Distributions of water transit times (TTDs), and related storage-selection (SAS) distributions, are spatially integrated metrics of hydrological transport within landscapes. Recent works confirm that the form of TTDs and SAS distributions should be considered time variant-possibly depending, in predictable ways, on the dynamic storage of water within the landscape. We report on a 28 day periodic-steady-state-tracer experiment performed on a model hillslope contained within a 1 m3 sloping lysimeter. Using experimental data, we calibrate physically based, spatially distributed flow and transport models, and use the calibrated models to generate time-variable SAS distributions, which are subsequently compared to those directly observed from the actual experiment. The objective is to use the spatially distributed estimates of storage and flux from the model to characterize how temporal variation in water storage influences temporal variation in flow path configurations, and resulting SAS distributions. The simulated SAS distributions mimicked well the shape of observed distributions, once the model domain reflected the spatial heterogeneity of the lysimeter soil. The spatially distributed flux vectors illustrate how the magnitude and directionality of water flux changes as the water table surface rises and falls, yielding greater contributions of younger water when the water table surface rises nearer to the soil surface. The illustrated mechanism is compliant with conclusions drawn from other recent studies and supports the notion of an inverse-storage effect, whereby the probability of younger water exiting the system increases with storage. This mechanism may be prevalent in hillslopes and headwater catchments where discharge dynamics are controlled by vertical fluctuations in the water table surface of an unconfined aquifer. Plain Language Summary Volumes of water reside within landscapes for varying amounts of time before they are discharged to a stream. That length of time determines how long the water has to interact chemically with soil and rock, and therefore influences the chemistry of water that ends up in stream channels. Quantifying the full range and variability of those travel times remains a challenge. We built an experimental hillslope, which allows us to keep track of all the water that enters and exits the soilsomething that is difficult to accomplish in open environmental systems. We introduced chemically distinct water into the hillslope at specific points in time and followed the movement of that water within, and upon exit from the soil. We discovered that the water being discharged from the hillslope tends to have resided in the landscape for shorter lengths of time when the hillslope is very wet (like a wetted sponge) than when it is very dry (like a dry sponge). This insight helps us understand how different rainfall regimes, and the associated wetness of the landscape, can potentially influence water transit times through the landscape, and their relationship with stream chemistry.

The samples for this study were adopted from the drilling cores for the slope-stability monitoring project inside the campus of NSYSU. Stratigraphically the strata belongs to the Gutingken Formation and is lain below the Kaohsiung Limestone. Two cores were selected for this research, one is W-2 (N: 2504008.088; E: 174168.943, 60m in length) and the other is S-4 (N: 2503968.458; E: 174009.179, 55m in length). The thickness of the Gutingken Mudstone in cores W2 and S4 is 38.7m and 21.8m, respectively. Each sample was obtained at every 10 cm interval for W2 and 30~40 cm for S4 with an average weight of 40 g. This study mainly contains two parts: analyzing the planktonic foraminifera for their carbon and oxygen stable isotopic compositions and dating the downcore records by correlating with the nannobiostratigraphy. Particular is the stable isotopic compositions of planktonic foraminifera in these terrestrial sedimentary sequences which has not been done in Taiwan before. Overall the mudstone analyzed in this study falls in the biostratigraphic range of small Gephyrocapsa Subchron, which spreads within 1.242 Ma~1.031 Ma. according to previous report. The age range is further constrained at about 1.186~1.065 Ma based on the oxygen isotope record and thus can be regarded as a high-resolution isotopic stratigraphy within the small Gephyrocapsa subchron. The average sedimentation rate inferred by the best age model from these cores is about 31cm/ky. It shows a progressive decrease in sedimentation rates: the younger the strata, the lower the sedimentation rate. On the contrary, the sedimentation rate varies dramatically at the lower part of the record. The turbidity current might be a potential factor responsible for the change. In addition, the spectral analysis of £_18O data presents a comparatively significant cycle of about 2.5ky through out the record. It might indicate a periodic forcing which influenced the environment during sediment depositation. The £_13C record obtained from this study fail to reflect the high productivity during the glacials. The mechanism that might affect the productivity in the area is not clear and still needs advanced research.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 63-65). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 63-65). Also available on the Internet.

The Fox River Belt forms a segment of the Circum-Superior Belt that comprises a series of ca. 1900 Ma volcanosedimentary belts located around the margins of the Superior Province. The Fox River Belt is a north-facing homoclinal sequence, composed of a rift-related sedimentary sequence, intercalated with thick sequences of komatiites and tholeiites, and intruded by mafic-ultramafic intrusions. Geological mapping, whole rock geochemistry and S, Nd- and Hf-isotope geochemistry of the magmatic and sedimentary units within the belt were used to obtain a better understanding of the magmatic and tectonic history of the belt and its relation with other segments of the Circum-Superior Belt. The compositional variation observed in the volcanic rocks (19% to 5% MgO) can be accounted for as the product of fractional crystallization. Trace element patterns as well as εNd and εHf values (-4 to +8 and +4 to +18 respectively) indicate that the magmatism within the belt was the product of partial melting of depleted mantle that was locally contaminated with sediments or gneiss. A plume origin for this melting event is proposed based on the high degree of partial melting, the large volume of magma, and the presence of a radiating dyke swarm. The 250 km long Fox River Sill appears to have behaved as a magma conduit during part of its history. Several intervals within the sill show enrichment and depletion of PGE. The KO Zone PGE-Cu-Ni mineralization (up to 5ppm PGE) formed from magmatic sulphides whose tenor was upgraded by the upward percolation of evolved intercumulus magma. Contaminated Lower Intrusions and the lower margin of the Fox River Sill are considered particularly prospective for hosting Ni- Cu-PGE mineralization.

The Fox River Belt forms a segment of the Circum-Superior Belt that comprises a series of ca. 1900 Ma volcanosedimentary belts located around the margins of the Superior Province. The Fox River Belt is a north-facing homoclinal sequence, composed of a rift-related sedimentary sequence, intercalated with thick sequences of komatiites and tholeiites, and intruded by mafic-ultramafic intrusions. Geological mapping, whole rock geochemistry and S, Nd- and Hf-isotope geochemistry of the magmatic and sedimentary units within the belt were used to obtain a better understanding of the magmatic and tectonic history of the belt and its relation with other segments of the Circum-Superior Belt. The compositional variation observed in the volcanic rocks (19% to 5% MgO) can be accounted for as the product of fractional crystallization. Trace element patterns as well as εNd and εHf values (-4 to +8 and +4 to +18 respectively) indicate that the magmatism within the belt was the product of partial melting of depleted mantle that was locally contaminated with sediments or gneiss. A plume origin for this melting event is proposed based on the high degree of partial melting, the large volume of magma, and the presence of a radiating dyke swarm. The 250 km long Fox River Sill appears to have behaved as a magma conduit during part of its history. Several intervals within the sill show enrichment and depletion of PGE. The KO Zone PGE-Cu-Ni mineralization (up to 5ppm PGE) formed from magmatic sulphides whose tenor was upgraded by the upward percolation of evolved intercumulus magma. Contaminated Lower Intrusions and the lower margin of the Fox River Sill are considered particularly prospective for hosting Ni- Cu-PGE mineralization.

This thesis is divided into two parts and covers biosynthetic studies on two secondary metabolites, tropic acid in Part I and piliformic acid, in Part II.(S)-Tropic acid is the acid moiety of the alkaloids hyoscyamine and scopolamine, which are produced by a number of plants of the Solanacae family. An intriguing rearrangement of the L-phenylalanine side chain gives rise to the isopropanoid (S)-tropic acid skeleton. The detailed nature of the rearrangement has however remained elusive despite continued interest over the years. In chapter two the identification of intermediates between L-phenylalanine and (S)-tropic acid is discussed, which has placed (R)-D-phenyllactic acid as an immediate precursor. The stereochemical features of the rearrangement are described in chapter 3 and finally in chapter 4 a mechanism for the rearrangement is proposed. This is based on information obtained from the incorporation of various isotopically labelled precursors to tropic acid into two of the minor alkaloids, 3a-2'-hydroxyacetoxytropane and 3a- phenylacetoxytropane. This work was carried out in collaboration with Dr Richard Robins at the AFRC Institute of Food Research in Norwich. Piliformic acid is elaborated by the slow growing fungus Poronia piliformis. The incorporation of a number of isotopically labelled substrates into piliformic acid has revealed a mixed biosynthetic origin, comprising C(_8) and C(_3) fragments. These have been shown to be of acetogenic and citric acid cycle origins respectively. The C(_8) fragment has been further demonstrated to be a degradation product of a longer chain fatty acid. The mode of coupling of the two fragments has been investigated and suggests the intermediacy of a novel a-carboxyoctanoate. A pathway for the assembly of piliformic acid, involving a 1,3-hydrogen shift, is proposed, consistent with the above findings. These results are the subject of chapter 6.

A database containing previously published geochronologic, geochemical, and isotopic data on Mesozoic to Quaternary igneous rocks in the Himalayan-Tibetan orogenic system are presented. The database is intended to serve as a repository for new and existing igneous rock data and is publicly accessible through a web-based platform that includes an interactive map and data table interface with search, filtering, and download options. To illustrate the utility of the database, the age, location, and Hf-t composition of magmatism from the central Gangdese batholith in the southern Lhasa terrane are compared. The data identify three high-flux events, which peak at 93, 50, and 15 Ma. They are characterized by inboard arc migration and a temporal and spatial shift to more evolved isotopic compositions. Plain Language Summary A new database with a web-based interface is presented that contains compiled geochronologic, geochemical, and isotopic data on igneous rocks in the Himalaya-Tibetan orogen.

Page 214 Not included in thesis. / <p> Hydrothermal carbonate was introduced into igneous rock in the Timmins area during an early, sea water alteration event when calcite (δ13C = 0 to -3o/oo) filled the primary porosity of basalt flows and during a later hydrothermal event when mafic and ultramafic igneous rock were altered into a zoned sequence consisting of an inner zone of ferroan or magnesian carbonate flanked by calcite- and chlorite-rich assemblages. The younger intense carbonate alteration event predated or was synchronous with regional metamorphism and deformation and was focused along structurally induced, permeable zones. Gold was introduced during and after the intense carbonate alteration.</p> <p> Away from carbonaceous sediments, δ13C-values of the ferroan carbonate are very uniform (-3.5 to -5o/oo) regardless of stratigraphic position, size, or gold tenor of the alteration zone. As carbonaceous sediments are approached, 13C of the ferroan carbonate becomes upto 4o/oo heavier. The 13C of the CO2 and δ18O and δD of the water components of the hydrothermal fluid are estimated to have been -3 to -6, +5 to +10, and -40 to -60o/oo respectively. The geological controls on the distribution of carbonate alteration, and the stable isotopic values of the hydrothermal components suggest that the H2O-CO2 hydrothermal fluid was of magmatic origin, a result of mantle degassing.</p> / Thesis / Doctor of Philosophy (PhD)

<p> The frequency spectrum of a diatomic linear chain with randomly placed isotopic impurities is calculated using a Green's function formalism. The calculation follows a method devised by Langer, and yields the density of states exactly to first order in the concentration of impurities. It is found that polarisation mixing causes no problem and the results are analogous to those of Langer for the monatomic chain. Results are presented for various ratios of impurity mass to replaced mass, for which impurity bands are found above the optical band and in the gap between the accoustic and optical bands. A self consistent calculation is also discussed.</p> / Thesis / Master of Science (MSc)