Theses and Dissertations at Montana State University (MSU)
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Item Syn-orogenic magmatism, mid-crust exhumation, and placer gold deposition: the Anaconda metamorphic core complex of western Montana(Montana State University - Bozeman, College of Letters & Science, 2020) Howlett, Caden James; Chairperson, Graduate Committee: Andrew K. Laskowski; Andrew K. Laskowski was a co-author of the article, 'Determining the source of placer gold in the Anaconda metamorphic core complex supradetachment basin using detrital zircon U-PB geochronology, pioneer district, western Montana' submitted to the journal 'Geosphere' which is contained within this thesis.; Aislin N. Reynolds and Andrew K. Laskowski were co-authors of the article, 'Farallon slab-removal as a driving force of metamorphic core complex formation in the western USA: details from the Anaconda metamorphic core complex of western Montana' submitted to the journal 'Tectonics' which is contained within this thesis.Since their initial discovery in the late 1960's, metamorphic core complexes have remained of high interest in tectonics research. Early uncertainty regarding the mechanics of slip along low-angle normal (detachment) faults is now accompanied by controversy surrounding the relationship between magmatism and large-magnitude extension. As deeply exhumed geologic structures that record lithospheric thermomechanical processes, investigating core complex formation is crucial to understanding how the mid-crust behaves in extensional tectonic settings. In some regions, the exhumation of these structures is also linked to the formation of economically valuable mineral deposits, making them of notable societal importance. This thesis is a two-part investigation of core complex evolution that addresses the concepts above, formatted with introductory and concluding chapters that bound two main chapters prepared for publication. Chapter two consists of a study that tests the utility of using detrital zircon (DZ) U-Pb geochronology and DZ unmixing models to determine the source of placer gold. New zircon U-Pb (n=1,058) and Lu-Hf (n=61) isotopic data are presented from four placer deposit samples extracted from the Pioneer District of western Montana. Geochronology and DZ unmixing modeling suggest that gold from the placer deposits was derived from vein and skarn lode sources in northern footwall of the Anaconda metamorphic core complex (AMCC). Our data offers the first DZ-based support for previous interpretations that the Late Cretaceous Royal Stock pluton precipitated gold along its contact with overlying Proterozoic through Mesozoic supracrustal rock, and was subsequently weathered, transported, and deposited in the AMCC supradetachment basin during the Late Oligocene-Early Miocene. Chapter three consists of an integrated geologic, geochronologic, thermochronologic, and isotopic investigation of the AMCC footwall. Results suggest that the AMCC is an example of a core complex that was primed for large-magnitude extension through crustal thickening and voluminous magmatism. It is proposed that buckling of the Farallon slab, marked by the onset of 'ignimbrite flare up' volcanism, was responsible for the initiation of AMCC extension. Furthermore, a compilation of MCC cooling ages and ages of Cenozoic volcanics across the western USA suggest that removal of the Farallon Plate was a primary driver of Cordilleran core complex formation.Item Mining for empire: gold, American engineers, and transnational extractive capitalism, 1889-1914(Montana State University - Bozeman, College of Letters & Science, 2018) Bartos, Jeffrey Michael; Chairperson, Graduate Committee: Billy Smith; Tim LeCain (co-chair)Between 1889 and 1914, American mining engineers drew on their experience in mining in the American West into management positions with prominent mining finance firms in the British Empire. The careers of three engineers, Hennen Jennings, John Hays Hammond, and Herbert Hoover, demonstrate their influence on British gold mining investment and on the imperial system. The professional biographies of these engineers demonstrate their racialized labor practices, access to technology and capital, ideas about management, and willingness to interfere in the politics and economies of sovereign nations for the interests of the mining finance industry, notably the Transvaal Republic and late Qing China. In their actions in the colonies, they employed the latest mining technologies to extract gold from low grade ores, imposed labor conditions on the basis of race (including the legal foundations of Apartheid in South Africa), and directed investment capital toward profitable mining in support of the monetary gold standard and shareholder dividends. Along with hundreds of other mining engineers, they oversaw a world-historical expansion of the world's gold supply through the expansion of gold mining on the Witwatersrand in the Transvaal Republic and in Western Australia, effectively doubling the world's supply of gold in two decades. These engineers were agents of transnational extractive capitalism and the British and American empires. As an integral component of their careers, they operated in the core of empire: major centers of investment such as London and New York, the media and publishing worlds, and even world's fairs. They communicated their professional activities and technical developments through the Engineering and Mining Journal, the premier mining publication of the era. They promoted world's fairs, ensuring that mining was prominently featured as an aspect of civilization at these expositions. They also acted as public intellectuals, speaking and publishing on topics of empire, well beyond the purview of the mine. Based on archival research, contemporary technical journals and media accounts, and autobiographical documents, this dissertation analyzes the influence of American Mining Engineers, both good and bad, in shaping the British Empire and the modern world system before the outbreak of World War 1.Item Development of polarizing spectral bandpass filter using dual subwavelength metallic gratings(Montana State University - Bozeman, College of Engineering, 2017) Hohne, Andrew Joseph; Chairperson, Graduate Committee: Wataru NakagawaRecent work in climate science has shown the need for a polarizing spectral bandpass filter in order to passively and remotely determine cloud water phase. Presented here is a novel design of such a filter based on two subwavelength gold gratings separated by a dielectric surface relief grating. It is shown that a Fabry-Perot resonance occurs in the cavity between the gold gratings while surface plasmon polariton resonances occur at the two metal/dielectric interfaces. It is further shown that these two resonance effects couple together to create a spectral bandpass that is high and narrow enough for the remote sensing application. These resonance effects can be changed in shape and position by adjusting the width, height, period, and separation between the gold gratings. It is further observed that the surface plasmon polariton resonances also have the effect of suppressing light transmission at certain wavelengths, allowing the spectral bandpass shape to be tuned, reducing out-of-band transmission. The polarizing effect of these gratings results from the rejection of light polarized along the grating rulings, a phenomenon that is well documented to occur in subwavelength wire grids. Experimental data on prototype gratings show good agreement with predicted performance calculated using numerical rigorous-coupled wave analysis once we account for uncertainties in the material properties and device geometry due to fabrication and processing variabilities. This numerical method is used in conjunction with analytical approximations like zero-order effective medium theory to develop a design process that can be extended to any wavelength in the shortwave infrared region. All devices undergo a final global parameter optimization procedure to account for any subtle near-field effects. Finally, I present designs of three devices optimized for operation at wavelengths of 1550 nm, 1640 nm, and 1700 nm. These devices share characteristics that make them able to be simultaneously fabricated on the same substrate, a crucial step if they are to be built into an array. The final devices all have a peak transmission of greater than 80%, and spectral widths of less than 40 nm.Item Kinetic modeling of gold nanoparticle formation for radiation dose prediction(Montana State University - Bozeman, College of Engineering, 2017) Akar, Burak; Chairperson, Graduate Committee: Jeff Heys; James Wilking (co-chair)Nanoparticles have numerous uses in the biomedical sciences, and this study focused on use of gold nanoparticles (GNPs) for measuring ionizing radiation dose. GNPs synthesized at various radiation doses were experimentally characterized and two mathematical models were developed to simulate the synthesis process. The first is based on the Finke-Watzky model and predicts the rate of soluble gold salt conversion to GNPs, and the second model is based on a population balance model and predicts nanoparticle concentration and size distribution. The model parameters that provided an optimal fit to experimentally gathered data were determined, and both models were able to capture the experimental absorbance time trends. The population balance model, however, had the greater predictive power as it was able to capture mean particle size trends that were consistent with experimental measurement.Item The use of composted municipal waste to revegetate a high elevation mine site(Montana State University - Bozeman, College of Agriculture, 1993) Vodehnal, Gary LynnItem Geochemical characteristics of a waste rock repository at a western gold mine(Montana State University - Bozeman, College of Agriculture, 1997) Outlaw, Jason DwayneItem A linear development(Montana State University - Bozeman, College of Arts & Architecture, 1984) Hoke, Carey Laurence; Chairperson, Graduate Committee: Richard HelzerJewelry provides a framework with a long historical tradition. I work within that tradition and find it both comfortable and challenging. While submitting to the functional restriction of the brooch (that it pin), there remain many possibilities to be explored. In this group of pins, I have tried to allow that function to remain unconcealed while still dealing with aesthetic considerations. There is a technical challenge inherent in the making of jewelry which fascinates me. The possibilities for mechanical inventions as well as manipulation of the image are unlimited. Sometimes I emphasize these technical solutions, while at other times I prefer to hide them as much as possible in order to play logic against the illogical. In many cases, the properties of the materials themselves suggest solutions to technical problems, thereby contributing to the aesthetic development of the piece. Tantalum, for example, is a malleable metal which maintains strength and integrity even when drawn out to thin wire. It cannot readily be silver soldered, however, and this has led me to develop other means of connection which then become a part of the visual content. All of the pieces in this group deal with line in some way. In some it is the literal spring tension that is emphasized. The line is pulled around and then restrained. In others, it is a playful disappearance and reappearance of the line that is important. I choose different metals for their color, their degree of strength and resilience, and their ability to support and maintain a quality of precision and elegance. I am concerned also with subtle variations in surface texture and pattern. The hollow forms and packaged shapes possess a sense of mystery because they are enclosed, encased spaces. Many of these soft forms have their source in rock shapes - the solidity and softness, and intimations of an interior space within, as of an egg. These forms contrast with the straight-forward, obvious lines that compose the rest of the piece. Playful and sensuous shapes are juxtaposed with sharp, dangerous looking ones. Patterns are often imposed on or into the surfaces of these organic or less controlled forms. Essentially logical human structures, patterns act on the form in much the same way that the intrusion of man-made structures on the environment can often be very beautiful and mysterious. The word 'jewelry' evokes many images. Fashion, personal beauty, and wealth are most frequently brought to mind as associated with the possession of jewelry. In part, I make jewelry in order to dispell these cliches about the function of jewelry. Jewelry, properly worn, is for the wearer, not the spectator. It has a character and implications, disturbing or pleasant, for the wearer. It should stimulate a sense of intimacy and affinity between person and object. It should contain a sense of mystery and magic, if only in the imagination of its owner.Item Hydrology of a waste rock repository capping system at the Zortman Mine(Montana State University - Bozeman, College of Agriculture, 1997) Warnemuende, E. A.Item Hydrologic evaluation of tailings covers at the Golden Sunlight Mine(Montana State University - Bozeman, College of Agriculture, 1994) Strong, Murray RandalItem Concentrated iron pyrite mine waste as an amendment for alkaline soils(Montana State University - Bozeman, College of Agriculture, 1994) Smith, Troy C.