Archaeocyatha from the Lower Cambrian of Wolf Lake and Quiet Lake areas in the Yukon Territory are described and illustrated. The fossils occur in carbonate rocks and are well preserved. Much of the necessary structural detail of the fossils is clearly observed in thin-sections and on polished surfaces of the specimens. The collection contains twenty-three species, twelve of which are new species. The new species described are: Ajacicyathus yukonensis, Coscinocyathus multiporus. Coseinocyathus cassiariensis, Coscinocyathus inequivallug, Coscinocyathus serratus, Coscinocyathus veronicus, Coscinocyathus tubicornus, Carinacyathus perforatus, Pyenoidocyathus solidus, Loculicyathus elliptieus, Metacoscinus poolensis, and Claruscyathus ketzaensis. The genera Carinacyathus and Loculicyathus are reported for the first time in North America. The Yukon fauna is dominated by Coscinocyathidae and Pycnoidocyathidae, showing close relationship to faunae in the Cordilleran region of British Columbia. It also shows relationship to Siberian and Australian faunae. This fauna is very different from the archaeocyathid assemblages in Nevada and California, where the dominant forms are Ethmophyllidae and Ajacicyathiclae. Arehaeocyatha have been instrumental in determining the age of rocks underlying a large area of the Yukon Territory. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Permanent electrode arrays were set up at ten monitoring sites from Whitehorse, Yukon, to Fort St. John, British Columbia, in order to gain a clearer perspective of the effectiveness of electrical resistivity tomography (ERT) monitoring over an annual cycle of freezing and thawing. This research forms part of a longer-term project that is attempting to use ERT to examine changes in permafrost resulting from climate change. Inter-site and intra-site variability were examined by installing and maintaining data-loggers to monitor active layer and shallow permafrost temperatures, air temperatures, and snow depths at each site from August 2010 – August 2011. Additional site information was collected on each ERT survey date, including frost table depths, snow depths, and vegetation heights. Based on nearby community records, the climate in the region has been warming by a rate of 0.3 to 0.5 °C per decade since 1970. The permafrost at all ten sites was characteristic of sporadic discontinuous and isolated patches permafrost zones, and is classified as Ecosystem-protected. Nine of the ten permafrost sites had permafrost that was thinner than the 14 or 7 m penetration depth of the ERT survey (three-layer system consisting of an active layer, permafrost, and sub-permafrost perennially unfrozen zone). The most predictable results were achieved at the two-layer system site (active layer overlying permafrost to the base of the profile) in each of its virtual resistivity boreholes, relative resistivity change comparisons, and mean near-surface apparent resistivity progressions. ERT is an effective method of delineating permafrost boundaries in thin permafrost environments and does show strength when monitoring areas of seasonally frozen ground. Repeat surveys at a site indicate seasonal changes in three-layer conditions, but not as predictably as those in a two-layer system. In order to receive the most accurate information regarding permafrost extent and thickness, it appears ideal to conduct ERT surveys annually, within the same month as the previous year’s survey.

This study presents a geochemical characterization of stream waters draining the sedimentary exhalative (SEDEX) Tom and Jason Pb-Zn deposits and surroundings in the MacMillan Pass, Yukon. Streams sampled have wide ranging pH values of 3 to 8.2. Dissolved metal concentrations vary widely with water source and pH. Of note, streams draining the Tom and Jason deposits are acidic and neutral respectively, which greatly affects metal solubility. The Tom Deposit drainage is extremely high in dissolved and fine sediment fraction lead, as well as dissolved zinc. Neutral streams draining the Jason deposit have less dramatic metal concentrations, but do show elevated dissolved zinc and fine sediment fraction lead concentrations. Modelling using the thermodynamic equilibrium program PHREEQC and XRD analysis indicate that ferricrete hardpans underlying acidic drainages are formed where drainage water is saturated with respect to schwertmannite. Ferrihydrite is formed where the rapid mixing of waters increases the pH rapidly. An aluminium oxy-hydroxide, likely gibbsite, precipitates where pH levels exceed 4.5, however it appears to dissolve with decreasing pH. This study looks at dissolved, suspended and fine fraction sediments to provide a more complete view of metal movement under various conditions which may be useful to both exploration and environmental fields.

Palynological and maturation data are combined to reconstruct the burial and thermal history of three oil wells in the Beaufort-Mackenzie Basin. From south to north, the three wells are Netserk F-40, Tarsuit A-25, and Orviiruk 0-03. Each well was examined palynologically and zoned based on species ranges of pollen, spores, fungi, and algal cysts. Using local extinction events of zonally diagnostic species to define the tops of intervals, seven informal palynozones are presented: Laevigatosporites (Pleistocene); ChenopodipoJlis (Pliocene to early Pleistocene); Ericipites (middle to late Miocene); Selenopemphix-1 (middle to late Oligocene); Integricorpus (early Oligocene); Araliaceoipollenites (late Eocene to early Oligocene); Pistillipollenites (middle Eocene). Correlations within the basin indicate that the proposed zonation may be useful for local correlations. Correlations outside the basin indicate that the palynological assemblages from the Beaufort-Mackenzie Basin may not be as isolated and endemic as first thought. A high recovery of algal cysts is attributed to less harsh maceration techniques, and confirms a significant population of cysts from a region in which they were formerly believed to be relatively scarce. The palynology does not exhibit an increase in marine influence with decreasing proximity to the basin margin. Instead it shows a consistent, strong terrestrial influence throughout each well. The large terrestrial discharge from the Mackenzie River is interpreted to have masked the effect of basin proximity on the palynology of the area. The study wells are dominated by terrestrial Type III organic matter. Recycled and terrestrial inert material often make up over 95 % of the residues. These results support a terrestrial source for the offshore oils in the Beaufort -Mackenzie Basin. There is a small but consistent presence of potential oil-generating material throughout each well (amorphous and liptinite). The liptinite is largely composed of pollen grains, spores, and leaf cuticle. Algal cysts are present but less abundant. If the observed amounts of amorphous and liptinite material continue to some depth, where the required level of thermal maturation might be reached, these sediments could act as source rocks for hydrocarbons. The rare occurrence of resinite in the study wells questions the resinite source theory for the hydrocarbons in the basin The sediments in each of the three study wells are immature to total depth, and could not be the source of Tertiary oils in the Beaufort - Mackenzie Basin. The levels of maturity in the wells, and the low maturation gradient calculated for Netserk F-40 (0.07 Ro/km), suggest that thermal maturation will only be achieved at much greater depths. This is most likely due to rapid sedimentation rates in the basin during the Tertiary. By combining the zonations from Chapter 3 with the maturation data from Chapter 4, the burial and thermal history of each study well is reconstructed. Using a modified version of Lopatin's method, paleo-geothermal gradients are calculated for each well. In each case, the gradient that best accountes for the measured maturities is 15 °C/km. The calculated gradient is approximately 1/2 to 1/3 of the present geothermal gradients for the wells. The gradient is in agreement with those previously calculated from similar basins, and is considered responsible for the failure of any of the study wells to encounter effective source rocks. Source rocks of Tertiary oils in the Beaufort-Mackenzie Basin will only exist at greater depths than those encountered in this study. Prospective targets may therefore be located adjacent to sites where vertical migration of hydrocarbons is likely, such as steeply-dipping faults. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

This project examines arsenic in plants growing near closed or reclaimed gold mines located in the traditional territories of two Yukon First Nations. A total of 238 soil and plant samples (comprising 9 different species) were collected from Mt. Nansen, Arctic Gold and Silver, and Venus Mine tailing properties. At each property, samples were collected near the suspected point source of contamination, approximately 1 -3 km away, and from background sites. Species were chosen for their ethnobotanical significance to the Little Salmon/Carmacks and the Carcross/Tagish First Nations, based on interviews with Elders and other knowledgeable people. Total and inorganic arsenic concentrations were determined using ICP-MS and AAS instrumentation, and organic arsenic concentrations were calculated from the difference. Uptake of arsenic by plants was low compared to soil arsenic concentrations. In both plants and soil, the arsenic form was predominantly inorganic. Concentrations in berries at all three sites were low or undetectable, and are therefore considered safe to eat under Health Canada tolerable daily intake guidelines for inorganic arsenic. At Mt. Nansen, the lichen "caribou moss" (Cetraria/Cladina spp.), Bolete mushrooms (Leccinum spp.), and the medicinal shrubs willow (Salix spp.) and Labrador tea (Ledum groenlandicum/L. decumbens spp.) had high mean arsenic concentrations around point sources or at sites up to 1.5 km away. These localized high concentrations will not likely affect foraging animals, given their constant movement. However, Carmacks residents could avoid gathering all species with elevated arsenic around the Mt. Nansen mining property until reclamation is complete. / Arts, Faculty of / Geography, Department of / Graduate

The importance of integrating technology across the curriculum has been prominent in educational literature for the past decade. Numerous obstacles have been identified and documented surrounding the successful integration of technology in public schools. Access to hardware, appropriate software, professional training for educators, technical and financial support to sustain meaningful uses of technology in schools are the primary areas to be addressed when designing a comprehensive information technology implementation strategy for educational environments. The obstacles are clear, but many educational leaders have failed to develop a model which successfully addresses the challenge of integrating the use of technology as a tool for teaching and learning and as a means of constructing new knowledge for and by students. This paper will explore how technology facilitates learning through inquiry and how inquiry supports a constructivist/constructionist approach to teaching and learning for students and professional staff. This will lead to an examination of how inquiry and constructivism advance the integration of technology in education and how it provides a venue for developing communities of inquiry in schools. A framework for two initiatives developed for Yukon schools will be presented which address many of the challenges common to the successful integration of technology in public schools today. Both initiatives, the Computer Resource Teacher Model (CRTM) and Technology Learning Communities (TLC), promote integrative and constructive uses of technology through an inquiry-based approach to teaching and learning with computers. / Education, Faculty of / Curriculum and Pedagogy (EDCP), Department of / Graduate

Glacier surges are periods of dynamic instabilities which result in semi-regular alternating periods of slow flow, termed the quiescent phase, and fast flow, termed the active phase. This study uses remotely sensed imagery, digital elevation models, glacier velocity datasets, and in situ oblique photographs to reconstruct the surge history and dynamics of Fisher Glacier to better characterize surging in the southwest Yukon and assess the risk posed by this glacier’s surges on surrounding regions. Fisher Glacier has previously been identified as a surge-type glacier but, until now, it had not been the focus of any detailed studies. We find evidence that Fisher Glacier underwent two surges during the study period from 1948 to 2022. Visual analysis of characteristic surge features on the glacier surface show that the glacier was in quiescence from <1948 to at least 1963. In 1972, an advanced terminus position, intense surface crevassing, and high point velocities suggest that a surge had recently terminated, corroborating a previous report of a surge occurring around 1970. This was followed by a 40-year quiescent phase from ~1973-2013 during which the terminus underwent consistent retreat, totaling a terminus-wide average of 2058 ± 8 m (up to 3567 ± 8 m in certain sections). Velocities during the quiescent phase were low (generally <50 m yr⁻¹), but underwent a slow multidecadal increase starting around 1985, spreading from the center of the glacier towards the head and the terminus. A pre-surge buildup phase beginning in ~2008-2010 resulted in velocities of up to ~200 m yr⁻¹. The active phase of the surge initiated in winter 2013/14 and was characterised by a velocity increase to ~1500 m yr⁻¹ that propagated both up- and down-glacier from the surge nucleus in the mid-region (~22 km upglacier from the terminus). Velocities peaked at >2100 m yr⁻¹ in the winter/early spring of 2016 at ~12 km from the terminus. The surge resulted in a mean terminus-wide advance of 868 ± 8 m, intense surface crevassing and a downglacier transfer of mass from the reservoir zone to the receiving zone. The terminus area increased in elevation by a mean of ~80 m. In July 2016, the surge rapidly terminated within a period of ~1 month, although velocities at the head and the terminus took a few more months to slow to quiescent values. Since then, average annual velocities along the centerline have been lower than pre-surge velocities, the crevasses have closed up, and the rate of ice surface elevation change has been negative across the entire glacier. Fisher Glacier’s surge dynamics suggest predominantly hydrologically controlled surging, but with some aspects more representative of thermally controlled surging. Thus, we propose that more than one mechanism might be at play in controlling its surges, although further research is required to confirm this. Under current climate conditions, it is unlikely that Fisher Glacier could dam the nearby Alsek River and cause a glacier lake outburst flood.

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High latitude areas have been identified in most GCMs as regions where global warming will appear earliest and be the greatest. Since much of Canada's north is underlain by permafrost, a warming of 3-5°C could cause widespread erosion and thermokarst. The Arctic coastal zone is particularly vulnerable, as it lies at the interface between terrestrial systems dominated by permafrost, and marine systems dominated by sea ice and wave action. This study aims at understanding some mechanisms of arctic coastal erosion, such as thermoerosional niches and block failure. The final goal of this research is to identify the areas of Herschel Island, Yukon Territory, which are likely to experience the greatest magnitude of change in the near future. This information is then coupled with a climate change scenario in order to predict future coastal erosion in the area.