The Early Permian (Sakmarian to Kungarian) Raanes and Great Bear Cape formations of the Sverdrup Basin were deposited at a time of ocean cooling, and are interpreted to reflect a subtropical setting. Pelmatozoans, bryozoans, and brachiopods are the predominant fossils throughout the extent of these two units, with local occurrences of large fusulinids and colonial corals. This mixed photozoan-heterozoan assemblage is similar to the sediments of modern-day subtropical settings. Although the Raanes and Great Bear Cape have warm-water rocks below, and cool-water rocks above, the fossil assemblages in these formations were dependent upon changes in oceanography and sea-level. Three distinct phases, as determined by water depth and temperature, occur. First, the rocks of the Raanes and lower Great Bear Cape are deep water and heterozoan in nature. Second, the middle Great Bear Cape limestones record a time of shallow, subtropical waters. Finally, the upper Great Bear Cape is shallow-water, but cooling had progressed to a point that precluded the occurrence of any photozoan components, regardless of depth. Due to evolutionary changes in other subtropical biota, the most reliable fossil indicator of subtropical deposition in the rock record is large benthic foraminifera (including fusulinids) in an otherwise heterozoan assemblage. The identification of limestones representative of these conditions should, therefore, be identifiable at times in the Earth’s history when large benthic foraminifera lived in shallow marine environments. The Great Bear Cape Formation subtropical facies underwent post-depositional changes that are manifest as calcite cements, iron-oxides, glauconite, and silica. Isopachous calcite cements precipitated in intraskeletal pore spaces as well as around the outside of grains. Glauconite, which is an authigenic marine mineral, has been oxidized to iron oxide, and both minerals post-date, or are included within, the isopachous cements. The isopachous cements must, therefore, have also formed in the marine environment. Where they are precipitated around pelmatozoan fragments, these originally high magnesium calcite cements have been neomorphosed to single-crystal epitaxial cements at the same time as mineral stabilization of the biofragments. These cements then seeded the growth of further epitaxial cement in the meteoric environment. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2007-08-21 10:58:18.958

The Lower Parmeener Supergroup consists of 500 to 900 metres of marine and terrigenous sedimentary rocks, deposited in the high-latitude Tasmania Basin during the late Carboniferous to middle Permian, at the end of the late Paleozoic ice age. Two bioclastic carbonate units, the Darlington and Berriedale limestones, are of particular interest due to their formation in this polar, cold-water environment. Both limestones contain ice-rafted debris scattered throughout, signifying numerous icebergs, and are under- and over-lain by glendonitic siltstone indicating near-freezing seawater. Despite the unusual environment, seawater in the Permian Tasmania Basin was, with the exception of an anomalously high 13C value, isotopically and chemically similar to modern seawater. These limestones consist of a high-abundance, low-diversity heterozoan assemblage, dominated by large, robust brachiopods, bryozoans, and Eurydesma bivalves. Sponge spicules and crinoids are locally important constituents. The carbonates are interpreted to have been deposited in mid-shelf environments during sea-level highstands, where the faunal communities were beyond the depths of grounding icebergs, and sufficiently outboard from terrigenous sediment influx and brackish water. Growth and preservation of biogenic carbonates were promoted by up-welling of nutrient-rich water, which sustained high levels of primary productivity in the water column and phosphate concentrations in the sediment. Lower Parmeener Supergroup carbonates were exposed to a complex series of diagenetic processes, commencing on the seafloor and continuing during rapid burial. Limestone composition was further modified by diagenetic fluids associated with the intrusion of Mesozoic igneous rocks. Alteration in the marine paleoenvironment was both destructive and constructive; although dissolution took place there was also coeval precipitation of fibrous calcite cement, phosphate, and glauconite. These processes are interpreted to have been promoted by mixing of marine waters and enabled by microbial degradation of organic matter. In contrast, meteoric diagenesis was insignificant, being confined to minor dissolution and localized cementation, although mechanical compaction was ubiquitous. Chemical compaction was instigated at burial to depths of approximately 150 m, and promoted extensive precipitation of ferroan calcite. Diagenesis may well have ended here, except for the subsequent intrusion of massive Mesozoic diabases and associated injection of silicifying fluids into the limestones. Finally, fractures associated with Cretaceous uplift were filled with late-stage non-ferroan calcite cement. / Thesis (Ph.D, Geological Sciences & Geological Engineering) -- Queen's University, 2008-04-23 11:12:58.461 / NSERC

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Thesis (M.Sc. Environmental Science)--University of Waikato, 2007. / Title from PDF cover (viewed May 6, 2008) Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Earle F. McBride. Vita. Includes bibliographical references. Also available from UMI.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 66-70). Also available on the Internet.

Thesis (Ph.D.)--Memorial University of Newfoundland. / Typescript. Restricted until May 1997. Bibliography: leaves 218-234. Also available online.

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Available also in an electronic version.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 66-70). Also available on the Internet.