Rozprawy doktorskie na temat „Yukon”
Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: Yukon.
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Yukon”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
1
Clement, David T. "Fluvial geomorphology of the Yukon River, Yukon Flats, Alaska". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0015/MQ47994.pdf.
Pełny tekst źródła
2
Pretzlaw, Troy. "Pattern, composition and resource selection of terrestrial vertebrates across the Yukon forest to tundra transition". Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101166.
Pełny tekst źródłaStreszczenie:
Ecotones are gradients of change between expanses of similar species composition. These regions often mark co-occurring range limits for several species, and thus are ideal for elucidating ecological and biogeographical phenomena. The forest to tundra transition (FTT) is one of the world's most prominent ecotones, but remains poorly studied especially with regard to vertebrate species occurrence. Vertebrate diversity, ecological structure and resource selection were characterized across the Yukon FTT using diversity metrics, ordination, hierarchical clustering, and resource modeling. The FTT represents an abrupt drop in vertebrate species richness within the more gradual, continental scale diversity gradient. Despite the patchiness and complexity in vegetative structure over this ecotone, the terrestrial vertebrate community is divisible into boreal, taiga, and tundra compartments. Most species conform to resource associations reported closer to the core of their range, generating remarkably consistent habitat and species associations despite a complex patchwork of contrasting habitat types.
3
Eiché, Greg. "Petrology of quaternary alkaline lavas from the Alligator Lake volcanic complex, Yukon Territory, Canada". Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65987.
Pełny tekst źródła
4
Knight, Eleanor. "Thermochronology of Early Jurassic Exhumation of the Yukon-Tanana Terrane, West-central Yukon". Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/22933.
Pełny tekst źródłaStreszczenie:
This study utilised U-Pb geochronology, and 40Ar/39Ar and (U-Th)/He thermochro-nology to delineate arc magmatism, metamorphism, and exhumation of the pericratonic Yukon-Tanana terrane in the McQuesten map area of west-central Yukon, Canada. SHRIMP U-Pb ages delineate Mid to Late Paleozoic arc magmatism and fit key units into the regional lithotectonic framework of the terrane. The juxtaposition of unmetamorphosed and predomi-nantly undeformed Devono-Mississippian rocks in the northwest of the study area with polydeformed and up to amphibolite facies metamorphosed rocks in the southwest suggests a crustal-scale discontinuity, the Willow Lake fault, bounds the two domains. The asymmetric distribution of 40Ar/39Ar ages across the fault suggest it is extensional, and was active in the Early Jurassic. Zircon (U-Th)/He ages delineate erosion of rocks in the northwest through the upper crust during the Late Triassic and Late Jurassic to Early Cretaceous followed by Mid-dle Cretaceous erosion of the southwestern domain and possibly fault reactivation.
5
Boucher, Stéphanie 1974. "Diversity and zoogeography of Brachycera (Diptera) in disjunct grasslands of the southern Yukon". Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21515.
Pełny tekst źródłaStreszczenie:
The diversity and zoogeography of Diptera (Brachycera) of disjunct xeric grasslands in the southern Yukon were studied. Over 20,000 flies were collected representing 32 families and 213 species. In terms of abundance, the predacious guild dominated (54% of total specimens) due mostly to the family Chamaemyiidae which represented 45% of all specimens. In terms of diversity, the phytophagous and parasitoid guilds were dominant (25.5% of total species each). The most diverse families were Agromyzidae (32 species), Chloropidae (31 species), Tachinidae (23 species) and Pipunculidae (20 species). Thirty-four undescribed species were collected and 58 species were recorded for the first time in the Yukon. Zoogeographic analysis indicates that the Diptera fauna of these grasslands is dominated by widespread Nearctic or Holarctic species, but the fauna also includes southern grassland species with disjunct distributions, and species endemic to Beringia. The presence of endemic and disjunct species suggests that these grasslands were present in Beringia during the Wisconsinan and acted as a refugium for grassland Diptera.
6
Baker, Ted. "Church planting in the Yukon". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ26816.pdf.
Pełny tekst źródła
7
Lambden, Allison Jill. "Food security of Canadian Arctic indigenous women". Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99342.
Pełny tekst źródłaStreszczenie:
This secondary data analysis used a cross-sectional survey of 1771 Yukon First Nations, Dene/Metis, and Inuit women. The aims were to evaluate access to traditional food (TF) and market food (MF), identify perceived advantages of TF and MF, and explore under-studied characteristics of FS in Arctic Canada. Results indicate considerable regional variation in ability to afford adequate food, varying between 26 and 58%. Similarly, regional variation was reflected in the percentage of women who had access to hunting or fishing equipment. Participants described culturally relevant FS indicators: food needed to be natural, fresh, tasty, varied, healthy, safe, accessible, and convenient. Between 10 and 38% of participants noticed recent changes in the quality or health of TFs. Caribou, moose, and seal were popular TFs and considered particularly healthy. This study emphasizes the importance of TF for Arctic indigenous women's FS and the dynamic nature of FS in this population.
8
Abercrombie, Shirley May. "Petrology, geochronometry and economic geology : the Zeta tin-silver prospect, Arsenic Ridge, west-central Yukon (115P/14 and 116A/03)". Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/28880.
Pełny tekst źródłaStreszczenie:
Arsenic Ridge is located in the northwestern part of the Lost Horses batholith, Syenite Range, Yukon Territory. This area is within the Omineca Crystalline Belt of the Canadian Cordillera. North American miogeoclinal rocks of the upper Precambrian to Lower Cambrian Grit Unit were northwardly thrust onto Ordovician to Silurian Road River Formation during the Late Triassic to Early Jurassic arc-continent collision. Small mid-Cretaceous (83 to 100 Ma, K-Ar on biotite), epizonal felsic intrusions were emplaced in radiogenic Sr-enriched metasedimentary rocks of the ancient continental margin (pericratonic sedimentary prism).
The mid-Cretaceous (syenite phase, 87+3 Ma, K-Ar on biotite; granite phase, 95+3 Ma, K-Ar on biotite) Lost Horses batholith is a circular, S-type, composite pluton within the Selwyn Basin. The Selwyn Basin is an epicontinental trough partially bounded on the west by the Cassiar Platform and on the east and northeast by carbonate rocks of the MacKenzie Platform. S-type plutons are a product of Hercynotype arc-continental collisional tectonics.
The zoned intrusive rocks along Arsenic Ridge, from core to rim, have been classified as tourmaline orbicular granite, granite, quartz syenite and syenite. With increasing SiO₂ : (1) the major elements--Al₂O₃ , FeO, MgO, CaO, TiO₂, MnO and P₂O₅--tend to decrease,(2) trace elements--Zr, V, Sr, Ni, and Ba--are characterized by extreme depletions, and (3) the trace element, Rb, is slightly enriched. The syenite is alkaline whereas the quartz syenite, granite, granite dyke, and tourmaline orbicular granite are sub-alkaline. Magmatic differentiation of the pluton is demonstrated by a decreasing trend of (Na₂O + K₂O) and TiO₂ with increasing SiO₂, and by an increasing Rb content with a decrease in Ba and Sr. The estimated partial pressure of water during formation of the Lost Horses granite melt is broadly estimated as >10 kbar. Electron microprobe traverses across orthoclase megacryst cores and rims identified a concentration of albite lamellae in the rim and barium, strontium and calcite rich cores. The latter is indicative of a melt undergoing progressive depletion of barium by fractional crystallization.
The age of the batholith is early Late Cretaceous, approximately 97 Ma. This was determined from early Late Cretaceous dates of 95+3 Ma from K-Ar on biotite and 88+4 Ma from K-Ar on a hornblende, and a late Early Cretaceous date of 101+6 Ma from a whole rock-mineral (biotite, hornblende, total feldspar) Rb-Sr isochron.
Initial strontium ratios for the granitic rocks along Arsenic Ridge are about 0.712 suggesting that radiogenic strontium was derived mainly from melting and/or assimilation of old sialic crust during magma genesis. The model Rb-Sr age, TUR, for the granitic rocks on Arsenic Ridge is 238 Ma. This indicates that a dominantly upper mantle source is unlikely.
Pb-Pb isotope ratios for the zoned plutonic rocks, the surrounding sediments and the ore mineral separates plot between the pericratonic and Bluebell curves (from 0 Ma to 140 Ma mixing lines) indicating that the lead is a mix of upper crust and lower crust sources. Lead sulphide analyses from the Zeta prospect, Tombstone Range and the Keno-Galena Hill areas are indistinguishable from the feldspar rock lead. This shows that the lead source for these vein
deposits is the surrounding plutons and not the surrounding sedimentary rocks. The least radiogenic lead has a model age of about 100 Ma.
Nd/Sm and Nd analyses indicate that Arsenic Ridge granitic rocks were derived from, or assimilated, old crustal rocks whose Sm/Nd had been lowered at the time of separation from CHUR. Nd ratios for the granite and the feldspar megacrysts are all very close to 0.51210. The model Sm-Nd age, TDM , for a granite along Arsenic Ridge is 1.26 Ga. Approximate percentages of continental crust and mantle incorporated in the melt were calculated. If the contamination is upper crustal in origin then there was a maximum of 30% mantle incorporated in the melt. No mantle component is needed if the contamination source is lower crust. However, since granite ¹⁴³Sm/¹⁴⁴Nd ratios are close to the average continental crust ratio, the origin is upper crust with a small mantle component.
¹⁴³Nd/¹⁴⁴Nd and ⁸⁷Sr/⁸⁶Sr ratios for the granitic rocks from the Lost Horses batholith plot in the Phanerozoic quadrant of Faure (1986) and are similar to values from the Sierra Nevada batholith. Epsilon values of Nd and Sr
suggest the granite is S-type which agrees with the field, petrographic and chemical evidence. The granite plots within the field for miogeoclines as determined by Farmer and DePaolo (1983 ).
The Zeta tin - silver greisen vein prospects lie in both the Ordovician - Silurian metasediments of the Road River Group at the northeastern contact, and in the zoned, mid-Cretaceous Lost Horses batholith. Mineralization on the property occurs in two forms: (1) cassiterite bearing greisen veins in hornfelsed quartzite, and (2) greisen veins (sulphide and quartz with minor tourmaline, and tourmaline and quartz with minor sulphide in granitic rocks). K-Ar muscovite dating of the sericitic cassiterite greisen (87.0+3.0 Ma), indistinguishable from the K-Ar biotite date for the syenite phase of the batholith (86.8+2.7 Ma), establishes a genetic relationship between the two.
The following four-stage model describes the evolution of the Lost Horses batholith: stage 1, initial melting, stage II, melt accumulations and assimilation, stage III, diapiric rise and chemical differentiation (fractional crystallization), and stage IV, magmatic hydrothermal. This
last stage generated tin-silver vein and greisen mineralization. The source for this lithophile mineralization and associated S-type granitic rock is dominantly from a sialic clastic wedge with upper crustal geochemical characteristics.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
9
Petrie, Meredith Blair. "Evolution of eclogite facies metamorphism in the St. Cyr klippe, Yukon-Tanana terrane, Yukon, Canada". Thesis, The University of Iowa, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=3628428.
Pełny tekst źródłaStreszczenie:
The St. Cyr klippe hosts well preserved to variably retrogressed eclogites found as sub-meter to hundreds of meter scale lenses within quartzofeldspathic schists in the Yukon-Tanana terrane, Canadian Cordillera. The St. Cyr area consists of structurally imbricated, polydeformed, and polymetamorphosed units of continental arc and oceanic crust. The eclogite-bearing quartzofeldspathic schists form a 30 by 6 kilometer thick, northwest-striking, coherent package. The schists consist of metasediments and felsic intrusives that are intercalated on the tens of meter scale. The presence of phengite and Permian age zircon crystallized under eclogite facies metamorphic conditions indicates that the eclogite was metamorphosed in situ with its quartzofeldspathic host.
I investigated the metamorphic evolution of the eclogite-facies rocks in the St. Cyr klippe using isochemical phase equilibrium thermodynamic (pseudosection) modeling. I constructed P-T pseudosections in the system Na2O-K2O-CaO-FeO-O2-MnO-MgO-Al2O 3-SiO2-TiO2-H2O for the bulk-rock composition of an eclogite and a host metatonalite. In combination with petrology and mineral compositions, St. Cyr eclogites followed a five-stage clockwise P-T path. Peak pressure conditions for the eclogites and metatonalites reached up to 3.2 GPa, well within the coesite stability field, indicating the eclogites reached ultrahigh-pressure conditions. Decompression during exhumation occurred with a corresponding temperature increase.
SHRIMP-RG zircon dating shows that the protolith of the eclogites formed within the Yukon-Tanana terrane during early, continental arc activity, between 364 and 380 Ma, while the metatonalite protolith formed at approximately 334 Ma, during the Little Salmon Cycle of the Klinkit phase of Yukon-Tanana arc activity. Both the eclogites and the metatonalites were then subducted to mantle depths and metamorphosed to ultrahigh-pressure conditions during the late Permian, between 266 and 271 Ma. The results of our study suggest portions of the Yukon-Tanana terrane were subducted to high-pressure and ultrahigh-pressure conditions. This is the first report of ultrahigh-pressure metamorphism in the accreted terranes of the North American Cordillera. Petrological, geochemical, geochronological, and structural relationships link the eclogites at St. Cyr to other eclogite localities in Yukon, indicating the high-pressure assemblages form a larger lithotectonic unit within the Yukon-Tanana terrane.
10
Petrie, Meredith Blair. "Evolution of eclogite facies metamorphism in the St. Cyr Klippe, Yukon-Tanana Terrane, Yukon, Canada". Diss., University of Iowa, 2014. https://ir.uiowa.edu/etd/4718.
Pełny tekst źródłaStreszczenie:
The St. Cyr klippe hosts well preserved to variably retrogressed eclogites found as sub-meter to hundreds of meter scale lenses within quartzofeldspathic schists in the Yukon-Tanana terrane, Canadian Cordillera. The St. Cyr area consists of structurally imbricated, polydeformed, and polymetamorphosed units of continental arc and oceanic crust. The eclogite-bearing quartzofeldspathic schists form a 30 by 6 kilometer thick, northwest-striking, coherent package. The schists consist of metasediments and felsic intrusives that are intercalated on the tens of meter scale. The presence of phengite and Permian age zircon crystallized under eclogite facies metamorphic conditions indicates that the eclogite was metamorphosed in situ with its quartzofeldspathic host.
I investigated the metamorphic evolution of the eclogite-facies rocks in the St. Cyr klippe using isochemical phase equilibrium thermodynamic (pseudosection) modeling. I constructed P-T pseudosections in the system Na2O-K2O-CaO-FeO-O2-MnO-MgO-Al2O3-SiO2-TiO2-H2O for the bulk-rock composition of an eclogite and a host metatonalite. In combination with petrology and mineral compositions, St. Cyr eclogites followed a five-stage clockwise P-T path. Peak pressure conditions for the eclogites and metatonalites reached up to 3.2 GPa, well within the coesite stability field, indicating the eclogites reached ultrahigh-pressure conditions. Decompression during exhumation occurred with a corresponding temperature increase.
SHRIMP-RG zircon dating shows that the protolith of the eclogites formed within the Yukon-Tanana terrane during early, continental arc activity, between 364 and 380 Ma, while the metatonalite protolith formed at approximately 334 Ma, during the Little Salmon Cycle of the Klinkit phase of Yukon-Tanana arc activity. Both the eclogites and the metatonalites were then subducted to mantle depths and metamorphosed to ultrahigh-pressure conditions during the late Permian, between 266 and 271 Ma. The results of our study suggest portions of the Yukon-Tanana terrane were subducted to high-pressure and ultrahigh-pressure conditions. This is the first report of ultrahigh-pressure metamorphism in the accreted terranes of the North American Cordillera. Petrological, geochemical, geochronological, and structural relationships link the eclogites at St. Cyr to other eclogite localities in Yukon, indicating the high-pressure assemblages form a larger lithotectonic unit within the Yukon-Tanana terrane.
11
Hercz, Anna Veronica. "Residential land use planning and housing in Whitehorse, Yukon Territory : public involvement in the land development process". Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74048.
Pełny tekst źródła
12
Jansen, Rebecca June 1980. "Yukon Heritage Conservation Districts: Case Studies and Strategies for Success". Thesis, University of Oregon, 2010. http://hdl.handle.net/1794/11044.
Pełny tekst źródłaStreszczenie:
xii, 190 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.The success of heritage conservation districts as a more holistic approach to heritage resource management has been documented around the country. Yukon, Canada has expressed a desire to move beyond traditional approaches to establish district designations. Through detailed examinations of the evolution of districts and of the progression of historic sites management in Canada and the Yukon, best practices will be established and measured against the unique challenges faced in the Territory. Further, an examination of the potential benefits and challenges are discussed and measured against three case studies: downtown Dawson City, Takhini North in Whitehorse and Carcross, Yukon. The case studies provide tangible evidence for the successful implementation of heritage conservation districts as a way to preserve and enhance the Yukon's historic sites.
Committee in Charge: Dr. Michael Hibbard, Chair; Barbara Hogan
13
De, krom Valentina. "A geomorphic investigation of retrogressive thaw slumps and active layer slides on Herschel Island, Yukon Territory /". Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59632.
Pełny tekst źródłaStreszczenie:
This thesis investigates the geomorphology of retrogressive thaw slumps and active layer slides on Herschel Island, northern Yukon Territory. In particular, it examines the formation and morphology of both landforms, and the ground ice characteristics of retrogressive thaw slumps. During 1988-1989 a number of retrogressive thaw slumps and active layer slides were surveyed and monitored. Field and laboratory investigations involved (1) documentation of landform distribution, setting and morphology, (2) examination of processes of landform formation, and (3) the examination of cryostratigraphy, ground ice characteristics and material properties.Retrogressive thaw slumps developed in areas of low to moderate slopes underlain by a variety of sediments with ice contents up to 4500% (on a dry weight basis). Slump headwall retreat rates of up to 19.5 m/yr were recorded. By comparison, active layer slides developed on steeper slopes underlain mainly by marine silts and clays. The sediments exposed in the slide floors and headwalls displayed no visible ground ice, but moisture contents were between 15-35%. Retrogressive thaw slumps and active layer slides form by entirely different processes. However, they do occur in close association and are influenced by many of the same parameters.
14
Lantuit, Hugues. "Mapping permafrost and ground-ice related coastal erosion on Herschel Island, southern Beaufort Sea, Yukon Territory, Canada". Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82270.
Pełny tekst źródłaStreszczenie:
Climate change and warming have been linked to enhanced coastal erosion in the arctic. Specifically, permafrost is believed to be thawing at greater rates, and wave dynamics are expected to increase in intensity. As a result, thermokarst activity, which includes the occurrence of retrogressive thaw slumps, will be more frequent along arctic coasts.The availability of airborne and spaceborne imagery in the arctic over the last fifty years has made possible the temporal analysis of permafrost and ground ice-related erosion. The objectives of this thesis are (1) the creation of a large scale database for horizontal coastal retreat on Herschel Island for the 1952-2000 timespan, (2) the investigation of retrogressive thaw slump activity over the same period and its relation to coastal erosion, and (3) the elaboration of stereophotogrammetric techniques to investigate retrogressive thaw slump activity volumetrically. Herschel Island, located on the northern coast of the Yukon Territory, was chosen as the study site for this research, because of the widespread presence of retrogressive thaw slumps and the lack of data for coastal erosion during the last fifty years.
Photogrammetric tools were used to create orthorectified and stereo-images of the Island for the years 1952, 1970, 2000 and 2004 from airphoto archives and Ikonos (1 m resolution) imagery. Coastal erosion was found to be stable or declining on Herschel Island except in the vicinity of retrogressive thaw slumps. In addition, retrogressive thaw slumps were identified on the imagery and observed to have increased in frequency for the 1952-2000 period.
Stereophotogrammetric analysis of two retrogressive thaw slumps showed that eroded sediment volumes from these landforms are considerable and should be included in future assessments of sediment release from arctic coasts to the oceanic shelves.
15
Kerr, Tricia D. "Direct and indirect energetic influences on juvenile red squirrel survival, recruitment, and reproduction". Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99189.
Pełny tekst źródłaStreszczenie:
This thesis evaluates how developmental conditions influence settlement, survival, and yearling primiparity in juvenile red squirrels. This was accomplished by comparing the fates of offspring from food supplemented versus non-supplemented mothers, and by using logistic regression to evaluate the effects of body mass, resource availability, and reproductive parameters on juvenile success. Maternal nutrition, previous and present year's cone production, and body mass contributed significantly to settlement and survival during all juvenile life history stages (emergence, settlement, and overwinter survival). Heavier than average juveniles were also more likely to reproduce as yearlings. Nevertheless, natal body mass was not a predictor of recruitment, indicating persistent influence of early developmental conditions on life history fates above and beyond mass effects. A greater impact of resource availability than body size on fitness among red squirrels may reflect this species' reliance on hoarded food rather than body fat for energy reserves.
16
Thomson, Jason David. "Protected area co-management in the Yukon". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0002/MQ31871.pdf.
Pełny tekst źródła
17
Morehouse, Neil. "Implementing sustainable forest management in the Yukon". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ62031.pdf.
Pełny tekst źródła
18
McDonald, Bruce Walter Robert. "Geology and genesis of the Mount Skukum tertiary epithermal gold-silver vein deposit, southwestern Yukon Territory (NTS 105D SW)". Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26448.
Pełny tekst źródłaStreszczenie:
The Tertiary Mt. Skukum gold - silver epithermal vein deposit occurs 65 km southwest of Whitehorse in the Yukon Territory. Veins are hosted by a sequence of nearly flat-lying Eocene Skukum Group andesitic volcanic rocks of the Mt. Skukum Volcanic Complex, part of the Sloko Volcanic Province which unconformably overlies these intrusive complexes as well as metamorphic rocks of the Yukon Group.
Major known mineralized zones occur within a regional halo of propylitic alteration centered on a fault-bounded graben within Main Cirque in the southwestern corner of the Mt. Skukum Volcanic Complex. Each zone consists of steeply-dipping quartz-carbonate-sericite veins associated with major faults and rhyolite dykes which bound blocks of the graben.
Precious metals occur as electrum and native silver as fine grains averaging 15 to 20 microns and locaIly exceeding 1 mm across, in veins containing only trace amounts of sulphides. Fluid inclusions indicate that vein minerals were deposited from hydrothermal fluids averaging 313°C with an average salinity of 0.7 weight percent NaCl equivalent. Primary inclusions show that depositional fluids existed under two pressure regimes; one close to hydrostatic, the other approaching lithostatic. Both reflect depths of deposition of about 470 m below paleosurface. Variable fluid pressures reflecting similar depths of deposition combined with variable liquid to vapour ratios in primary inclusions as well as abundant textural evidence of hydrothermal brecciation indicate that boiling was common during mineralization.
Oxygen and carbon isotope composition of minerals in the deposit and surrounding wall rocks indicate that depositional fluids were meteoric in origin with no contribution from magmatic sources. Large depletions in 0¹⁸ content of andesitic rocks in the deposit area indicate a minimum water rock ratio over the life of the deposit of 0.81:1. Precious metals at the Mt. Skukum deposit were emplaced at relatively low temperature in a near surface environment by a circulating, meteoric water dominated, hydrothermal system driven by a heat source associated with the rhyolite dykes. Gold, leached from andesitic volcanic rocks and metamorphic and granitic rocks was precipitated with quartz and carbonate in permeable conduits such as fault zones, and breccia bodies.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
19
Kinnard, Christophe. "Development of solifluction lobes, Kluane Range, Yukon Territory". Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26502.
Pełny tekst źródłaStreszczenie:
Solifluction lobe process and morphology were studied on an alpine slope (1800 m a.s.l) above Kluane Lake, south-western Yukon Territory. Contemporary rates of surface movements, measured by theodolite survey, were found to be greatest in the first two weeks of spring thaw, and movements were consistently faster on lobe treads than on lobe risers. Precise monitoring of thaw-consolidation parameters on a lobe indicated that most thaw-settlement occurred when the soil was saturated to the surface. At the slope scale, surface rates increased downslope in response to gradients in soil moisture, while long-term rates of lobe advance, inferred from 14C dating of buried organic horizons, were found to be similar among 12 dated lobes. The internal stratigraphy and age distribution of these lobes together suggest periodic advance of the fronts. Observations of lobe stratigraphy with the age distribution of buried humus points towards a conceptual model of lobe development involving the slow accumulation of soliflucted material behind a rigid riser, the progressive steepening of the riser and build-up of stress, and finally the rupture of the front and its extensive collapse on to the slope. The period for this developmental cycle was estimated to be about 600 years. This internal cycle of lobe development constitutes a serious buffer to climatic influence and must be taken into account when using solifluction lobes as paleoclimate sources.
20
Frayne, Theresa Lynn. "An examination of the Development Assessment Process, Yukon". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq24465.pdf.
Pełny tekst źródła
21
Livingstone, David Bernard Carleton University Dissertation Geography. "The northeast Yukon; development within a conservation framework". Ottawa, 1986.
Znajdź pełny tekst źródła
22
Glennie, Linda Cuffableness. "Space use in a population of least chipmunks in the Southwest Yukon". Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27929.
Pełny tekst źródłaStreszczenie:
This thesis describes an investigation of space use in least chipmunks at Kluane Lake, in the southwest Yukon. I examined demography, home range and habitat use patterns in the population. Based on live-trapping data from two grids over two summers, mean number of animals on the study area was 22.6/grid, similar to chipmunk numbers measured there over the previous four years. The population was lower than is generally found in the same species further south, although year-to-year stability was typical. Chipmunks preferred open forest and shrub-land to closed-canopy forest, which is also typical of the genus. Home range sizes measured using telemetry averaged 4.86 ha, higher than in any previously published study of the genus.
I examined the relationship between social spacing and space use. Home range overlap averaged 93.4%; chipmunks do not appear to defend exclusive core areas. Provoked interactions among neighbours suggested that social dominance was based on age, weight, and breeding condition, rather than ownership of space. Although provoked interactions were generally aggressive, the telemetry data suggest that such behaviour was artifactual. Comparing the encounter frequency of radio-collared animals to that generated by a random model showed that chipmunks avoided encounters, except when harvesting seasonally abundant food.
Grid-trapping did not increase food or cover availability enough to affect home range size. There was evidence that the presence of traps affected use distribution but not enough to invalidate trap-based home range estimates. Comparison of trap and telemetry based estimates of home range size yielded no significant differences.Science, Faculty of
Zoology, Department of
Graduate
23
Grant, Steven Lloyd. "Geochemical, radiogenic tracer isotopic, and U-Pb geochronological studies of Yukon Tanana terrane rocks from the Money klippe, southeastern Yukon, Canada". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq22600.pdf.
Pełny tekst źródła
24
Saxby, Donald William. "Sampling problems and hydraulic factors related to the dispersion of scheelite in drainage sediments, Clea property, Yukon Territory". Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24913.
Pełny tekst źródłaStreszczenie:
Multifractional analysis for scheelite (G=5.9-6.1), magnetite (G=5.2), heavies (G>3.3), mediums (3.3Earth, Ocean and Atmospheric Sciences, Department of
Graduate
25
Kuntz, Zoé. "Electrical Resistivity Tomography Investigations of Discontinuous Mountain Permafrost and its Relation to Elevation and Vegetation, Yukon". Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35577.
Pełny tekst źródłaStreszczenie:
This study seeks to better understand the relationship between permafrost, elevation and vegetation cover, and to test the hypothesis that changes in mountain permafrost distribution and characteristics occur at vegetation type boundaries, as they do in latitudinal permafrost.
Twelve electrical resistivity tomography (ERT) surveys were completed at vegetation transitions on selected slopes near Whitehorse and Dawson, Yukon, in July 2015. Wenner arrays with 2 m spacing between electrodes were used to complete the 80-280 m long surveys. Organic layer thickness and vegetative species composition were recorded in a transect for each survey. Ground-truthing via frost probing, pit digging, and ground temperature data from past and present weather stations aided in the analysis of ERT profiles.
Several different resistivity patterns are present along the profiles. These patterns indicate some presence of permafrost along most of the slopes sampled. Exceptions include south-facing slopes free of permafrost and a few slopes with inconclusive resistivity interpretations due to complex resistivity patterns and ground-truthing difficulties.
Overall, the results indicate that changes in permafrost distribution and characteristics do not consistently occur at vegetation type boundaries. At the scale examined, treeline is not as important a demarcation point for changes in permafrost as initially thought. Changes in organic mat, surficial geology, and snow cover (via micro-topography) appear to be as important as vegetation variation. These local controls play a significant role on permafrost distribution across both altitudinal and latitudinal forest-tundra ecotones. However, the propensity of alpine environments for cold air drainage and surface lapse rate inversions can create differences between the permafrost trends across altitudinal and latitudinal ecotones.
26
Moher, Meghan. "(U-Th)/He Thermochronology of the Aishihik Batholith, Central Yukon: Evidence for Stable Crust in the Cretaceous". Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37347.
Pełny tekst źródłaStreszczenie:
The 190-180 Ma Aishihik batholith is located in southcentral Yukon in the North American Cordillera. Low-temperature (U-Th)/He thermochronology is used to assess the thermal history of the batholith and the surrounding host rock to provide an understanding of the Jurassic-Cretaceous tectonism. The Yukon Tanana terrane (YTT) shows a steady cooling of ~5°C/m.y from the Early Jurassic to the Late Cretaceous, when it reaches the surface. Sections of YTT adjacent to the batholith exhibits moderate cooling rates of 7°C/m.y from the Early to Late Jurassic and then slows down to 1.5°C/m.y until reaching the surface in the Late Cretaceous. The batholith itself exhibits relatively fast cooling from the Early to Late Jurassic (15°C/m.y) and then slows down (1.5°C/m.y) until it reaches surface conditions in the Late Cretaceous. All rocks are at the surface at the latest by the Late Cretaceous with no evidence that there were any subsequent substantial thermal events, which indicates that the Yukon has a mature landscape compared to the rest of the North American Cordillera.
27
Hart, Craig J. R. "Mid-Cretaceous magmatic evolution and intrusion-related metallogeny of the Tintina Gold Province, Yukon and Alaska". University of Western Australia. Centre for Global Metallogeny, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0062.
Pełny tekst źródłaStreszczenie:
[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
28
Schmok, Jeffrey Peter. "Sedimentology and chronology of neoglacial Lake Alsek, Yukon Territory". Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26068.
Pełny tekst źródłaStreszczenie:
Neoglacial Lake Alsek has formed many times during the last 3000 years when Lowell Glacier has blocked the flow of Alsek River. Although the basin is now empty, evidence for former lakes includes: valley-side beaches, driftwood strandlines, ice-rafted erratics, vegetation discontinuities, and unusually large (outburst-flood related) bedforms. The largest fillings covered approximately 463.0 km² of the valley bottom and were approximately 28.37 km³ in volume. The associated outburst floods produce instantaneous peak discharges estimated at 1.09 x 10⁵ m³ s⁻¹.
Alsek valley sediments were examined for a record of past fillings and drainings. Physical, stratigraphic, and lithofacies analyses were conducted on sediment cores. Five facies assemblages are defined and used to interpret depositional environments: (1) matrix supported diamicton interpreted as a deposit of iceberg-rafted sediment, (2) sands interpreted as tractive current deposits, (3) massive muds interpreted as rapidly deposited lake margin derived sediment, (4) laminated muds interpreted as distal glaciolacustrine deposits, and (5) carbonaceous muds interpreted as eutrophic pond organic detritus deposits.
Facies sequence analysis indicates non-randomly ordered sedimentary sequences. Cyclic sedimentation is not indicated. Many occurrences of erosional unconformities indicate either depositional hiatuses or an unknown amount of missing sediment. A single radiocarbon date of 2840 ¹⁴C years B.P. underlies 1.04 m of Lake Alsek sediment. This dated material overlies approximately 1.5 m of sediment presumably associated with Lake Alsek. The potential for absolute dating of the Lake Alsek stratigraphy has been shown to be quite high.Arts, Faculty of
Geography, Department of
Graduate
29
Stubens, Thomas Camillo. "A geostatistical analysis of the Venus Mine, Yukon Territory". Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27997.
Pełny tekst źródłaStreszczenie:
This thesis describes a geostatistical analysis of the Venus deposit in the Yukon Territory.
The Venus Mine is located on Tagish Lake, approximately 1.5 miles north of the Yukon/B.C. border. It is a gold, silver, lead, zinc bearing quartz vein of late Cretaceous to early Tertiary age occurring in porphyritic andesite of the Mount Nansen Group volcanics.
Three companies have attempted to mine Venus since its discovery in the late 1890's. In all three cases the operating company could not profitably mine the deposit and was forced to shut down. Overestimation of the ore reserves and problems with grade control were the main problems encountered by the failed operations.
The study reported here applied a well-established geostatistical methodology to the Venus deposit. Over 3500 chip samples of the vein, collected at regular intervals along all development drifts and raises, were used in this analysis. Semi-variograms were calculated of 3 variables: vein thickness, gold accumulation and silver accumulation. After fitting semi-variogram models to the calculated curves the 3 variables were kriged and the results were plotted on maps showing the kriged estimates in each of the 2039 blocks. The maps illustrate clearly the size, location and orientation of the ore zones.
The ore reserves of the Venus mine were calculated using the kriged block estimates. The proven and probable reserves above a cut-off of $130/ton (Cdn), assuming gold and silver prices of $520/oz (Cdn) and $7.80/oz (Cdn) are 108,577 tons grading 0.3 oz Au/ton (+/- 1.18%) and 6.05 oz Ag/ton (+/- 1.29%).
Interpretation of the maps and the ore reserve estimates led the author to make several recommendations for future mining of the Venus deposit.Applied Science, Faculty of
Mining Engineering, Keevil Institute of
Graduate
30
Gray, Glenn Thomas. "International cooperation in the Alaska-British Columbia-Yukon Region". Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/28685.
Pełny tekst źródłaStreszczenie:
The primary purpose of this thesis is to investigate transboundary cooperation in the Alaska-British Columbia-Yukon Region (ABCY Region). The study focuses on political relations about environmental and natural resource issues. It is argued that there are more appropriate means for cooperative planning in the transborder region than presently employed. Current relations between the three jurisdictions will be evaluated followed by recommendations for improving them.
Government cooperation occurs through a complex network of federal, sub-national, regional and local channels. International conflicts in the region have occurred throughout recorded history but means addressing them have changed throughout time. Despite some persistent problems, Alaska-Canadian relations are for the most part amicable.
The federal governments have historically had a major presence in Alaska and the Yukon while B.C. manages most of its land. Resource economies of all three jurisdictions follow cycles of booms and busts. Subsistence hunting and fishing and government payments help soften the busts. Access, distances to markets, power shortages, and poor resource markets provide substantial economic dilemmas.
International institutions have been developed for a wide spectrum of issues yet few of them are capable of addressing the relationships between resource sectors. Three notable institutions have been used to address
multi-sector issues: the Trialteral-Heads-of-Government (THOG) meetings, legislative exchanges, and meetings between Juneau and Whitehorse. Institutions for cooperation are generally Insufficient, they are short-lived, and cooperation occurs on an ad hoc basis.
Because most of the region is undeveloped, an excellent opportunity exists to design institutions capable of anticipating and mitigating future environmental and land use problems early on. It is recommended that a proactive, integrated approach involving regional and local interests be instituted. Relations need to be structured enough to encourage regular interaction yet flexible enough to respond to change.
The relationship could be strengthened by augmenting existing institutions and creating a few new ones. It is recommended that general guidelines for cooperation be developed. Annual THOG meetings should be supplemented by meetings of a coordinating committee and sectoral subcommittees. Communication between on-the-ground managers should be encouraged. Conflict resolution procedures should also be considered to assure timely response to problems. A major recommendation of this thesis is the creation of international regional conferences. These meetings would provide a foundation for future negotiations about the major issues in each of five sub-regions along the border.Applied Science, Faculty of
Community and Regional Planning (SCARP), School of
Graduate
31
English, Elizabeth Anne. "Cultural tourism planning, a case study, Dawson City, Yukon". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0011/MQ26767.pdf.
Pełny tekst źródła
32
Esdale, Julie Anne. "Geoarchaeological studies at the Dog Creek Site, northern Yukon". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0015/MQ47025.pdf.
Pełny tekst źródła
33
Fox, David. "Observations of massive ground ice, Hershel Island, Yukon Territory". Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=106608.
Pełny tekst źródłaStreszczenie:
The rapid change in climate currently being recorded in the Western Canadian Arctic is projected to have a major influence on the permafrost ground that underlies more than half of Canada's landmass. The isolation of this vast landscape has inhibited scientific research consequently limiting the body of knowledge on sub-surface permafrost features. Specifically, there is limited information about massive ground ice units, large tabular bodies of ice with a gravimetric moisture content greater than 250% (percent dry weight). Massive ground ice bodies originate from the burial of surface ice, such as glaciers or snowbanks or from the in-situ freezing of groundwater, termed intrasedimental ice. The environmental history held within the ice provides valuable information on the progression of past climates and the high water content frozen within this ice can cause widespread changes on the topography, infrastructure and ultimately the people of this region who use the land. Located in the headwalls of retrogressive thaw slumps on Herschel Island, Yukon, natural exposures of massive ground ice provided an ideal setting for studying ice units with uncertain origins. Within this study, seventeen distinct massive ice units, observed in four different exposures, were sampled for laboratory analysis. The aim of this research is to resolve the origin of these less understood massive ice bodies with a recently developed tool that analyzes the molar ratios of atmospheric gases occluded within the ice units. This is supported with the recognized method of cryostratigraphy, O-H stable isotopes analysis and geochemical measurements. The results of these tests, presented in two manuscripts, reveal a complicated cryotic history that identifies massive ice units with atmospheric and intrasedimental characteristics. An isolated unit of white ice observed in the upper portion of a retrogressive thaw slump exhibits a strong atmospheric signature with low atmospheric gas ratios of N2/Ar and δD vs. δ18O regression line that closely parallels the local meteoric water line (LMWL). An atmospheric origin for this unit of ice is further supported by low conductivity values measured within the ice unit. These chemical investigations combined with an equally conclusive cryostratigraphic examination suggest that this massive ice unit is a recently buried snowbank. A proposed model of snowbank burial is also presented to clarify and support this conclusion. A distinctive unit of blue coloured ice exposed at an ocean bluff contained occluded gasses with molar ratios of N2/Ar and O2/Ar gas that were strongly correlated to the same gas ratios measured in the current atmosphere. A vertical transect within a large retrogressive thaw slump on the south shore of the island distinguished seven separate massive ice units in addition to an ice wedge. Two of the units measured revealed intrasedimental ice origins due to low N2/Ar atmospheric gas ratios and high conductivity values. A third isolated unit of white ice, confined by unconformities, reflected a molar gas ratio of N2/Ar that strongly correlated with the N2/Ar ratio of the current atmosphere measured during the study. An atmospheric source for this ice was further supported by a δD vs. δ18O regression line similar to that of the LMWL. These findings provide a new layer of interpretation adding to the previously established body of knowledge and produce a more decisive explanation to the origin of massive ice units on Herschel Island. This work is relevant for understanding the origin and nature of the massive ice units, the geomorphic response to past climates and providing important information for the responsible development and management of this landscape in the future both on Herschel Island Territorial Park and throughout the Western Canadian Arctic.Le changement rapide du climat actuellement observé dans l'Arctique de l'Ouest Canadien devrait avoir une influence majeure sur le pergélisol représentant plus de la moitié de la masse continentale du Canada. L'isolement de ces vastes étendues a limité les efforts de recherche scientifique à leur sujet et par conséquent le niveau de connaissances des caractéristiques du pergélisol. Plus particulièrement, peu d'information existe au sujet des unités massives de glace de sol, c'est-à-dire de grands corps tabulaire de glace avec une teneur en humidité gravimétrique supérieure à 250% (pour cent en poids sec), que l'on retrouve dans ces régions. Ces glaces de sol peuvent provenir de l'enterrement d'étendue de glace en surface, tels que des glaciers, des bancs de neige, ou encore de la congélation in situ d'eaux souterraines, autrement nommées glaces intrasedimental. La glace de sol peut fournir de précieuse information sur l'historique et l'évolution des climats passés. La haute teneur en eau congelé dans la glace peut causer d'importants changements dans la topographie, pour les infrastructures et ultimement pour les habitants de cette région qui font usage du sol.Situé dans le mur de tête de glissements de dégel rétrogressif de l'île Herschel au Yukon, des affleurements de glace souterraine fournissent un cadre idéal pour étudier des unités de glace ayant des origines incertaines. Pour la présente étude, dix-sept unités de glace massive distinctes, observée dans quatre expositions différentes, ont été échantillonnés pour l'analyse en laboratoire. Le but de cette recherche est de comprendre l'origine de ces unités de glace massive moins bien connues en faisant usage d'un outil récemment développé permettant d'analyser les rapports molaires entre differents gaz atmosphériques occlus à l'intérieur des unités de glace. Cette approche repose sur la méthode reconnue de cryostratigraphy, sur l'analyse d'isotopes stables O-H ainsi que sur des mesures géochimiques. Les résultats de ces tests, présentés en deux manuscrits, révèlent une histoire cryotique complexe identifiant des unités de glace massive avec des caractéristiques atmosphériques et intrasedimental.Une unité isolée de glace blanche ayant été observée dans la partie supérieure d'un glissements de dégel rétrogressif présente une signature atmosphérique forte avec de faibles ratios de gaz atmosphériques N2/Ar ainsi qu'une droite de régression δD vs. δ18O qui se rapproche étroitement de la ligne d'eau locales météorique. L'hypothèse d'une origine atmosphérique pour cette unité de la glace est soutenu par de faibles valeurs de conductivité mesurées à meme l'unité de la glace. Ces études chimiques combinées à un examen cryostratigraphique tout aussi concluant suggèrent que cette unité massive de glace est en fait un banc de neige récemment enterré. Un modèle d'enterrement de banc de neige est également présenté à clarifier pour appuyer cette conclusion.Une unité distincte de glace de couleur bleue exposée par un bluff océanique contient des gaz occlus avec des ratios molaires de N2/Ar et de O2/Ar fortement corrélées aux mêmes ratios mesurées dans l'atmosphère actuel. Deux des unités mesurées révélé une origines de glace intrasedimental en raison du faible taux de N2/Ar gaz atmosphériques et d'une conductivité élevée. Une troisième unité de glace blanche isolée et confinée reflète un ratio molaire des gaz N2/Ar fortement corrélée avec le ratio N2/Ar de l'atmosphère actuel. Une origine atmosphérique pour cette unité de glace est aussi soutenue par une ligne de régression δD vs. δ18O similaire à celle de l'LMWL.Ces résultats fournissent une nouvelle couche d'interprétation qui s'ajoute aux connaissances précédemment établies et fournissent une explication plus robuste quant à l'origine des unités de glace massive sur l'île Herschel.
34
Nakano, Tomoko. "Dietary intake and anthropometry of DeneMétis and Yukon children". Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80340.
Pełny tekst źródłaStreszczenie:
Anthropometcic measurements and 24h-recall interviews were conducted on Dene/Metis and Yukon children, and food choice questionnaire interviews were conducted on the mothers of the children. On average, 32% of the children were above the 85th percentile of BMI-for-age in the 2000 CDC Growth Charts. The dietary nutrient intakes were compared to the DRI values. Vitamin A, calcium, phosphorus, vitamin D, vitamin E, dietary fiber, omega-6 fatty acids, omega-3 fatty acids, and magnesium intakes were low. Excessive nutrient intake was not observed. Imbalance of energy intake from carbohydrate and fat and excessive energy intake from total sugar and saturated fat were observed. Market foods were a major part of the diet. Traditional food contributed 4.6% of total energy intake. Frequently mentioned factors as having an influence on food selection were cost, health, children's preference and acceptability, traditional food and market food availability, and women's preference.
35
Mercier, Éric. "Précambrien de Coal Creek Dome (montagnes Ogilvie, Yukon, Canada)". Lille 1, 1985. http://www.theses.fr/1985LIL10080.
Pełny tekst źródłaStreszczenie:
Le secteur cartographie à 1/50000, représente 1200 km². Une série essentiellement précambrienne de plus de 10 km d'épaisseur cumulée y affleure. Cette série a été divisée en 28 unités lithostratigraphiques regroupées en 3 groupes. Ces groupes sont séparés par des coupures majeures attribuables respectivement : à une phase compressive synschisteuse et à une phase distensive synchrone d'une importante érosion et des intrusions basiques. Cette dernière, ainsi que la tectonique syn-dépôt du groupe III seraient représentatives d'un rifting ayant engendré le Bassin de Selwyn. Un système de corrélation est présenté. Un nouveau modèle d'évolution est proposé, pour le Nord de la cordillère canadienne au précambrien.
36
Crookshanks, Sarah. "High-energy sedimentary processes in Kluane Lake, Yukon Territory". Thesis, Kingston, Ont. : [s.n.], 2008. http://hdl.handle.net/1974/1219.
Pełny tekst źródła
37
Williams, Deborah J. (Deborah Jane) Carleton University Dissertation Geography. "Predicting the location of permafrost in central Yukon Territory". Ottawa, 1995.
Znajdź pełny tekst źródła
38
Nagy, Murielle Ida. "Caribou exploitation at the Trail River site, northern Yukon". [Whitehorse] : Yukon, Heritage Branch, 1990. http://catalog.hathitrust.org/api/volumes/oclc/22388292.html.
Pełny tekst źródła
39
Chanteloup, Francoise (Francoise Noelle) Carleton University Dissertation Sociology and Anthropology. ""Modelling drinking behaviour among aboriginal and non-aboriginal males and females in the Yukon; an analysis of the Yukon alcohol and drug survey."". Ottawa, 1994.
Znajdź pełny tekst źródła
40
Nelson, Faye Elizabeth, i University of Lethbridge Faculty of Arts and Science. "Late cenozoic magnetostratigraphy of Selkirk volcanics and associated sediments, west-central Yukon". Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2006, 2006. http://hdl.handle.net/10133/357.
Pełny tekst źródłaStreszczenie:
Brunhes, Matuyama, Kaena and Mammoth age basaltic lava (Selkirk Volcanics - TQS) as
well as interbedded sediments were sampled in west-central Yukon Territory, Canada.
Paleomagnetic sampling of basalt mapped as TQS along a 370 kilometre transect
suggests that early eruptions of TQS occurred coevally over a significant distance to the
north of Fort Selkirk. Basal basalt at Ne Ch'e Ddhawa pre-dates continental glaciation in
Yukon and is older than the Fort Selkirk Vent (Lower Mushroom), previously thought to
be the oldest eruptive vent at Fort Selkirk. The high confining pressures required to form
pillow lava suggest subglacial eruptions at Mushroom section. An Early Pleistocene Fort
Selkirk glaciation sequence (till and outwash) was reversely magnetized and assigned to
the Late Matuyama chron between oxygen isotope stages 62 and 56 inclusive. A lateral
moraine on Ne Ch'e Ddhawa was reversely magnetized and therefore assigned to one of
the younger Pre-Reid glaciations.
ixi, 123 leaves : ill. (some col.) ; 29 cm.
41
Darling, Samantha. "Velocity Variations of the Kaskawulsh Glacier, Yukon Territory, 2009-2011". Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23511.
Pełny tekst źródłaStreszczenie:
Laser altimetry and satellite gravity surveys indicate that the St Elias Icefields are currently losing mass and are among the largest non-polar sea level contributors in the world. However, a poor understanding of glacier dynamics in the region is a major hurdle in evaluating regional variations in ice motion and the relationship between changing surface conditions and ice flux. This study combines in-situ dGPS measurements and advanced Radarsat-2 (RS-2) processing techniques to determine daily and seasonal ice velocities for the Kaskawulsh Glacier from summer 2009 to summer 2011. Three permanent dGPS stations were installed along the centreline of the glacier in 2009, with an additional permanent station on the South Arm in 2010. The Precise Point Positioning (PPP) method is used to process the dGPS data using high accuracy orbital reconstruction. RS-2 imagery was acquired on a 24-day cycle from January to March 2010, and from October to March 2010-2011 in a combination of ultra-fine and fine beam modes.
Seasonal velocity regimes are readily identifiable in the dGPS results, with distinct variations in both horizontal velocity and vertical motion. The Spring Regime consists of an annual peak in horizontal velocity that corresponds closely with the onset of the melt season and progresses up-glacier, following the onset of melt at each station. The Summer Regime sees variable horizontal velocity and vertical uplift, superimposed on a long-term decline in motion. The Fall Regime sees a gradual slowing at all stations with little variation in horizontal velocity or vertical position. Rapid but short accelerations lasting up to 10 days were seen in the Winter regimes in both 2010 and 2011, occurring at various times throughout each regime. These events initiated at the Upper Station and progress down-glacier at propagation speeds up to 16,380 m day-1 and were accompanied by vertical uplift lasting for similar periods. Three velocity maps, one from the winter of 2010 and two from the fall/winter of 2011, produced from speckle tracking were validated by comparison with dGPS velocity, surface flow direction, and bedrock areas of zero motion, with an average velocity error of 2.0% and average difference in orientation of 4.3º.
42
Plouffe, Alain 1963 Carleton University Dissertation Geology. "Drift prospecting and till geochemistry in Tintina Trench, southeastern Yukon". Ottawa.:, 1989.
Znajdź pełny tekst źródła
43
Sproule, Brenda (Brenda Jean) Carleton University Dissertation Geography. "Topoclimate and agriculture in Takhini River Valley, Southern Yukon Territory". Ottawa, 1996.
Znajdź pełny tekst źródła
44
Turner, Jennifer 1979. "Investigating the effects of climate change and sea level rise on the coastal processes of the Beaufort Sea, Yukon Territory". Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81448.
Pełny tekst źródłaStreszczenie:
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.
45
Batal, Malek. "Sociocultural determinants of traditional food intake across indigenous communities in the Yukon and Denendeh". Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38184.
Pełny tekst źródłaStreszczenie:
Chronic non-communicable diseases related to excessive or unbalanced dietary intakes are on the rise among some Indigenous populations in Canada. Nutritional problems of Indigenous peoples arise in the transition from a traditional diet to a market diet characterised by highly processed foods with reduced nutrient density. This study used food frequency and 24-hour recall questionnaires to quantify traditional food intake in 18 communities in Denendeh (Western Northwest Territories) and the Yukon. These data allowed comparisons between the two regions (Yukon and Denendeh) and the two seasons of data collection (summer and winter, perceived to be the seasons of highest and lowest traditional food intake, respectively). Food choice in general is affected by a multitude of factors determined by individual, societal and environmental influences. In this study, individual, household, and community correlates of traditional food intake were assessed in order to construct a multivariate statistical model to describe the correlates of the quantity and diversity of traditional food intake in the Western Canadian Arctic. The variables used in this study reflected household demography, market food affordability, access to traditional food, individual characteristics such as age and gender, and perceptions about traditional food. The analysis of the associations between the traditional food correlates and traditional food intake in terms of quantity and diversity allowed for the description of the profile of men and women who are high consumers of traditional food in both regions. This study described and used a tool to measure traditional food diversity, which may be an appropriate indicator of the process of dietary change experienced by Indigenous Peoples in Denendeh and the Yukon.
46
De, Pascale Gregory P. "Massive ice in coarse-grained sediments, Western Canadian Arctic". Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82217.
Pełny tekst źródłaStreszczenie:
Destruction of ecosystems and infrastructure can be caused by melting of massive ice within permafrost. To predict potential melting caused by natural and human disturbance, we need to know the nature and origin of massive ice deposits. The purpose of this research was to evaluate the nature of massive ice in coarse-grained sediments that accepted theories suggest should not occur.Degradation of ice-rich granular resources is expensive and difficult to rehabilitate and can cause developmental thermokarst, overestimation of granular resources, disturbance of wildlife habitat and create conflicts with traditional land uses.
To locate massive ice we used a resistivity geophysical technique and to characterize the ice we used geochemical, petrographic and stratigraphic techniques. The resistivity technique detected bodies of massive ice and ice-rich sediments and coarse-grained sediments at high resolutions and laboratory analysis reveal that the ice was of glacial origin.
These findings indicate that massive ice of glacial origin occurs in coarse-grained sediments in permafrost. The techniques used in this study could form the basis of a predictive model of massive ice occurrence.
47
Folkard, Nicholas Francis Goring. "An experimental study of the plant-arthropod-bird food chain in the southwestern Yukon". Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/28985.
Pełny tekst źródłaStreszczenie:
I describe an experimental study of the importance of food limitation and predation at three trophic levels in a terrestrial food web. The study system was the herb layer vegetation - arthropod - insectivorous bird food chain in the boreal forest near Kluane Lake, southwestern Yukon. Since little is known about boreal bird communities, I conducted a descriptive study of the community of passerine and piciform birds at Kluane in addition to the main study. Variable circular plot point counts were used to estimate bird populations in 1987 through 1990. Species' habitat preferences, use of foraging substrates and diets were studied in 1988 and 1989. Population densities, species richness and evenness were all low. Yellow-rumped warblers (Dendroica coronata) and dark-eyed juncos (Junco hyemalis) dominated the community. Common species differed markedly in their habitat preferences, and showed generally low overlaps in their use of foraging substrates. There was little evidence of dietary specialization. There was rather little spatial variation in the community, and species composition and total density remained approximately the same through time. However, there were large fluctuations in some species' populations between 1987 and 1989.
The experimental study was conducted at two scales. Chemical fertilizer was applied to two 570m x 570m areas in 1987, 1988 and 1989. I compared arthropod populations, bird populations and bird reproductive performance in these areas with those in two control areas. Two experiments using 5m x 5m plots were performed in 1988 to examine the effects of fertilization on plants and arthropods in more detail, and to study the responses of these trophic levels to the exclusion of passerine birds and mammalian herbivores. All three trophic levels responded positively to
fertilization, but the results were variable and there were no very large increases in biomass or population size. Dark-eyed juncos nested one week earlier in fertilized areas, which may have enhanced their reproductive success. Passerine exclusion did not increase arthropod biomass, but exclusion of mammalian herbivores increased plant biomass. "Bottom-up" limitation by food appears to dominate this system, but "top-down" limitation also operates at at least one level. More work is needed to fully understand how the system functions.Science, Faculty of
Zoology, Department of
Graduate
48
Schwartzburg, Richard E. C. "Physical limnology of a small sub-arctic alpine lake, Yukon Territory". Thesis, University of Ottawa (Canada), 1986. http://hdl.handle.net/10393/5493.
Pełny tekst źródła
49
Lovatt, Angeline. "Characteristics of low-level temperature inversions, Whitehorse Yukon Territory: 1956--2003". Thesis, University of Ottawa (Canada), 2009. http://hdl.handle.net/10393/28207.
Pełny tekst źródłaStreszczenie:
Near-surface air temperature inversions are a common element of northern environments. Seasonal and inter-annual variations of low-level inversion characteristics were examined using 47 years of twice-daily radiosonde data from Whitehorse airport (1956-2003). Nocturnal low-level inversion events occurred throughout the year in 68% of the 0400h PST radiosonde ascents. Afternoon (1600h PST) inversion events, in contrast, were primarily a winter phenomena, limited to 24% of the readings between October and March, and were deepest and strongest during the winter months. Shorter, weaker, lower magnitude inversions appeared progressively more frequently during the 1974-2003 warming at Whitehorse. The impact (1956-2003) of regular low-level inversions on near surface temperatures in the Yukon River Valley is estimated to be an average annual reduction of -3.4°C. That is to say, in the absence of surface-based temperature inversion effects, the mean annual near-surface-temperature for Whitehorse (-0.7°C) would exceed 1°C, a temperature threshold at which permafrost could not be maintained. Overall inversion impact declined by about 1.5°C between 1956-1973 and 1974-2003.
50
Kremer, Marian. "Incorporation of Vegetation into Mountain Permafrost Distribution Models, Southern Yukon Territory". Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28597.
Pełny tekst źródłaStreszczenie:
Three groups of variables (Digital Elevation Model [DEM]-derived variables, fieldwork-derived vegetation variables, and satellite imagery-derived vegetation variables) were combined in Classification and Regression Tree (CART) models to determine the utility of vegetation-based variables for mountain permafrost distribution modelling in the southern half of the Yukon Territory. Four variables were measured in the field: canopy openness, vegetation height, organic mat thickness, and dominant species. Using Landsat TM and ETM+ imagery, three variables were calculated: a Normalized Difference Vegetation Index (NDVI), a vegetation classification, and a canopy closure classification. Individual variables were also examined to determine the one most useful for representing vegetation when modelling permafrost presence or absence. Additionally, models for each of five study areas spread across 5° of latitude were compared to examine the transferability of each variable.
The addition of vegetation variables to the CART models created with DEM-derived variables resulted in only a minimal increase in the overall accuracy. Dominant species proved to be the most useful variable, but the relationship between permafrost and each species differed among study areas. Only black spruce (Picea mariana) was consistently classified as permafrost probable and lodgepole pine (Pinus contorta var. latifolia) and trembling aspen (Populus tremuloides) were classified as permafrost improbable over all study areas. These results indicate that models of permafrost distribution across large areas are not likely to be enriched sufficiently by the inclusion of vegetation variables while models covering smaller areas may benefit from the inclusion of vegetation variables. The CART models tended to show a high accuracy in the prediction of areas with no permafrost which could be useful for the purposes of infrastructure development. CART models have not previously been used in permafrost modelling and the high accuracies they produced may indicate their utility for modelling the complex relationships among the variables affecting permafrost.