Thesis (Professional Degree)--University of Missouri, School of Mines and Metallurgy, 1930. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed October 30, 2009) Includes bibliographical references (p. 27) and index (p. 28).

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Thèse (M.Sc.T.) -- Université du Québec à Chicoutimi, 2002. / Bibliogr.: f. 179-185. Document électronique également accessible en format PDF. CaQCU

Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1922. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed June 4, 2009) Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1983. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 100-107).

From Introduction: For at least two centuries and a corresponding number of generations of geologists and miners there has been active argument concerning the origin of certain types of carbonate hosted mineral deposit. The characterization of the type itself was and still is debatable. Objections have been raised to grouping several examples under one heading because each has its individually distinctive features. ·This is especially applicable to the carbonate hosted lead-zinc "sedimentary" deposits. The type that will be discussed in the text to follow is composed chiefly of galena, sphalerite, barite and fluorite, with pyrite , marcasite and chalcopyrite as conspicuous accessory ore minerals. Exceptions to this general copper deficient characteristic displayed by the sedimentary carbonate-hosted lead-zinc deposits are the deposits at Tsumeb and Kombat, Namibia. These deposits are hosted by the carbonate sequence of the Otavi Shelf sediments, and copper, in the form of tennantite, chalcopyrite and bornite, is the major ore constituent. Calcite, aragonite, dolomite and quartz are the commonest nonmetallic gangue minerals but siderite and silica may also be present. In contrast with other lead and zinc sulphide (volcanogenic) deposits, those to be considered here seldom carry noteworthy amounts of silver or any other precious metals. Commonly the country rock is a carbonate; limestone or dolomite, but deposits in. sandstone, shale and conglomerate are not unknown. Characteristic features are ore bodies that extend parallel or nearly so with the bedding although many such deposits are partly, or completely developed along crosscutting fissures and breccias. Some observers regard these fissure fillings as evidence for a magmatic source of the metals, whereas others regard them as an indication of remobilization of ions, metals or minerals orginally present in low-grade stratiform deposits elsewhere in the stratigraphic succession.

Economically important Mississippi Valley type zinc-lead deposits exist in a late Proterozoic dolomite, the Society Cliffs Formation, at north Baffin Island, District of Franklin, N.W.T., Canada. The Society Cliffs Formation ranges from 1,000 to 2,000 feet in thickness and is underlain by up to 2,000 feet of black, organic-rich shale, the Arctic Bay Formation, and overlain by either black shale and limestone of the Victor Bay Formation or by red, fine- to coarse-grained clastic rocks of the Strathcona Sound Formation. Disconformities exist between each of the formations. Society Cliffs Formation has undergone at least four temporally distinct episodes of karstification since its deposition. The most important karst episode, with respect to the formation of the zinc-lead deposits, occurred during the hiatal interval between the deposition of the Victor Bay Formation and the deposition of the Strathcona Sound Formation. During this hiatal interval a holokarst developed in Society Cliffs Formation and a large integrated cave system of the Mammoth Cave-Flint Ridge Cave System type was formed; i.e. long, nearly horizontal, tubular passages were formed during initial periods of base-level stabilization, followed by the development of sub-vertical canyons beneath the tubes when the base-level dropped. After this karst episode the Society Cliffs Formation was deeply buried and the cave system was partially or completely filled with sulphide and carbonate minerals. The zinc-lead deposits are characterized by banded structure which comprises pyrite, relict marcasite, sphalerite and galena interlayered with sparry dolomite. The zinc-lead deposits contain several sedimentary structures that were formed by a chemical deposition-chemical corrosion process. These include cross-stratification, cut-and-fill and onlap. Onlap indicates the paleocaves were filled from the floor up. The meteoric waters which formed the caves did not form the zinc-lead deposits because the temperature of ore deposition was between 200°C and 150°C, the calculated oxygen isotope composition of the ore fluid is +12.8 per mil, and mineral stability and isotopic data indicate the oxygen fugacity decreased during ore deposition. The sulphide sulphur isotope composition of the zinc-lead deposits has a relatively narrow range about +26 per mil, similar to that of sulphate evaporite (+23.7 per mil) which exists locally within the Society Cliffs Formation. Lead isotope data indicate the lead in the deposits was derived by at least a two-stage process from a source with a uniform uranium-thorium ratio. The ore fluid and contained metals are postulated to have been derived from the Arctic Bay Formation during a late-stage dewatering of the shale. Sulphide deposition may have been caused by the chemical reduction of sulphate which existed in the ore fluid when the ore fluid entered hydrocarbon-filled caves. The hydrocarbons were probably expelled from the Arctic Bay Formation shale during an earlier stage of thermal metamorphism and dewatering. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

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Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1931. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed February 9, 2010) Includes bibliographical references (p. 38-39).

The Damara-Katanga orogen in central-southern Africa represents an area of 1.73xl0⁶ sq. km. The region is considered one of the wealthiest metallogenic provinces in the world. Successful exploration for stratabound base-metal deposits has taken place at this particular area since the introduction of more organised methodology in the early 1920s. The genesis, location and distribution of the ore deposits are related to their tectonic settings. Geodynamic evolution of the orogen, which initially formed part of a complex Pan-African rift system, comprises the following stages rifting; downwarping, including spreading on the western portion; syn-orogeny and late-orogeny. Two major tectonic events in the history of the region have been identified: the Katangan (900-750 Ma) and the Damaran episodes (750-500 Ma). Timing of mineralisation of ore deposits has been related to the evolutionary stages of the orogen. Genetic models of the most productive deposits are briefly discussed in this dissertation. The sedimentological, geochemical, paleogeographic and structural features can be employed as geological guidelines for integrated exploration programmes. Discoveries of major deposits and prospects in the orogen are also summarised, focussing on the exploration methods employed. The cost-effective use of the exploration techniques includes the classical copper-lead-zinc soil sampling for residual soils such as those in the Copperbelt area. Airborne magnetics and electromagnetics and follow-up ground geophysics have proved successful in areas where the cover is transported in the search for shallow ore deposits such as the Matchless massive sulphides. Remote sensing, geochemical and geophysical techniques have been tried in covered areas of western Botswana. The lack of geological control makes this interpretation difficult. A detailed geological mapping and the use of geochemical and geophysical techniques has been used to delineate carbonate-hosted base-metal deposits at the Otavi Land. The more expensive traditional methods necessary for the delineation of orebodies, such as pitting, trenching and drilling, are also discussed. Using a sequential approach, a possible exploration strategy is suggested, outlining the cost-effective use of remote sensing, geochemical and geophysical techniques. Standardisation in basic geological information is required for future successful explorations in the Damara-Katanga orogen, as well as attractive mining policies. In the event of their implementation, exploration perspectives are promising, specifically in terms of ore potential.