No description available.

The Sustut Group within the study area is a nonmarine succession of fine to coarse grained elastics, deposited in an alluvial fan environment. Regionally, the Sustut Group is divisible into the Tango Creek and Brothers Peak Formations. In the study area, the two formations are entirely Late Cretaceous (Campanian to Maastrichtian) in age, based on palynological evidence. In the southern Sustut Basin, only the uppermost 400 m of the Tatlatui Member of the Tango Creek Formation is exposed. Sediments of the Tatlatui Member are divided into fine and coarse grained lithofacies. The fine grained lithofacies is composed of interbedded mudstone, siltstone and fine grained sandstone, which is interpreted as an alluvial plain deposit. Pebble conglomerate interbedded with coarse to medium grained sandstone comprise the coarse grained lithofacies which is considered to be a braided river deposit. The Brothers Peak Formation comprises 1 000 m of diverse elastics and tuffs, which are divisible into the lower and upper Laslui Member, and the overlying Spatsizi Member. The lower Laslui Member conformably overlies the Tatlatui Member of the Tango Creek Formation, and is characterized by several fining upwards sequences of cobble conglomerate to medium grained sandstone, attributed to deposition by high energy braided streams in the mid-fan region of an alluvial fan complex. Sediments of the upper Laslui Member are divided into a fine grained lithofacies consisting of mudstone, interbedded with lesser amounts of siltstone, fine grained sandstone and tuff beds, and a coarse grained lithofacies composed of orthoconglomerate, paracong1omerate and coarse grained sandstone. The fine grained lithofacies comprises the majority of the sequence and is interpreted as an alluvial plain deposit. Coarse grained sediments of the upper Laslui Member were likely deposited during stages of high water discharge, by major distributaries, sheetfloods and debris flows. The Spatsizi Member is gradational from the upper Laslui Member and is composed of sandstone/mudstone sequences interpreted as sandy braided stream deposits of an alluvial plain. Detrital components of the Tango Creek and Brothers Peak sandstones are mainly chert, quartz, plagioclase and volcanic rock fragments. Paleocurrent measurements and provenance considerations suggest source terranes were located to the east during Tango Creek deposition, and to the west during Brothers Peak deposition. In the southern Sustut Basin, the Tango Creek Formation documents uplift and erosion in the Omineca Belt and Paleozoic rock units, following accretion of the first composite terrane (terrane I) to the North American Margin. The Brothers Peak Formation is considered a result of local uplift and volcanic activity, accompanying the accretion of a second composite terrane (terrane II). / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The boundary between the Omineca Belt and the Intermontane Belt in Central British Columbia represents the suture between autochthonous North America (Barkerville Terrane) and several allochthonous terranes accreted from the west In the Quesnel Lake region allochthonous sedimentary and volcanic rocks of Quesnellia Terrane, accreted in the Jurassic, are in sharp tectonic contact with underlying siliclastic and carbonate metasedimentary rocks. The Ogden Peak study area is located 10 km east of and structurally below this suture zone and is thus well situated for observing deformational styles within the autochthonous package. Rocks exposed near Ogden Peak comprise the Hadrynian(?) to Paleozoic(?) Snowshoe Group and local diabasic intrusions. These rocks record a deformational history involving four phases of folding (D₁-D₄) and later brittle faulting (D₅). Earliest recognizable structures consist of recumbant isoclinal folds with a well-developed transposed foliation. This foliation is tightly folded about northwest trending, southwest verging second phase structures. Northwest trending third phase structures and northeast trending fourth phase structures occur as both crenulations and open buckles. Southeast dipping faults cut all earlier structures with tens of meters of normal offset Phase 1 and Phase 2 fold styles are compatible with a flattened buckle fold mechanism of formation, associated with elevated temperatures and reduced viscosity contrasts across layering. Later fold styles are controlled by higher viscosity contrasts and detachment along layering. All phases of deformation are dominated by semi-brittle mechanisms of dislocation slip and glide, mechanical twinning, and microcracking. Temperature activated diffusional creep is only locally active and does not contribute appreciably to total strain. The mineral assemblage garnet-staurolite-kyanite defines a metamorphic peak late in D₂. Metamorphic temperatures of approximately 530° C at 6.0 kb have been determined using garnet/biotite geothermometry. Extensive retrograde metamorphism spans D₃ and D₄, overprinting prograde assemblages and providing evidence for abundant fluids late in deformation. Late phase 1 diabase dykes locally intruded an area to the southeast of Ogden Peak. Major and trace element analyses of samples from these intrusions suggest a calc-alkaline, volcanic arc affinity. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

No description available.

The close association of lead-zinc deposits with dolomite and dolomitic limestone and the common occurrence of these deposits within dolomitic envelopes in limestone present an interesting and challenging problem to economic geologists. A review has been made of the manners in which dolomite and lead-zinc ore are found to be associated. Possible reasons for the association of dolomite and ore and processes by which lime stones in the vicinity of lead-zinc deposits may be altered to dolomite have been considered. Dolomites in general are believed to be very favorable host rocks for lead-zinc ore but whereas this favorability may facilitate the localization of ore in primary dolomites, it can hardly be regarded as the primary localizing factor in those deposits which occur within dolomitized zones in limestone. The alteration of limestone in the vicinity of lead-zinc deposits may be best attributed to magnesium-rich hydrothermal solutions, the magnesium of which is not genetically related to the parent magma. The mechanism proposed by Faust, whereby magnisium-rich solutions are derived from dolomites which have been thermally dissociated in the vicinity of an intruding magma, adequately fulfils the requirements of a dolomitizing agent. If we can assume that ore-bearing solutions have arisen from the same magma that brought about the dissociation of a pre-existing dolomite, then dolomite and ore may necessarily be closely associated by reason of dolomitizing and ore-bearing solutions having been localized by the same structural controls. A study of specimens from the Jackpot property, Ymir, B.C., a deposit occurring in dolomitized limestone, has revealed little information with respect to the process of dolomitization other than indicating that dolomitization preceded sulphide mineralization. Most of the sulphide mineralization at the Jackpot property occurs within calcitic zones in dolomite. It is believed that dolomite has been replaced by the sulphide minerals and has been later partially replaced by calcite in the zones of sulphide mineralization. If Faust’s proposal that magnesium-rich solutions may be derived from a thermally dissociated dolomite in the vicinity of an intruding magma is valid, one may conclude that at a late stage in the hydrothermal activity, when magnesium has been largely removed from the thermally dissociated dolomite, the solutions may become relatively rich in the less soluble calcium carbonate. These later calcium carbonate-rich solutions may be responsible for the replacement of dolomite by calcite in the mineralized zones. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The Strangward Copper Property lies in the front range of the Rocky Mountains, northeastern British Columbia, near the headwaters of the South Tetsa River. It is readily accessible from the Alaska Highway (mile 392) at Summit Lake, B.C. by a pack trail approximately 20 miles in length. Sedimentary rocks exposed on the property consist of dense, fine grained lime stones , and siliceous limestones, and calcareous and carbonaceous sandstones, and thick bedded and massive white feldspathic quartzites. They have been gently folded into anticlines and synclines with northwesterly trending axes. (Rocks of claim group "C" in the foothills are closely folded black shales). There are many vertical faults, some occupied by diabase dykes from 30 to 125 feet in width. The general trend of the faulting is northwesterly. The main ore controls are as follows; (1) Most well defined faults are occupied in places by quartz-carbonate veins which are erratically and sparsely mineralized. In general, faults provided access for mineralizing solutions; hence are considered a primary control in the formation of mineral deposits. (2) Carbonaceous sandstone, as indicated by the locations of four showings, seemed to be most favorable for the deposition of copper minerals within the veins although replacement of the rock was not observed. (3) Fractures, up to 1 inch in width and a few inches in length, filled by copper minerals were observed in brittle white feldspathic quartzite. It is believed that thick beds of quartzite, cut by one or more sets of faults, constitute a structurally favorable host rock. (4) Pyrite replacement deposits, the largest 10 feet in width and 50 feet or more in length, were seen in many places within altered diabase dykes. Although only traces of copper minerals have been found, the existence within these dykes of large, low grade copper replacement deposits is a possibility. (5) Sparse copper mineralization was observed in several places within the altered limestone adjacent to two large dykes. There is a possibility of replacement deposits within this zone of alteration (perhaps 15 or 20 feet in width). (6) Mineralization has not been found in the unaltered upper limestone. This formation however, cannot be regarded as an unfavorable host rock for replacement or vein deposits by the limited amount of work done during the 1950 field season. Study of a dozen polished sections shows two primary copper sulphides, chalcopyrite and bornite, to be present, with chalcopyrite the more abundant of the two. Chalcocite is abundant in some sections but is apparently supergene. However, some primary chalcocite occurs as ex-solution intergrowths with bornite. Secondary covellite is also abundant. Hydrous iron oxides and malachite form the bulk of some sections. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Vancouver Island offers varied relief from coastal plains to high mountains in the central portion of the Island. The coastline is broken, especially in the Western Coast, illustrating beautifully the work of glaciers, and thereby providing Vancouver Island with excellent harbours. These inlets also help in the exploitation of the timber resources of the Island. From these mountains spring up rivers that provide electric power for domestic and industrial uses. The southeastern coastal plain, which is highly developed, varies in width from a mile to a few miles. The glacial soils, with favourable topography, are put to intensive use around the area of urban concentrations, to supply the local markets. Climates differ from one part of the region to another. The Western Coast has an annual rainfall over one hundred inches as compared to about forty inches in the southeast. The northern part of the Island is cloudy, but the south is known for sunshine. Topography, helped by climate, makes Vancouver Island a major forest region and the forest accounts for the prosperity of the region. Forestry is the main primary occupation on Vancouver Island. Most of the secondary and tertiary industries of the Island depend upon forests for their raw material. Forest products contribute a major portion of the Island's export. Pulp and paper production is expanding rapidly. It is the physical and economic factors that make Vancouver Island one of the leading producers of forest products in Canada. Agricultural activity is limited to the southeastern part. Specialized crops are the most favoured ones because they bring high revenues. Dairying and poultry are well developed. Dairy accounts for fifty percent of the total value of the farm products. Because of sub-division and the encroachment by the urban expansion on the farm land, farms are becoming smaller and the number of part time farms is increasing. Fishing is important in some local areas, but processing of fish products is declining. The main fishing regions lie to the northeast and the other is to south and southeast of the Island. In terms of catch, herring leads in quantity, but Salmon is the most valuable. Mining contributes about nine million dollars annually. Structural materials are the most valuable types of production. Coal mining, which was once prominent, is declining, but the Comox fields might change the picture again. Iron and copper are also mined. Because of the favourable climate and opportunities for work, the population of Vancouver Island is increasing steadily. The southeastern part is densely populated. Population consists of many national groups but those of British origin are most numerous. / Arts, Faculty of / Geography, Department of / Graduate

The Big Ledge property is a group of claims in the Upper Arrow lake area, opposite St. Leon hot springs and about 7 miles west of the lake itself. The property is underlain by rocks of the Hamill series of late Precambrian age. These rocks are composed of schists, paragneisses, and crystalline limestone. Intimately associated with these rocks are pegmatite, and banded gneissic and granitic rocks of the pegmatite-gneiss complex of the Nelson batholith. The structure of the Precambrian rocks along the ledge is regular. The beds strike approximately east-west and their average dip is about 40 degrees to the south. The mineralized zone appears to be conformable with the enclosing rocks. However, instead of swinging to the south as one would expect with a decrease in elevation of 3000 feet to the east, the zone continues to outcrop in roughly the same east-west direction throughout its length. This seems to indicate a structural control of some sort if the mineralization is to be attributed to hydrothermal solutions. The mineralization of the Big Ledge is confined to a zone remarkable for its continuity and uniformly low grade. Pyrrhotite is the most abundant sulphide, sphalerite and pyrite occur in about equal quantities, and galena is present in minor amounts. The mineralization does not extend across the entire width of the ledge but is confined to bands or lenses a few inches to several feet thick within the zone. In these bands the sulphides occur either as disseminations in or as massive replacements of silicate minerals that are the products of metamorphism of impure dolomitic limestones. Commonly massive bodies of sulphides appear to be associated with pegmatitic intrusives in the mineralized zone. Geological reconnaissance and laboratory investigations indicate at least two distinct kinds of metamorphism. The first type, regional metamorphism, is indicated by the prevalence of garnet-mica schist throughout the Upper Arrow lake area. The second kind, thermal metamorphism, is apparently restricted to the mineralized zone. It is thought that the thermal metamorphism was the first of a sequence of events, including injection of the pegmatitic material and circulation of hydrothermal solutions that resulted in the low-grade mineralization of the Big Ledge. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Hydrothermal wallrock alteration is an important feature of the gold quartz veins of the Pioneer, and Bralorne Mines in the Bridge River district, British Columbia. In the principal host rocks, Bralorne soda diorite and Pioneer greenstone, the alteration is evidenced by bleaching and, to a limited extent, by the formation of a reddish-brown alteration material to a maximum distance of 2 or 3 feet from the vein walls. By microscopic means, the principal alteration minerals are determined to be chlorite, carbonate, sericite, pyrite, and arsenopyrite with some local biotite. In the minor host rocks, Bralorne soda granite and acid dykes, the hydrothermal alteration is not readily apparent to the naked eye. It consists essentially of sericitization although chlorite, biotite, carbonate and pyrite occur in minor quantities. The hydrothermal wallrock alteration in these four host rocks, has caused an increase in carbon dioxide, potash, sulphur and arsenic and a decrease in silica and soda. The above changes in the wallrock, together with the observed mineralogical nature of the veins, is typical of Lindgren's meso thermal mineral deposits. The high temperature minerals, biotite and tourmaline, are formed in minor amounts by mineralizing solutions introduced prior to the depostion of gold. An important feature of the Pioneer-Bralorne Gold Belt is the uniformity of the nature of quartz veins and of hydrothermally altered wallrock over a vertical range of over 3,000 feet. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

This study investigates the morphologic approach to sediment transport analysis and applies it to the Vedder River, British Columbia. The approach is based on the assumption that changes in channel morphology indicate sediment transport in the river. Despite the connection between these phenomena, only a few studies have examined this relation. The procedures, assumptions and limitations of the morphologic approach are discussed. It is more straightforward to construct a sediment budget for bed material than for wash material, as bed material travels relatively small distances. The Vedder River is a cobble gravel river with dyked banks. Therefore it is a good location for a study of the morphologic approach as bed material can be distinguished easily from wash material. The results of this study are important as aggradation in Vedder River has resulted in major flooding problems. Cross-section survey data were used to estimate volume changes along the Vedder River for incorporation into sediment budgets for several periods over the last decade. The construction of a sediment budget requires knowledge of at least one transport rate or transfer distance. Although the zero downstream transport assumption used in this study was found to be incorrect, it was retained as there are no transport rate measurements. Furthermore, the transport assumption is probably within the error ranges of the sediment budgets. Most of the errors in the sediment budgets were attributed to uncertainty in volume change estimates. When volume change estimates were calculated for different sets of cross-sections, the values varied significantly. This indicates that there is bias in the results. It is difficult to evaluate the degree of bias without a knowledge of actual channel changes. It. was found that the uncertainty in the transport estimates at Vedder Crossing ranged from ±8% to ±25%. These values compare favourably with error analysis results of direct measurements in the Fraser River (see McLean and Church, 1989). An analysis was performed to evaluate the cross-section density that is necessary to obtain a reasonable representation of actual channel changes. The average distance between cross-sections should be relatively smaller in reaches which have large variability in channel change patterns. It was suggested that cross-section spacing in the Vedder River should average between 250 and 300 m. The sediment budget results provide valuable information about the patterns of channel change and the magnitude of flows responsible for large amounts of deposition in the Vedder River. It was found that significant aggradation occurs during exceptional flood events. Most of the material is deposited in the several kilometers immedatiately upstream of the Vedder Canal. The morphologic approach provides a good method for evaluating the sediment transport regime of a river. The usual management time-scale ranges from several years to decades, which is coincident with the time-scale of this approach. Furthermore, the total field effort is less than that required for direct measurements. / Arts, Faculty of / Geography, Department of / Graduate