Thesis (Ph.D.)--University of Ottawa, 2008. / Includes bibliographies.

Thesis (M.A.Sc.)--University of Ottawa, 2007. / Copyright date: 2008. Includes bibliographies.

A Portuguese clay (BRN) from the North East city of Bragança was collected and characterized in terms of health treatment and applied towards the preparation of nanocomposites with Polylactide (PLA). The silt-clay fraction of BRN is mainly composed of smectite with less illite, kaolinite and other minerals. The physicochemical properties are applicable for the topical applications and are mainly influenced by smectite. With the hazardous elements present, further bioavailability tests should be conducted. PLA nanocomposites with BRN and Wyoming montmorillonite SWy-2 (MMT) were respectively prepared through the solution casting method with ultrasonic stirring and using cetyltrimethylammonium bromide (CTAB) as the surfactant. The X-ray diffraction patterns show the exfoliated structures in most samples. Thermal gravimetric analysis reveals the increased thermal stability of the nanocomposites. The complexes were also characterized by nitrogen adsorption, infrared analysis and nuclear magnetic resonance for comparing the differences between BRN and MMT.

The geochemistry of surface media above two known U deposits were examined to observe any possible dispersion products could be detected from them, and based on these findings, improved geochemical exploration techniques are proposed to reduce cost of finding undiscovered U resources. This study examined the materials overlying the Phoenix deposits, which have indicated resources of approximately 58.2 million lbs U3O8 grading 15 wt% that lie at 400 m depth below surface at the unconformity between the overlying Athabasca sandstones and Paleoproterozoic basement rocks. Aqua regia digestion, ammonium acetate at pH 5 and hydroxylamine leaches revealed U, Pb, Co, Ni, Mo, and W anomalies in humus and U, W and As anomalies in B-horizon soils above the ore zones and the basement location of a deposit-hosting, northeast-trending “WS Hanging Wall” shear zone over a three year period. These metal signatures suggest likely upward transport of metals from the deposits to overlying sandstones, and subsequently into the overlying till and soils. This study also looked at materials above the Millennium U deposit, which has indicated resources of 68.2 million lbs U3O8 grading 4 wt% at ~750 m depth that occurs along a major fault in granites & metamorphosed pelites of Paleoproterozoic age below the Athabasca sandstones. Soil samples taken over the surface projections of an ore-hosting fault and the ore zone yielded anomalous values in U, Ni, Cu and Pb in aqua regia digestion of humus and U, Cu and Pb values in ammonium acetate leach of pH 5 of B-horizon soils. Hydroxylamine leach did not yield as many anomalies as ammonium acetate leach. Measured 4He/36Ar ratios of gas dissolved in water-filled drill holes were observed to be up to about 700 times the atmosphere value for air-saturated water, revealing the presence of radiogenic 4He that was likely produced from decaying U and released in the groundwater above the deposit. Our results suggest upward migration of metals to surface through porous sandstone and fault systems at Phoenix, and upward migration of metals along faults and He gas at Millennium. Both studies indicate the importance of the traverse method of sampling over targets perpendicular to the last major ice-flow event to discern U deposits that are defined by other means.

Thesis (Ph.D.)--University of Ottawa, 2008. / Includes bibliographies. Also available via the World Wide Web.

Thesis (Ph.D.)--University of Ottawa, 2008. / Includes bibliographies.

Thesis (M.Sc.)--University of Ottawa, 2008. / Includes bibliographies.

Thesis (M.Sc.)--University of Ottawa, 2008. / Includes bibliographies.

Thesis (M.A.)--University of Ottawa, 2005. / Includes bibliographical references.

The geochemistry of surface media above two known U deposits were examined to observe any possible dispersion products could be detected from them, and based on these findings, improved geochemical exploration techniques are proposed to reduce cost of finding undiscovered U resources. This study examined the materials overlying the Phoenix deposits, which have indicated resources of approximately 58.2 million lbs U3O8 grading 15 wt% that lie at 400 m depth below surface at the unconformity between the overlying Athabasca sandstones and Paleoproterozoic basement rocks. Aqua regia digestion, ammonium acetate at pH 5 and hydroxylamine leaches revealed U, Pb, Co, Ni, Mo, and W anomalies in humus and U, W and As anomalies in B-horizon soils above the ore zones and the basement location of a deposit-hosting, northeast-trending “WS Hanging Wall” shear zone over a three year period. These metal signatures suggest likely upward transport of metals from the deposits to overlying sandstones, and subsequently into the overlying till and soils. This study also looked at materials above the Millennium U deposit, which has indicated resources of 68.2 million lbs U3O8 grading 4 wt% at ~750 m depth that occurs along a major fault in granites & metamorphosed pelites of Paleoproterozoic age below the Athabasca sandstones. Soil samples taken over the surface projections of an ore-hosting fault and the ore zone yielded anomalous values in U, Ni, Cu and Pb in aqua regia digestion of humus and U, Cu and Pb values in ammonium acetate leach of pH 5 of B-horizon soils. Hydroxylamine leach did not yield as many anomalies as ammonium acetate leach. Measured 4He/36Ar ratios of gas dissolved in water-filled drill holes were observed to be up to about 700 times the atmosphere value for air-saturated water, revealing the presence of radiogenic 4He that was likely produced from decaying U and released in the groundwater above the deposit. Our results suggest upward migration of metals to surface through porous sandstone and fault systems at Phoenix, and upward migration of metals along faults and He gas at Millennium. Both studies indicate the importance of the traverse method of sampling over targets perpendicular to the last major ice-flow event to discern U deposits that are defined by other means.