Glacier movement produces numerous secondary structures including layers formed by different types of ice and the preferred crystallographic orientation of constituent grains. This thesis describes structures on Athabasca Glacier and shows how they are related to systems of stress that produce glacier flow. The surface of Athabasca Glacier can be divided into an area of prominent layers of coarse ice near the glacier margin and another formed by less distinct thick layers of fine ice in the central quarter of the ice tongue to within 800 m of the terminus. The coarse layers trend subparallel with the glacier walls and dip steeply towards the centre. In contrast, layers of fine ice near the glacier centre are near vertical and trend parallel with the direction of flow. The layers are deformed about a transverse vertical plane into a series of "similar" folds with limbs commonly separated by narrow cracks subparallel with the axial plane. Because the coarse layers near the margins, and the fine layers near the centre do not change in shape, size or attitude down the length of the glacier they must be formed at or near their present position. Cv measurements of ice grains at 25 locations on the ablation surface give fabric diagrams that represent real stress fabrics that have two or more areas of concentration containing up to 7% of the data. The diagrams may be separated into two distinct groups according to their location on the ice surface. Fabric diagrams from coarse layers near the margins have two or more maxima clustered near the pole to the layering. Diagrams from contorted fine layers near the middle of the glacier have most data concentrated in the north east quadrant, but maxima are independent of the attitude of any ice layers. In most diagrams, maxima fall on the locus of a small circle of constant radius. The observed radius lies between 30° and 50°, and the centre, located in approximately the same position in all diagrams, represents a line subparallel with the direction of glacier flow. The two types of ice and their distinct fabric indicate that two different stress systems exist in a glacier. Ice near the margin is under shear while that near the centre is under compression. In laboratory experiments, increase in the rate of creep may be attributed to some process of recrystallization. Test specimens that have recrystallized under compression are composed of small grains with Cv axes that tend to be oriented in a small circle about the unique stress axis. Fabrics of compressed ice are identical to those obtained from ice near the centre of many glaciers and show that if ice deforms most readily by glide within the basal plane, the final orientation fabric depends upon the local plane of movement and not the plane of maximum resolved shear stress. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

This thesis presents the results of a combined cathodoluminescence (CL) and electron paramagnetic resonance (EPR) spectroscopic study of quartz from the uranium-mineralized Athabasca Basin. CL imaging not only distinguishes detrital quartz grains from their secondary overgrowths but also is able to differentiate two generations of overgrowths in the Athabasca sandstones. Moreover, the Athabasca quartz samples are characterized by three types of bright CL: 1) haloes around U- and Th-bearing mineral inclusions, 2) patches associated with U-bearing minerals in matrices or pores and 3) continuous rims in samples with or without any visible U-bearing minerals. These three types of bright CL are all of constant widths of ~35-45 Ým, indicative of bombardments of alpha particles emitted from the 238U, 235U and 232Th decay series. CL spectral analyses show that the radiation damaged areas, relative to their undamaged hosts, are characterized by intense but broad emission bands at ~350 nm and 620-650 nm. <p>Detailed EPR measurements of the Athabasca quartz samples revealed six paramagnetic defects: one oxygen vacancy center (E1'), three silicon vacancy hole centers (O23¡V/H+(I), O23¡V/H+(II) and O23¡V/M+) and two O2¡V peroxy centers. Moreover, dissolution experiments using concentrated HF showed that that the silicon vacancy hole centers and the peroxy centers are concentrated in the radiation-damaged rims/fractures, whereas the oxygen vacancy center (E1') is evenly distributed in quartz grains. CL and EPR data of quartz samples after isochronal annealing experiments suggest that the silicon vacancy hole centers and the peroxy centers are most likely responsible for the characteristic ultraviolet CL and the red CL, respectively. <p>CL haloes in detrital quartz grains are ubiquitous in the Athabasca sandstones. CL patches are also widespread but are best developed in altered sandstones close to the unconformity or faults/fractures. Continuous CL rims, however, are more restricted in occurrences and are best developed at the high-grade Cigar Lake and McArthur River deposits, where they are restricted to lithological boundaries and faults and are pervasively developed in mineralized samples and associated alteration haloes close to the unconformity. At the Key Lake deposit, continuous rims occur only in mineralized samples close to the unconformity. Continuous CL rims are absent in basement rocks below mineralization, including those at the Cigar Lake and McArthur River deposits. The occurrence of radiation damages in Athabasca quartz have also been confirmed by detailed EPR measurements, which are significantly more sensitive than CL imaging. <p>Continuous CL rims on Athabasca quartz grains most likely record bombardments of alpha particles emitted from U-bearing mineralization fluids. Therefore, their associations with the unconformity, lithological boundaries and faults provide direct evidence for those structures being the pathways for mineralization fluids. The exclusive occurrence of continuous CL rims on detrital quartz grains and the abundance of U-bearing minerals in both generations of overgrowths suggest that U mineralization must have commenced during early diagenesis and continued during the formation of overgrowths. The absence of significant radiation damages in altered basement rocks supports the hypothesis that the basement was not a major source for uranium mineralization in the Athabasca basin. The common occurrence of CL haloes in euhedral quartz grains and CL patches associated with U-bearing minerals in faults, fractures and voids provide further (visual) evidence for late remobilization of uranium.

This thesis presents the results of a combined cathodoluminescence (CL) and electron paramagnetic resonance (EPR) spectroscopic study of quartz from the uranium-mineralized Athabasca Basin. CL imaging not only distinguishes detrital quartz grains from their secondary overgrowths but also is able to differentiate two generations of overgrowths in the Athabasca sandstones. Moreover, the Athabasca quartz samples are characterized by three types of bright CL: 1) haloes around U- and Th-bearing mineral inclusions, 2) patches associated with U-bearing minerals in matrices or pores and 3) continuous rims in samples with or without any visible U-bearing minerals. These three types of bright CL are all of constant widths of ~35-45 Ým, indicative of bombardments of alpha particles emitted from the 238U, 235U and 232Th decay series. CL spectral analyses show that the radiation damaged areas, relative to their undamaged hosts, are characterized by intense but broad emission bands at ~350 nm and 620-650 nm. <p>Detailed EPR measurements of the Athabasca quartz samples revealed six paramagnetic defects: one oxygen vacancy center (E1'), three silicon vacancy hole centers (O23¡V/H+(I), O23¡V/H+(II) and O23¡V/M+) and two O2¡V peroxy centers. Moreover, dissolution experiments using concentrated HF showed that that the silicon vacancy hole centers and the peroxy centers are concentrated in the radiation-damaged rims/fractures, whereas the oxygen vacancy center (E1') is evenly distributed in quartz grains. CL and EPR data of quartz samples after isochronal annealing experiments suggest that the silicon vacancy hole centers and the peroxy centers are most likely responsible for the characteristic ultraviolet CL and the red CL, respectively. <p>CL haloes in detrital quartz grains are ubiquitous in the Athabasca sandstones. CL patches are also widespread but are best developed in altered sandstones close to the unconformity or faults/fractures. Continuous CL rims, however, are more restricted in occurrences and are best developed at the high-grade Cigar Lake and McArthur River deposits, where they are restricted to lithological boundaries and faults and are pervasively developed in mineralized samples and associated alteration haloes close to the unconformity. At the Key Lake deposit, continuous rims occur only in mineralized samples close to the unconformity. Continuous CL rims are absent in basement rocks below mineralization, including those at the Cigar Lake and McArthur River deposits. The occurrence of radiation damages in Athabasca quartz have also been confirmed by detailed EPR measurements, which are significantly more sensitive than CL imaging. <p>Continuous CL rims on Athabasca quartz grains most likely record bombardments of alpha particles emitted from U-bearing mineralization fluids. Therefore, their associations with the unconformity, lithological boundaries and faults provide direct evidence for those structures being the pathways for mineralization fluids. The exclusive occurrence of continuous CL rims on detrital quartz grains and the abundance of U-bearing minerals in both generations of overgrowths suggest that U mineralization must have commenced during early diagenesis and continued during the formation of overgrowths. The absence of significant radiation damages in altered basement rocks supports the hypothesis that the basement was not a major source for uranium mineralization in the Athabasca basin. The common occurrence of CL haloes in euhedral quartz grains and CL patches associated with U-bearing minerals in faults, fractures and voids provide further (visual) evidence for late remobilization of uranium.

Unconformity-related uranium deposits in the Athabasca Basin represent a significant global resource of uranium. One such deposit, the Phoenix Deposit, discovered in 2007 on Denison Mine’s Wheeler River property, shares similarities with other deposits in the Basin. The Phoenix Deposit is located at the apex between a basement shear structure, and the unconformity between the crystalline basement and overlying sandstones. The shear structure extends into the sandstones, this structure controls the distribution of alteration minerals in the basement and early alteration phases in sandstones. The shear structure extending to sandstones is not spatially associated with late alteration phases associated with the uranium deposit, suggesting that the structure was not important for uranium mineralisation. Bulk rock compositions of sandstones show chimney-like distribution of elements above the uranium deposit. The most notable ones are the distribution of yttrium, and boron. Rare earth elements and yttrium are not soluble in aqueous fluids at low temperatures and they are enriched in uranium ore. Therefore, the chimney-like distribution of elements are attributed to uraniferous hydrothermal activity in sandstones. Petrographic and chemical analysis of alteration associated with the Phoenix Deposit shows two types of tourmaline, a pre-ore (Tur 1) in the basement, which is likely a metamorphic product (Tur1) and a syn-ore magnesiofoitite (Tur 2) in the basement and the sandstones. Three generations of chlorite are identified within the alteration halo of the Phoenix Deposit; an early Fe-rich clinochlore (C1) in the basement and sandstones, the second generation, Mg-rich sudoitic chlorite (C2) in the basement, and a late, sudoitic chlorite (C3) in the basement and sandstones. Illite shows three types; an early and late M1 and a late M2. M1 is found as two polytypes, 1Mc and 1Mt, in the basement and sandstones, with the 1Mt having a spatial relationship with the uranium deposit. Late M2 illite is coarse-grained and occurs in the basement and sandstones. Near Infrared (NIR) spectra of sandstones overlying the deposit shows absorption features between 600 and 700 nm. It is considered that these absorption features appear to have been produced during late hydrothermal activity and may have a temporal as well as spatial relationship with uranium mineralisation.

Oil sands mining companies in Alberta, Canada, are planning to create wetlands for the bioremediation of mining waste materials as part of a reclamation strategy. To assess feasibility, experimental wetlands mimicking proposed reclamation scenarios were constructed on mining leases. This research assessed the health of tree swallows (<i>Tachycineta bicolor</i>) nesting on these sites where they were naturally exposed to a mixture of chemicals including unrecovered bitumen, naphthenic acids (NAs) and polycyclic aromatic hydrocarbons (PAHs). Endpoints reflecting health were compared among three experimental wetlands and one reference site. In order to specifically investigate toxicity of NAs to birds, an experimental exposure to NAs was also conducted on a subset of nestlings on the reference site. <p> In 2003 and 2004, approximately 50 breeding pairs (total, per year) nesting on the following sites were monitored: Suncors Consolidated Tailings and Natural Wetlands; Syncrudes Demo Pond and Poplar Creek reference site. In 2003, reproductive success was very low on OSPM-sites compared to the reference site, but was relatively unaffected in 2004. Compromised reproductive performance in 2003 was linked to harsh weather, during which mortality rates of nestlings reached 100% on the site with the highest levels of PAHs and NAs, while they did not surpass 50% on the reference site. In 2004, mortality rates were low but nestlings from OSPM-sites weighed less and showed greater hepatic detoxification efforts (etoxyresorufin-o-deethylase activity) than those on the reference site. Furthermore, nestlings on OSPM-sites exhibited higher levels of thyroid hormones and suffered parasitic burdens (Protocalliphora spp.) approximately twice that of those on the reference site. Several of these findings may be associated with low post-fledging survival, suggesting that wet landscape reclamation strategy is not optimal for avian species and may require improvement. <p> As part of a separate study investigating toxicity of naphthenic acids, twenty nestlings from the reference site were randomly selected for an experimental exposure. Nestlings received 0.1 ml/day of NAs (15g/L) orally from day 7 to day 13 of age while being reared normally by their free-ranging parents. Nestling growth, hematocrit, blood biochemistry, organ weights and etoxyresorufin-o-deethylase activity (EROD) activity appeared unaffected by naphthenic acids. No toxic changes were detected on histopathological evaluation of major organs. These findings suggest that for nestlings reared on oil sands reclaimed sites, exposure to other chemicals such as polycyclic aromatic hydrocarbons is a greater concern than exposure to NAs. However, this study did not investigate the chronic or reproductive toxicity of naphthenic acids. More research still needs to be conducted as a part of an assessment of the sustainability of wet landscape reclamation because a previous study found that chronic exposure to NAs severely compromised reproduction in mammals.

Oil sands mining companies in Alberta, Canada, are planning to create wetlands for the bioremediation of mining waste materials as part of a reclamation strategy. To assess feasibility, experimental wetlands mimicking proposed reclamation scenarios were constructed on mining leases. This research assessed the health of tree swallows (<i>Tachycineta bicolor</i>) nesting on these sites where they were naturally exposed to a mixture of chemicals including unrecovered bitumen, naphthenic acids (NAs) and polycyclic aromatic hydrocarbons (PAHs). Endpoints reflecting health were compared among three experimental wetlands and one reference site. In order to specifically investigate toxicity of NAs to birds, an experimental exposure to NAs was also conducted on a subset of nestlings on the reference site. <p> In 2003 and 2004, approximately 50 breeding pairs (total, per year) nesting on the following sites were monitored: Suncors Consolidated Tailings and Natural Wetlands; Syncrudes Demo Pond and Poplar Creek reference site. In 2003, reproductive success was very low on OSPM-sites compared to the reference site, but was relatively unaffected in 2004. Compromised reproductive performance in 2003 was linked to harsh weather, during which mortality rates of nestlings reached 100% on the site with the highest levels of PAHs and NAs, while they did not surpass 50% on the reference site. In 2004, mortality rates were low but nestlings from OSPM-sites weighed less and showed greater hepatic detoxification efforts (etoxyresorufin-o-deethylase activity) than those on the reference site. Furthermore, nestlings on OSPM-sites exhibited higher levels of thyroid hormones and suffered parasitic burdens (Protocalliphora spp.) approximately twice that of those on the reference site. Several of these findings may be associated with low post-fledging survival, suggesting that wet landscape reclamation strategy is not optimal for avian species and may require improvement. <p> As part of a separate study investigating toxicity of naphthenic acids, twenty nestlings from the reference site were randomly selected for an experimental exposure. Nestlings received 0.1 ml/day of NAs (15g/L) orally from day 7 to day 13 of age while being reared normally by their free-ranging parents. Nestling growth, hematocrit, blood biochemistry, organ weights and etoxyresorufin-o-deethylase activity (EROD) activity appeared unaffected by naphthenic acids. No toxic changes were detected on histopathological evaluation of major organs. These findings suggest that for nestlings reared on oil sands reclaimed sites, exposure to other chemicals such as polycyclic aromatic hydrocarbons is a greater concern than exposure to NAs. However, this study did not investigate the chronic or reproductive toxicity of naphthenic acids. More research still needs to be conducted as a part of an assessment of the sustainability of wet landscape reclamation because a previous study found that chronic exposure to NAs severely compromised reproduction in mammals.

Earth’s hydrology is made up of complex systems which are spatially varied and influence a number of ecosystem processes. Complex ecosystems, in this case, are defined as those involving multiple bodies of water and land masses which are seasonally connected to one another through various processes, resulting in an intricate aquatic and terrestrial relationship in a single area. There have been advances in how we study these environments, yet it remains important to determine the most efficient tools in order to accurately monitor ecosystem health in these regions. Monitoring water quality in freshwater-dominated, wetland systems is costly and often impractical due to the remote locations of areas of interest. By exploring the methods of analysis in which remotely sensed data can be used to monitor changes in the spatial patterns of water quality, it is possible to study these complex ecosystems in a more frequent and effective manner.

Peatlands comprise of approximately half of the Athabasca oil sands region, many of which overlay some of the world’s largest bitumen deposits where surface mining for this resource has permanently altered the landscape. By law, companies must reclaim disturbed landscapes into functioning ecosystems including integrated upland-wetland systems with the objective of forming sustainable peat-forming wetlands. This thesis presents six years (2013 – 2018) of water balance and associated salinity data from one of the two existing constructed upland-wetland systems, the Sandhill Fen Watershed (SFW), a 52-ha upland-wetland built on soft tailings to evaluate the hydrological and hydrochemical performance and its potential to be self-sustaining. Following a considerable decrease in hydrological management, the dominant water balance components changed from primarily horizontal (inflow and outflow) to vertical fluxes (precipitation and evapotranspiration) which increased inundation, encouraged salt accumulation and changed plant communities. Results suggest that current conditions are not favourable for fen-peatland development as marsh-like conditions have developed, limiting water conserving functions and the ability to persist long-term in a changing climate. In terms of winter processes, topography currently controls snow accumulation, redistribution and melt at SFW while the role of vegetation in these processes is expected to increase as it continues to develop. Runoff ratios of snowmelt from hillslopes were drastically different than those previously reported for reclaimed peatland watersheds highlighting the influence of different soil materials used during construction. Under various climate change scenarios of a warmer and wetter climate, results from the Cold Regions Hydrological Model indicate that the influence of winter processes will decrease, potentially putting reclaimed systems at greater risk of moisture stress. Substantial hydrochemical changes have occurred as salinity was relatively low at the study onset as high volumes of inflow and outflow prevented ion accumulation. Over time, salinity continued to increase year-over-year throughout SFW from 2013 to 2018 in the wetland and margin areas. This increase in site-wide salinity was attributed to the shift in dominant water balance fluxes, changes in water table position and increased mixing of SFW waters with deeper saline groundwater that underlies the system. Based on its current conditions, it is unlikely that SFW will support peat-forming vegetation. It is recommended that design strategies shift to incorporate characteristics found in undisturbed saline peatlands that are capable of supporting peat-forming vegetation in a saline environment. / Thesis / Doctor of Philosophy (PhD) / A better understanding of the hydrological functioning of reconstructed peatlands in the Athabasca oil sands region is required as it is a novel approach in this region and there is potential for thousands of hectares of land that will require this reclamation in the future. Due to their recent establishment potential trajectories of constructed peatlands have yet to be fully analyzed as only recently has sufficient data been collected to evaluate the hydrological and hydrochemical functioning and provide insight on its overall success. While design strategies may seem sound, these constructed systems are completely human-made and it is unclear how they will develop and function in a highly disturbed landscape. Thesis results suggest that current conditions are not favourable to sustain a peatland as marsh-like conditions have developed which will limit its ability to persist long-term in a dry and changing climate. It is recommended that design strategies shift to incorporate characteristics found in undisturbed saline peatlands that are capable of supporting peat-forming vegetation in a saline environment. Due to the many challenges associated with reclamation in this region, lessons learned from this pilot project will help guide future peatland construction.

Les circulations de fluides aux interfaces entres les socles cristallins et leur couvertures sédimentaires sont des événements majeurs de transferts élémentaires dans la croûte. Dans de nombreux contextes, des fluides de bassins peuvent pénétrer dans les socles de faible perméabilité, interagir avec eux, y lessiver des métaux, et donner lieu à des concentrations métalliques, notamment en Pb, Zn, Cu, Ag et U. Les gisements d’uranium de type discordance du bassin d’âge protérozoïque de l’Athabasca (Canada), sont des témoins essentiels de ce type de circulations de fluides, et sont des objets modèles pour comprendre les mécanismes et les conséquences de tels événements. Les inclusions fluides permettent d’échantillonner et d’analyser directement les paléofluides. Malgré les difficultés d’analyse, ces objets de taille micrométriques apportent des informations importantes sur les propriétés des fluides. Les techniques d’analyse disponibles (microthermométrie, LA-ICP-MS, écrasement-lessivage, écrasement sous vide) permettent de reconstituer la température, la pression, la composition chimique détaillée des fluides, dont les teneurs en métaux, ainsi que la composition isotopique de l’hydrogène de l’eau, du chlore et du carbone du CO2 dissous. De plus, l’analyse de la composition isotopique de l’oxygène et du carbone des minéraux dans lesquels sont piégées les inclusions fluides apporte des informations complémentaires sur la température des fluides et les interactions fluides-roches. Cette approche a été utilisée sur six gisements d’uranium du Bassin de l’Athabasca, et a permis d’apporter les résultats suivants, potentiellement généralisables à l’ensemble du bassin. (1) Deux saumures, une calcique et une sodique ont circulé et se sont mélangées à la base du bassin et dans le socle au cours de la formation des gisements à environ 150 ± 30°C. (2) Ces deux saumures ont transporté de l’uranium, dont les concentrations exceptionnelles et très hétérogènes (entre 0.2 et 600 ppm) indiquent qu’il a été lessivé dans le socle. (3) Ces saumures ont une origine commune et se sont formées essentiellement par évaporation en surface de l’eau de mer, et mélange avec des fluides issus de la dissolution de minéraux évaporitiques. (4) La saumure calcique s’est formée par interaction entre la saumure sodique et les roches du socle. (5) Les interactions des saumures avec les minéraux et le graphite du socle, la radiolyse de l’eau, et la synthèse de bitumes ont contrôlé la composition isotopique en oxygène, hydrogène et carbone de ces saumures. / Fluid circulations between crystalline basements and their sedimentary covers are major events for element transfer in the crust. In numerous settings, basinal fluids penetrate the low-permeability basement, interact with basement lithologies, leach metals, leading to metal concentrations, notably Pb, Zn, Cu, Ag and U. Unconformity-related uranium deposits from the Proterozoic Athabasca Basin (Canada) are crucial witnesses and useful tools for the understanding of mechanisms and consequences of such fluid events. Fluid inclusions allow us to directly sample and analyze paleofluids. Despite analytical difficulties, these micrometer size objects provide key information on fluid properties. Available analytical techniques (microthermometry, LA-ICP-MS, crush-leach, in-vacuo crushing) provide reconstruction of temperature, pressure, detailed fluid chemistry, including metal concentrations, as well as isotopic composition of water hydrogen, chlorine and of dissolved CO2 carbon. In addition, analysis of isotopic composition of oxygen and carbon from minerals in which fluid inclusions are trapped provide supplementary information on fluid temperatures and fluid-rock interactions. This approach was used on six uranium deposits from the Athabasca Basin and provided the following results, which can be potentially generalized to the entire basin. (1) Two brines, a calcium-rich brine and a sodium-rich brine have circulated and mixed at the base of the basin and in the basement at the time of formation of uranium deposits, at temperature close to 150 ± 30°C. (2) Both brines have transported uranium, whose exceptional and highly heterogeneous concentrations (0.2 to 600 ppm) indicate that it was leached in the basement. (3) Both brines share a common origin and were formed mainly by surface evaporation of seawater and mixing with fluids originating from dissolution of evaporitic minerals. (4) The calcium-rich brine was formed by interaction between the sodium-rich brine and basement lithologies. (5) Interaction with basement minerals and graphite, water radiolysis, and bitumen synthesis were the main controls on the oxygen, hydrogen and carbon isotopic composition of brines.

Athabasca River Basin is located in an area which is affected by many factors. During the last century, the global warming manifests here, resulting primarily into increasing temperatures and glaciers melting in the headwaters area. Much of the middle reaches watershed is used for agriculture, for irrigation of which water from the Athabasca River is pumped. In recent years, controversial development of bituminous sands mining is carried out in the basin. Although it represents a real energy source, the mining requires large amounts of water, which is largely drawn from the Athabasca River. The work therefore analyzes the runoff change in the upper, middle and lower reaches during the last forty years. Along with the time series air temperature changes and precipitation totals, which can also explain runoff changes, are analyzed. Powered by TCPDF (www.tcpdf.org)