scholarly journals Ice-Cored Moraines in South-Western Ellesmere Island, N.W.T., Canada

1971 ◽  
Vol 10 (59) ◽  
pp. 245-254 ◽  
Author(s):  
R. A. Souchez
Keyword(s):  
Outer Zone ◽  
Ellesmere Island ◽  
North West ◽  
Ice Cap ◽  
The North ◽  
Ice Surface ◽  
Time Required ◽  
Lithological Composition

AbstractThe north-west margin of the main ice cap in south-western Ellesmere Island is fringed by ice-cored moraines. The formation of these moraines seems to be more complex than simple upwarping of the foliation bands at the margin of the ice cap. At one locality, where outer and inner zones can be distinguished on the basis of lithological composition, debris in the outer zone is composed of material from farther back under the ice cap than debris in the inner zone. In another locality, localized ridges cross each other independently of the trend of the main ridge.The time required to obtain the quantity of debris forming the moraine at the ice surface is estimated to be between 65 and 300 years.

scholarly journals Ice-Cored Moraines in South-Western Ellesmere Island, N.W.T., Canada

1971 ◽  
Vol 10 (59) ◽  
pp. 245-254 ◽  
Author(s):  
R. A. Souchez
Keyword(s):  
Outer Zone ◽  
Ellesmere Island ◽  
North West ◽  
Ice Cap ◽  
The North ◽  
Ice Surface ◽  
Time Required ◽  
Lithological Composition

AbstractThe north-west margin of the main ice cap in south-western Ellesmere Island is fringed by ice-cored moraines. The formation of these moraines seems to be more complex than simple upwarping of the foliation bands at the margin of the ice cap. At one locality, where outer and inner zones can be distinguished on the basis of lithological composition, debris in the outer zone is composed of material from farther back under the ice cap than debris in the inner zone. In another locality, localized ridges cross each other independently of the trend of the main ridge.The time required to obtain the quantity of debris forming the moraine at the ice surface is estimated to be between 65 and 300 years.

A reinterpretation of Scottish ‘hummocky moraine’ and its significance for the deglaciation of the Scottish Highlands during the Younger Dryas or Loch Lomond Stadial

1993 ◽  
Vol 130 (3) ◽  
pp. 301-318 ◽  
Author(s):  
Matthew R. Bennett ◽  
Geoffrey S. Boulton
Keyword(s):  
Environmental Conditions ◽  
Field Survey ◽  
Spatial Scales ◽  
Younger Dryas ◽  
North West ◽  
Scottish Highlands ◽  
Ice Cap ◽  
The North ◽  
Loch Lomond

AbstractThe aim of this paper is to demonstrate that much of the ‘hummocky moraine’ present within the northern part of the LochLomond Readvance ice cap formerly situated in the North West Scottish Highlands may be interpreted as suites of ice-front moraines deposited during active decay. These landforms can be used to reconstruct ice cap decay, whichleads to important insights into the shrinking form of the ice cap and associated environmental conditions. Evidence has been collected from 10803 airphotographs and from detailed field survey. It is presented at three spatial scales.

scholarly journals Part I: The Ogive Banding

1954 ◽  
Vol 2 (16) ◽  
pp. 423-428
Keyword(s):  
The South ◽  
Outlet Glacier ◽  
North West ◽  
South Eastern ◽  
Ice Cap ◽  
The North

AbstractMorsárjökull is a small outlet glacier of Vatnajökull, Iceland. Two outlet streams from the ice cap unite at the foot of a precipitous step and carry a well-developed medial moraine; the north-west glacier stream is fed by a steep ice fall, the south-eastern one has been fed only by avalanches since 1938.The movement of the glacier was measured and showed that the alternate dark and light ogives were one year’s movement apart. Their characteristics are described and tentative suggestions concerning their mode of origin are proposed.

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.

WIRELINE FORMATION-TESTER PERFORMANCE ON THE NORTH WEST SHELF

1975 ◽  
Vol 15 (1) ◽  
pp. 127
Author(s):  
M. D. Agostini
Keyword(s):  
Single Point ◽  
Test Method ◽  
Reservoir Rock ◽  
Relative Reduction ◽  
Well Testing ◽  
North West ◽  
Drill Stem ◽  
The North ◽  
Order Of Magnitude ◽  
Time Required

The formation-interval-tester was introduced to the North West Shelf in December, 1970 Originally it was used as a first-look test method, with drill stem testing retained as the standard evaluation technique in all potential reservoir sections. Systematic use of this technique in parallel with drill-stem testing has allowed the accumulation of a significant volume of comparative data. This has provided a unique opportunity to examine the validity of wireline-testing as an alternative to the more traditional method of reservoir evaluation.The wireline-tester has been found to be a reliable indicator of movable hydrocarbons in reservoir rock, after experience allowed the development of regional interpretation limits. Such variables as gas:oil ratios and oil gravities are determined within acceptable limits of accuracy. Formation pressure determinations are consistent' and are thought to be more reliable than those derived from drill-stem-testing. With the data available it is normally possible to calculate the indicated formation permeability. This however being a single point determination the result is of questionable value. Experience has shown that "order of magnitude" agreement is normally achieved between wireline-tester permeabilities and those determined from drill-stem-testing in the same interval.The reduction in cost resulting from the application of this technique is particularly significant. Savings may be related directly to the relative reduction in rig time required by this operation compared with that required for drill-stem-testing. As the cost of offshore operations increases rapidly the resultant savings will grow in significance.Also of concern in all well-testing operations is the risk to which the rig and personnel are subjected. On floating offshore rigs the flowing well condition required by drill-stem-testing requires the acceptance of certain associated risks. Wireline testing is by comparison a risk-free operation.The recognition of the inherent limits of this approach to well testing is important if satisfactory results are to be achieved. Where the required reservoir parameters are those that can be satisfactorily determined with the wireline tester it offers a real alternative to the more traditional evaluation techniques.

scholarly journals Equilibrium-Line Altitudes, Mass Balance, and July Freezing-Level Heights in the Canadian High Arctic

1975 ◽  
Vol 14 (71) ◽  
pp. 267-274 ◽  
Author(s):  
R. S. Bradley
Keyword(s):  
Mass Balance ◽  
High Arctic ◽  
Equilibrium Line ◽  
Canadian High Arctic ◽  
North West ◽  
Freezing Level ◽  
Ice Cap ◽  
The North ◽  
Devon Ice Cap ◽  
Axel Heiberg Island

Equilibrium-line altitudes on the White Glacier, Axel Heiberg Island, and the north-west sector of the Devon Ice Cap are shown to be closely related to mean July freezing-level heights at nearby upper-air weather stations. An inverse relationship between July freezing-level heights and mass balance on the Devon Ice Cap is also shown. Reasons for such correlations are suggested and some limitations of the relationship are outlined. Recent lowering of the freezing level in July is discussed in relation to the theoretical “steady-state” equilibrium-line altitudes in the Canadian high Arctic. It is suggested that positive mass-balance years have predominated over a large part of northern Ellesmere Island and north-central Axel Heiberg Island since 1963, and some glaciological evidence supporting this hypothesis is given.

Colliding Continents

2013 ◽  
Author(s):  
Mike Searle
Keyword(s):  
Indian Plate ◽  
Mountain Range ◽  
Polar Regions ◽  
Geological Evidence ◽  
North West ◽  
Ice Cap ◽  
The North ◽  
West Himalaya ◽  
Tectonically Active ◽  
The Himalaya

The Himalaya is the greatest mountain range on Earth: the highest, longest, youngest, the most tectonically active, and the most spectacular of all. Unimaginable geological forces created these spectacular peaks. Indeed, the crash of the Indian plate into Asia is the biggest known collision in geological history, giving birth to the Himalaya and Karakoram, one of the most remote and savage places on Earth. In this beautifully illustrated book, featuring spectacular color photographs throughout, one of the most experienced field geologists of our time presents a rich account of the geological forces that were involved in creating these monumental ranges. Over three decades, Mike Searle has transformed our understanding of this vast region. To gather his vital geological evidence, he has had to deploy his superb skills as a mountaineer, spending weeks at time in remote and dangerous locations. Searle weaves his own first-hand tales of discovery with an engaging explanation of the processes that formed these impressive peaks. His narrative roughly follows his career, from his early studies in the north west Himalaya of Ladakh, Zanskar and Kashmir, through several expeditions to the Karakoram ranges (including climbs on K2, Masherbrum, and the Trango Towers, and the crossing of Snow Lake, the world's largest ice cap outside polar regions), to his later explorations around Everest, Makalu, Sikkim and in Tibet and South East Asia. The book offers a fascinating first-hand account of a major geologist at work-the arduous labor, the eureka moments, and the days of sheer beauty, such as his trek to Kathmandu, over seven days through magnificent rhododendron forests ablaze in pinks, reds and white and through patches of bamboo jungle with hanging mosses. Filled with satellite images, aerial views, and the author's own photographs of expeditions, Colliding Continents offers a vivid account of the origins and present state of the greatest mountain range on Earth.

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 Breaching of an ice dam at Qorlortossup tasia, south Greenland

2005 ◽  
Vol 42 ◽  
pp. 297-302 ◽  
Author(s):  
Christoph Mayer ◽  
Thomas V. Schuler
Keyword(s):  
Drainage Basin ◽  
Drainage Pattern ◽  
Outlet Glacier ◽  
Ice Cap ◽  
The North ◽  
Ice Surface ◽  
Lake Formation ◽  
Additional Water ◽  
Exact Size ◽  
The Stability

AbstractIn July 2003 an ice-dammed lake was suddenly drained in an outburst flood at Qorlortorssup tasia in south Greenland, the site of a projected hydropower station. The lake developed during the first decades of the 20th century as a result of the recession of the ice cap in this area. It used to drain over a shallow rock spillway towards Sermeq kangigdleq, the adjacent outlet glacier to the north. In order to assess the hazard potential and the additional water contribution from the enlarged catchment, the glacial lake and its surroundings were investigated. Based on the analysis of available historical data, field investigations and model results, the history of lake generation and the sudden outbreak were reconstructed. With the lake formation the ice dam lost its connection to the ice cap. The flood was initiated after the ice surface became low enough for the lake water to overflow the glacier towards Qorlortorssup tasia basin, creating a gully through the glacier which drained approximately 55 × 106 m3 of water over a period of 8-10 days. Thanks to the stability of the dam and the downstream damping of the flood, there was no serious threat to a farm that is situated close to the planned power-station site. In the future, we expect much smaller floods, as a result of partial closure of the gully by ice movement or snowdrift in the winter. The new drainage pattern into Qorlortorssup tasia basin, however, will be a permanent situation. The amount of this new water contribution can only be roughly estimated since the exact size of the drainage basin is not well known.

scholarly journals Evidence of a Periodic Ice-Cliff Avalanche on North-West Ellesmere Island, N.W.T., Canadian High Arctic

1987 ◽  
Vol 33 (113) ◽  
pp. 68-71 ◽  
Author(s):  
D. J. A. Evans ◽  
T. G. Fisher
Keyword(s):  
High Arctic ◽  
Ellesmere Island ◽  
Canadian High Arctic ◽  
Periodic Activity ◽  
North West ◽  
Ice Cap ◽  
Melt Water

AbstractEvidence of a recent (1985) ice-cliff avalanche from an outlet lobe of a small plateau ice cap on north-west Ellesmere Island is discussed. Former avalanche events are evidenced by debris lying outside the 1985 avalanche material. Periodic activity seems to be linked to the build-up of melt water in the crevasses of the outlet lobe during the melt season. The exact magnitude and frequency of events are unknown. Some implications to geomorphology and the sedimentology of sub-polar glaciers are discussed.

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