northern hemisphere, including Ellesmere island at the Canadian Arctic, while a reactive gas, sulfur dioxide (SO2) will not reach the ice cap. The measured global transport rates of 137Cs and 239+240Pu were 67% and 1.1%, respectively. These measured rates were for the historical man-made hazardous materials and probably obtained for the longest distance of global transport over 10,000 km. Assuming there was a consistency in climate for the next 10,000 years, the chronological anthropogenic deposits, mainly of 239+240Pu, could be detected in the ice layer between 97–98 m from the snow surface at 11,999 AD on the Agassiz ice cap. Even if there were no improvements in the radioactive analytical method used, the ice layers for the 1945–1980 period could still be easily identified with the present analytical technology. Hopefully this study will find a way to use our generation's artefacts for the benefit of our future descendants.

The historical residue trend of PCBs in the Agassiz Ice Cap, Ellesmere Island, Canada

1995 ◽  
Vol 160-161 ◽  
pp. 117-126 ◽  
Author(s):  
D.J. Gregor ◽  
A.J. Peters ◽  
C. Teixeira ◽  
N. Jones ◽  
C. Spencer
Keyword(s):  
Ellesmere Island ◽  
Ice Cap

Comparison of 105 Years of Oxygen Isotope and Insoluble Impurity Profiles from the Devon Island and Camp Century Ice Cores

1979 ◽  
Vol 11 (3) ◽  
pp. 299-305 ◽  
Author(s):  
David A. Fisher
Keyword(s):  
Oxygen Isotope ◽  
Flow Line ◽  
Ice Cores ◽  
Devon Island ◽  
Ice Cap ◽  
Particulate Concentration ◽  
The Difference ◽  
Impurity Profiles ◽  
Level Lowering ◽  
Present Site

Oxygen-isotope profiles for the Devon Island ice cap and Camp Century Greenland are affected by a number of variables, some of which must have been the same for both sites. The two δ(18O) records spanning about 120,000 years are brought into relative alignment by comparison of major δ features, and subsequent verification that the insoluble particulate concentration records were also in phase for this alignment. The difference between the δ profiles is shown to be mainly a function of the altitude of the accumulation area for Camp Century. This altitude seems to have been higher than present for the last 100,000 years, suggesting the present flow line through the site has never been shorter. The maximum altitude for the Camp Century accumulation area is 1500 m above the present site and is almost synchronous with the maximum in particulate concentration that occurs at 16,000 yr B.P. The synchronism is likely due to the maximum sea-level lowering that exposed vast areas of continental shelf to wind erosion.

scholarly journals The Hans Tausen drill: design, performance, further developments and some lessons learned

2007 ◽  
Vol 47 ◽  
pp. 89-98 ◽  
Author(s):  
Sigfús J. Johnsen ◽  
Steffen Bo Hansen ◽  
Simon G. Sheldon ◽  
Dorthe Dahl-Jensen ◽  
Jørgen P. Steffensen ◽  
...  
Keyword(s):  
Mechanical Design ◽  
Ice Cores ◽  
Lessons Learned ◽  
Niels Bohr ◽  
Deep Drilling ◽  
Niels Bohr Institute ◽  
Design Performance ◽  
Ice Cap ◽  
Drill Design

AbstractIn the mid-1990s, excellent results from the GRIP and GISP2 deep drilling projects in Greenland opened up funding for continued ice-coring efforts in Antarctica (EPICA) and Greenland (NorthGRIP). The Glaciology Group of the Niels Bohr Institute, University of Copenhagen, was assigned the task of providing drilling capability for these projects, as it had done for the GRIP project. The group decided to further simplify existing deep drill designs for better reliability and ease of handling. The drill design decided upon was successfully tested on Hans Tausen Ice Cap, Peary Land, Greenland, in 1995. The 5.0m long Hans Tausen (HT) drill was a prototype for the ~11m long EPICA and NorthGRIP versions of the drill which were mechanically identical to the HT drill except for a much longer core barrel and chips chamber. These drills could deliver up to 4m long ice cores after some design improvements had been introduced. The Berkner Island (Antarctica) drill is also an extended HT drill capable of drilling 2 m long cores. The success of the mechanical design of the HT drill is manifested by over 12 km of good-quality ice cores drilled by the HT drill and its derivatives since 1995.

scholarly journals Glaciological Investigations of the Tropical Quelccaya Ice Cap, Peru

1980 ◽  
Vol 25 (91) ◽  
pp. 69-84 ◽  
Author(s):  
Lonnie G. Thompson
Keyword(s):  
Rainy Season ◽  
Ice Core ◽  
Ice Cores ◽  
Dry Season ◽  
Radioactive Material ◽  
Polar Regions ◽  
Near Surface ◽  
Ice Cap ◽  
Activity Measurements ◽  
Quelccaya Ice Cap

AbstractGlaciological results of the continuing investigations of the Quelccaya ice cap located at lat. 13° 56’ S., long. 70° 50’ W., in the Cordillera Oriental of southern Peru are presented. Ice cores to a depth of 15 m have been retrieved from the summit dome (5650 m), middle dome (5543 m), and south dome (5480 m) and sampled in detail for microparticle, oxygen-isotope, and total-β-activity measurements. Results of these core analyses indicate that although the summit of this ice cap is only 300 m above the annual snow line and the firn is temperate, an interpretable stratigraphic record is preserved. The marked seasonal ice stratigraphy is produced by the marked seasonal variation in regional precipitation. High concentrations of microparticles and β- radioactive material occur during the dry season (May-August). Microparticles deposited during the rainy season are larger than those deposited during the dry season. On the Quelccaya ice cap the most negative δ18O values occur during the warmer rainy season (the opposite occurs in polar regions). The near-surface mean δ value of – 21‰ is remarkably low for this tropical site where the measured mean annual air temperature is – 3°C The seasonality of the microparticles, total β activity, and isotope ratios offers the prospect of a climatic ice-core record from this tropical ice cap.

Diatoms in Ice Cores, a new proxy for reconstructing past wind strength in the Amundsen-Bellingshausen Seas region, Antarctica

2021 ◽  
Author(s):  
Dieter Tetzner ◽  
Liz Thomas ◽  
Claire Allen
Keyword(s):  
Antarctic Peninsula ◽  
Ice Cores ◽  
Environmental Parameters ◽  
Time Frame ◽  
Regional Variability ◽  
Atmospheric Circulation Patterns ◽  
Surface Temperatures ◽  
Circulation Patterns ◽  
And Shifts ◽  
Basal Melting

<p>In the last decade, several efforts have been carried out to assess the causes of the current rapid recent warming measured on West Antarctica and Antarctic Peninsula. The increase in wind strength and shifts in atmospheric circulation patterns have shown to play a key role in driving the advection of warm air from mid-latitudes to high-latitudes. Winds are also responsible for driving surface melting in the ice shelves, enhancing the removal of surface snow, and for promoting basal melting through the upwelling of deep warm water. All these combined have shown to produce substantial effects on environmental parameters, such as sea surface temperatures, sea ice extension, air surface temperatures and precipitation.</p><p>Even though winds are fundamental components of the climatic system, there is a lack of reliable long-term observational wind records in the region. This has hindered the ability to place the recent observed changes in the context of a longer time frame.</p><p>In this work, we present annual and sub-annual records of marine diatoms preserved in a set of ice cores retrieved from the southern Antarctic Peninsula and Ellsworth Land region, Antarctica. The diatom abundance and species assemblages from these ice cores prove to represent the local/regional variability in wind strength and circulation patterns that influence the onshore northerly winds.  The spatial distribution of these ice cores enabled to identify regional trends (coastal/inland) and to validate the proxy across the region. Our findings highlight the potential this novel proxy to produce an annual reconstruction of westerly winds in the Amundsen - Bellingshausen seas region.</p><p> </p>

scholarly journals Reconnaissance of a Small Ice Cap Near St Patrick Bay, Robeson Channel, Northern Ellesmere Island, Canada

1973 ◽  
Vol 12 (66) ◽  
pp. 417-421 ◽  
Author(s):  
G. Hattersley-Smith ◽  
H. Serson
Keyword(s):  
Ellesmere Island ◽  
Direct Result ◽  
Ice Caps ◽  
Ice Cap

A reconnaissance was made of one of two small ice caps near the Robeson Channel coast of northern Ellesmere Island. It is shown that, after a period of net wastage, this ice cap is now thickening slightly and extending its margins. The present regime of the ice cap is a direct result of generally cooler summers in the last decade.

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 Apparent discrepancy of Tibetan ice core <i>δ</i><sup>18</sup>O records may be attributed to misinterpretation of chronology

2019 ◽  
Vol 13 (6) ◽  
pp. 1743-1752 ◽  
Author(s):  
Shugui Hou ◽  
Wangbin Zhang ◽  
Hongxi Pang ◽  
Shuang-Ye Wu ◽  
Theo M. Jenk ◽  
...  
Keyword(s):  
High Resolution ◽  
Ice Core ◽  
Ice Cores ◽  
Warming Trend ◽  
The Tibetan Plateau ◽  
Apparent Discrepancy ◽  
Ice Cap ◽  
Guliya Ice Core ◽  
Cooling Trend ◽  
Instrumental Period

Abstract. Ice cores from the Tibetan Plateau (TP) are widely used for reconstructing past climatic and environmental conditions that extend beyond the instrumental period. However, challenges in dating and interpreting ice core records often lead to inconsistent results. The Guliya ice core drilled from the northwestern TP suggested a cooling trend during the mid-Holocene based on its decreasing δ18O values, which is not observed in other Tibetan ice cores. Here we present a new high-resolution δ18O record of the Chongce ice cores drilled to bedrock ∼30 km away from the Guliya ice cap. Our record shows a warming trend during the mid-Holocene. Based on our results as well as previously published ice core data, we suggest that the apparent discrepancy between the Holocene δ18O records of the Guliya and the Chongce ice cores may be attributed to a possible misinterpretation of the Guliya ice core chronology.

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