School of Earth Sciences - Theses

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    Heat flow modelling in the Adelaide Geosyncline, South Australia and implications for geothermal resource exploration
    Musson, Alexander James ( 2008)
    The central theme of this research is the continental heat flow at the surface of the Earth. Radioactive heat production in the lithosphere and heat flux from convection in the asthenosphere are first order controls on surface heat flow. Accurate heat flow determinations are essential in understanding the geodynamics of the lithosphere and refining resource exploration models, in particular those related to geothermal resources. The focus of this investigation is confined to the understanding of heat refraction as a result of the heterogeneity and anisotropy of the geological subsurface, under a steady-state heat conduction regime. Within the South Australian Heat Flow Anomaly, an area of particular significance for geothermal resource exploration is the deep seated Torrens Hinge Zone, a strip of tectonic transition between the Archaean Gawler Craton to the west and the Neoproterozoic to Cambrian sedimentary cover of the Adelaide Geosyncline to the east. (For complete abstract open document)
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    Geologic and geomorphic applications of Aster satellite imagery, northern Flinders Ranges, South Australia
    Harper, Katherine Louise ( 2002)
    Multispectal ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) satellite data has been evaluated for geologic and geomorphic interpretations within the northern Flinders Ranges, South Australia. ASTER is a new remote sensing imaging system on board NASA’s Terra satellite, launched in December, 1999. ASTER measures the reflectance of the Earth’s surface within 14 bandwidths of the visible, near infrared, short wave infrared and thermal infrared sections of the electromagnetic spectrum, with a minimum spatial resolution of 15 m. ASTER has the ability to produce digital elevation models (DEM), important for understanding the dynamics of the landscape by draping false colour images over topography. The northern Flinders Ranges is one of the most diverse geological settings on the Australian continent, making it an ideal ‘test site’ to demonstrate the capabilities of the ASTER instrument. The area contains a range of geology from Precambrian basement to Quaternary desert landforms. The ability of ASTER Level 1B data to discriminate between the large range of lithologies is assessed. Geomorphic interpretations made from exploiting the high resolution ASTER data and DEM has revealed a significant record of post Pliocene landscape development, attributed to a combination of climatic and tectonic factors. Such features as incision morphology and the identification of palaeodrainages have enabled constraints to be placed on the Quaternary degradational and aggradational events. For example, estimates of Quaternary sediment flux rates in some areas of the study area are essentially extracted from ASTER DEM data. ASTER has persisted to be extremely useful in the study of aeolian landform morphology in regions surrounding the northern Flinders Ranges. The short wave infrared has proved useful for identifying areas of high surface moisture, directly relating to the depth to water table. The application of principal component analysis to ASTER short wave infrared data is used to accurately identify specific mineralogical character.
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    The Mine Creek region, Eyre Peninsula, South Australia: a structural analysis of the Kalinjala Shear Zone
    Karner, Tamara ( 2000)
    Mine Creek, located in the Eastern Eyre Peninsula, South Australia, exposes a natural cross section through the Kalinjala Shear Zone where it juxtaposes a sequence of granulite facies metasediments to the west from upper amphibolite granite gneisses to the east. The lithologies include biotite-garnet schists, forsteritic marbles, biotite-hornblende amphibolite, banded iron formation and quartz +feldspar +biotite +hornblende ± garnet megacrystic granite gneisses. These rocks preserve evidence of at least two deformation events. D1 formed a layer- parallel S1 foliation defined by peak garnet +biotite +quartz +feldspar assemblages, with no recognised folding. Associated with this deformation was the initiation of the NE-SW oriented, dextral transpressive, Kalinjala Shear Zone, which is up to 3km wide and 300km long. The shear zone is characterised by high-grade assemblages, steeply plunging stretching lineations (L1) and dextral kinematic indicators. The formation of S^C, fabrics, C' shear bands and local ultramylonitic zones indicates intense shearing and high-strain. D2 developed isoclinal F2 folds and a localised NE-SW orientated S2 axial planar cleavage, that was not pervasive. Progressive deformation and retrogression and subsequent tectonic reworking has created a highly recrystallised and structurally complex environment. A strain analysis of the augen gniess was undertaken using both finite strain methods and by qualitative examination of gneissic fabric intensity. Although finite strain estimation met with limited success, results demonstrate a significant component of flattening was responsible for producing strongly oblate strain markers. Analysis of shear zone fabric development reveals strain insensitive composite fabrics that do not accurately reflect the total amount of strain accommodated by the rock. Instead their oblique orientation, relative to the shear zone boundaries reflects non-coaxial strain and may be used as an important kinematic indicator. Deformation fabric analysis resolves the intensely strained nature of the lithologies of Mine Creek, these are dominated by S^C orthogneiss and layered mylonite fabrics. Low-strain fabric features in the granite gneisses are not preserved.
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    Sedimentology of the late Neoproterozoic Patsy Springs Canyon, Flinders Ranges, South Australia
    Mornane, Kate ( 2003)
    The Neoproterozoic Patsy Springs Canyon is located within the northern portion of the Adelaide Geosyncline, South Australia. The sedimentary structures found within the canyon fill are consistent with a deep marine origin, and include syn-sedimentary marine phosphates, marine cements, sandstones with partial Bouma sequences, abundant mudstones and various mass flow deposit types (including grain flows, debris flows and slumps). Structures indicative of tidal activity (previously interpreted to be of shallow water origin) are interspersed with Bouma sequences and mass flow deposits and are here interpreted as having been produced by deep-water tidal bottom currents. Rare structures resembling hummocky cross stratification are here interpreted as similarly being of deep-water origin. This deep water interpretation for the canyon fill contradicts previous shallow water models and alleviates the need for extraordinary changes in base level, required by such shallow water models. A deep-water submarine origin for the canyon is also more consistent with the lack of canyon-synchronous basin-wide unconformity and is more consistent with an open-ocean palaeogeography. This study has resolved some of the ambiguity surrounding the origin of the Wonoka canyons by providing sedimentological evidence to suggest that they may in fact represent ancient submarine canyons.