No description available.

Les méthodes de design et de construction des routes développés dans le sud canadien ont maintenant besoin d’être adaptés aux environnements nordiques du pays afin de prévenir le dégel dramatique du pergélisol lors de la construction d’une nouvelle route. De plus, le réchauffement climatique occasionne présentement d’importants problèmes de stabilité des sols dans le nord canadien. Ces facteurs causent des pertes importantes au niveau des capacités fonctionnelles et structurales de l’Alaska Highway au Yukon sur un segment de plus de 200 km situé entre le village de Destruction Bay et la frontière de l’Alaska. Afin de trouver des solutions rentables à long terme, le ministère du transport du Yukon (en collaboration avec le Federal Highway Administration du gouvernement américain, Transports Canada, l’Université Laval, l’Université de Montréal et l’Alaska University transportation Center) a mis en place 12 sections d’essais de 50 mètres de longueur sur l’autoroute de l’Alaska près de Beaver Creek en 2008. Ces différentes sections d’essais ont été conçues pour évaluer une ou plusieurs méthodes combinées de stabilisation thermique telles que le drain thermique, le remblai à convection d’air, le pare-neige / pare-soleil, le remblai couvert de matières organiques, les drains longitudinaux, le déblaiement de la neige sur les pentes et la surface réfléchissante. Les objectifs spécifiques de la recherche sont 1) d’établir les régimes thermiques et les flux de chaleur dans chacune des sections pour les 3 premières années de fonctionnement ; 2) de documenter les facteurs pouvant favoriser ou nuire à l’efficacité des systèmes de protection et ; 3) de déterminer le rapport coûts/bénéfices à long terme pour chacune des techniques utilisées. Pour ce faire, une nouvelle méthode d’analyse, basée sur la mesure de flux d’extraction de chaleur Hx et d’induction Hi à l’interface entre le remblai et le sol naturel, a été utilisée dans cette étude. Certaines techniques de protection du pergélisol démontrent un bon potentiel durant leurs 3 premières années de fonctionnement. C’est le cas pour le remblai à convection d’air non-couvert, le remblai à convection d’air pleine largeur, les drains longitudinaux, le pare-soleil / pare-neige et la surface réfléchissante. Malheureusement, des problèmes dans l'installation des drains thermiques ont empêché une évaluation complète de leur efficacité. / Road design and construction techniques developed in southern Canada definitely need to be adapted to northern environment to prevent dramatic permafrost thawing after new road construction. Furthermore, climate warming causes now important soil stability problems in the Canadian far north. All these factors lead to a loss of the functional and structural capacities of the Alaska Highway over a 200-km section mainly from Destruction Bay to the Alaska border. To find long term and cost-effective solutions, Yukon Highways and Public Works (in collaboration with the Alaska University Transportation Center, Transport Canada, le U.S. Federal Highways Administration, l’Université de Montréal and l’Université Laval) constructed 12 instrumented sections on the Alaska Highway near Beaver Creek (Yukon) in 2008. These sections experiment one or several combined methods of thermal stabilization such as convection air embankment, heat drains, snow/sun shed, grass-covered embankment, longitudinal culverts, reflecting surfaces and snow clearing on embankment slopes. The main objectives of this project are 1) to analyze the ground thermal regime and the heat fluxes for each of the 12 sections during their first three years in service; 2) to document all factors which can facilitate or disrupt the efficiency of the protection systems and; 3) to determine the long term costs / benefits ratio for every technique tested. In order to do this, a new method based on the calculation of heat extraction Hx and heat induction Hi index at the interface between the embankment and the natural ground has been used in this study. The permafrost mitigation techniques that showed good potential for cooling by reducing active layer thicknesses were the ACE uncovered, the longitudinal culverts, the snow/sun shed and the light-coloured aggregate BST (although this was only effective along the central part of the highway). Unfortunately, problems in the installation of the heat drain techniques prevented a full assessment of their effectiveness. The durability of the sections as well as their long-term cooling potential must also be assessed to complete the economic analysis provided in this study.

[Truncated abstract] The Tintina Gold Province (TGP) comprises numerous (<15) gold belts and districts throughout interior Alaska and Yukon that are associated with Cretaceous plutonic rocks. With a gold endowment of ∼70Moz, most districts are defined by their placer gold contributions, which comprise greater than 30 Moz, but four districts have experience significant increases in gold exploration with notable discoveries at Fort Knox (5.4 Moz), Donlin Creek (12.3 Moz), Pogo (5.8 Moz), True North (0.79 Moz), and Brewery Creek (0.85 Moz). All significant TGP gold deposits are spatially and temporally related to reduced (ilmenite-series) and radiogenic Cretaceous intrusive rocks that intrude (meta-) sedimentary strata. The similar characteristics that these deposits share are the foundation for the development of a reduced intrusion-related gold deposit model. Associated gold deposits have a wide variety of geological and geochemical features and are categorized as intrusion-centered (includes intrusion-hosted, skarns and replacements), shear-related, and epizonal. The TGP is characterized by vast, remote under-explored areas, unglaciated regions with variable oxidation depths and discontinuous permafrost, which, in combination with a still-evolving geological model, create significant exploration challenges. Twenty-five Early and mid-Cretaceous (145-90 Ma) plutonic suites and belts are defined across Alaska and Yukon on the basis of lithological, geochemical, isotopic, and geochronometric similarities. These features, when combined with aeromagnetic characteristics, magnetic susceptibility measurements, and whole-rock ferric:ferrous ratios define the distribution of magnetite- and ilmenite-series plutonic belts. Magnetite-series plutonic belts are dominantly associated with the older parts of the plutonic episode and comprise subduction-generated metaluminous plutons that are distributed preferentially in the more seaward localities dominated by primitive tectonic elements. Ilmenite-series plutonic belts comprise slightly-younger, slightly-peraluminous plutons in more landward localities in pericratonic to continental margin settings. They were likely initiated in response to crustal thickening following terrane collision. The youngest plutonic belt forms a small, but significant, magnetite-series belt in the farthest inboard position, associated with alkalic plutons that were emplaced during weak extension. Intrusion-related metallogenic provinces with distinctive metal associations are distributed, largely in accord with classical redox-sensitive granite-series. Copper, Au and Fe mineralisation are associated with magnetite-series plutons and tungsten mineralisation associated with ilmenite-series plutons. However, there are some notable deviations from expected associations, as intrusion-related Ag-Pb-Zn deposits are few, and significant tin mineralisation is rare. Most significantly, many gold deposits and occurrences are associated with ilmenite-series plutons which form the basis for the reduced intrusion-related gold deposit model

A Old Crow, petite communauté de Vuntut Gwich’in située aux confins du Yukon, s’étend un vaste territoire à la population multiple et variée. Parmi eux se trouve un impitoyable stratège : le loup. Il est aussi difficile de suivre ses traces que celles qu’il laisse chez les humains qui le côtoient. Le loup se révèle alors de multiples manières, à condition que le chercheur s’éloigne de ses idées préconçues et qu’il adopte une certaine flexibilité. Flexibilité d’autant plus nécessaire que le principal intéressé, ici les loups, ne se montre pas. Nous nous retrouvons alors non seulement à faire l’ethnographie d’individus à l’altérité radicale, mais invisible qui plus est. En face, se trouve pourtant un autre, à l’altérité insoupçonnée : le chien. Réputé comme étant le fidèle ami de l’homme depuis des siècles, ce sont pourtant des chiens bien différents qui errent dans les allées d’Old Crow. Indépendants et opportunistes, ces chiens n’ont pas grandchose à voir avec ces animaux de compagnies qui occupent les foyers à travers l’Occident. Des chiens autrement chiens. Des loups autrement loups. Un terrain à la croisée des chemins, de l’humain à l’animal, du tangible à l’intangible. Ces animaux n’usent pas de mots, et pourtant cette expérience ethnographique nous plonge dans un univers sensible, riche de sens et d’informations, nous invitant ainsi à reconsidérer la place de ces animaux dans nos ethnographies.

The prehistory of the Yukon-Kuskokwim Delta is poorly understood and the region today is home to the Yupiit, whose traditional lifeways revolve around animals. However, the fur trade and Christianity limit the use of ethnographic data to fully understand pre-contact human-animal relationships and subsistence in particular. The discovery of the prehistoric site of Nunalleq (15th-17th c. AD), therefore provides a unique opportunity to address this issue and opens a window to explore human responses to the Little Ice Age. In this research, a zooarchaeological analysis was undertaken to investigate animal exploitation at Nunallleq, potential changes in subsistence strategies and the nature of the faunal assemblage. Results suggest that people at Nunalleq focused primarily on salmon, marine mammals and caribou with migratory waterfowl possibly playing an important role at specific times of the year. This tripartite subsistence strategy appears to have provided the inhabitants of the site with the flexibility and necessary coping mechanisms to face potential environmental-related stress during the Little Ice Age by relying more on other resources, such as seals and caribou, when experiencing a reduced availability of salmon. The choice to settle at Nunalleq may have been strategic in order to have good access to multiple key resources simultaneously and it is suggested that perhaps the possible decline in salmon may be related to prehistoric warfare in the region. It is also highlighted that bone working and dog gnawing contributed to the formation the Nunalleq faunal assemblage. This raises further questions as to the nature and meaning of arctic and subarctic archaeofaunas and highlights the importance of multiple lines of evidence to document past human-animal relationships. This study better informs our understanding of Nunalleq forming a baseline for further subsistence studies in the Yukon-Kuskokwim Delta.

Orogenic gold mineralisation in schist terranes with few or no contemporaneous igneous intrusions is poorly understood. It is proposed in this thesis that the structural evolution of such terranes controls the generation of hydrothermal fluid pathways and thus the location of orogenic mineral deposits. Gold mineralisation in the Otago Schist, New Zealand and the Klondike Schist, Canada occurred in the latter phases of greenschist facies metamorphism as well as after metamorphism during Paleozoic-Mesozoic exhumation. In Otago, gold mineralisation occurred at a number of different times and structural levels as the schist belt was exhumed and rocks were brought up through the brittle-ductile transition. In Klondike Schist, gold mineralisation occurred in relatively brittle rocks after a period of regional compression and crustal shortening caused by the stacking of thrust sheets. Gold mineralisation in both schist belts is not associated with any coeval igneous activity. The earliest stage of gold mineralisation in the Otago Schist occurred in the Jurassic when mineralising fluids were progressively focussed into late metamorphic ductile shear zones such as the Hyde-Macraes Shear Zone (HMSZ), east Otago and Rise and Shine Shear Zone (RSSZ), central Otago. Both of these gold-bearing mineralised zones occur along mappable structural discontinuities or boundaries that separate structurally, metamorphically and lithologically distinct blocks. The HMSZ occurs in the hangingwall of an underlying low angle normal fault that juxtaposes mineralised lower greenschist facies rocks on to unmineralised upper greenschist facies rock. The RSSZ occurs in the footwall of an overlying low angle normal fault that juxtaposes unmineralised lower greenschist facies rocks on to mineralised upper greenschist facies rock. The two shear zones did not form as part of a single homogeneous structure. There are several other prospective late metamorphic boundaries that are different from later brittle faults that disrupt the schist. Late metamorphic gold mineralisation is characterised by both ductile and brittle structures, foliation-parallel shears, disseminated gold with sulphides in deformed schist and minor steeply dipping extensional veins. This style of mineralisation is the most prospective but can be subtle in areas without quartz veins. Hydrothermally altered rocks are enriched in gold, arsenic, tungsten and sulphur with minor enrichment of bismuth, antimony, mercury and molybdenum. Disseminated mineralisation in the HMSZ is associated with hydrothermal graphite however there is no hydrothermal graphite in the RSSZ. The next stage of gold mineralisation occurred in the Cretaceous during post-metamorphic exhumation of the schist belt and is characterised by steeply dipping, fault-controlled quartz veins, silicified breccias and negligible wall rock alteration. Most post-metamorphic veins strike northwest such as the ~25 km long Taieri river gold vein swarm, but there are other stibnite and gold mineralised structures that strike northeast (e.g., Manuherikia Fault system) and east-west (e.g., Old Man Range vein systems). The latest recognised stage of gold mineralisation is controlled by structures related to the initiation of the Alpine Fault in the Miocene and is characterised by steeply dipping quartz veins with abundant ankeritic carbonate in veins and ankeritic carbonate with gold in altered rocks. Hydrothermally altered rocks are enriched in arsenic, carbon dioxide and sulphur with minor enrichment of antimony. Gold-bearing veins at Bullendale, central Otago are of this type and are associated with a broad alteration zone. Gold-silver and gold-silver-mercury alloys occur in both Caples and Torlesse Terranes of the Otago Schist. Almost all mercury-bearing gold occurs in east Otago vein systems and mercury-free gold occurs in central and northwest Otago veins, irrespective of host terrane. There is no relationship between depth of vein emplacement and mercury content of gold. The Klondike Schist was emplaced as a series of stacked thrust slices in the Jurassic and thrust-related fabrics are preserved in all thrust slices. Strongly deformed carbonaceous schist horizons are spatially associated with thrust faults and graphite within these units is concentrated along spaced cleavage surfaces. Kink folding is best developed in the uppermost slices of Klondike Schist and overprints thrust-related fabrics. Gold-bearing veins formed in extension fractures controlled principally by pre-existing weaknesses such as kink fold axial surfaces. Normal faults correlated with a period of Late Cretaceous regional extension crosscut kink folds and offset gold mineralised veins. The main stage of mineralisation occurred after major regional compression and thrust stacking and before Cretaceous normal faulting. Gold-bearing veins are widely dispersed throughout the uppermost slices of Klondike Schist and are considered to be a sufficient source for Klondike gold placer deposits. Disseminated gold with pyrite is associated with gold-bearing veins in some Klondike Schist and this disseminated mineralisation expands the exploration target for these veins. Disseminated gold with pyrite, without quartz veins, occurs in some schist lithologies and is associated with chlorite alteration and weak silicification. The arsenic content of gold-mineralised Klondike Schist is much lower than mineralised Otago Schist and background concentrations of arsenic are much lower in Klondike Schist as well. No shear-related mineralisation has been discovered in Klondike Schist but due to its relatively poor exposure, this belt remains prospective for this style of mineralisation.

Thesis (D. Min.)--Midwestern Baptist Theological Seminary, 2005. / Abstract. Includes bibliographical references (leaves 157-158)

The following is a qualitative exploration of place identity, wilderness and cultural tourism interpreter guides, and sustainable tourism development in Canada’s Yukon Territory. Four research sub-questions are used to glean insights and advance this study: 1) how are Yukon place identities characterized in relation to remoteness?; 2) how is Yukon tourism positioned in relation to these place identities of remoteness?; 3) how is remoteness reflected in the place identities of wilderness and cultural tourism interpreter guides?; and 4) how do the place identities of wilderness and cultural interpreter guides influence the way they design and deliver their tourism activities? Recognizing the importance of “sense of place” as a tourism development tool, cultural geography was used to analyse guide place identity in relation to place-making and place-marketing processes. The study involved textual analysis of resident and tourist oriented documents, participant observation of guides and their tourism activities, and an analysis of place identity narratives identified in interviews with wilderness and cultural tourism guides. Three collective place identity narratives were used as a framework to examine place relationships in a tourism context: 1) Masculinist Narratives, 2) Narratives of the New Sublime, and 3) Narratives of Loss. In this study, place identity is explored in terms of the way it is expressed through, and influenced by, notions of “remoteness.” Remoteness is conceptualized as a social, cultural, historical and geographical construct that holds meaningful – if differently experienced and expressed – place identity values for residents and tourists alike. Remoteness is defined by the Yukon’s vast wilderness, its distance [real and perceived] from southern Canada and “civilization,” and its unique cultural makeup and history, especially with regard to lingering notions of an untamed frontier and its First Nations residents. Findings discuss infrastructure as a pivotal paradox; one that hinges on the “remote-accessible” nature of the Yukon’s tourism development question. Relationships between guide place identity, tourism experience authenticity and the nature of interpretation, type of tourism operation and tourism experience are identified and considered in relation to special interest tourism. Finally, implications for tourism and destination management and the goals of sustainable tourism development are discussed. / Tourism

Recently documented ice patch sites in the southwest Yukon are ideal for evaluating precontact hunter-gatherer land-use patterns in the western subarctic. Located in the alpine of the mountainous regions of the boreal forest, ice patches are associated with well preserved hunting equipment, caribou (Rangifer tarandus) dung and an abundance of faunal remains dating to over 8000 years ago. However, current models are inadequate for explaining caribou hunting at ice patches as they tend to emphasize large-scale communal hunts associated with latitudinal movements of caribou. Much less is known about the alititudinal movment of caribou and the associated hunting forays to ice patches in the alpine. Based on literature from caribou biology an altitudinal hunting model is proposed. During summer months caribou are predictable in their use of ice patches for relief from insect harassment. Pollen dated from caribou dung frozen in organic layers from the Granger (JdUt-1) and Friday Creek (JcUu-1) ice patches was analysed and compared to pollen assemblages from modern caribou dung to test whether ancient caribou were using these locations during summer months. The multivariate statistical technique, Nonmetric Mutlidimensional Scaling shows that ancient pollen assemblages are unlike any modern dung. Results indicate that pollen derived from dung is complex and various temporal transformations and taphonomic factors such as: (i) the use of modern analogue samples; (ii) changes in phenology; (iii) mode of pollination and; (iv) caribou feeding strategies must be understood before making interpretations on seasonality from dung pollen. I propose that a qualitative model of seasonal pollen signatures also be used to evaluate ancient pollen spectra, especially when there is no modern analogue. Regardless of these factors, the identification of a diversity of forbs and the presence of insect-pollinated taxa such as Polemonium and Epilobium suggest that some of the dung was deposited by caribou in the summer. Ancient hunters, knowing that caribou aggregate in mixed herds on ice patches in summer months, took advantage of this behaviour. Hunting equipment found on ice patches indicates that atlatls (8360± 60 to 1250± 40 yrs BP) and bow and arrows (1300 ± 70 to 90 ± 40 yrs BP) and hunting blinds were part of the ice hunting strategy. Faunal analysis suggests caribou was the primary game animal hunted at ice patches, although sheep (Ovis dalli) may have been important at some locations. Developing an altitudinal migration model provides a fuller picture of caribou hunting at alpine locations in the southwest Yukon and assists in understanding Holocene precontact hunting and land-use patterns in the western subarctic.

An acid rock drainage (ARD) stream emanating from the Zn-Pb XY-deposit in the Yukon Territory was examined in order to evaluate the physico-chemical and geochemical processes governing the distribution of dissolved elements from the creek. The creek showed very high concentrations of metals (300 mg/L Fe, 500 mg/L Zn, 15 000 µg/L Ni, 1300 µg/L Cu and 4500 µg/L Cd), low water temperatures (1 – 12°C) and was acidic to moderately acidic (pH 3.1 – 5.0). It was found that this stream experienced a strong seasonal evolution, with increased sulphate and metal concentrations and decreased pH over the course of the summer. The mineral precipitates that formed under low pH conditions were a mixture of schwertmannite, goethite, jarosite and barite, while those that formed under moderately acidic conditions were a mixture of jurbanite, hydrobasaluminite, gibbsite and an X-ray amorphous Al-sulphate phase. Most of the mineral precipitates were of inorganic origin, although microbes may have played a role in mineral formation and trace metal sequestration in some of the precipitates. All of the mineral precipitates contained anomalous concentrations of trace elements (up to 1.5 % wt Zn) and showed a seasonal evolution in their mineralogy, both of which were determined to be a function of the pH and prevailing geochemical conditions. The geochemistry of the ARD creek draining the XY-deposit was compared to another ARD creek in the area that was likely draining shales. The two creeks were compared in order to determine if ARD geochemical characteristics can be used as a tool for the mineral exploration industry.