A literature survey indicated that little was known about the effects of commercial clearcutting on stream and watershed solution chemistry. To investigate these effects, five small watersheds were studied in the University of B.C. Research Forest. Three of the watersheds were equiped with weirs, stream height recorders, and soil-air-water thermographs. Soil pits were dug in the three calibrated watersheds and equiped with surface runoff collectors and hanging water column tension lysimeters. Samples of - precipitation above the forest, throughfall (through forest and slash), surface runoff, forest floor leachate, mineral soil leachate near the bottom of the rooting zone, groundwater, and streamwater - were collected at regular intervals and analyzed for pH, electrical conductivity, alkalinity as bicarbonate, K, Na, Mg, Ca, Fe, Mn, Al, Cl, P, N, S, and Si for periods of up to three years prior to clear-cutting and two years after clearcutting. Streamwater was also analyzed for dissolved oxygen and suspended sediment. Sampling was carried out for periods of up to three years prior to clearcutting and up to two years following clear-cutting. The streams were characterized by high discharges from late autumn until early summer and low discharges from May until October, with almost no contribution from snowmelt runoff. Response to precipitation was fairly rapid and it was hypothesized that stormflow arose mainly from flow of water through macrochannels in the soil. Visual observations and chemical data were consistent with this hypothesis. Evapotranspiration from the gauged watersheds was estimated to be about 85 cm per year by subtracting streamflow outputs from precipitation inputs and 65 cm per year using theoretical methods. The discrepancy between these two values was attributed to an unmeasured leakage of water, particularly from the untreated control watershed which rendered too low the streamflow outputs. There was an increase of 30.8 cm in runoff from one watershed, and 27.6 cm from another during the first six months of the dormant season immediately following clearcutting. During this period runoff from the control watershed was 141.5 cm. Stream temperatures underwent annual cycles with winter minima close to 0°C and summer maxima close to 17°C. Diurnal temperature fluctuations were slight and usually less than a few degrees. Clearcutting caused an increase in both maximum and minimum stream temperatures during the first dormant season following clearcutting. The few measurements which were made of suspended sediment, together with visual observations, indicated that concentrations were usually negligible in the streams. Dissolved oxygen concentrations in streams were usually close to 100% saturation and underwent annual cycles with maximum values in winter and minimum values in late summer and early autumn. Clearcutting had little effect on dissolved oxygen values during the cooler wetter months but caused very pronounced decreases during summer and early autumn. This was attributed to the biological and chemical oxygen demands of decaying slash in the streams. Stream chemistry exhibited little diurnal variation but considerable variation with discharge. Sodium, calcium, magnesium, dissolved silica, and bicarbonate concentrations, and electrical conductivity and pH decreased with increasing discharge, whereas potassium and nitrate concentrations exhibited some increases and some decreases. Chloride and sulphate concentrations were generally not significantly related to discharge. In the undisturbed ecosystems, chemical concentrations, pH, and electrical conductivity throughout the systems were generally highest in late summer and early autumn and lowest in winter and early spring. This was attributed to seasonal cycles of geological and biological activity with accumulation of weathering and decomposition products occurring during dry, warm summers. These were flushed through the system in autumn, with solutions becoming progressively more dilute throughout the winter until the onset of warmer weather. Nitrate concentrations tended to be higher in winter than in summer which was attributed to greater nitrogen uptake by organisms in summer. The most abundant ions in precipitation and throughfall were hydrogen, sulphate, and chloride, while calcium, bicarbonate, and sulphate were dominant in all the other types of water samples. There was a general increase in chemical concentrations to maximum values in forest floor leachate followed by a decrease to minimum values in groundwater, and a slight increase again in streamwater. The lowest pH values were in throughfall (4.0-4.5) followed by a steady increase through the system to maximum values in stream-water (6.5-7.0). Clearcutting increased the pH of water reaching the forest floor and surface runoff but decreased the pH of mineral soil leachate, groundwater, and streamwater. It generally decreased chemical concentrations in water reaching the forest floor and in surface runoff, and, to a lesser extent, in forest floor and mineral soil leachates, but it increased concentrations in groundwater and, to a lesser extent, in streamwater. A most notable increase throughout the system was in the concentration of potassium which was attributed to the relative ease with which potassium is leached from decaying vegetation. Increases in nitrate concentrations were particularly high in groundwater. Streamwater concentrations of potassium, iron, calcium, dissolved oxygen, and probably manganese, were significantly affected by clearcutting; concentrations of all these chemicals increased, except dissolved oxygen which decreased. Slight increases in magnesium, nitrate, sulphate, and chloride concentrations, and electrical conductivity, and decreases in pH and bicarbonate concentrations were also observed. All changes were most noticeable during the low flow periods of late summer and early autumn. There were no obvious effects on sodium, aluminium, ammonium, dissolved silica, and phosphate concentrations. In terms of chemical budgets, there was a general net loss of calcium, sodium, magnesium, potassium, and sulphur from all the watersheds, in their undisturbed state, while nitrogen was accumulated and phosphorus underwent very little change. The chloride balance changed from year to year with losses one year and gains the next. Chemical outputs increased relative to inputs with increasing precipitation so that net losses were greater in winter than in summer. Chemical budgets and stream chemistry at Haney were compared to the results of other studies, particularly one in the nearby Seymour watershed (Zeman, 1973). At Haney, clearcutting significantly increased potassium losses and decreased nitrogen gains in one watershed and significantly increased potassium, sodium, magnesium, and chloride losses in another watershed. From the nutrient viewpoint, it appears that clearcutting has not impaired the mechanisms for nutrient retention in the ecosystems of the type present in the study area. This may not be the case for all ecosystems in coastal B.C., or for other forestry practices, such as slashburning. The study has pointed out the need for further work to quantify the role of macrochannels in soils with respect to hydrologic and chemical behaviour of watersheds. It has also pointed out the danger of extrapolating to larger ecosystems the results of lysimeter studies. Chemical analysis of groundwater may offer a more accurate means of estimating chemical losses from soils than do lysimeters. / Forestry, Faculty of / Graduate

This thesis is an examination of the origins and development of the British Columbia ranching community and livestock industry. The argument is based on the assumption that the settlement of the Southern Interior Plateau stimulated the growth of a peculiar agricultural economy dependent primarily on stock raising, which in turn, played a prominent role in the region's political, economic and social development. The British Columbia ranching frontier was preceded by the practical foundation of agriculture and animal husbandry in the Oregon country under the guidance of the Hudson1s Bay Company and its maturity under the independent American settler. With the discovery of gold in British Columbia, the American ranching frontier extended northward temporarily to fulfill the demands of the mining market and in the process the Interior livestock industry was established. Through the implementation of a pre-emption system and the hesitant introduction of pastoral leases, the colonial administrations slowly came to realize that the settlement of the Interior Plateau depended initially upon the promotion of stock raising. In its first stage of settlement, the isolated ranching frontier did not experience serious competition for site nor did one ethnic, social or economic group control the region's development. With the gradual decline of the mining industry and the frustrations surrounding the transcontinental railway, the new province of British Columbia entered a decade of economic recession. For the Interior ranching community, however, it represented a period of gradual economic expansion and growing influence in the political sphere. Once railway construction was finally commenced in 1880, the ranchers' concentration upon stock raising during the past two decades stimulated a period of unparalleled prosperity and land consolidation for the established Interior ranching population. After 18 8 5 the character of Interior settlement and the livestock industry began to experience the inevitable transitions of a more mobile and industrialized society. While the cattle ranchers, as the largest landowners, maintained a comfortable livelihood, they were visibly alarmed by the formation of large ranching companies and the growing competitive strength of the Alberta ranching frontier. Nevertheless, while the broader problems of the ranching industry now required a more united front, the established ranchers continued to operate on an independent, individualistic basis. Ultimately, this led to tension within the ranching community itself and a declining role in the economy of the province. / Arts, Faculty of / History, Department of / Graduate

This thesis is comprised of four self contained chapters that report the results of a study on the stormflow hydrology of small forested watersheds in the Coast Mountains of southwestern British Columbia. The chapters discuss the general characteristics of the study watersheds and their instrumentation, the generation of stormflows from small forested watersheds, the stormflow (channel-phase) characteristics of one study watershed with steep topography, and the evaluation of initial changes in peak stormflow following logging of another study watershed. Chapter I. The characteristics of the study watersheds with respect to regional climate, physiography, soil hydrologic characteristics and forest cover were evaluated and summarized from available information. Emphasis is placed on the hydrologic characteristics of the watershed soils. The instrumentation of the study watersheds pertinent to the present study is also described. Due to the highly permeable nature of the watershed soils, the physical setting of the study watersheds favor a Rapid response of streamflow to rainstorms. On one study watershed this rapid response characteristic is reinforced by its steep topography and high drainage density. Chapter II. The problem of stormflow generation from small forested watersheds is dealt with by analyzing results from studies completed by the author and other workers in Jamieson Creek watershed and vicinity and by making field examinations in the same study area. A review is made of stormflow generation models, followed by analyses of rainfall intensity, saturated soil hydraulic conductivity and depression storage of the study area. These analyses revealed that overland flow rarely, if ever, occurs on coastal watersheds with hydro-logic environments similar to that of the study area. Instead, rain water takes alternate subsurface pathways through the soil to the stream channel. Observations made by the author in the study area and in other watersheds in this coastal region confirmed the existence of these alternate routes of water flow. Two types of subsurface stormflow pathways have been identified by earlier workers: (1) the matrix of forest floor and mineral soil beneath and (2) channels within or passing through the mineral soil. In the study area most soil channels were developed from dead or decaying roots. After passing through these two types of pathways, subsurface stormflows feed the expanding stream channel system laterally while rainfall is feeding the system from above. Subsurface stormflows are mainly in the form of saturated return flow from the ground and seepage flow through saturated stream banks. The stream channel system expansion during, and contraction after, a storm was measured in a small sub-watershed in the study area. It was found that the rate of stormflow from a watershed was closely related to the rate at which the stream channel expanded in response to the storm. From theestudy it is concluded that the model of subsurface stormflow from a variable source area is more appropriate than the other two models in describing stormflow generation in this coastal region. Chapter III. Stormflow characteristics of Jamieson Creek watershed, a small, steep, and forested watershed in the Coast Mountains of southwestern British Columbia, were evaluated by the analysis of 41 storm hydrographs from 1970-1974. During the study period, the rainfall amount per storm event varied from 5 to 330 mm, with the majority of the storm durations ranging from 20 to 60 hours. On the average, the fraction of storm rainfall that appeared as stormflow was 44 percent, varying from 2.5 to 81 percent. A significant number of major storms produced stormflow that accounted for more than 60 percent of the storm rainfall. Instantaneous peak flows varied considerably with storms, ranging from about 10 to 1,370 -1-2 1 s km and appeared to be mainly affected by the rainfall amount and distribution before the occurrence of the peak flow. Rising time (time to the peak) was short, usually within 30 hours, depending upon the rainfall distribution before the occurrence of the peak flow. Lag time was found to be relatively constant and short, ranging from 5 to 15 hours with an average of 8.5 hours. It is suggested that to derive lag time from characteristics of small watersheds, soil hydrologic properties should also be included with those parameters that are generally used. Stormflow amount was highly correlated with rainfall amount with 92 percent of its variance being accounted for. Antecedent base-flow rate was proposed as an index of watershed soil water storage prior to the storm hydrograph rise. One set of data from Jamieson Creek watershed and four additional data sets from two small steep watersheds in the Coweeta Hydrologic Laboratory were used to assess, through multiple regression analysis, the usefulness of antecedent baseflow rate in improving stormflow-rainfal1 relations. For all data sets, the inclusion of antecedent baseflow as a second independent variable significantly improved the stormflow estimate in comparison to that when rainfall amount was the only independent variable. Recession limbs of storm hydrographs varied with individual storms, depending on the degree of recharge to the watershed storage by the storm and the spatial distribution of such storage over the watershed. The stormflow characteristics of Jamieson Creek watershed reflect the influence of not only climatic conditions but also watershed characteristics: (1) shallow but highly permeable soils, (2) steep watershed slopes and stream channels, and (3) high drariinage density. The stormflow characteristics can be interpreted in terms of the generation of stormflow from a variable source area of the watershed. A comparison of the stormflow characteristics of Jamieson Creek watershed and the adjacent Elbow Creek watershed indicated that stormflow from the former usually has a sharper peak, higher peak flow ratio and steeper recession than stormflow from the latter, but both have very similar rising times. Differences in the streamflow response of the two watersheds could be caused by their differences in some topographical features. However, these differences also suggest that leakage from Elbow Creek, revealed in a preliminary field investigation, may deserve more detailed study. Chapter IV. This chapter provides the first quantitative Canadian information with respect to the impact of logging on peak stormflow. The paired-watershed technique was used to evaluate the initial changes in peak streamflow during storm periods following logging of a small watershed in the U.B.C. Research Forest, near Haney, B.C. Contrary to the majority of similar studies elsewhere, the analysis indicates that significant peak flow changes after logging occurred as follows: (1) an increase in the time to the peak, and (2) a decrease in the magnitude of the peak. The changes can be explained by (1) the degree of ground surface disturbance associated with the logging and (2) the stormflow generation mechanisms of the study area. Visual examination after the logging indicated that ground surface disturbance did not reduce the soil infiltration capacity to the extent that overland flow resulted. Workers in an earlier study speculated that forest floor disturbance could result in closure of some of the entrances to soil channels, thus increasing temporary water storage in the soil matrix. This, they further speculated, would result in reduced subsurface stormflow and, consequently, lower peak flow. The results of the present study tend to support the speculations, that the closure of some soil channel entrances is responsible for lower peak flow after logging. However, this study indicated that peak flow magnitude decreased mainly because of the flattening out of the hydrograph as a result of increased time to the peak (delayed peak rather than earlier hydrograph rise,). It is suggested that a lower rate of stormflow transmission through the soil matrix caused this increased time to the peak and, consequently, lower peak flow magnitude. Implications of this study for better water management are suggested. / Graduate and Postdoctoral Studies / Graduate

This thesis provides an analysis of the drop trailer traffic moving between the B.C. Mainland and Vancouver Island. Drop trailers are semi trailers which are literally dropped at the ferry terminal to be transported across the Strait of Georgia without the accompaniment of the power unit and driver. This specialized service is provided only by the British Columbia Coastal Steamship Service, a subsidiary of CP. Rail. One objective of the thesis is to analyze the economics of shipping via drop trailer as opposed to a live unit, or one that includes the driver and tractor unit such as is provided by the B.C. Ferries. A second objective is to determine the size and importance of the market, and to forecast future requirements. A third objective is to analyze the physical facilities available to determine their capacity and possibilities for expansion. The B.C.C.S.S. facility in downtown Vancouver is under pressure from various groups to relocate to a more suitable location. Thus a final objective is an analysis of the benefits and costs of relocating the B.C.C.S.S. terminal to the north Richmond area. Since the drop trailer industry is very specialized, and captive to the B.C.C.S.S., very little information is published or available concerning it. Thus the author has had to rely primarily on discussions with all the parties involved, namely the B.C.C.S.S., City of Vancouver, and numerous carriers. One of the by-products of the thesis is a body of information and data pertaining to the drop trailer industry, that can be used for future research in related topics. The analysis of the economics of shipping via drop trailer shows a substantial savings potential, even though the actual ferry cost is greater. The savings are generated by the elimination of idle driver and tractor time. This saving was estimated at $49.20 per one way trip. During the past decade the volume of drop trailer traffic has been increasing steadily even though railcar traffic has been on the decline. This increase is causing the B.C.C.S.S. to approach the capacity of the present system. Political and physical pressures have raised the issue of relocating the terminal A benefit-cost analysis of a particular alternative, a partial relocation to the north Richmond area shows there can be substantial benefits for carrier as well as the B.C.C.S.S. / Business, Sauder School of / Graduate

The landscapes of British Columbia, prominently modified by glaciation, present many large and varied wetlands. These wetlands have not been well delineated nor classified although they are being rapidly modified for residential, agricultural and industrial developments. Some federal and provincial agencies are currently undertaking inventory and classification based largely on soil profile characteristics. To complement these efforts, particularly for management purposes, this study was undertaken in which predominantly plant-mediated processes were examined. The investigations were limited to the maritime marshes of south western British Columbia with study sites located in the Pitt, Brunswick and Iona marshes. Estimates of productivity were obtained from single and sequential harvesting of the aerial vegetation. Peak standing crops varied between species and between sites. Species differences were attributed to plant characteristics such as photosynthetic canopy development and shoot configuration. Peak standing crops were also related to environmental variables such as climate, water regime, salinity and substrate nutrient status. Data from sequential harvesting revealed that most emergents experienced a rapid growth in the spring and early summer declining with the onset of cold weather in the fall. Time of peak production differed markedly between species depending on presence or absence of overwintered photosynthetic shoots, time of shoot emergence and seasonal shoot mortality rates. Studies of belowground organs showed that roots and rhizomes may comprise up to 85 percent of the total phytomass of emergent vegetation emphasizing the importance of this fraction in wetland functions and processes. The main routes of disposition of the emergents were identified as the grazing route, accumulation route and the detrital route. Grazing was relatively unimportant in the marshes. Any grazing of the living vegetation was carried out largely by gastropods, earthworms, insects and resident and migrant waterfowl. Minimal grazing of the marsh vegetation appeared to be related to unfavourable wetland conditions, high levels of structural constituents and low levels of nitrogen in the plants. Quality of the vegetation declined sharply with age. Low ash levels and high phenolic content were also implicated in the minimal grazing of the Pitt marsh vegetation. Total energy content appeared to be unimportant in this regard. Organic matter accumulation was a distinct feature of the marshes studied. There was more organic matter accumulation in the Pitt than in the Brunswick marsh. Accumulation also seemed to be more uniform over large areas in the Pitt marsh than in the tidal marshes. Data from old growth samples indicated that a large portion of the phytomass produced in the marshes enters the detrital pathway via decomposition. Factors affecting decomposition rates were discerned largely from litter bag trials and in vitro decomposition studies. Fragmentation of litter by physical forces generally preceded biological degradation. Such comminution was more marked in the Fraser delta marshes where tidal and freshet activities are predominant. Temperature was a significant factor affecting disappearance rates. The rates were generally lower in the "cooler" Pitt marsh than in the "warmer" Brunswick marsh. Low soil temperatures together with low oxygen tensions were responsible for the relatively low decomposition rates in buried litter samples. Decomposition rates also reflected the chemical composition of the emergent vegetation. Less fibrous species such as Carex lyngbyei were more readily degraded than more fibrous species such as Carex sitchensis. Leaching of readily degradable plant materials occurred in significant quantities both in living and dead vegetation. Leaching losses in living shoots averaged 64 mg/g leaf dry matter in 4 days. Variations in stomatal number, shape and distribution were implicated in the possible mechanisms controlling leaching losses in living emergent vegetation. In dead shoots, dry weight losses of up to 50 percent were recorded over a four month period. Such losses were attributed mainly to leaching. High initial losses in the litter bag and in vitro decomposition trials were also suggestive of leaching. / Land and Food Systems, Faculty of / Graduate

The Poplar copper-molybdenum porphyry deposit, located 270 km west of Prince George, is centered in a late Upper Cretaceous differentiated calc-alkaline stock, which intruded Lower and Upper Cretaceous sedimentary rocks. The stock is capped by late Upper Cretaceous volcanic flow rocks. The lower Cretaceous Skeena Group consists of intermediate tuff, siltstone, and interbedded sandstone, which steeply dip to the south. This unit is unconformably overlain by a moderately sorted polylithic pebble conglomerate belonging to the Upper Cretaceous Kasalka Group. The Poplar Stock, which hosts mineralization, includes a border phase of hornblende quartz monzodiorite porphyry which grades in to a central biotite quartz monzonite porphyry. The stock is intruded by several post-ore dyke units, which include porphyritic dacite, porphyritic rhyolite, felsite, and andesite. Ootsa Lake porphyritic volcanic flow rocks overly the deposit, and are dacite in composition. Pre-ore, and post-ore rock units have been K-Ar dated, and are within analytical error of each other, having a mean age of 74.8 ±2.6 Ma. The deposit is covered extensively with glacial till and alluvial sediments. Therefore the majority of geologic information was obtained from logging the drill core from 34 diamond drill holes, twelve of which were logged in detail using a computer compatible logging format. Information logged in this manner was used in statistical studies , and for producing computer generated graphic logs and plots of various geologic parameters, along two cross-sections through the deposit. Alteration zoning at the Poplar porphyry consists of a 600 m by 500 m potassic alteration annulus which surrounds a 300 m by 150 m argillic alteration core. These are enclosed by 750 m wide phyllic alteration zone, which is itself bordered by a low intensity propylitic alteration zone. Phyllic alteration is defined by the occurence of sericite, and is the most abundant type of alteration present. Potassic alteration, recognized by the occurence cf secondary K-feldspar and/or secondary biotite, is most closely associated with chalcopyrite and molybdenite. At least two episodes of alteration are recognized at the Poplar porphyry. The first was contemporaneous with mineralization, following intrusion and crystallization of the Poplar Stock. This episode consisted of potassic alteration in the center of the deposit, which surrounded a 'low grade1 core, and graded out to phyllic and propylitic alteration facies at the periphery. The second alteration event took place after the intrusion of the post-ore dykes and consisted mainly of hydrolytic alteration of pre-existing alteration zones which were adjacent to more permeable centers, such as faults, contacts, and highly jointed areas. This alteration event is responsible for the anomalous central argillic zone, and the alteration of dykes, in addition to probably intensifying and widening the phyllic alteration halo surrounding the deposit. Chalcopyrite and molybdenite were deposited in the potassic zone at approximately 375° C and less than 250 bars, with relatively low oxygen, and relatively high sulfer, activities and moderate pH. As the potassic alteration zone was invaded by more acidic solutions feldspars were altered sericite and clay, and chalcopyrite was destroyed to form pyrite and hematite. Copper was removed from the system. Statistical studies include univariant one-way and two-way correlation matrices, and multivariant regression analysis. Statistical correlations generally support empirical correlations made in the field. These include positive correlations between various potassic alteration facies minerals, and these minerals and chalcopyrite and molybdenite. Multivariant regression analysis was used to determine which alteration minerals were best suited for indicating chalcopyrite and molybdenite. These minerals are quartz, biotite, magnetite, sericite, K-feldspar, and pyrite. Large error limits and poor correlation statistics in the results from these studies are attributed to deviations from normal distributions for all minerals. A possible cause of this may have been the multistage alteration events that the deposit has undergone. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Lead isotope analyses of galena from multiple ore deposits restricted to specific tectono-stratigraphic terranes can provide information on the age and origin of the lead. In this thesis, three separate studies of lead isotopes applied to the metallogenesis of parts of the Canadian Cordillera are presented. Lead isotope data from quartz-gold vein deposits and volcanogenic and related deposits in the Insular Belt group plot in four distinct clusters on Pb-Pb plots. Each cluster corresponds to a specific deposit type and host rock category. Two parallel evolutionary trends in the lead isotopic composition exist: 1) Sicker-hosted volcanogenic deposits to Sicker-hosted veins, and 2) Karmutsen and Bonanza-hosted volcanogenic and related deposits to Karmutsen and Bonanza-hosted veins. The trends indicate a genetic relationship between host rock and isotopic composition. These observations favour a host rock source for the lead in vein deposits and, by association, a comparable source for the gold. Plutonic or abyssal direct sources of metals are not consistent with the lead isotopic data. It is suggested that the gold was extracted from the country rock, and concentrated as veins by hydrothermal activity related to Tertiary plutons. Vein deposits are isotopically distinct from volcanogenic and related deposits, providing an empirical test for distinguishing syngenetic from epigenetic deposits. Karmutsen and Bonanza-hosted deposits are more depleted in 207Pb than similar deposits in Sicker Group rocks, indicating significantly different sources for volcanic components of these two important rock units. Lead isotope data from quartz-gold veins in the Cariboo area of the Omineca Belt, and from similar veins in the adjacent Intermontane Belt indicate that these two vein types are genetically unrelated. A mid-Mesozoic model age calculated for the Cariboo gold mineralisation event indicates that all of the deposits examined are clearly epigenetic, despite reported stratiform textures at the Mosquito Creek mine. K-Ar dates from a quartz-barite vein and from regionally metamorphosed phyllite support a synmetamorphic origin for the veins, but a distal plutonic origin is not ruled out. Recent work by Godwin and Sinclair (1982) has shown that syngenetic, shale-hosted, sedimentary exhalative deposits in the autochthonous part of the Canadian Cordillera contain lead which has evolved in a high U/Pb environment. This 'shale' curve evolution model applies to deposits which have an upper crustal (host-rock) lead source. Ainsworth-Bluebell, Carmi and Slocan camps, and lead associated with the Moyie intrusions, all contain lead which plots substantially and variably below the 'shale' curve. Their departures from this curve provide evidence for a second, uranium poor, possibly lower crustal lead source, for which a growth curve, referred to as the Bluebell curve, can be constructed. The lead data are interpreted within the framework provided by these two growth curves. Mixing of lead between these two lead reservoirs is proposed to explain the linear array of data from Slocan and Carmi camps. Mixing lines, joining points of equal time on the two growth curves, provide a method for interpreting lead data from these deposits. Introduction of relatively unradiogenic lead into the upper crust via magmas which originated in the lower crust is invoked to explain the mixing. The three studies considered here illustrate the differences in lead isotopic characteristics of different tectono-stratigraphic terranes and show that the development of local models for the interpretation of common lead isotope data has application to exploration. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

On the recent lobe of the Fraser River Delta, peat deposition is occurring in three distinct settings: the distal delta plain, the transitional upper delta to lower delta plain, and the upper delta plain to alluvial plain. Each de-positional setting contains a unique sequence of lithofacies and biofacies. Distal lower delta plain peats, although widespread, form a thin, discontinuous peat network dominated by a sedge-grass facies. The peats contain numerous intercalations of silt and silty clay, with a moderate to high pH and a high concentration of sulphur values. The peats overlie a thin fluvial sequence, which in turn overlies a thick coarsening upward sequence of prodelta clay and silty clay. Peats from this environment will form thin lenticular seams of high ash and high sulphur coal. The coal maceral precursors in the peat suggest that the base of the coal will be comprised mainly of desmocol1inite, whereas near the top of the seam oxyfusinite, macrinite, and interlaminated cutinite and vit-rodetrinite would be common. Initial lower delta plain-upper delta plain peats developed from interdistributary brackish marshes. High concentrations of sulphur and ash in these peats decreased in overlying freshwater sedge-grass facies as the delta prograded and the natural levees formed. Sphagnum dominated communities eventually succeeded in areas where fluvial influence was minimal. Laterally, however, along active channel margins, sedge-grass peats intercalate with silty clay overbank and sandy splay deposits. A thin fluvial unit of fining upward sand, silt and clay and a thick sequence of coarsening upward prodelta clay and silty clay underly the deposit. These peats will form relatively thick, widespread coal seams. The seams will be thin and possibly discontinuous adjacent to channels and areas where extensive splaying has occurred. High sulphur concentrations will be confined to the base of seams. The maceral precursors suggest that interbanded telenite, cu-tinite and cerenite will be abundant in the base of the seam and will grade vertically into suberinite, telocollinite, and telenite rich coal. Stumps which will form massive telenite will occur locally. Alluvial plain peats accumulated in freshwater backswamp environments. Earliest sedge-clay and gyttjae peats developed over thin fining upward cycles of silty sand, silt and clay and inter laminated silt, and silty clay of flood origin. Overlying sedge grass and Sphagnum peats are horizontally stratified and form sharp contacts with.bordering flood sediments, at active channel margins, sedge-grass peats intercalate with overbank silty clay to form well developed natural levees, these peats will form a thick seam of high quality coal. The microlithotype composition is comprised of vitritic carbar-gillites and liptites near the base of the seams, and will shift to a clarite and then primarily vitrite near the top. Compared to delta plain peats, maceral distribution will be less complex. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The Thor-Odin gneiss dome is one of several structural culminations along the eastern margin of the Shuswap terrain. The gneiss domes have previously been ascribed both to diapiric uprise of granitic gneisses and to interference of late-stage buckle folds. The ages of rocks in the gneiss domes have also been the subject of controversy. Age estimates range from Archean to Mesozoic. This study provides the basis for a detailed model for a new interpretation of the structural evolution of the Thor-Odin gneiss dome. Prior to doming, this area was characterized by the formation of large-scale nappe structures and imbrication of Archean basement rocks with the cover rock sequence. The first period of deformation (Phase One) consisted of large-scale infolding of the cover rock sequence into the basement rocks. The Pingston fold in the core of the dome is a product of this event. The second period of deformation (Phase Two) was marked by the forcing of wedges of basement into the cores of northerly-moving nappes. The third period of deformation (Phase Three) was co-axial with Phase Two and consisted of imbrication and refolding of the upper levels of the stack of Phase Two nappes. Strain analysis based on fold shape, distorted lineation patterns and elliptical strain markers demonstrate that finite strains are highest in the imbricated zone between the Basement Cored Nappe Domain and the Cover Rock Domain. Flattening strains are anomalously low in the Autochthonous Core Gneiss Domain. Analysis of Phase Two fold axes distorted into flattened small circles by Phase Three folds shows that Phase Three strain magnitude √(λ₂/ λ₁) varies from 0.81 to 0.49. Rb-Sr whole rock geochronometry has revealed evidence for three Precambrian events within the basement gneisses. Unmigmatized metasedi-mentary basement gneisses form a six-point errorchron with an age of 2.73±0.20 Ga. Granitic gneisses previously dated at 1.96 Ga by the U-Pb zircon technique, give reset ages for gneiss/vein whole rock suites with ages in the range 750 to 860 Ma. Common lead systematics of stratabound sulfide deposits in the cover rock sequence suggest that the cover rocks are Cambrian in age, in agreement with earlier lithological correlations. The lead isotope ratios suggest the deposits were ultimately derived from an approximately 2.0 Ga basement terrain. The outcropping gneissic basement rocks of the Shuswap are dominantly granitic gneisses which give 2.0 to 2.2 Ga Rb-Sr whole rock dates.; Ductile deformation in the terrain appears to have ended by 150 Ma, as this corresponds to the ages of several post-tectonic intrusions which crosscut Phase Three folds and impose a contact metamorphic overprint on the regional metamorphic pattern. The Nelson Batholith is a post-tectonic batholith which intrudes both the Shuswap terrain and the Kootenay Arc to the east. Two sample suites were collected from the different batho-lithic phases and analyzed by Rb-Sr whole rock methods with the following results: Suite I - Porphyritic monzonite with alkali feldspar megacrysts from the West Arm of Kootenay Lake give a seven-point isochron with an age of 158 ± 16 Ma and an initial ratio of 0.7069 ± 0.0001. Suite I has a Rb-Sr feldspar, date of 153 ± 26 Ma, a K-Ar hornblende date of 143 ± 5 Ma, and a K-Ar biotite date of 60 ± 2 Ma. It seems likely that the K-Ar dates have been disturbed by thermal events subsequent to emplacement of the batholith. Suite II- Medium grained granodiorite from the southern tail of the Nelson Batholith gives a nine-point whole rock isochron with an age of 162 ± 6 with an initial ratio of 0.7065 ± 0.0001. Taken together, these data provide significant new information on the nature and timing of the events that formed the metamorphic core zone of the southern Canadian Cordillera. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

This study describes an investigation of the potential for pioneer grass-legume communities to stabilize and ameliorate geologically-fresh soil leading to the establishment of a self-sustaining, progressive plant succession on a surface-mined subalpine site. The study area is located 2,000 m above sea level in the Canadian Rocky Mountains. Field surveys at the site indicated extremely limited invasion of reclaimed areas (3-7 years old) by native species from the adjacent subalpine forest. Soils on revegetated sites were generally warmer and drier than soils of the associated forest and have less than half the content of fine soil fragments (<2 mm). Field studies revealed chronological trends in grass-legume communities at four sites revegetated during 1974-1978 including: species composition, legumes (Trifolium repens L., T. hybridum L. and Medicago sativa L.) performing increasingly poorly on the older sites; biomass changes, a shoot to root ratio (S/R) decreasing from 2.3 to 0.2 as the communities aged; and litter accumulation which continued even on the oldest site. Fertilizer (13-16-10) operationally applied at 150 -391 kg/ha enhanced the growth of Dactylis glomerata L. and litter degradation, and acidified the soil. Nitrogen fertilization was also associated with two clear inverse relationships identified between D. glomerata and Festuca rubra L. biomass, and between soil pH and phosphorus levels. In greenhouse tests grasses were revealed to be more efficient soil nitrogen consumers than were legumes and nitrogen fixation decreased significantly (P<0.01) and linearly with increasing grass seeding rates. In the presence of grasses, nitrogen fixation was positively correlated with aboveground legume biomass at all nitrogen fertilizer levels tested. The results further revealed that operational seeding and fertilizer rates at this site may not optimize plant productivity and the ability of legumes to fix nitrogen symbiotically. Field trials based upon the experimentaly derived combination (17.5 : 30 : 50 kg/ha grass seeding rate : legume seeding rate : nitrogen fertilizer rate) would be desirable to evaluate these data on the site. Other potential practical implications from this study are: (1) The need for improved legume establishment, involving legume seed germination, species and variety selection, and selection of Rhizobium strains. (2) Improved control of the operational fertilizer application. (3) Alteration of grass and legume species composition of the present seed mix. (4) Selective placement of initial material (overburden or spoil) handling. A modification of the acetylene reduction assay, "the open system" technique, was developed for evaluation of legume nitrogen fixation of mine spoils. Although the unit developed is limited to detection of the presence or absence of ethylene, calibration with the closed system of ethylene levels obtained by the open system appeared feasible. Further refinement of the system for quantitative use would increase its usefulness in nitrogen fixation studies of legumes on mine spoils, nitrogen fixing woody plants in forests, and legumes in grassland sods. / Land and Food Systems, Faculty of / Graduate