For many women, body weight is a health concern both in relation to physical health and to social and psychological health. Both overweight and underweight are associated with increased risks to health. Furthermore, the literature largely supports the view that sociological and psychological factors influence a woman's perception of weight and body image. In the Western world, weight loss efforts among women are high, and even those who are within or below the healthy weight range are trying to lose weight. Relatively little is known about weight loss efforts among Yukon women.. Moreover, it is not known whether societal pressures surrounding weight are similar in the Yukon and the rest of Canada. For reasons related mainly to its northern geographical location and culture, and because of the health implications related to women's weight issues, this study was conducted to determine the prevalence of Yukon women trying to lose weight; to determine the weight loss practices of Yukon women; and to compare the characteristics of women who are trying to lose weight vs. those who are not; women who are satisfied with their weight vs. those who are not; and women who are at health risk due to overweight or underweight vs. those with healthy weights. Data for a representative sample of non-pregnant, non-institutionalized women > 15 years of age (n=711) were obtained from the population-based 1993 Yukon Health Promotion Survey. Those living in the census unorganized portions of the Yukon were not included in the sample. The prevalence of weight loss efforts in the Yukon (51.8%) was higher than the published value for women in the rest of Canada (39%). Among Yukon women with body mass index (BMI) values classified as overweight, possible overweight, healthy weight, and underweight, 80%, 67%, 46%, and 9%, respectively, were trying to lose weight. The corresponding values for the rest of Canada are lower. The most frequent weight loss practices were dieting (35.8%), changing diet and exercise (26.1%), and sensible eating (17.2%). Compared to women not trying to lose weight, women trying to lose weight were younger (35.8 ± 13.2 vs 38.6 ± 15.0 yr, P<0.01), were more likely to be employed (71.6% vs 64%, P<0.05), had higher BMI values (25.7 ± 4.1 vs 22.3 ± 3.9 kg/m2, P<0.0001), and were more likely to be dissatisfied with their current weight (88.5% vs 35.6%, P<0.0001). Both groups reported similar food consumption and activity patterns, yet women trying to lose weight had more positive nutrition behaviours and health knowledge. The mean eating knowledge index (EKI) score was significantly higher (2.36 ± 2.89) for women trying to lose weight than for women not trying to lose weight (1.75 ± 3.44). Similarly, the mean eating behaviour index (EBI) score was higher (4.19 ± 3.83 vs. 3.46 ± 4.94, respectively). Weight loss efforts did not appear to be related to the Yukon environment since neither First Nations status nor length of residence in the Yukon varied for women trying to lose weight and women not trying to lose weight. Yukon women who were overweight were less likely to live in Whitehorse, were older, were more likely to be poor, and were less likely to engage in vigorous physical activity three or more times per week compared to those with healthy weights; however, their food consumption patterns and nutrition knowledge and behaviour scores did not differ. Overweight women expressed less satisfaction with their quality of life and with their physical health and social relationships. Yukon women who were underweight were more likely to be poor and to find it difficult to afford the basic necessities and less likely to indicate they were eating well enough to maintain good health compared to healthy weight women. Both groups had similar activity patterns and food consumption patterns; yet, underweight women had lower scores for nutrition knowledge and behaviour (EKI: 1.03 ± 2.97 vs. 2.38 ± 3.24; EBI: 2.68 ± 4.71 vs. 4.07 i 4.51). Underweight women and healthy weight women rated their quality of life similarly. Based on this study, it appears that many Yukon women, regardless of weight status, are engaging in weight loss efforts. Furthermore, the goal of losing weight, rather than relative weight status, seems to be an important motive for healthy eating and for seeking health knowledge. Being physically active in the Yukon appears to be influenced by time of year and other barriers. Self-ratings of health were associated with engaging in weight loss efforts and with relative weight status. Overall, the findings of this study suggest that weight loss efforts of Yukon women are similar to those of the dominant Western society. In view of the findings of this study, health promotion messages should incorporate healthy eating, regular physical activity, and the concept of healthy weight and positive body image to deter weight loss efforts among women who do not need to lose weight. Tailored approaches which consider the different characteristics of the groups in this study may prove to be useful.

For many women, body weight is a health concern both in relation to physical health and to social and psychological health. Both overweight and underweight are associated with increased risks to health. Furthermore, the literature largely supports the view that sociological and psychological factors influence a woman's perception of weight and body image. In the Western world, weight loss efforts among women are high, and even those who are within or below the healthy weight range are trying to lose weight. Relatively little is known about weight loss efforts among Yukon women.. Moreover, it is not known whether societal pressures surrounding weight are similar in the Yukon and the rest of Canada. For reasons related mainly to its northern geographical location and culture, and because of the health implications related to women's weight issues, this study was conducted to determine the prevalence of Yukon women trying to lose weight; to determine the weight loss practices of Yukon women; and to compare the characteristics of women who are trying to lose weight vs. those who are not; women who are satisfied with their weight vs. those who are not; and women who are at health risk due to overweight or underweight vs. those with healthy weights. Data for a representative sample of non-pregnant, non-institutionalized women > 15 years of age (n=711) were obtained from the population-based 1993 Yukon Health Promotion Survey. Those living in the census unorganized portions of the Yukon were not included in the sample. The prevalence of weight loss efforts in the Yukon (51.8%) was higher than the published value for women in the rest of Canada (39%). Among Yukon women with body mass index (BMI) values classified as overweight, possible overweight, healthy weight, and underweight, 80%, 67%, 46%, and 9%, respectively, were trying to lose weight. The corresponding values for the rest of Canada are lower. The most frequent weight loss practices were dieting (35.8%), changing diet and exercise (26.1%), and sensible eating (17.2%). Compared to women not trying to lose weight, women trying to lose weight were younger (35.8 ± 13.2 vs 38.6 ± 15.0 yr, P<0.01), were more likely to be employed (71.6% vs 64%, P<0.05), had higher BMI values (25.7 ± 4.1 vs 22.3 ± 3.9 kg/m2, P<0.0001), and were more likely to be dissatisfied with their current weight (88.5% vs 35.6%, P<0.0001). Both groups reported similar food consumption and activity patterns, yet women trying to lose weight had more positive nutrition behaviours and health knowledge. The mean eating knowledge index (EKI) score was significantly higher (2.36 ± 2.89) for women trying to lose weight than for women not trying to lose weight (1.75 ± 3.44). Similarly, the mean eating behaviour index (EBI) score was higher (4.19 ± 3.83 vs. 3.46 ± 4.94, respectively). Weight loss efforts did not appear to be related to the Yukon environment since neither First Nations status nor length of residence in the Yukon varied for women trying to lose weight and women not trying to lose weight. Yukon women who were overweight were less likely to live in Whitehorse, were older, were more likely to be poor, and were less likely to engage in vigorous physical activity three or more times per week compared to those with healthy weights; however, their food consumption patterns and nutrition knowledge and behaviour scores did not differ. Overweight women expressed less satisfaction with their quality of life and with their physical health and social relationships. Yukon women who were underweight were more likely to be poor and to find it difficult to afford the basic necessities and less likely to indicate they were eating well enough to maintain good health compared to healthy weight women. Both groups had similar activity patterns and food consumption patterns; yet, underweight women had lower scores for nutrition knowledge and behaviour (EKI: 1.03 ± 2.97 vs. 2.38 ± 3.24; EBI: 2.68 ± 4.71 vs. 4.07 i 4.51). Underweight women and healthy weight women rated their quality of life similarly. Based on this study, it appears that many Yukon women, regardless of weight status, are engaging in weight loss efforts. Furthermore, the goal of losing weight, rather than relative weight status, seems to be an important motive for healthy eating and for seeking health knowledge. Being physically active in the Yukon appears to be influenced by time of year and other barriers. Self-ratings of health were associated with engaging in weight loss efforts and with relative weight status. Overall, the findings of this study suggest that weight loss efforts of Yukon women are similar to those of the dominant Western society. In view of the findings of this study, health promotion messages should incorporate healthy eating, regular physical activity, and the concept of healthy weight and positive body image to deter weight loss efforts among women who do not need to lose weight. Tailored approaches which consider the different characteristics of the groups in this study may prove to be useful. / Land and Food Systems, Faculty of / Graduate

The Brown McDade Mine is a recent gold-silver discovery in the Yukon Territory, halfway between Whitehorse and Dawson. It lies in the area unglaciated during the Pleistocene Period. Diamond drilling and stripping in 1946 indicated commercial values across a width of 10 feet and over a length of 1000 ft. The geologic structure is that of a Late Tertiary, dyke-like body of quartz feldspar porphyry cutting quartz diorite of Jurassic or later age. This body has a Northwest strike and dips steeply west. The ore zone lies in the porphyry and is believed genetically related to it. The mineralization consists of a cherry-like fine grained blue quartz, with disseminated sulphides comprising less than 5% of the mass. Metallic minerals are pyrite, arsenopyrite, and sphalerite, with lesser amounts of galena, chalcopyrite, tetrahedrite, stibnite, bournonite, jamesonite and gold. The gold is associated with the pyrite in fine particles, the majority less than 150 microns in size. The gold-silver ratio is about one to ten. Sericitization and carbonatization are the chief forms of hydrothermal alteration, while considerable limonite, and around the ore zone, jarosite, have been produced by weathering. On the basis of comparisons with known deposits, the Brown McDade is considered to belong to the deeper epithermal type. It should continue to reasonable depths although the ore shoots are likely to be erratic. The area south of the main ore zone, underlain by schistose rocks will probably be unfavorable for the occurrence of ore. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

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

Clinton Creek asbestos deposit is situated at 77 kilometres northwest of Dawson City on Clinton Creek in Yukon Territory. Yukon Metamorphic Complex of Ordovician to Devonian age (470 Ma, Rb-Sr date) covers most of the Clinton Creek area. The most prominent metamorphism of the area occurred in Permian time (245 to 278 Ma, K-Ar dates). Based on intensity and style of deformation of ultramafic bodies and country rocks it is suggested that the ultramafic rocks were emplaced probably during the Permian period. Tintina fault is a weak zone along which the alpine ultramafic bodies of Clinton Creek and probably some of the others along and close to the Tintina Trench were tectonically emplaced. These were later folded and metamorphosed with the country rocks. During latest Cretaceous-earliest Tertiary time (64.9 Ma, K-Ar date) the area was intruded by acid intrusive rocks. The youngest undeformed and fresh basalt is probably of Selkirk volcanics equivalent. Three prominent phases of deformation were delineated. Probably the oldest and most complex phase occurred during the Permian, along with the initial movement of the Tintina fault. Small, tight, isoclinal folds are characteristics of this phase. The structural trend (300* to 315') is roughly parallel to the direction of the Tintina Trench. Due to later deformations changes in direction of fold axes of this phase (190* to 350") is common. The second phase of deformation gave rise to large recumbent folds with trends varying from 270" to 290' with southerly vergence. Third phase of deformation gave rise to antiform structure of regional scale. The Porcupine and Snow Shoe ultramafic bodies are mined for chrysotiile asbestos. A few other ultramafic bodies contain appreciable amount of chrysotile-fibre but not of adequate quantity to be mined. Most of the ultramafic bodies are sheared or massive, and are devoid of known chrysotile-fibre. In general, if serpentinization is less than 75 percent there is no chance of commercial mineralization. Fairly intense fractures are essential to provider adequate openings for chrysotile-fibre formation in ore grade concentrations. Chrysotile-fibre bearing serpentinized ultramafic masses within argillite unit or at the contact of argillite and other units seem to carry ore grade or substantial amount of chrysotile-fibre. Evidence of Clinton Creek asbestos deposit mainly supports formation of chrysotile-fibre as fracture filling. Although evidence of fracture filling rather than replacement seems convincing and exists on a wide scale, a few evidence indicates replacement characteristics on minor scale. The main phase of mineralization is believed to occur at the end of Cretaceous when acid intrusive rocks intruded the vicinity of the Clinton Creek area. These intrusions could have provided warm aqueous solution to react with the existing serpentine along fractures. This resulted deposition of chrysotile-fibre in an essentially closed system. Analysis of isotopic dates of the Yukon Crystalline Plateau shows a distinct grouping of igneous activity at mid Cretaceous and latest Cretaceous time. Some isotopic dates of igneous and metamorphic rocks ranging from 135 to 230 Ma show a distinct younging trend away from the Tintina Trench. The trend suggests that the date at the Tintina Trench is about 200 Ma, and 2'50 kilometres perpendicular distance from the trench is 150 Ma. The apparent horizontal rate of isotherm migration is about 0.5 cm/yr. However, more data is required to confirm the speculation that the Tintina Trench represents an extinct geosuture and vanished ocean. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The map area is a four miles by ten miles strip that extends westward from the summit of Potato Hills. The centre of the map area lies about thirty miles north of Mayo, Y.T. Exposure is poor in many parts of the area, because of the thick Pleistocene cover. The rocks in the area are quartzites of the precambrian Yukon Group. Quartzite is generally micaceous and contains interbedded phyllite. Regional metamorphism (greenschist facies) has affected these rocks. An early bedding plane foliation has been modified by two distinct phases of folding. A granodiorite stock with related sills of similar composition has intruded the metamorphic assemblage and a five hundred feet wide thermal metamorphic aureole that contains corundum has been developed in the metasedimentary rocks around the stock. East trending and later north trending faults have disrupted the rocks. Mineralization in the area is of various types. Silver-lead-antimony veins occur in the west. A preliminary study of their mineralogy shows them to contain jamesonite, galena, sphalerite, chalcopyrite, pyrite, arsenopyrite, tetrahedrite and boulangerite in a gangue of siderite and dolomite. Secondary minerals include bindheimite or stetefeldite, anglesite, goethite, scorodite, covellite and chalcosite. Two stages of Pleistocene ice advance have modified the topography. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The Mount Brenner stock has intruded folded sedimentary and meta sedimentary rock that lie 40 miles northeast of Dawson City, Yukon Territory. The stock consists of four major concentric zones: (l) an outer zone of fine to medium-grained augite-biotite monzonite; (2) a zone of very coarse-grained monzonite porphyry; (3) an intermediate zone of porphyritic horn blende monzonite; and (4) a central zone of coarse-grained pink quartz monzonite porphyry. Except for the outer zone, all rock types are porphyritic and the alignment of feldspar phenocrysts gives the rocks a primary flow structure which conforms to steeply outward dipping gradational internal contacts. All external contacts are sharp. The regional structural trend is modified in the vicinity of the stock so that beds are generally conformable with the intrusive contact. From structural evidence, it is concluded that at the present level of erosion, the stock was emplaced by forceful injection. The different rock zones of the stock can be accounted for by differentiation of an augite-biotite monzonite magma by a combination of crystal fractionation , volatile and alkali diffusion, and multiple intrusion. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

During the summer of 1969 a thermal drilling and deep ice-temperature measurement program was carried out on the Fox Glacier, Yukon Territory. The thermal drilling resulted in seven instrumented holes at six locations on the glacier, three reaching bedrock. Temperature measurements indicated that the glacier was below the pressure-melting point throughout and that memory of a disturbed thermal regime existed. Estimates of geothermal heat flow were determined and an anomalous value of 4.73 μcal/cm² sec obtained. Bottom temperature models were developed which indicate the possibility of basal melting. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

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

The Macmillan Pass area is underlain by Hadrynian to Middle Devonian fine grained sedimentary strata and volcanic rocks of Selwyn Basin. Widespread occurrences of Upper Devonian debris flows and turbidites record uplift and erosion of older rocks to the west or northwest. Deposition of overlying, locally derived coarse clastic assemblages are related to subsequent formation of a graben-like, fault-bounded trough in the study area. Continued slow subsidence of the down dropped basin is reflected by anomalously large thicknesses of an overlying siliceous black shale unit. Upper Devonian strata are unconformably overlain by Mississippian(?) peri-tidal or shallow water clastic sedimentary rocks which record a gradual, northward sea level transgression. Paleozoic and older rocks are intruded by Cretaceous granitic bodies. Stratiform barite-lead-zinc mineralization on the Tom claims is contained in two tabular zones separated by a fault. Both zones occur at the transition between Upper Devonian locally derived coarse clastic rocks and overlying basinal shales. The two mineralized bodies together contain nine million tons of ore grade material averaging 8.6% Pb, 8.4% Zn and 2.8 oz/ton Ag, based on initial development work. The Tom West Zone, studied in detail, consists of seven stratiform mineral horizons, each with distinctly different characteristics. Ore textures vary from massive quantities of poorly bedded galena, sphalerite and pyrite to finely laminated barite and cherty argil lite with disseminated sulphide minerals. A mineralized and altered breccia body underlies the stratiform massive sulphide mineralization. Time-stratigraphic reconstructions of a cross-section through the Tom West Zone, with accompanying mineralogical and assay data, predicate a multi-stage genetic model. Each mineralizing event is time related to localized tectonic activity which resulted in the formation of depressions on the seafloor. Ore forming constituents were carried by geothermal fluids, ascending along cross-stratal permeability provided by deep-seated faults and venting to the seafloor through the breccia body. Exhalative fluids were initially relatively high temperature, cooling gradually through the life of the geothermal system. Observed metal and mineralogical zonation within the stratiform mineralization reflects these processes. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Unknown