The Witwatersrand basin is loaded with carbon. The carbon deposits locations are not site specific. Many localities where deposits occur are related to the structure and the sedimentology of the particular area. The purpose of this thesis is to document and describe the distribution of carbon in the Witwatersrand basin and to establish the mechanisms controlling emplacement. The approach used was a multidisciplinary one incorporating aspects of sedimentology and macro to mesoscopic tectonic structures and their relationships with carbon distribution patterns to establish the controls on carbon emplacement. One of the major controls on carbon deposition is structural geology. Bedding parallel fractures that cut pebbles with carbon fill is indicative of the influence of bigger and more forceful movements within the ore body. The thesis begins with a back ground study of all the major theories and ends with a possible explanation for the influence of structure and sedimentology on the deposition of carbon, and a new catalyst for the dehydration reaction that could lead to the deposition of carbon. The various types of carbon have been classified and grouped to specific sedimentological and tectonic structures. These types are deposited in lithofacies horizons that are not related in space to one another. They also differ in texture. Type A is observed in reefs and bedding planes, bedding parallel fractures and on fault planes. Type B consists of massive carbon and vug type carbon. Carbon on the reef contacts in most cases is developed on intersections with fluid pathways (phylonites or shear zones) which are characterised by the alignment of the minerals within the pathway. Carbon precipitation is controlled by the type of footwall and the amount of fluid pathways. The higher the occurrence of bedding parallel fractures the more consistent the emplacement of carbon. Phylonites are classified as follows: Type 1 exhibits a low degree of deformation and the minerals show a low degree of orientation. Type 2 exhibits a medium degree of deformation and the minerals show a larger degree of orientation. Type 3 phylonite is where all the original sedimentary character of the original rock has been sheared and the deformation gives rise to a foliated rock with a distinctive foliation. It is suggested that the large extensional faults in the Free State Gold Fields and the Master Bedding plane fault in the West Rand Gold Fields are conduits for the fluids into the Basin. The in-flow of fluids is from below the reef horizons. It is further speculated that in the Free State, the fluids had a north-easterly transport direction. The SEM analyses showed new mineral associations. The mineral phases are shown in three dimensions and the order of precipitation can be deduced. The element tantalum was prominent in one of the high grade samples. The most prominent mineral in the fluid pathways within the matrix of the various reefs is pyrophyllite. The carbon is emplaced within the pyrophyllite within a fluid pathway and this is indicative of the sequence of mineralization. The uranium replaced the pyrophyllite and the pyrite crystallized in a fracture within the pyrophyllite. It is concluded that the three main minerals: carbon, uranium and gold all came in at the same time into the basin. A hydrothermal origin for carbon and associated minerals is supported by the study. The proposed hypothesis to explain the timing and origin of carbon and gold into the Witwatersrand Basin is that of the 2.02 Ga Vredefort Impact event. Gold and uranium are inferred to have been transported by the carbon plasma that originates from the mantle during the Vredefort Impact event.

The late Neoproterozoic Salient Platform (Byng Formation, upper Miette Group), located 50 km northwest of Jasper, Alberta, contains one of three known occurrences worldwide of the Cloudina-Namacalathus fossil assemblage. / The Salient Platform initiated in relatively deep water (minimum 30-50 m) on Mount Machray. Lowermost carbonates on Salient Mountain and The Colonel were deposited in quiet environments behind the developing stromatolitic reef. The upper two thirds of the platform formed in shallow water and consists of huge, elongated Platella and Cryptozoon bioherms, within which most shelly fossils are found. Carbonate production is terminated by Gog Group siliciclastic sedimentation. Thin, shell-bearing stromatolitic carbonates discovered within the lowermost Gog Group bring into question the current position of the Precambrian-Cambrian boundary in the southern Rocky Mountains (western Canada). / Petrographic and geochemical data indicate that the Salient Platform has undergone significant diagenetic alteration. delta13C values of microsparitic limestones appear to retain a primary isotopic signature, which correlates well with coeval late Neoproterozoic successions worldwide.

The Grey River Area lies on the south coast of Newfoundland. In general, it includes the land between Grey River and Haie de Vieux, lat. 470 40’ - 47°50’, long. 51’001 - 57°15 1. The area may be reached by steamer, which runs weekly between Port aux Basques and Argentia. The nearest major settlement is Burgeo, 24 miles west along the coast; Ramea, a minor fishing port lies 12 miles southwest on Ramea Island. The Grey River area is 87 miles due south of Buchans. It is accessible from the air, and both Grey River and Long Pond have adequate facilities for landing small sea planes. The Grey River fishing settlement lies on Grey River, about half a mile from the open sea. It is built on a small triangular alluvial cone, about 400 by 600 feet in dimension, inhabited by 30 families, with a total population of 250. The settlement is bordered on two sides by cliffs, which rise steeply to 800 feet above sea level. Inland, the country is uninhabited. / fr

Since geologists first observed deformed rocks, they have attempted to reproduce the structures they saw by using models. The purpose of the models was to achieve an understanding of the cause of the structures, of the way in which they were produced and the stages through which they passed during their formation.

North of Fond du Lac River estuary, at the east end of Lake Athabaska, is an extensive area underlain by a complex of dark colored hypersthene-bearing rocks, which has been mapped as a norite intrusion.

The Sutton Mountains form the principle western tectonic element of the Appalachian Mountain system of Southern Quebec and a northern continuation of the Green Mountains in Vermont. In the area under study the Sutton Mountains are underlain by a fairly-uniform assemblage of schists of the lower greenschist facies which are generally referred to as the Sutton Schists. Thin quartz layering and a uniformly-developed schistosity, generally parallel to this layering, form a bread anticlinal arch, the Green Mountain - Sutton Mountain anticline, in which several schistosities and associated lineations are developed. The schists grade to the east and to the west perpendicular to the regional trend into less metamorphosed sedimentary rocks of various types and ages ranging from Precambrian(?) to Cambrian. [...]

p.2 missing from manuscript. / The system Fe-C-0-S was studied in detail in the temperature range 75°-800°C. In general, when H2o was added to the system, it lowered the stability of the assemblages by some l5°-20°C. The limit of stabi lity of siderite in presence of the following assemblages was determined for total pressures of 2OOO, 1000 and approximate1y 1 bar. [...]

The Thetford-Black Lake area, Megantic County, Quebec, has been one of the most important producers of chrysotile asbestos for over 60 years. The asbestos has been obtained either from a large mass of partly serpentinized peridotite, thought to be laccolithic in shape, or from a narrow body of serpentinized peridotite that parallels the structural trend of the area, known as the Pennington Dyke. The mines and open pit workings of the larger mass have always encountered light-coloured holocrystalline dykes which vary in composition from a diorite to a quartzitic vein, but which are always referred to by the miners and mine operators as "granite". Small deposits of chromite are found in the same mass, associated with an olivine-rich phase of the peridotite. Here again, "granite" dykes are encountered, although not as extensively as in the asbestos workings. The object of this thesis is, by the study of published reports on these acidic intrusives and with the help of some original studies, to report on their petrographic character and their distribution, and draw conclusions as to their age, origin, and economic importance.

Igneous rocks in the Chugach metamorphic complex (CMC) of southern Alaska form part of the Sanak-Baranof belt, a series of forearc plutons believed to have been formed by subduction of a spreading ridge. Trace element and Nd-Sr isotopic data suggest that magmas were derived from the mixing of two sources: melted accretionary wedge sediments and mafic material underplated at the base of the wedge as the ridge was subducted. Metabasaltic amphibolites at Yakutat Bay found to be derived directly from material of MORB composition are further evidence that this underplated mafic source existed. Ridge migration along the Alaskan margin was generally towards the east. However, new U-Pb and $\sp{40}$Ar/$\sp{39}$Ar geochronology data show that within the CMC this movement was probably complicated by the subduction of a transform, causing the locus of magmatism to appear to jump from Van Cleve Glacier to Yakutat Bay at 54 Ma.

<p> The Pennsylvanian-Permian Fountain Formation is an arkosic conglomeratic sandstone that was deposited in fluvial environments along the eastern flanks of the ancestral Rocky Mountains. The formation owes its pinkish red color to hematite cement that was precipitated early in its diagenetic history. Within the formation are whitened strata that crosscut laminations and facies boundaries, indicating that they are the result of a post depositional process. Whitened features are seen in core, indicating that they are not caused by modern weathering processes. Whitened strata similar to those present in the Fountain Formation are usually the result of the migration of reducing fluids. These fluids reduce and remove hematite cement leaving the fluid migration pathways whitened. Fluids that can cause large-scale reduction and removal of iron oxides include basinal aqueous brines and hydrocarbons. </p><p> Whitening within the Fountain Formation appears in a predictable stratigraphically-controlled manner and is most common in coarse channel sandstone facies that are adjacent to laterally continuous paleosol mudstones. The predictable distribution of whitened strata in outcrop suggests that fluid followed preferential pathways. Outcrop analysis indicates that these pathways are closely associated with thin paleosol mudstones and overbank deposits that seem to have focused the paleo-fluids that then flowed laterally along them in the coarser channel sandstones. Laterally continuous paleosol mudstones therefore may have played an important role in determining the spatial location of paleo-fluid migration pathways. Fluids moved through the formation as stringers that took up less than 15% of the total rock volume. </p><p> The Fountain Formation has a complex diagenetic history and has undergone multiple stages of cementation. A late stage dolomite cement contains organic matter, hydrocarbon inclusions, and is associated with bitumen. This cement is restricted to whitened strata and likely precipitated from a hydrocarbon-bearing fluid. The hydrocarbon-bearing fluid may have been the fluid that was responsible for whitening sections of the Fountain. Fluid inclusion data indicate that the precipitation of this cement took place after the formation was buried to a depth of at least 1.3km, which would have been during or after Laramide deformation. The presence of bitumen and hydrocarbon inclusions in strata that were not buried to hydrocarbon generating depths indicates that the hydrocarbon-bearing fluid likely migrated through the formation from deeper in the basin. </p><p> The amount of whitening in outcrop decreases in the northern study sites and may be related to a decrease in coarse channel sandstone facies. The lesser abundance of those facies at northern study sites may be because those sites were further from the sources for coarse material and were associated with lower energy environments. Although there is less whitened rock at the northern sites, the amount of fluid that passed through them may have been similar to the amount of fluid that passed through the southern sites. Evidence of this is a higher amount of feldspar alteration in whitened strata in the northern site, which may have been caused by more fluid flow per volume of rock because there were fewer coarse channel facies to act as conduits.</p>