A study was undertaken to determine some of the chemical and mineralogical characteristics of the Alberni Slay, a Vancouver Island soil which is the representative of the concretionary Brown Group of soils. Chemical analyses showed that iron, silica and aluminum are leached from the profile and though considerable quantities of these elements are precipitated on the surfaces of peds in the deeper horizons of the soil, no horizon of accumulation was formed. The retention of iron in the surface horizon in the form of free iron oxides maintained the percentage of iron in that horizon comparable with the percentage in the C horizon, and resulted in the formation of highly stable concretions in the A-B horizon of the soil. The formation of concretions seemed to have been influenced by the high magnetite content of the soil. The interaction between the positively charged surface of the magnetite particles and organic anion complexes of the cations of the first transitional series impeded the movement of these complexes through the slowly permeable soil and permitted absorption and precipitation to form concretions. The x-ray analyses of the clays revealed a weathering sequence in which chlorite was developed, from weathered primary minerals. The formula for the chlorite separated from the surface horizon clays was calculated and it was found to be a dioctahedral Al-chlorite which had been predicted by Grim and by Brindley, but which had not been previously identified in soils. / Land and Food Systems, Faculty of / Graduate

No description available.

Includes bibliographical references. / 1 v. : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis investigates the nature and origins of minerals of a group known as layer (sheet) silicates or phyllosilicates. It consists of a collection of research papers grouped into 3 categories: modulated layer silicates, clay silicates and the weathering of rocks and minerals, including the formation of clay minerals. Central to the research has been the use of X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). All three research categories were carried out simultaneously. / Thesis (D.Sc.)--University of Adelaide, Dept. of Geology and Geophysics, 1999

Thesis (Ph. D.)--School of Civil and Environmental Engineering, Georgia Institute of Technology, 2004. Directed by J. Carlos Santamarina. / Vita. Includes bibliographical references (leaves 183-192).

The permeable press experiment was performed for aqueous clay mineral systems to understand the relationship between the water film thickness and the applied permeable pressure. Water film thickness between particles was calculated from the particle size and the linear drying shrinkage of pressed bodies. The permeable press experimental results were compared to the calculated total interaction pressures between particles using the DLVO theory. The kaolinite and the metakaolinite had the same particle shape. Kaolinite particles were crystalline, and metakaolinite particles were short-range order. The kaolinite had the point of zero net charge, PZNC, at pH 5.7. However, the kaolinite showed multi-cross points at pHs 4.6, 5.7, 6.2, and 7.2. These multi-cross points were in agreement with the theoretical titration using the two-site surface complex reaction model by Carroll-Webb and Walther. On other hand, the metakaolinite had the PZNC at pH 7.2 as a common intersection point. If the zeta potential at pH(PZNC) is identical to the silica basal surface potential, the silica surface charge densities are calculated as - 2.6 μC cm⁻² for the kaolinite and - 2.7 μC cm⁻² for the metakaolinite, respectively. The calculated surface charge density is equivalent to one aluminum atom substituted in 54 silicon atoms in the silica tetrahedral layer. The total interaction pressures using the DLVO theory corresponded to the permeable press experimental results of the metakaolinite-0.1 M NaCI systems. The surface of the metakaolinite was estimated to have immobile water layers between 5 and 8 molecules thick. The metakaolinite samples cracked in experiments when the applied permeable pressure increased. This phenomenon can be explained by a vanishing capillary pressure: contacting immobile layers. The permeable press experimental results of all the kaolinite systems were significantly higher than the calculated total interaction pressures. The slope of the natural log of the permeable pressure and the water film thickness of the kaolinite systems indicated the existence of a longer-range repulsive pressure than that of the metakaolnite systems. The DLVO theory cannot explain the kaolinite systems because the nature of materials, such as an atomic configuration of the surface, which induces the structural forces, is not considered.

No description available.

No description available.

No description available.

Includes bibliographical references. / 1 v. : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis investigates the nature and origins of minerals of a group known as layer (sheet) silicates or phyllosilicates. It consists of a collection of research papers grouped into 3 categories: modulated layer silicates, clay silicates and the weathering of rocks and minerals, including the formation of clay minerals. Central to the research has been the use of X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). All three research categories were carried out simultaneously. / Thesis (D.Sc.)--University of Adelaide, Dept. of Geology and Geophysics, 1999

Originally presented as the author's Thesis (Helsinki). / Includes bibliographical references (p. [97]-103).