School of Earth Sciences - Theses

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    Altitudinal distribution of vegetation in the headwaters of the Wongungarra River, Victoria
    WATSON, FRED ( 1993)
    Changes in vegetation composition with respect to altitude were investigated in the sclerophyllous forests of the Australian mountain region. Vegetation was surveyed at 148 sites along two transects which were located to maximise variation in altitude and minimise the influence of environmental factors not directly related to altitude. The measurement, simulation, and estimation of environmental variables revealed that this aim was met except at the end-points of the transects where secondary influences are present.
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    Western Victoria lava flow and regolith mapping using Landsat imagery
    Valle, Esteban ( 1991)
    The South Ripon area 35 km west of Ballarat was mapped using Landsat TM imagery. The aim of the project was to use the TM data to map the regolith. The regolith forms the majority of the surface. Detailed fieldwork revealed that the regolith could be separated into four main types. These were 1. Later Newer Volcanics (stony rises). 2. Earlier Newer Volcanics. 3. Granites, and 4. Cambro-Ordovician rocks. Of these the granites and stony rises were identified easily as their soil-regolith cover were sufficiently different from the monotonous shades associated with the Earlier Newer Volcanics (ENV) and Cambro-Ordovician rocks. The TM images were treated by several techniques, of which a linear contrast stretch resulted in images comparable with those obtained with principal components and band ratios.
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    A structural analysis of Wanna, South Australia: the comparative behaviour of Mafic dykes and granite during deformation
    Bales, Thomasin ( 1996)
    Strain localisation that produces varying foliation development, folding, and patterns of boudinage has led to structural features within, and between, the two main lithologies at Wanna, South Australia at amphibolite facies, these lithologies being the megacrystic granite gneiss of the Donington Granitoid Suite, and the Tournefort dykes which cross-cut the gneiss. The structural elements differ between, and within each lithology-for example, the megacrystic granite gneiss has a reasonably pervasive foliation, whereas deformation features in the Tournefort dykes tend to be localised into areas of high strain. Cross-cutting relationships are used to constrain the temporal relationships between structural elements, and the development of the different structural features explained in terms of rheological behaviour of the lithologies. The relative rheological behaviour of the principal lithologies was thus found to vary over space, as well as over time. Geothermometry of mafic assemblages was used to constrain the temperatures at which different structural features developed, which were all found to be in the order of about 720°C and occurring under fluid-rich, upper amphibolite conditions.
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    The geology of the Pyramid and Tonghi Creek areas, East Gippsland
    Spiers, Peter D. ( 1984)
    A study of the geology of the Club Terrace region is being undertaken with two major aims: 1) to provide a clearer picture of the structural geology and geological history of the region and, using this, 2) to investigate Ag, Cu, Pb, and Zn mineralization present in the region with emphasis on producing a model for ore genesis.
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    Geology of the Dookie District (Part I) & Trace element distributions within some major stratiform orebodies (Part II)
    Smith, Robert Neville ( 1973)
    Part I: The Cambrian rocks outcropping in the Dookie district consist of a series of altered igneous rocks (diabases), a variety of pyroclastic rocks and cherts. The igneous rocks are thought to have been originally tholeiitic, having undergone low grade burial metamorphism, hydrothermal alteration and possibly contact metamorphism. Field evidence indicates that at least one of the igneous bodies is intrusive, probably a sill. The relation between these rocks and Cambrian rocks elsewhere in Victoria is discussed. The lithology and structure of an area of folded Ordovician and Silurian — L. Devonian sediments outcropping to the south of the main Cambrian massif is reviewed. Part II: Trace elements Tl, Ag and Au abundances in whole rock samples from a number of important stratiform basemetal orebodies have been determined by neutron activation analysis. Suites of samples were taken from the HYC Zn-Pb-Ag deposit at McArthur River, N.T., the Cu-Pb-Zn deposit of Rosebery, Tasmania and a Karoko type orebody from Shakanai, Japan. While the distribution of Au and Ag in the three deposits were found to closely follow those of Cu and Pb respectively, a higher Ag/Au ratio is apparent in the HYC deposit. In the other deposits, probably formed at temperatures greater than 200°, high concentrations of Au are explainable in terms of high temperature transport via chloride or thiocomplexing, while in the HYC deposit, formed below 150°, hydrothermal transport of comparable amounts of Au is considered unlikely. In response to lower temperature, strongly reducing conditions and restricted circulation, Tl concentrations in the HYC deposit are markedly greater than those in the remaining deposits. At McArthur River, significant enrichments in Tl occur up to, 250 metres stratigraphically above the main ore shales, and the geochemical significance and practical value of such metal haloes about stratiform orebodies are discussed.
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    Mobility of base metals through regolith, Broken Hill, N.S.W.
    Lulofs, Damien ( 1993)
    Regolith profiles over and around zones of Pb-Zn mineralisation were investigated at Maybell and Stirling Vale, located in the Broken Hill region, N.S.W. Metasediments and metavolcanics of the Proterozoic Willyama Supergroup crop out in the study areas, with quartz-gahnite horizons hosting mineralisation. Desert loam soils in the study areas have a transported origin. Locally transported sheetwash deposits overlie a relict aeolian deposit which sits on relatively fresh Proterozoic bedrock. Mineralogy of the regolith profile is consistent with depth and landscape position. Quartz-gahnite horizons form topographic highs in both areas, containing up to 13.5% Zn. Gossanous material is associated with the quartz-gahnite rocks. No base metal containing secondary minerals were present in this weathered material but there were high proportions of iron oxides containing substantial amounts of base metals. Surrounding soils were anomalous in Zn, Cu and their pathfinders Cd and As, which outlines a mobilisation of base metals. Similar anomalies were expressed in stream sediments. Calcrete in the area, contained no anomalous levels of Zn, due to the low solubility of Zn at high pH. The majority of base metals in soils were associated with amorphous iron oxides and silicates (presumably gahnites). These metal bonding sites indicate, dispersion haloes in the regolith are due to a combination of physical and chemical dispersion. In this example of transported regolith profiles in an arid terrain, Zn and Cu are both physically and hydromorphically dispersed from weathering quartz-gahnite horizons.
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    Geology of the lookout area, Eyre Peninsula, South Australia
    Annear, Joshua A. ( 1996)
    The Lookout Area, southern Eyre Peninsula, South Australia forms part of the Lincoln Batholith with outcropping Donington Granitoid Suite units of Palaeo-Proterozoic age (l840-1800Ma) and both syn-plutonic and intrusive mafic dykes. The area was surveyed and mapped at 1:500 to produce a detailed geological map including the form surface trend of structural features. The units, incorporating felsic, intermediate and mafic gneisses intruded by the mafic dyke sequences, preserve high strain mylonitic deformational features with well developed fabrics in the felsic units. The Mafic dykes are boudinaged and display asymmetries attributed to antithetic back-rotation due to extensional shear. Kinematic indicators including shear band formation, parasitic folding and strain shadows suggest a kinematic history of initial sinistral deformation post-dated by dextral west-up oblique shear associated with the formation of the principal foliation. This is in turn post-dated by local sinistral shearing. The strain associated with the deformation can be measured by use of porphyroclast shape and distribution. These results indicate that the strain is locally variable, from constrictional to flattening, but generally constrictional with an extensional ratio of approximately 6:1. The metamorphic conditions preserved by the mineral assemblages analysed through the average PT method using THERMOCALC are; 700-850°C and 5.8-6.8 kbar. This mineral assemblage indicates metamorphism in the area has achieved upper-arnphibolite to lower granulite facies metamorphism at some stage in the PT history of the area.
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    The Buchan group sediments and their application to industrial uses
    Duyker, Melissa J. ( 1993)
    Technological advancements in the paper industry, which utilise calcium carbonate rather than kaolin as coaters and fillers, is the motivation behind establishing suitable limestone resources in Victoria. The relatively pure Buchan Group Limestones in East Gippsland have practical applications in this industry. The two major controls on the geochemistry of the carbonates are: a) the depositional environment; b) the diagenetic history. The two main units analysed, including the Buchan Caves Limestone, and the Murrindal Limestone, have been deposited in environments conducive to the formation of relatively clay-poor carbonates. The predominant low-energy subtidal conditions prevailing in the deposition of the Buchan Caves Limestone, permitted higher concentrations of clay and organic matter. The Murrindal Limestone harbours sediments that are both clay-rich (McLarty Member) as a result of quiet lagoonal conditions, and extremely clay poor (Rocky Camp Member), the consequence of a high-energy, biohermal environment. In both units, burial and diagenesis are the mechanisms by which further impurities are added, transported or transformed throughout the carbonate profile. Statistical evaluations with respect to the calcium oxide, content, indicate that the Rocky Camp Member is a very high- grade resource. Both the Buchan Caves, and the McLarty Member Limestones are variable grade resources which vary from low- to highgrade. However, Si02,, Fe203, MnO, and MgO content determines the potential application of the Buchan Group Sediments to the paper industry. In all units, mean contaminant values are high, and generally exceed the specifications of the paper industry for fillers and coaters. Potential quarry locations are identified at Murrindal and in South Buchan. These sites offer a combination of very high-grade limestones, relative lack of impurities, and conform to the regulations of quarry development operations.