Rare occurences of coeval late Wisconsin glacigenic diamictons and ice-proximal sediments with a diverse faunal assemblage provided an opportunity to test the viability of the glacigenic sediments as proxy paleoclimate indicators.
In this dissertation I present a tectonic, geochemical, and thermal history for the Witwatersrand basin, located on the Archean Kaapvaal craton, South Africa. The foreland basin tectonic setting of the Central Rand Group controls both the chemical and the thermal evolution of the basin, and unifies the basin evolution model presented here.
Various geochemical parameters including type and abundance of organic matter (TOC), sulfide-sulfur quantities, fluctuations in bottom-water anoxicity (DOP), metal content differences, and sulfur isotope variations have been assessed in order to characterize Midcontinent Pennsylvanian black shales. Based on these geochemical parameters, the deposits can be grouped into three types: Mecca-type, Heebner-type, and Shanghai-type.
The Brassfield Formation is a very thin, highly condensed carbonate unit that encompasses most of the Llandovery (8.5 MMYR) and covers much of the eastern midcontinent. Fifty-six Brassfield outcrops exposed around the flanks of the Cincinnati arch comprise three members, four facies tracts, and seven lithofacies. The three types of condensation recognized in the Brassfield (dynamic bypass, punctuated deposition, and sediment starvation) are related to sea level fluctuations, manifested as a hierarchy of sequence orders, that ultimately controlled the spatial and temporal distribution of facies.
Little is known about the hydraulic fracturing of soil, although the technique holds potential for several environmental engineering applications. The dissertation research consists of laboratory experiments, where hydraulic fractures were created by injecting dyed glycerin into colluvium contained in a triaxial pressure cell, and a field test, where hydraulic fractures were created by injecting guar gum gel at shallow depths in glacial drift. The laboratory tests showed that hydraulic fractures are readily created in clayey-silt colluvium. Furthermore, hydraulic fractures created in soil with positive pore pressure were filled with two fluids: one injected to create the fracture, and pore fluid that infiltrates into the fracture tip. The length of the infiltrated tip increases with increasing fracture length.
The nature of taphonomic overprint affecting the fossil records of the regular echinoid Families Cidaridae, Diadematidae, Toxopneustidae and Echinometridae is investigated using a synthesis of actualistic and literature-derived data. The actualistic portion of this study focuses on the following extant members of the four families: Eucidaris tribuloides, Diadema antillarum, Tripneustes ventricosus and Echinometra lucunter. Population censuses of these animals in tropical reef and near-reef environments demonstrate that the distribution of macro- and microscopic skeletal material does not reflect the distribution of the living fauna. Field experiments with freshly-killed carcasses of Eucidaris, Diadema and Echinometra indicate that loss of all organic tissue occurs within six days after death, reducing these echinoids to essentially bleached carcasses.
This dissertation is a contribution toward low pressure geochemistry and petrology of alkaline rocks. In order to analyze the phase equilibria in multiply saturated potassic alkaline systems, experiments were performed at one atmosphere pressure and under the $\rm f\sb{O2}\sim QFM$ buffer. Range of temperature covered in this study is 1060-1250$\sp\circ$C. In addition, temperature and composition dependency of low pressure mineral-melt equilibria involving olivine, pyroxenes, plagioclase, nepheline, and leucite were modeled using empirical equations.
Petrographic study of the Deicke and Millbrig K-benonite beds (altered volcanic ash) of Rocklandian age has revealed that they can be distinguished by their non-clay mineralogy. The Deicke phenocryst assemblage is primarily labradorite, Fe-Ti oxides, apatite, and zircon, while the Millbrig assemblage is primarily andesine, quartz, biotite, apatite, and zircon. The Deicke is altered dacitic ash, while the Millbrig is altered rhyodacitic ash.
The petrographic and compositional characteristics of detrital magnetite and ilmenite separated from 31 modern sand samples derived from 8 known igneous and metamorphic parent rocks indicates that magnetite is a useful provenance indicator. In contrast, detrital ilmenite shows no trends with variations in parent rock and its use in provenance research is suspect.
The hydrology of a thin colluvium hillside at the Delhi Pike landslide complex, approximately 15 km west of downtown Cincinnati, is controlled by infiltration and evapotranspiration. Pore water pressures approach $-$10 m H$\sb2$O during summer and autumn, but rise to $-$1 m H$\sb2$O or higher after several days of steady winter rains. This state of near saturation is maintained until large trees leaf out and pore pressures fall dramatically in late spring.