Thesis (Ph. D.)--University of California, 1918. / Bibliography: p. 13-15.

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The interpretation of leached outcrops as guides to the specific minerals from which they were formed has been developed to a rather high degree by earlier workers, among whom Boswell and Blanchard deserve particular mention. In the present work, a gossan that led to the discovery of a lead deposit is described. Since many hand specimens of the limonite from this gossan lack the characteristic boxwork structures described by the authors above, microscopic investigations of thin and polished sections were carried out. However, the gossan is classified into six types mainly on the basis of its physical properties. At least three of these are correlated with types described by Boswell and Blanchard, one of pyrite derivation and the others from galena. The relative solubility of different limonite types in dilute HC1 was not found to be of as much value as some writers have indicated. The mineral deposits to which the limonite pointed the way have not been sufficiently exposed to allow detailed study, but the presence of tremolite and phlogopite in an area of disseminated mineralization indicates that this portion at least may be of contact metamorphic origin. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

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Thesis (B.S.)--University of Alaska, 1940. / Alaska "Territorial Department of Mines reports" or "TDM reports" are a collection of reports, notes and maps written by Dept. employees working out of several field offices throughout the territory. Series titles and numbers within the collection were retrospectively assigned with the exception of the few written after statehood (1959). Report contains information on the Yukon River Mining Region, Circle Quadrangle. Includes bibliographical references (leaf 80). Also available in electronic format via Internet.

Thesis (M.S.)--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 February 10, 2010) Includes bibliographical references (p. 63-64).

The Batopilas Mining District was a major silver producer, with estimated historic production of more than 300 million ounces. Orebodies consist of high-grade silver in the forms of native silver, acanthite and proustite hosted dominantly in calcite veins. Recent exploration has facilitated the reexamination of the geologic features and origin of the enigmatic native silver district. Sulfur, lead, and strontium isotopic studies have been conducted to constrain the fluid and metal sourcing. [delta]³⁴SvCDT isotope signatures for galena, sphalerite and pyrite range from -8 to -2, -6 to 0, and -5 to 3°/₀₀, respectively. A fractionation temperature of 227±25 °C can be obtained using average sulfur isotope values for galena and sphalerite. Galena lead isotopic values show two distinct signatures. Samples of massive-replacement style mineralization have ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb values of 18.742 and 18.747, 15.611 and 15.618, and 38.512 and 38.535, respectively. For vein samples, the corresponding values range from 18.799 to 18.817, 15.623 to 15.639, and 38.603 to 38.655. The lead isotopic signatures for vein galena have lower thorogenic lead content than other ore deposits in the Sierra Madre Occidental, suggesting a different source of metals. Vein calcite samples have ⁸⁷Sr/⁸⁶Sr isotopic compositions ranging from 0.707551 to 0.70590 (±0.000009) and Sr concentrations ranging from 51 to 246 ppm. These vein components may reflect mixed deep-marine sedimentary and Precambrian basement sources. A reconnaissance fluid inclusion study was conducted to better constrain fluid temperature and composition. The minerals studied included quartz, fluorite, and two types of sphalerite. The average eutectic temperatures obtained are -38°C, -31°C, and -43°C, respectively, indicating a complex mineralizing brine. Homogenization temperatures averaged 143°C, 165°C, and 174°C, and the NaCl equivalent weight percents averaged 4, 7, and 17, respectively. Fluids involved in vein mineralization are different from those typical of epithermal vein Ag-Au deposits, and may represent sedimentary brines that have circulated through the underlying basement. / text