Diagenesis and sequence stratigraphy have been formally treated as two separate disciplines in sedimentary petrology. This thesis demonstrates that synergy between these two subjects can be used to constrain evolution of reservoir quality in sandstones. Such integrated approach is possible because sequence stratigraphy provides useful information on parameters such as pore water chemistry, residence time of sediments under certain geochemistry conditions, and detrital composition, which ultimately control diagenesis of sandstones. Evidence from five case studies and from literature, enabled the development of a conceptual model for the spatial and temporal distribution of diagenetic alterations and related evolution of reservoir quality in sandstones deposited in paralic environments. Diagenetic alterations that have been constrained within the context of sequence stratigraphy include: (i) formation of kaolinite and intragranular porosity, and mechanical infiltration of clay minerals in sandstones lying at variable depths below sequence boundaries, (ii) formation of pseudomatrix and cementation by calcite, dolomite, and siderite in lag deposits at parasequence boundaries, (iii) cementation by kaolinite, pyrite, and calcite in sandstones lying in the vicinity of parasequence boundaries with coal deposits, (iv) formation of glaucony in condensed interval at parasequence boundaries, transgressive and maximum flooding surfaces, (v) formation of berthierine in fluvial-dominated deltaic deposits of the highstand systems tract, (vi) cementation by calcite in bioclastic sandstones of the transgressive systems tract, and (vii) formation of kaolinite in fluvial deposits of the lowstand systems tract. The distribution of such alterations put important constrains for the pattern of burial diagenesis (e.g., formation of chlorite, illite, quartz), related evolution of reservoir quality in sandstones, and distribution of baffles and barriers for fluid flow in the context of sequence stratigraphy.

Field studies encounter several complicating factors not studied in the models. Examples are oblique convergence, heterogeneous materials and thermal softening by intruding magmas. Within the deeply eroded Svecokarelian orogeny, studies in eastern Bergslagen indicate strain accommodation of the N-S orogenic shortening by regional E-W folding and shear along the conjugate Singö Shear Zone and Ornö Banded Series. Rising temperature resulted in migmatites affecting the strain accommodation resulting in decoupling and rotation of folds along one of the deformation zones. Deformation zones developed in convergent orogens have been studied in both analogue models and in nature. These studies have focused on a number of important factors controlling strain accommodation during orogenesis. The models show that the shape of the leading edge of the indenting continent controls whether the initial suture remains active or if an effective indenter develops, the spacing and number of faults, the width of the orogen and the height of the mountains. All these characteristics depend on the rate and spatial distribution of erosion and sedimentation. Erosion decreases the importance of effective indenters and favors shearing on existing faults leading to steeper, longer lived shears bounding narrow orogens. If sediments load the margin (e.g. foreland), the thrusts propagate further outboard widening the orogen. The strain that is accommodated by compaction and shearing along deep décollement and conjugate imbricate shears is episodic in time. This work links episodes of increased rates of erosion and sedimentation to episodes of high uplift rates, i.e. the development of new imbricate thrusts or pop-up wedges.

The thermal history of the Earth, from planetary accretion and core differentiation up to the present time, is of paramount importance for understanding our planet. The thermal evolution of the core and the mantle dictate the generation of the Earth's internal magnetic field and its evolution through time. In this dissertation, I study scenarios for the thermal and magnetic evolution of the Earth, using numerical simulations for mantle convection and implementing recent geochemical models for the mantle and core. The conditions for which a magnetic field can be generated in the Earth's core are studied using parameterized models for energy and entropy. The model devised in this project couples the results of the numerical simulations with the parameterized models for the core, to produce a global thermal and magnetic history, with feed-back between events happening in the mantle and the core.<p> The dissertation presents an analysis of the scenarios that can be constructed from implementing new constraints into the thermal models for the mantle and core and emphasizes the most relevant scenarios which can be applied to the Earth's evolution, consistent with physical parameters, and geochemical and magnetic constraints known to date. In addition, I discuss the relevance of some of the scenarios which appear incompatible with the Earth's evolution, but are reminiscent of the evolution of other terrestrial bodies.<p> The results of this work show that the most successful scenarios for the thermal and magnetic evolution require the presence of small amounts of core internal heating in the form of radioactive potassium, or a slightly increased concentration of radioactive elements at the base of the mantle, due to isolated, if the base of the mantle is less mobile and acts as a thermal insulator between the core and the overlying convective mantle primordial reservoirs. Successful scenarios are also obtained if the base of the mantle is less mobile and acts as a thermal insulator between the core and the overlying convective mantle. If the base of the mantle is less mobile and acts as a thermal insulator between the core and the overlying convective mantle.

The Forsmark Nuclear Plant is one of the largest in Sweden and produces around one sixth of the total electrical energy in the country. It is situated on the east coast of Sweden in the Uppland region. Nuclear waste has to be properly handled every year and Forsmark is one site proposed for long-term storage of all spent fuel from Swedish nuclear power reactors. This potential high-level repository (a low-level one already exists in the area) will be based on the KBS-3 design process, which consists of 6000 iron-copper capsules where the waste will be stored for 30 years and finally buried 500 m down, isolated from the environment for100.000 years. Before using the disposal site, numerous investigations must be done in the area so the risks are reduced as much as possible. These investigations include drilling of cored boreholes down to 1000 m depth. In this study the KFM01A borehole (figure 1.1) was used with different shot points to analyze possible anisotropy in the subsurface. The anisotropy in rocks can be due to different mechanisms as crystal and mineral grain alignment, crack and pore space alignment and thin layer anisotropy (Rowlands J. et al., 1993). For this purpose a shear wave splitting analysis was done in an attempt to determine both orientation and density of fractures. Shear wave splitting has shown to be a very effective method detecting fractures, providing an unique ability to measure anisotropic seismic attributes that are sensitive to fractures (James E. Gaiser, 2004). This can be useful in many domains as in oil companies to improve reservoir management (James E. Gaiser, 2004) or as an imaging tool in fracture-controlled geothermal reservoirs, to monitor fluid pressure in the cracks and changes in crack density (Tang Chuanhai, 2005). Shear wave splitting studies have also been done in seismology for crustal studies (Rowlands J. et al., 1993). When shear waves enter anisotropic medias they split in two approximately orthogonal components, where the faster and slower components will travel parallel and perpendicular to the fracture planes respectively. The time delay will depend of the amount of anisotropy and the path length. Different methods can be used to evaluate the anisotropy; polarization diagrams (Crampin et al., 1986), linear moveout plots of the horizontal components (Li et al.,1988).The procedure described by Li et al. (1988) are the techniques that are used in the present study. The fractures orientation is also analyzed and compared with the general stress components in the area using well bore information from previous studies, as well as the general tectonic characteristics of the zone.

The thermal history of the Earth, from planetary accretion and core differentiation up to the present time, is of paramount importance for understanding our planet. The thermal evolution of the core and the mantle dictate the generation of the Earth's internal magnetic field and its evolution through time. In this dissertation, I study scenarios for the thermal and magnetic evolution of the Earth, using numerical simulations for mantle convection and implementing recent geochemical models for the mantle and core. The conditions for which a magnetic field can be generated in the Earth's core are studied using parameterized models for energy and entropy. The model devised in this project couples the results of the numerical simulations with the parameterized models for the core, to produce a global thermal and magnetic history, with feed-back between events happening in the mantle and the core.<p> The dissertation presents an analysis of the scenarios that can be constructed from implementing new constraints into the thermal models for the mantle and core and emphasizes the most relevant scenarios which can be applied to the Earth's evolution, consistent with physical parameters, and geochemical and magnetic constraints known to date. In addition, I discuss the relevance of some of the scenarios which appear incompatible with the Earth's evolution, but are reminiscent of the evolution of other terrestrial bodies.<p> The results of this work show that the most successful scenarios for the thermal and magnetic evolution require the presence of small amounts of core internal heating in the form of radioactive potassium, or a slightly increased concentration of radioactive elements at the base of the mantle, due to isolated, if the base of the mantle is less mobile and acts as a thermal insulator between the core and the overlying convective mantle primordial reservoirs. Successful scenarios are also obtained if the base of the mantle is less mobile and acts as a thermal insulator between the core and the overlying convective mantle. If the base of the mantle is less mobile and acts as a thermal insulator between the core and the overlying convective mantle.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 117-130). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 117-130). Also available on the Internet.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 132-150).

Thesis (M. Sc.)--York University, 2000. Graduate Programme in Physics and Astronomy. / Typescript. Includes bibliographical references (leaves 59-61). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ67758.

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