Pioneer gold mine is 100 miles north of Vancouver in the Bridge River area of the Lillooet Mining Division, British Columbia. The mine has been worked extensively for more than 30 years and has produced over a million ounces of gold. The gold occurs in ribboned quartz veins which average less than three feet in width and are classified as mesothermal. The gold content of the veins is variable and it occurs, with a small amount of sulphides. Gold values greater than 0.5 oz. Au/Ton are considered economic. The Pioneer mine occurs in a northwesterly trending zone, called the Cadwallader Gold Belt, formed by the Hurley-Noel formation of sedimentary rocks and the Pioneer formation of volcanic rocks. The gold-quartz veins are genetically related to the Bralorne intrusions which occur within the rocks of this zone. There is a repetition of these formations in the Pioneer property, which can be explained by normal movement on a fault. A wide zone of serpentine marks the position of this fault, which is called the Cadwallader Break. This Break is a first order fault and can be related to second order faults formed during the same period of deformation. These second order faults are now occupied by quartz and form the veins which are mined. Planes of liquid inclusions in the quartz of the quartz veins have attitudes similar to those of the megascopic planes of rupture. These planes of inclusions were formed by the annealing of microscopic fractures in the quartz veins. The attitude of these fractures was determined by the same deformation which produced the megascopic fractures, including the 'Cadwallader Break'. The Bralorne intrusion in the mine area is composed of the Bralorne diorite and soda granite which contain albite as their only feldspar. No evidence has been formed to indicate that the intrusion is formed by the process of granitization. Sodic solutions, possibly parts of the final differentiate of the magma which formed the Bralorne intrusion have caused albitization of the intrusion and the Pioneer formation. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Kinskuch Lake area covers a fifty-square mile portion of the Portland Canal district of western British Columbia. Kinskuch Lake lies near the eastern border of the Coast Mountains, approximately twelve miles north of the port of Alice Arm. Reconnaissance mapping of the area on a scale of 1" = 1000’ was done during part of the summer of 1956. Rock specimens collected in the field were examined microscopically and the results of the latter investigation form the greater part of this thesis. The interbedded volcanic and sedimentary rocks of Kinskuch Lake area were deposited during the period of Mesozoic volcanism and sedimentation which was widespread throughout western British Columbia and southeastern Alaska. Near Kinskuch Lake, the earliest products of Mesozoic volcanism are represented by augite porphyry volcanic breccias, crystal tuffs, flows and flow breccias outcropping along the western margin of the map area. Augitic volcanics are overlain to the east by interfingering felsitic breccias and tuffs, sedimentary rocks and greenstone. East of Kinskuch Lake, the latter rocks pass gradationally into a thick overlying sequence of felsitic volcanic breccia, crystal tuffs and feldspar porphyry flows. The youngest rocks outcrop near the eastern margin of the map area. Here, argillites and conglomerates overlie felsitic volcanic breccia and interbedded tuff. The Mesozoic volcanic and sedimentary rocks were folded, faulted and intruded by keratophyric and lamprophyric dykes. As a last stage in the geological sequence of events, volcanic rocks at the southeast corner of Kinskuch Lake were altered and mineralized. Highly fractured or sheared greenstone and felsitic volcanics were altered to chlorite, pyrite, epidote, sericite quartz and calcite. Minor chalcopyrite mineralization accompanied rock alteration and many small quartz-carbonate veins cut the altered rocks. Some of the latter veins carry pyrite, chalcopyrite and traces of sphalerite and galena. Albitization of some of the igneous rocks outside the altered zone accompanied the widespread carbonate alteration. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The regional geology of the McDame Area is described briefly and a detailed description of the "Contact Group" mineral claims within this area is presented. The "Contact" vein deposit described herein is apparently unique, as far as geological literature is concerned, in its primary mineral associations. This vein, in a contact-metamorphic environment, possesses the form and textural characteristics of a mesothermal deposit. Typical high, medium and low temperature minerals are present in relationships that suggest unbroken deposition in the vein and a genetic relation to both the associated intrusive and related pyrometasomatic deposits. The occurrence and origin of native sulfur, wad, and hydrocarbon in the vein are discussed. Alabandite (MnS), which is a common constituent, is classified, on grounds of ex-solution phenomena, as having crystallized at temperatures greater than those previously assigned to it. The role of manganese in this deposit is given special attention. The conclusion is reached that the Contact Vein was formed at shallow depth under conditions of high but rapidly falling temperature and locally high pressure. Accordingly, it illustrates telescoping within the mesothermal-pyrometasomatic range of physical conditions. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Aiken Lake map-area lies in the Cassiar District of north-central British Colombia between 56°00' and 57°00’ north and longitudes 125°00' and 126°00' west. It is a relatively rugged, glaciated area lying almost entirely within the Omineca-Cassiar Mountain System. The oldest rocks within the map-area are quartz-mica schists, garnetiferous schists and quartzites of probable Proterozoic age conformably overlain by Lower Cambrian chlorite schists, slates, quartzites, and limestones. A relatively large area of these Proterozoic and Cambrian rocks has been further metamorphosed to feldspathized quartzite and gneiss. A total of nearly 30,000 feet of interbedded volcanic pyroclastic and true sedimentary rocks ranging in age from Devonian or Mississippian to Upper Triassic outcrops in a broad belt across the central part of the map-area. These rocks are intruded by dykes, sills, stocks, and batholiths of Upper Jurassio or Lower Cretaceous age. The intrusive bodies range from granite to pyroxenite in composition, granodiorite being the dominant rock type. A body of conglomerate at least 5500 feet thick of probably Lower Cretaceous age, containing many pebbles of intrusive rocks, is faulted into Triassic or Upper Palaeozoic rocks. The Proterozoic and Lower Cambrian rocks have been folded, apparently during their period of metamorphism, into large anticlinoria. The planes of schistosity of the metamorphosed rocks lie approximately parallel to the limbs and to the crests of the anticlinoria. The grade of regional metamorphism of these rocks increases uniformly as lower stratigraphic horizons are reached. Known mineral deposits within the area are almost entirely confined to the Lower Cambrian and Proterozoic schists and limestones, or to the aureoles of the Jurassic-Cretaceous igneous bodies. Those in the Lower Cambrian and Proterozoic rocks are typically of the lead-zinc-silver type. Many of these mineral occurrences have no known association with igneous rocks. The deposits found within the aureoles of the Jurassic-Cretaceous igneous bodies have characteristic gold-quartz, gold-copper, or copper-lead mineralization. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

No abstract included. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The Stewart mining camp in northwestern British Columbia is abundantly mineralized with widely distributed, texturally and mineralogically varied, precious and base metal deposits. This report documents the geologic setting of the mining camp and the geologic features of the major mineral deposit types. The Stewart camp is underlain by a 5-kilometre-thick Upper Triassic to Lower Jurassic (Norian? to Toarcian) island arc complex of calc-alkaline basalts, andesites and dacites with interbedded sedimentary rocks. Coeval (211-189 Ma) hornblende granodiorite plutons intruded the arc at two to five kilometres depth. Rocks were deformed during mid-Cretaceous (110 ± 5 Ma) tectonism that produced north-northwest-trending folds, penetrative fabric and lower greenschist facies regional metamorphism (290°±20°C, 4.5 ±1.5 kb). Mid-Eocene (54.8-44.8 Ma) biotite granodiorite of the Coast Plutonic Complex intruded the deformed Mesozoic arc complex. Two mineralizing events formed over 200 mineral occurrences in the district. These two metallogenic epochs were brief (< 5 million years), regional-scale phenomena characterized by different base and precious metal suites. The Early Jurassic ore-forming episode produced Au and Au-Ag-Zn-Pb-Cu deposits. The mid-Eocene episode produced Ag-Pb-Zn ± W ± Mo deposits. Early Jurassic deposits have a characteristic lead isotope signature (²⁰⁶Pb/²⁰⁴Pb = 18.816; ²⁰⁷Pb/²⁰⁴Pb = 15.617) and include gold-pyrrhotite veins, gold-silver-base metal veins, and stratabound pyritic dacites. All Early Jurassic mineral occurrences are late- to post-intrusive deposits that were emplaced in andesitic to dacitic host rocks at the close of volcanic activity, about 190-185 million years ago. Transitional gold-pyrrhotite veins (Scottie Gold mine) formed in en echelon tension gashes developed in country rock around Early Jurassic plutons during late magma movement. Epithermal gold-silver-base metal veins and breccia veins (Big Missouri and Silbak Premier mines) were deposited along shallower sub-volcanic faults and in hydrothermal breccia zones formed along dyke contacts. Stratabound pyritic dacite tuffs (Mount Dilworth and Iron Cap prospects) formed where venting fumarolic fluids and hotspring pools deposited abundant fine pyrite in local areas on a cooling ignimbrite sheet. Eocene deposits also have a characteristic lead isotope signature (²⁰⁶Pb/²⁰⁴Pb = 19.147; ²⁰⁷Pb/²⁰⁴Pd = 15.627) and include silver-rich galena-sphalerite veins, gold-silver skarns and, beyond the study area, porphyry molybdenum deposits. These mineral occurrences are related to Middle Eocene plutons of the Coast Plutonic Complex. All are late- to post-intrusive deposits emplaced about 50-45 million years ago. Mesothermal silver-lead-zinc veins (Prosperity/Porter Idaho and Riverside mines) were deposited in brittle zones along major fault structures. Skarns (Oral M and Red Reef prospects) developed where plutons cut limestone or limy siltstone units within minor turbidite sequences. Major porphyry molybdenum deposits (Kitsault mine and Ajax) developed where mid-Eocene stocks were emplaced in thick turbidite sequences. Diagnostic features such as lead isotope ratios, stratigraphic and plutonic associations, alteration assemblages, sulphide mineralogy and textures, and precious metal ratios allow discrimination amoung these different deposit types. Using these criteria, the most prospective areas for each deposit type have been targetted for exploration. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Record sections from partially reversed refraction lines in northern British Columbia show that the amplitudes of upper mantle arrivals vary smoothly with distance. The pattern of crustal arrival amplitudes is not smooth. Normalization of the seismograms to remove the amplification caused by shot size and instrument response show the effects of recording sites on Pn amplitudes are minimal. Models derived from ray theory indicate a crust which thins from about 40 km in the Omineca Crystalline Belt to about 25 km in the Insular Trough. The average Pn velocity is 8.06 km/s. The average crustal velocity is 6.4 km/s. The secondary energy would indicate the models are greatly simplified. A time-term profile between the Omineca Crystalline Belt and the Coast Mountains suggests a Mohorovicic transition which is characterized by two significant topographic wavelengths. The shorter (200 km) wavelength correlates roughly with the Cordilleran structural elements of Wheeler et al. (1972). The larger (800 km) wavelength may have tectonic significance. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The Ajax-Monte Carlo property is a small porphyry copper deposit located approximately six miles south of Kamloops, British Columbia on the south flank of the Iron Mask Batholith. The Batholith and successor intrusives were emplaced in a northwest-trending structural element named the Carabine Creek Lineament. Early phases of the batholith were basic and coarse-grained and form the core of the complex. Later phases, of intermediate to acidic composition, were emplaced along the structurally weak margins of the core. Three stages of fracturing were recognized at the property. The earliest brecciated the coarse-grained phases prior to the emplacement of the fine-grained intrusions. The second stage of fracturing was synchronous with the alteration; the final stage created the stockwork in which the mineralization was concentrated. The propylitic alteration facies developed at the property is typical of porphyry copper deposits except that only minor quantities of quartz are present. The potassic facies is distinctly different in that it lacks abundant red orthoclase and biotite. Pyrite and chalcopyrite are the most abundant sulfides; and bornite is occasionally observed. Magnetite is a common accessory in the basic intrusives. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The northerly trending Hozameen, Yale and Hope faults transect the northwesterly trending Custer Gneiss and Hozameen, Ladner and Jackass Mountain Groups. Yale Fault separates gneisses of the Hozameen Group to the east from Custer Gneiss to the west. The Custer Gneiss, as herein restricted, is compositionally distinct from the Hozameen Group and shows a period of early deformation not present in the Hozameen Group. During the Cretaceous, regional deformation and greenschist facies metamorphism of the biotite zone affected rocks between the Yale and Hozameen faults. These rocks grade into gneisses of the hornblende hornfels facies within a few hundred yards of the Spuzzum Quartz Diorite and Yale Intrusions. This restricted contact metamorphism contrasts with the widespread, high temperature and pressure metamorphism found in this and other areas around the Spuzzum Quartz Diorite on the west side of the Hope fault. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The geology of the East Sooke peninsula comprises a core of olivine gabbro, peripherally uralitized and bounded on the north and east by upper Eocene Metchosin basalts of submarine origin. The gabbro intrudes the basalts which are unconformably overlain by sediments of the Sooke Formation of Miocene-Oligocene age. The Sooke gabbro intrusion is an elliptical body of slightly differentiated olivine gabbro which is composed of calcic plagioclase and clino-pyroxene with minor olivine and orthopyroxene. The gabbro does not exhibit any obvious cryptic or cumulate layering of the type which characterises many other layered basic igneous intrusions. Instead steeply dipping structures such as weak layering, foliation and lineation are believed to be flow structures. Intensity of uralitization of the olivine gabbro increases near the margin of the intrusion and towards fractures which appear to have acted as channelways for a convective flow of hydrous fluids within and around the hot intrusion. Concentrations of copper sulphides, deposited from these fluids, are found in structurally favourable areas. The gabbro intrusion is thought to mark the position of a volcanic neck or feeder, now exposed by erosion of a thick sequence of Eocene submarine basalts which built up from ocean floor in a manner similar to the Hawaiian chain of oceanic islands. An hypothesis of oceanic origin for the basalt and gabbro sequence is complemented by reinterpretation of the geophysical data from south Vancouver Island. The Metchosin basalts and gabbro intrusions are thought to represent an oceanic suite of rocks emplaced by ohduction on the southern tip of Vancouver Island. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate