Earth’s climate can exist in many stable states that are vastly different from the modern climate state. Understanding modern and future climate requires a thorough understanding of the full range of possible climate states and the processes that trigger transitions between states. Quantitative reconstructions of past climate variables provide constrains on the magnitude, mechanisms and feedbacks involved in producing stable climate states. As such, they provide insights into past climate states unobservable today. This thesis focuses on quantifying three metrics of past climate systems: (a) quantitative rainfall amount, which provides means for assessing how the spatial distribution of rainfall changed in the past, (b) the isotopic composition of past rainwater (δP ), which provides means for understand- ing how atmospheric circulation changed in the past, and (c) relative humidity, which provides estimates of evaporative processes and hydrospheric fluxes. The regions studied are in the two far reaches of the Asian continent. In eastern Asia, changes in rainfall amount and δP over the past 125 ka were studied using geomorphological evidence from a closed basin lake in Inner Mongolia, China and compound-specific δDwax and δ13Cwax from organic molecules in lake sediments. In western Asia, the research focused on processes that govern modern δP and modern δDwax and δ13Cwax in soils. In addition the hydrological regime of the Eastern Mediterranean and the Levant during the Last Glacial Maximum were studied using evidence from speleothem δ18Oc and foraminifera δ18O. These records provide empirical and quantitative information about rainfall amount, δP and relative humidity at singular locations, and as such provide the building blocks for producing coherent large-scale reconstruction of the migration of rain-belts in the past.

Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on November 1, 2007) Includes bibliographical references.

Thesis (M.S. - Hydrology and Water Resources)--University of Arizona. / Includes bibliographical references (leaves 119-128).

Thesis (Ph.D.)--University of Wollongong, 2004. / Typescript. Includes bibliographical references: p. 366-393.

Thesis (Ph.D.)--University of Alberta, 2010. / Title from PDF file main screen (viewed on Apr. 13, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Department of Earth and Atmospheric Sciences, University of Alberta. Includes bibliographical references.

Thesis (doctoral)--Faculté des sciences de Paris, (197-?). / Includes bibliographical references (leaves [43]-[46]).

The Bandelierkop Formation of the Southern Marginal Zone (SMZ) of the Limpopo Belt consists of metamorphosed ultramafic, mafic and sedimentary rocks. Metamorphic conditions indicated by the petrography of these different rock groups are consistent with upper amphibolite to granulite facies. The ultramafic and mafic rocks are geochemically akin to peridotitic-pyroxenitic intrusive rocks and high-Mg basalts respectively. Metamorphism of these two rock groups in the SMZ was an essentially closed system process, except for the highly volatile phases such as H₂O and CO₂. The metasediments appear to represent a sequence of high (Mg+Fe)-greywackes and/or deep-water shales with minor amounts of iron formation material. The unusually mafic character of the metasediments can be ascribed to a high ultramafic + mafic source component to the original sediment. Some modification of the major and trace element compositions of the pelitic rocks has been caused by the removal of partial melts and the metamorphism of the pelitic rocks is not therefore considered to have occurred under closed system conditions. Variable extraction of partial melts is implied by the chemical variations shown by the pelitic rocks and is also suggested by the presence of large pegmatitic felsic bodies which are commonly found close to the pelitic rocks. Detailed petrographic study of the Bandelierkop Formation rocks suggests an increase in metamorphic grade, and/or a decrease in water activity, from south to north within the Southern Marginal Zone. Peak metamorphic conditions of 730°C + 65°C at pressures of 6.1 ± 1.5 kbars may be deduced from a careful application of several cation thermometers and barometers on selected mineral analyses. A rigorous application of garnet-biotite thermometry to the pelitic rocks indicates that the transition from orthoamphibole gneisses in the south to orthopyroxene-bearing rocks in the north of the SMZ terrane, is a function of changing biotite composition and/or decreasing water activities rather than an increase in metamorphic temperatures. In contrast to the major and trace element data, the stable isotope data for the ultramafic and mafic rocks in the SMZ indicate open system behaviour for some of these rocks, but closed system behaviour for the pelites. Extraction of SO to 70% partial melts from the pelitic rocks, should not, however, have affected the δ¹⁸O value of the restite. Petrological and stable isotope data in the SMZ rocks are consistent with retrogression in all these rocks and open system behaviour for oxygen in some ultramafic and mafic rocks, being caused by the crystallization and accompanying fluid release of melts produced during prograde metamorphism of the pelitic rocks. Small scale (-5 to 30m's) heterogeneity is implied by both oxygen and carbon stable isotope compositions of closely spaced rock samples, even for those collected from within large "shear zones", suggesting small fluid/rock ratios for most of the samples in the high-grade terrane or heterogeneous stable isotopic compositions of the fluids. Furthermore, a similarity in mineral-mineral stable isotope fractionation factors is observed for all the pelitic rocks, including the orthoamphibole gneisses found immediately south of the orthopyroxene isograd. These features preclude the presence of pervasive fluid infiltration after peak metamorphism. Two implications are, that granulite facies metamorphism in the SMZ terrane was not caused by an influx of mantle derived CO₂-rich fluid and, that the orthoamphibole gneisses are not retrogressed equivalents of the granulites found to the north of the orthopyroxene isograd. It is suggested that this isograd represents a change in the water activities of the rocks during metamorphism. Apparent disequilibria in mineral - mineral stable isotope fractionations observed amongst different minerals within any one pelitic rock, may be explained by a combination of the crystallization of residual melt within these rocks and oxygen diffusion amongst minerals which have not reached their oxygen-closure. The concordant quartz-plagioclase, quartz-biotite and plagioclase-biotite oxygen isotope equilibration temperatures are taken to represent minimum crystallization temperatures for the melts (-560°C), while successively higher quartz-orthopyroxene, quartz-amphibole and quartz-garnet oxygen isotope equilibration temperatures are a function of increasing closure temperatures for the orthopyroxene, amphibole and garnet respectively. The minimum estimate to peak metamorphic temperatures is given by the quartz-garnet oxygen isotope temperature averaging 736 + 52°C. If oxygen diffusion experiments performed in hydrothermal systems are appropriate for the SMZ rocks, then cooling rates for the SMZ terrane could have been as low as 12 to 25°C/My over a temperature range of 480 to 600°C. Stable isotope modeling of hypothetical fluids that may have been in equilibrium with the high-grade rocks, suggests that a mixture of CO₂ and H₂O, with CO₂/H₂O mole ratios > 0.1 can precipitate both quartz and carbonate of stable isotope composition similar to those determined for quartz and carbonate from the mineralized Archaean lode gold deposits of the Murchison and Pietersburg greenstone belts. A model involving granulite facies metamorphism, partial melt extraction and subsequent release of fluids, Au, K and S upon crystallization of such melts, appears to be viable for gold mineralization occuring in the adjacent lower grade greenstone belts and in the high-grade terrane of the Southern Marginal Zone.

Recent years have seen increasing use of atmospheric radionuclides for dating and tracing hydrogeologic processes. Hydrologists often assume that meteoric sources of these nuclides are dominant in ground water and that age-dating methods are limited primarily by analytical detection capability. However, in some cases, subsurface production may also limit the usefulness of these nuclides for dating. Equilibrium radionuclide concentrations are calculated as a function of depth for a variety of rock types. Production mechanisms include fissioning of heavy radionuclides; spallation by cosmic-ray nucleons; capture of neutrons, a-particles, muons and protons; and photonuclear reactions. Calculations indicate that deep subsurface production of ³H, ¹⁴c, ⁸⁵Kr and ⁹⁹Tc is generally below detection but that deep production of ³⁶C1, ³⁹Ar, ⁸¹Kr and ¹²⁹I establishes limits to age-dating of water in most rocks. Parameters for estimating production of ¹⁰Be, ²²Na, ²⁶Al, ³⁷Ar, ³²Si, ⁴¹Ca and ⁷⁹Se are included in appendices. Evidence for in-situ production of ³⁶C1 and ¹²⁹I is presented for two field studies. Concentrations in ground water from the Stripa granite, Sweden, were determined by accelerator mass spectrometry. ¹²⁹I values range from 1,000 to 200,000 atoms/ml, compared to an estimated background concentration in pre-1945 water of 20 atoms/ml. The high levels are attributed to production by spontaneous fission of ²³⁸U in the granite (44 ppm U). ³⁶C1/C1 ratios range from 50-200 x 10 -15 compared to about 40 x 10⁻¹⁵ in meteoric recharge. An increase in ratios with depth has been attributed to production of ³⁶C1 by neutron- capture on ³⁵C1 and is used to set upper limits on the residence time of water in the granite. The validity of using ³⁶C1/C1 ratios as a monitor of deep lithospheric neutron fluxes was tested by measuring the ratios in Cl extracted from Stripa granite. The average ratio, 190 x 10⁻¹⁵, agrees with ratios calculated based on rock chemistry, 190 x 10⁻¹⁵, and on the measured neutron flux, 220 x 10⁻¹⁵. ¹²⁹I and ³⁸C1 were also measured in uranium ores from the Koongarra and Ranger deposits, N.T., Australia. Samples from the oxidized ore zone contain only 6-23% of the ¹²⁹I contents predicted for equilibrium, suggesting preferential loss of ¹²⁹I relative to U during weathering. ³⁶C1 is produced as a result of high neutron fluxes in the ore. Measured ³⁶C1/C1 ratios range from 3 x 10 -12 to 1 x 10⁻¹⁰, corresponding to apparent neutron fluxes of 2 x 10⁵ to 1 x 10⁷/cm²/yr.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2005. / Bibliography: leaves 139-147. Also available online.

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.