During the summer of 1968 a gravity survey was conducted over the Fox* Glacier, Yukon Territory, for the purpose of finding ice depths. Choice of the Fox Glacier was as a result of its predicted surge, and the survey was part of a long-term analysis of the physical condition of the glacier. Although seismic sounding was attempted, the thinness of the glacier prevented successful results. Analysis of the gravity measurements indicated 88m as the maximum depth; comparison with depths from three drilled holes showed that the gravity results were not seriously in error. A small near-surface temperature program was completed and the results identify the Fox as a sub-polar glacier. *This is not an officially accepted name. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

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

Casino porphyry copper-molybdenum deposit ia in the Dawson Range, midway between Dawson City and Whitehorse, Y.T. Mid-Cretaceous granitic rocks of the Klotassin batholith form the backbone of the Dawson Range and have intruded the Yukon Hetamorphic Complex of Paleozoic or earlier age. A 70 m.y. old volcanic unit, the Casino complex, intruded the Klotassin batholith, and is cogenetic with Casino deposit. Hear the deposit extrusive volcanic rocks are unknown but formation of a subvolcanic plug of feldspar porphyry was followed by an explosive event that formed a steeply plunging, conical breccia pipe. This permeable pipe, about 2,000 ft. (670m.) by 1,200 ft. (400m.) at the surface localized hydrothermal fluids that formed large concentrically zoned alteration patterns during upward and outward percolation. A potassic alteration facies core, about 1,500 ft. (500m.) in diameter, is centered approximately on the breccia pipe, and is characterized by secondary magnetite, biotite and potassium feldspar. This core is surrounded by phyllic (quartz, sericite, sulphide) alteration that extends about 1,000 ft. (330m.) into adjacent rocks of the Klotassin batholith. Chalcopyrite and molybdenite are concentrated in the phyllic zone along the potassic alteration side of a pyrite halo. Peripheral, weakly developed zones of argillic (clay-carbonate minerals) and propylitic (chlorite) alterations are present. This characteristic location of economically significant minerals within a zonal distribution of alteration minerals provides an important exploration guide for porphyry-type deposits in the area. Breccia formation and hydrotherrnal zoning appear interrelated and probably result from escape of metal-bearing saline solutions from "wet" magmas derived from an underlying Benioff zone associated with subduction of an oceanic plate. Supergene enrichment, preserved because the area is unglaciated, probably occurred mainly in the Paleogene and resulted in an increase in the grade of copper by an average factor of 1.7 through precipitation of chalcocite in a subhorizontal enriched zone. Copper added to this zone was extracted from up to 500 ft. (l70a.) of overlying capping rock. Controls for enrichment processes include grade of original hypogene copper, favourable breccia occurrence and alteration, and presence of pyrite. A plate-tectonic model relates the genesis of Upper Cretaceous to Tertiary porphyry-type deposits to the evolution of the western and central Canadian Cordillera. Existence of two Benioff zones is assumed from definition of two distinct younging trends of intrusive centres. The first Benioff zone, initiated west of the Queen Charlotte Islands near the Middle Triassic, continued activity until the early Tertiary when 50 m.y. old granitic rocks and associated porphyry deposits near the eastern boundary of the Coast Crystalline Belt were formed. The second Benioff zone, initiated near the earliest-Cretaceous, extended under the western margin of the North America plate and produced stocks and associated porphyry deposits that become younger from west to east across the Intennontane Belt. Intrusive activity associated with both Benioff zones ceased at about the same time, 50 m.y. ago, implying that they became imbricated. As a result, the North America plate overrode the Insular plate. Doubling of these plates is reflected in the late Mesozoic and Tertiary uplift and erosion of the Coast Crystalline Belt. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

No description available.

This thesis concerns the process and outcomes of my research involving a group of Southern Yukon beadwork objects, a project carried out on behalf of the MacBride Museum in Whitehorse, Yukon, in 1993. I studied the objects themselves, researched museum documentation of them, and subsequently interviewed several women elders/beadworkers. In the thesis I examine several ways of studying and researching material culture and provide an analysis of these methods. Looking at objects in different ways tells us something about the nature of them but raises new questions which I address here. Reviewing museum collections records tells us more about the institution and the institutional lives of the objects than about their original context and meaning. Asking elders about the objects inspires them to speak about many seemingly unconnected topics: history, personal and mythical stories, and long ago life and times. An underlying theme which emerged in interviews with elders was their commentary on cultural and societal change within the First Nations community and how this has affected the process of learning for younger generations. I argue that beadwork objects can be best understood as learning and teaching tools for First Nations people of every generation, that their creation and essence are linked to every aspect of the culture, and their reclamation cannot properly happen without observance of all of these connections.

This thesis concerns the process and outcomes of my research involving a group of Southern Yukon beadwork objects, a project carried out on behalf of the MacBride Museum in Whitehorse, Yukon, in 1993. I studied the objects themselves, researched museum documentation of them, and subsequently interviewed several women elders/beadworkers. In the thesis I examine several ways of studying and researching material culture and provide an analysis of these methods. Looking at objects in different ways tells us something about the nature of them but raises new questions which I address here. Reviewing museum collections records tells us more about the institution and the institutional lives of the objects than about their original context and meaning. Asking elders about the objects inspires them to speak about many seemingly unconnected topics: history, personal and mythical stories, and long ago life and times. An underlying theme which emerged in interviews with elders was their commentary on cultural and societal change within the First Nations community and how this has affected the process of learning for younger generations. I argue that beadwork objects can be best understood as learning and teaching tools for First Nations people of every generation, that their creation and essence are linked to every aspect of the culture, and their reclamation cannot properly happen without observance of all of these connections. / Arts, Faculty of / Anthropology, Department of / Graduate

A study of rare barium minerals from the Yukon Territory has resulted in the discovery of at least one and possibly five new species. The present investigation is concerned with one of these, a barium-calcium-iron-alumino-silicate, which is tentatively classed as an inosilicate and named keeleite. The optical and physical properties, a chemical analysis, and the calculation of its formula are presented. The mineral has also been successfully synthesized. An X-ray study of some supergene and alteration products present in the rocks revealed the presence of an interesting mixture of barium-calcium carbonate salts, similar to those obtained as laboratory products. A paragenesis Is also presented. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Cambrian (?) schists and phyllites of the Anvil Range, Yukon Territory, host three large stratabound lead-zinc deposits: Faro, Vangorda, and Swim. Because geological exploration is limited by a thick cover of glacial overburden, geochemical techniques were tested in the area. These include bedrock sampling for primary halos and geochemical marker horizons, and glacial overburden sampling for secondary dispersion patterns. Multi-element geochemistry of bedrock indicates that the schists and phyllites are not distinctive in one or any combination of the trace elements analyzed. However, some younger rocks are enhanced in various elements: amphibolite in Ni, Cr, Co, and Cu; rhyolite in Pb and Sn; and granite in Sn. Despite presence of glacial overburden, the trace element content of bedrock is reflected in soils. Soils overlying magnetic greenstones are enriched in Ni and Cu, whereas soils overlying granite are slightly enriched in Sn content. Detailed bedrock, overburden and soil sampling.at the Faro deposit reveals that primary Pb, Zn, Mo, and Ba halos exist about the ore zone. Mo parallels the visible alteration envelope, but Pb and Zn extend 100 feet into the hanging wall and 300 feet into the footwall. Ba extends 75 feet into the hanging wall but is not detected in the footwall. Secondary dispersion patterns are primarily related to the proximity of the Faro ore zone and type of parent material sampled. Till deposits have higher background and threshold values for Cu, Pb, and Zn than those of glaciofluvial deposits. Bath Pb and Zn distributions in overburden delineate the Faro #2 ore body; Zn extends to surface whereas Pb, in some cases, does not. This is a reflection of the type of overburden sampled. In general, Zn is the more consistent indicator of ore. The Zn anomaly is primarily hydromorphic in origin, cxZn having higher anomalous/threshold contrast than total Zn (11.1 for cxZn vs 4.8 for total Zn). The nature of the Pb anomaly is not understood. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Multifractional analysis for scheelite (G=5.9-6.1), magnetite (G=5.2), heavies (G>3.3), mediums (3.3<G<2.9), and lights (G<2.9), in drainage sediments downstream of the Clea tungsten-bearing skarn deposit, Yukon Territory, revealed three interdependent problems that complicate interpretation of results of drainage surveys for W: (1) Scheelite concentrations in stream sediments reflect, in part, hydraulic sorting rather than source distribution. (2) Low numbers of scheelite grains in stream sediments cause high random sampling and subsampling errors and present analytical difficulties. (3) Scheelite/heavies or scheelite/mediums ratios may not be appreciably higher downstream of scheelite-bearing skarn than barren bedrock, because scheelite, heavies and mediums occur in increased amounts in skarns (i.e. they covary in source materials). Hydraulic effects result in systematic changes in mineral distributions between high and low energy environments (characterized by coarse gravel and fine gravel to sand, respectively). Scheelite, magnetite, heavies and mediums concentrations in minus 10-mesh sediments are greater in high than low energy environments, and this relative enrichment increases with grain size and density (up to one-hundredfold for scheelite). Using a regression method, developed in this study, hydraulically equivalent sizes of magnetite and heavies were empirically determined for finer (3.0-3.5 phi and 3.5-4.25 phi) scheelite sizes. Ratioing the weight of scheelite to that of a hydraulically equivalent mineral greatly reduces hydraulic variability. Resulting profiles of hydraulically equivalent scheelite concentrations more clearly delineate locations of scheelite input to the stream. The rare-grain problem can be reduced at the sampling level by sampling from high energy environments (thereby exploiting hydraulic effects) and/or by sampling for finer scheelite. Heavy mineral separation is the most effective means of reducing the rare grain problem at the subsampling and analytical levels. The problem of covariance in source materials can best be remedied by ratioing to an individual (hydraulically equivalent) heavy mineral which has a constant and ubiquitous distribution in the area of interest. In this study, magnetite shows promise, but more information on its source distribution is needed. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

I argue that by understanding lithic technology as a total social fact, that is, as socially, culturally and politically constituted, it is possible to gain some insight into prehistoric social practice. An archaeological examination of the Nii 'ii site (KdVo-5), a prehistoric hunting stand locality in southwestern Yukon Territory, serves as a case study for this argument. Spatial reconstruction of this site indicates the presence of several social actors engaged in face-to-face interaction. Technological analysis of the lithic assemblage demonstrates that the observed variability in tool forms cannot be explained solely in terms of tool function; instead, it appears that the technical choices made by the occupants of KdVo-5 were socially and culturally mediated. I outline a theory of technological practice, based on practice-oriented social theory, in an attempt to understand the importance of these technical choices in the construction of social relationships at Nii 'ii.