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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Observations on Athabaska Glacier and their relation to the theory of glacier flow

Paterson, William Stanley Bryce January 1962 (has links)
The objects of the present study were to collect adequate data concerning the distribution of velocity in a typical valley glacier, to relate these to current theories of glacier flow, and if necessary to suggest modifications to these theories. Conventional field methods were used. Surface movement, both horizontal and vertical, was measured by triangulation of markers in the ice from fixed points on bedrock around the perimeter of the glacier. Movement at depth was determined by measurements in boreholes of the change of inclination with time. Seismic and gravity measurements of ice thickness were also available. The methods of measurement and computation are described and their accuracy is assessed. It was observed that the vertical velocity of the top of the pipe in each borehole is equal to that of the ice in its vicinity. Methods of analysing borehole data are critically reviewed in the light of this fact. A correction term for the curvature of the pipe is also used in the analysis. It is shown that, on the Athabaska Glacier, the longitudinal strain rate is not constant with depth, and that, for about 100 metres below the surface, the horizontal velocity is slightly greater than its surface value. Present theory does not cover these cases. Possible modifications are suggested. The assumption, sometimes made in the past, that the width of a valley glacier can be regarded as infinite, is shown to be unjustified. In the absence of a complete stress and velocity solution for the case of finite width, the stress solution is modified by the introduction of the "shape factor" in the stress solution. The relation between the second invariants of the strain rate and stress deviator tensors is compared with the simple power law as determined by laboratory experiments with ice. Comparison is made both for borehole measurements and measurements of change of surface velocity across transverse lines. Agreement is satisfactory, within the limits of experimental error, for all the borehole results and some of the surface movement results. This is interpreted as evidence that the underlying theory is not seriously in error. In particular, the basic assumptions, made by Nye, that the components of strain rate and stress deviator tensors are proportional, that the constant depends only on the second invariant of the stress deviator, and that the shear stress is only a slowly varying function of distance down the glacier, seem to be reasonable approximations. Of three laboratory flow laws, that of Glen for quasi-viscous creep gives the most satisfactory fit to the data. The fit would be improved if the mean temperature of the glacier were about -0.75°C rather than the pressure melting temperature. This point has not been checked because of technical difficulties. The results appear to show that the index in the power law is reduced at low stresses (i.e. less than about 0.5 bar). Other interpretations of the data are possible, however, so the result is not considered to be established. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
2

A petrographic study of rocks from the Box mine, Athabaska Lake

Killin, Alan Ferguson January 1939 (has links)
No abstract included. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate
3

Udržitelný rozvoj v Kanadě ve vztahu k těžbě ropných písků / Sustainable Development in Canada in Relation to Oil Sands Developments

Podhola, Adam January 2013 (has links)
The aim of this thesis is to evaluate to what extent Canada and Alberta have been fulfilling the principles of sustainable development as they have adopted in the 1990s from the essential U.N. documents - the Brundtland Report and the Rio Declaration- and to what extent both governments failed in providing and enforcing efficient environmental law protection as it is the basic premise for achieving sustainability. I assessed this level of sustainability in Canada and Alberta on the basis of a stronger and weaker sustainability theoretical framework. Author's presumption was that Canada, as it defined sustainable development in its legislation, acted according to stronger sustainability, which emphasizes stronger protective environmental measures. Given a very large scope of environmental impacts of oil extraction on different ecosystems, the sector of water resources was selected to serve as a case study to compare and analyze government and alternative reports assessing the sustainability of water management. Thus, the author follows how the oil industry in Alberta affects the water resources and how both governments of Canada and Alberta provide environmental protection to the water resources. In this respect the author illustrates how the government is reluctant towards the implementation of...

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