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The Global ETD Search service is a free service for researchers
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Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Fluid evolution during metamorphism and uplift of the massive sulfide deposits at Ducktown, Tennessee, U.S.A.Hall, Donald Lewis January 1989 (has links)
The Ducktown mining district, located in the southeastern corner of Tennessee within the Blue Ridge Province of the southern Appalachians, contains some of the largest metamorphosed pyrrhotite-pyrite-rich massive sultide deposits in the Appalachian-Caledonian orogen. Oxygen isotope temperatures of 530±20°C are consistent with previous estimates based on mineral thermobarometers (540±40°C; 6-7 kb) suggesting that minerals attained oxygen isotopic equilibrium during peak metamorphism and underwent little retrograde exchange. Fluid inclusion and petrologic data do not support the previous interpretation that low δ¹⁸O zones near orebodies are synmetamorphic, rather, a premetamorphic origin is indicated. Integrated fluid/rock ratios were low enough during and after metamorphism that premetamorphic spatial variations in δ¹⁸O were retained. However, hydrogen and carbon isotopes were homogenized throughout the area during or before metamorphism. The low δ¹⁸O zones surrounding the orebodies appear to have formed during sea—fIoor hydrothermal activity associated with ore deposition. The δ¹⁸O value of the fluid responsible for ore deposition, assuming a temperature of 300°C, is calculated to be -1 to +2 per mil, consistent with the interpretation that the ore fluid was modified seawater.
Calculation of theoretical C-O-H-S fluid speciation suggests that the fluid in equilibrium with clinopyroxene-bearing rocks was essentially H₂O+CO₂with XCO₂ = 0.10. However, primary fluid inclusions located in clinopyroxene contain signifticant quantities of CH₄. This discrepancy is explained by hydrogen diffusion into primary fluid inclusions and subsequent conversion of CO₂ to CH₄ during uplift in response to an fH₂ gradient between inclusion and matrix fluids. Low δD values of primary fluid inclusions are consistent with diffusive addition of isotopically light hydrogen after trapping.
Secondary inclusions in metamorphic quartz record a complex uplift history involving a variety of fluids in the C-O-H-N-salt system. lsochores calculated for these inclusions constrain the uplift path to have been initially concave toward the temperature axis. Over the pressure range 2.3 to 1.0 kb the uplift path became nearly isothermal at 215±20°C. lmmiscible H₂O-CH₄-N₂-NaCl fluids present during the isothermal stage of the uplift history were derived during Alleghanian thrusting by expulsion of pore fluids and maturation of organic matter in lower plate sedimentary rocks proposed to underlie the deposits. Average uplift rates of 0.1 mm/yr are suggested by the uplift path and available geochronologic data. / Ph. D.
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Removing Reds from the Old Red Scar: Maintaining and Industrial Peace in the East Tennessee Copper Basin from the Great War through the Second World WarSimson, William Ronald 19 March 2010 (has links)
This study considers industrial society and development in the East Tennessee Copper Basin from the 1890s through World War II; its main focus will be on the primary industrial concern, Tennessee Copper Company (TCC 1899), owned by the Lewisohn Group, New York. The study differs from other Appalachian scholarship in its assessment of New South industries generally overlooked. Wars and increased reliance on organic chemicals tied the basin to defense needs and agricultural advance. Locals understood the basin held expanding economic opportunities superior to those in the surrounding mountains and saw themselves as participants in the nation’s industrial and economic progress, and a vital part of its defense. The study upends earlier scholarship contending local industrial concerns acted proactively to challenges from farmers harmed by industrial pollution; investigation shows firms hesitated to initiate new production processes and manipulated local elections. Partisan developments woven amid all this underscore errors in assuming ancient regional affinity for Republicans. Confederate heritage gave Democrats an historic advantage that fractured before New Deal progressivism and expanding basin Republican power. Markets forced basin firms to merge and embrace technological change affecting working people’s relationships, forcing workers to improve skills or settle for low-skill jobs. Excepting TCC managers and supervisory staff, provincialism ruled; suspicions and competitiveness among workers grew as most miners lived a few scattered villages and most managers and craftsmen settled in the basin’s “Twin-cities” district. Early union efforts collapsed before union mismanagement, rational management and a company union based upon Sam Lewisohn’s ideals. Management managed to wrest control of its industrial relations despite the effects of Depression and the New Deal’s empowerment of workers. Workers’ infighting, reflecting neighborhood demographics and ideological differences, benefitted TCC; it convinced locals TCC could best protect industrial peace. The submissive AFL union installed fit of ownership’s nationally recognized program for industrial relations reliant on federal power. After competition crippled local industry, locals continued their reliance on government: to investigate the medical consequences of extraction work and coordinate environmental restoration. Recent regional anti-government populism makes the basin’s peculiar historic reliance on federal help engaging.
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