http://hdl.handle.net/10092/841 2013-06-18T15:34:01Z http://hdl.handle.net/10092/4509 Title: Geomorphological and geophysical investigation of the effects of active tectonic deformation on the hydrogeology of North Culverden Basin, North Canterbury Authors: Armstrong, Mark James Abstract: This thesis examines the complex interaction between the tectonic evolution of Culverden Basin and the Late Quaternary sediments, which form the aquifer-bearing deposits, using geological and geomorphological mapping as well as near-surface geophysical investigations. Along the eastern margin of Culverden Basin, the deformation associated with the actively widening Australian-Pacific plate boundary zone, has resulted in the evolution of Culverden Basin and the progressive inversion of the basin floor. The eastern margin of the basin is structurally controlled by a NE trending, complexly segmented range-front fault system and associated thrust-propagated anticlines forming the basin boundary. Basin inversion is driven by the westward propagation of footwall imbricate thrusts and associated folds. The inversion of the basin floor lead to the creation of sub-basins within the larger basin, which have controlled the distribution and architecture of the Late Quaternary stratigraphy. The Late Quaternary sedimentary record documents periods of climatically induced aggradation during cold conditions and degradation in the intervening warmer times. The interaction between the sedimentation and ongoing tectonic deformation has resulted in complex lithological relationships between the locally sourced alluvial fans and the glacial outwash deposits of the major rivers entering the basin. The architecture of the aquifers is therefore controlled by the changing fluvial regime and its interaction with the evolving sub-basins. The progressive evolution of the sub-basins leads to increasing complexities in the facies relationships and to the confinement of the deposits into progressively smaller portions of the sub-basins. Once the basin boundaries become emergent, the basin becomes isolated, and potentially cut-off from its groundwater recharge source. Leonard Mound is an actively evolving imbricate thrust system along the eastern margin of Culverden Basin that has isolated the Wynyard sub-basin from the central portion of Culverden Basin, during the Late Pleistocene and present. The emergence of Leonard Mound is preventing the recharge to the Wynyard sub-basin from the high yielding aquifers of the central portion of the basin. In the central portion of Culverden Basin, high natural recharge combined with an irrigation scheme has allowed for transformation of the basin into a major dairy farming centre. In contrast, the Wynyard sub-basin is still subjected to frequent summer droughts, making it desirable to find a better source of groundwater for the eastern margin of the basin. The hydrogeological model provided by the Culverden Basin almost certainly has wider implications to the groundwater resources of other basins in similar active tectonic settings. 2000-01-01T00:00:00Z http://hdl.handle.net/10092/7864 Title: Reactions of alcohols in acetic anhydride-mineral acid mixtures Authors: Hardman, M. J. Abstract: The reaction of 3β-cholestanol with acetic anhydride and sulphuric acid has been studied. A kinetic investigation has been made of the reaction of these reagents with cyclohexanol, 1-methylcyclohexanol and a series of benzyl alcohols. The relative rates for the reaction of some 6β-substituted-3β-acetoxycholestan-5α-ols in this system have been determined and the rates compared with that for 1-methylcyclohexanol. The reaction of 3β,6β-diacetoxycholestan-5α-ol with fluosulphonic acid has been shown to involve a "backbone" rearrangement terminated at a position intermediate between those usually found. The structure of one of the products has been determined and a structure is suggested for another product. 1967-01-01T00:00:00Z http://hdl.handle.net/10092/7863 Title: Studies of ion molecule reactive processes, electron impact ionisation, and inelastic collisions in state selected molecular beams Authors: Harris, Sean Anthony Abstract: Alkali metal ion sources have been designed for the production of Li+, Na+ and K+ ion beams. The thermionic emission of alkali metal ions from heated synthetic zeolites is utilised to produce the alkali ions. As a precursor to crossed beam studies of the reactions of the alkali metal ions with spatially oriented symmetric top alkyl halides, the ion molecule chemistry of K⁺ with CH₃X and tertiary C₄H₉X where X= Cl or Br has been examined for collision energies up to 5 e V using a Drift Tube Mass Spectrometer. The electron impact ionisation cross sections for the inert gases, H₂, N₂, SF₆, CC1₃H and the molecules CH₃X where X= H, F, Cl, Br, I, have been measured. The ionisation efficiency curves for Ar, CH₄, CH₃F, CH₃Cl and CH₃Br from threshold up to 200 e V have been determined. The cross sections for the loss of hexapole focused upper Stark state molecules from ∣JKM〉 rotational state selected molecular beams of CH₃F, CH₃Cl and CF₃H have been measured. The upper Stark state molecules are defocused from the beam in rotationally inelastic collisions with a. scattering gas introduced to the hexapole. The long range attractive van der Waals interaction between the colliding species has been used to account for the magnitude of the cross sections from consideration of rotational transitions of the ∣JKM〉 state selected beam molecules where ∆M = ±1 or ∆J = ±1. The seeded beam technique has been used to determine the velocity dependence of the defocusing cross sections. 1997-01-01T00:00:00Z http://hdl.handle.net/10092/7862 Title: Metal organic complexing in soil systems Authors: Gregor, Jan E. Abstract: The work described in this thesis is concerned with properties of soil derived fulvic acids. A method for isolating soil fulvic acids is described. The method makes use of the metal complexing agent pyrophosphate (pH 3) as the extractant. The hydrophobic XAD-7 resin was used for the selective separation of the non-ionic fulvic acids from the ionic extractant at low pH. Fulvic acids obtained after a single XAD-7 treatment had acceptably low ash contents (< 0.6%). Chemical and physical properties of these fulvic acids were compared with those of fulvic acids that had been subjected to high and low pH conditions (conditions normally encountered during traditional methods of extraction). The resultant changes in molecular weight (gel exclusion chromatrography), equivalent weight and protonation constants (potentiometric titrations) and in metal binding properties (ion selective electrode potentiometry, fluorescence spectroscopy and anodic stripping voltammetry) are discussed. The acid-base titration curves for fulvic acid have been interpreted in terms of fulvic acid having four structurally independent carboxyl groups, having mean pKn values pK₁ˈ .... pK₄ˈ. The results for six fulvic acids were in the range log K₁ˈ 7.2 - 6.5 (c 8% of total carboxyl acidity), log K₂ˈ 5.9- 5.3 (c 11%), log K₃ˈ 5.0- 4.1 (c 20%) and log K₄ˈ 3.2- 2.4 (c 60%). These residues indicate a low percentage (not more than 8%) of polyprotic acid residues (e.g. 1,2,3-tricarboxylic acid); these residues may be important complexing sites. A comparative study of fulvic acid complexing, both between fulvic acids and with model ligands, is reported. Ion selective electrode potentiometry, fluorescence spectroscopy and anodic stripping voltammetry were used to study copper(II) and lead(II) complexing. A variety of binding sites with different affinities for metal ions was indicated. The stronger binding sites are involved in binding at low metal concentration followed by weaker binding sites at higher concentrations of metal. Copper(II)-fulvic acid binding curves (i.e. % free metal vs. pH) are similar to those for citrate, malonate and aspartate, and were modelled numerically by mixtures of these competing ligands. The citrate ion was established as a useful model for describing the complexing reactions of fulvic acid. A detailed study has been made of the equilibrium reactions ofcitrate with protons and aluminium(III). The protonation constants for citrate are log K₁ 5.90, log K₂ 4.35 and log K₃ 2.91. The model best describing the A1(III)-citrate equilibria was found to be A1HL + (log β 11.02), AlL (8.35), A1 (HL)L²- (17.36), A1L₂ ᶟ- (13.40), A1L₂H­₁₄⁴- (pK A1L₂ ᶟ-, 6.07) and A1 (LH­₁)₂⁵- (pK A1L₂H­₁⁴-, 7.09). 1987-01-01T00:00:00Z