School of Earth Sciences - Theses

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    Investigations into diamond drilling and rock drillability: microscale and fullscale impregnated bits
    Siribumrungsukha, Boonsom ( 1980)
    Drill bits having cutting edges formed of a matrix of sintered metal powder impregnated with diamond bort (the so called "impregnated" diamond bits) have the potential to greatly increase the economy of diamond drilling, due to low production costs and long bit life resulting from reconditioning of the cutting edges. However, little detailed research into the performance of impregnated bits has been conducted, and the capacity to predict their field behaviour is limited. As a contribution to the knowledge of impregnated bit performance, this project has studied basic relationships between thrust, rotational speed and the penetration of diamond bits into rock, with particular attention paid to the development of techniques suitable for laboratory testing using miniature impregnated bits. A conventional bench drill and a radial arm drill were modified and instrumented to enable operating conditions to be controlled and drilling parameters to be measured and monitored, for microscale and fullscale drilling using impregnated drill bits. Bit performance and drilling characteristics were studied for four rock types, and rock drillability studies were carried out on seven rock types. Statistical relationships between penetration rate, specific energy, torque and drilling distance that were determined enable projection of drilling data from a standard "sharp" condition. A wear measuring device was developed to assess matrix wear of the impregnated microbits. Reconditioning was done by drilling medium-strength, abrasive Stawell sandstone. Initial penetration rate increases linearly with increases in thrust and/or rotational speed, but only within a limited range, depending on rock type and the other operating parameters. Matrix contact with the rock surface, "clogging" of the diamonds, time-dependency, and strength of diamonds and the diamond-matrix bond play important roles in these phenomena. Comparison of rock drillability between that of microscale and fullscale bits shows a straight-line relationship indicating the possibility to predict drilling performance in the field. Uniaxial compressive strength, tensile strength, and Sklerograf hardness can be used as a preliminary, but not reliable guide, to predict drillability. Petrographic characteristics and the relative scale of diamond size to grain size of minerals affect rock drillability.
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    Studies in Victorian Tertiary foraminifera neogene planktonic faunas
    Mallett, Clifford William ( 1977)
    Planktonic foraminiferal faunas are described for the interval late Early Miocene to the Pleistocene, in the Tertiary basins along the southern margin of Victoria, including the Otway Basin, the Port Phillip Embayment, and the Gippsland Basin. Ninety-two foraminiferal taxa are identified. The faunas are dominated in the Early Miocene by globigerinid and globigerinoidid species, by unkeeled globorotalids in the Middle Miocene, and by keeled globorotalids for most of the Late Miocene. Unkeeled globorotalids are again important in the Early Pliocene, but keeled species again reappear in the Late Pliocene and the Early Pleistocene. One Pleistocene, two Pliocene, two Late Miocene, and two Middle Miocene planktonic foraminiferal zones are recognised on the first appearance of the following species: Orbulina suturalis, Globorotalia mayeri, Globorotalia acostaensis, Globorotalia conomiozea, Globorotalia puncticulata, Globorotalia viola, Globorotalia truncatulinoides. Subzones are identified by the extinction of Globorotalia peripheroronda, and by the appearance of Globigerina nepenthes and Globorotalia plesiotumida. Foraminiferal datum levels are used to correlate the Victorian sections with the Italian stratotype sections, the New Zealand late Tertiary, and the N-zonation of Blow, and hence into the palaeomagnetic and radiometric time scales. In the Tertiary basins, the maximum extent of marine deposition occurred in the Early Miocene, and despite subsequent sea level falls, continuous marine deposition is found through the Middle Miocene and most of the Late Miocene in the Otway Basin and the Port Phillip Embayment. Shallowing within the Middle Miocene is reflected by breaks in the Gippsland Basin sections, and lithological changes in other basins. A major sea withdrawal occurred near the top of the Miocene. Small scattered Pliocene deposits indicate short high sea level phases at the base of the Pliocene, in the middle of the Pliocene, and about the Pliocene - Pleistocene boundary.
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    Mineralogy, geochemistry and origin of the Kalgoorlie gold deposits, Western Australia
    Golding, Lee Yvonne ( 1978)
    Rich gold-telluride lodes (steeply dipping and flatly dipping) and minor gold-quartz stockwork mineralization characterize the Kalgoorlie gold-field. The origin of these gold deposits, the relationship between deposits and then nature of the host rocks are the major problems considered in this thesis. Extensive diamond drilling at the essentially unmineralized southern end of the field provided excellent material for stratigraphic studies and for country rock analysis whilst ore samples were obtained from both mines and drill core.
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    Late Paleozoic glaciations of Eastern Australia
    Bowen, Richard L. ( 1959)
    In a re-analysis of the Late Paleozoic glaciations of Eastern Australia, close review of elements of paleogeography results in many new interpretations. New data appear from field studies of the details (including till fabric analyses in the Heathcote District of Victoria) of glacial stratigraphy in drift sequences of Victoria and South Australia. Analysis of sedimentary volumes in Tasmania and analysis of sedimentation during the Upper Carboniferous and Permian of New South Wales and Queensland adds more new information. Field reviews of sequences in the Finke District of the Northern Territory, Tasmania, New South Wales, and Queensland aid in understanding the effects of glaciations in those regions. All data known to the writer from extensive field examinations and review of published data may be incorporated into a unified history of the glacial times. Many lacunae exist, but analogy with studies of Pleistocene glacial drifts helps to bridge some gaps. Principally during the Middle and Upper parts of the Upper Carboniferous and in the Early Permian, highland centers in the northwest of Tasmania (the Macquarie Mountains) and in northeast New South Wales (the Clarencetown Mountains, a volcanic range) became loci for glacial formation and spread. From the former, glaciers spread east, north, and northwest. Upon advancing northwest, the Mt. Lofty-Kangaroo Island Ranges were encountered. These were breached with the establishment of glacial corridors, and a glacial lobe subsequently pushed about 600 miles further north-north-west. In that region, this glacial [?] [?] [?] joined a sheet from Western Australia. Also, in pushing north from the Macquarie Mountains, the glaciers apparently advanced 900+ miles to the Springsure District of Queensland. From the Clarencetown Mountains, piedmont glaciers radiated east (to the sea near Mt. George, Booral, and Limeburner’s Creek), south, and west to fill subsiding basins with glacial deposits and some volcanic effusions. Additionally, some glaciers spread east from the epi-Kanimblan mountains of New South Wales. Thick drift sequences left by these spreading glaciers have been preserved in favourable sites. Fluvial and lacustrine deposits in the drifts demonstrate the presence of interstadial and interglacial conditions, but the entire interval may be considered a single glacial epoch much resembling the Pleistocene, although that of the Late Paleozoic probably was much longer. After wastage of the glaciers, cold weather (at least during winters) persisted, for many phenomena found in the Permian sediments seem best related to climates which were cold at least part of the year. Notable among these are the erratics so widely distributed through the marine Permian sediments of eastern Australia. Such erratics seem best explained as phenomena resulting from the transport by winter ice floes of material eroded from glacial drift left on the land by earlier glaciations.
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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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    Structural analysis of selected duplex soils
    Knight, Michael John ( 1971)
    The profile characteristics, geographical extent and general environmental relationships of duplex soils are described. They are shown to be an important group in Australia and particularly in Victoria. The variety of approaches and definitions employed by investigators of soil structure are discussed. These are contrasted with the definition used in this thesis which incorporates the concepts of spatial distribution and orientation of vectorial fabric elements in the soil. The importance of describing structural features at a number of scales is emphasized. At each scale an attempt is made to quantitatively describe (where possible) the three or two-dimensional geometrical properties of the soil components. A structural classification of duplex soils that incorporates a number of descriptive geometrical elements is proposed. A detailed study is made of the structure and related chemical, physical and mineralogical properties at an undisturbed site (Boorook) in Western Victoria. The ground surface at the Boorook site is described as being deformed into gilgai microrelief. It is demonstrated that soil structural analysis can be usefully employed to develop a swelling mechanism that explains how the Boorook gilgai probably formed. The data and subsequent analysis tends to place some doubt on mechanisms proposed by past workers. A detailed study is also reported from a site (Hartwell) near Melbourne. The site is described as being illustrative of profiles that show little or no internal and ground surface deformation. An unfolded stoneline is considered to be the principal structural feature. The mechanism for the formation of the stoneline is shown to probably involve gravitational settling of the grains in a fluid-like medium. Regional investigations of profiles throughout Western and Central Victoria and New Guinea are also described. It has been found that the principles and techniques of soil structural analysis can also be applied to buried soil structures. By these means it has been possible to establish that buried fold-like structures seen in section in a road cutting at Terang, are in fact relics of gilgai. Experimental models have assisted the investigations into the structure of duplex soils and have provided additional information on the dynamic interaction of moisture with the soil components. The main processes and sequences in the genetic development of structure of duplex soils as discussed in the light of observations of natural structures and experimental results. Attention is drawn to the differences between the dominant structural processes in the two main horizons of the profile. The approach of soil structural analysis is formalized for profile studies into the discipline of Structural Pedology. The principles of Structural Pedology threaded through the body of the thesis are summarized and shown to be very similar to those of Rock Fabric Analysis. The need for an interdisciplinary approach in this field is emphasized. It is shown that soil structural analysis is not limited to Pedology but rather can be applied to a number of academic and applied problems in a variety of disciplines that include Engineering (Soil Mechanics), Earth Sciences, Agriculture, Soil Erosion and Conservation.
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    Structural geology of the area between Bacchus Marsh and Blackwood
    Lam, Peter W. H. ( 1968)
    Scope of study: This thesis is concerned primarily with the structural geology of the Ordovician basement rocks along the Lerderderg River Gorge and its two main tributaries. Deformation of the Ordovician rocks constituted the fundamental interest that led to the detailed study of structural elements at various scales. Fabric diagrams were widely used in structural of macroscopic structures. Micro-fabric analysis was not applicable because of low grade regional metamorphism and the fine texture of the rocks. A computer programme used in the preparation of the various fabric diagrams greatly increased the efficiency and accuracy of the study of the structural geometry and symmetry of the deformed Ordovician rocks. A brief description is given of the Permian glacial deposits, the Cainozoic alluvial deposits, the Older and Newer Basalts, the quartz veins, and the different types of dykes.
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    The geology, petrology and geochemistry of the Otway formation volcanogenic sediments
    Duddy, Ian Ross ( 1983)
    The geology, petrology and geochemistry of the Early Cretaceous Otway Formation have been investigated in detail and used to determ ine the nature of the source rocks and to develop a model for the diagenetic and low-grade metamorphic readjustments. The fluviatile Otway Formation was deposited in continental rift grabens that stretched some 1000 km along the southern coast of Australia during the Early Cretaceous. The main areas of deposition in the Otway, Gippsland and Bass Basins contain an estimated 100,000 cubic kilometres of detritus. The major part of this detritus was derived from pyroclastic material which has been shown by the fission track dating studies to have been derived from contemporaneous volcanism. The pile of volcanogenic material comprising the Otway Formation is at least 3 to 4 km thick in the main basins. The sediments are entirely non-marine and were deposited by large scale multichannel streams cut in extensive floodplains. The streams deposited thick multistorey channel sandstones in sheet-like bodies and a diverse spectrum of overbank mudstones and fine-grained sandstones. The complex channel sandstones fine upwards but have numerous erosional breaks indicating repeated flood cycles. Whereas the channel deposits have internal features consistent with braided stream channels the overall system has a large proportion of floodplain which was been considered in the past to have been a feature of meandering channels. The oversupply of volcanogenic detritus is considered to have been responsible for the development of the multiple channel depositional system in a climate of high seasonal rainfall. Whole rock chemical analyses of all lithologies in the sedimentary suite, recalculated i.nto a set of normative minerals, have proved useful in the distinction and description of sedimentary rocks in general. P20S was found to be useful for the identification of Early Cretaceous soil forming processes. The study of the chemical composition of detrital minerals has demonstrated the usefulness of this approach in the identification of the nature of the source magmas of volcanogenic sediments. For the Otway Formation, analyses of clinopyroxenes, amphiboles, feldspars and sphene in particular, have shown that high potassium dacitic to shoshonitic volcanism dominated during Early Cretaceous rifting. The new data on the geology and mineralogical and chemical features of the Otway Formation have application to the study of diagenesis and low-grade metamorphism in volcanogenic sediments in general. (From Abstract)
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    The geology and hydrogeology of the Corangamite region
    Thompson, Bruce R. ( 1971)
    Tectonic activity after the early Cretaceous resulted in a complete change in the depositional environment in the sedimentary basin - the Otway Basin - located to the south of the Western Highlands of Victoria and to the west of Melbourne. ThiS Basin became subject to increasing marine influences and the sediments deposited include thick sequences of Miocene marls: the Gellibrand Marl. The water in the marls and in the underlying sands of the Dilwyn Formation is saline near Lake Corangamite but elsewhere water of good quality is found in the sand aquifers, indicating that tectonic activity has caused the local isolation of the lower formation from the effects of flushing by fresher groundwater. Continued tectonic activity and associated volcanic activity during the Miocene and Lower Pliocene resulted firstly in the regression of the sea then the development of the internal drainage characteristic of the Corangamite Region. The sea probably retreated to the southeast as indicated by the unusual parallel physiographic features which have influenced the flows of 'earlier' Newer Volcanic lavas in the Curdie River area and the subsequent development of this river's drainage system. These features are probably related to remanent coast strandlines. The quality of the groundwater found in the 'earlier' lavas is generally poor but the basalts and tuffs of the 'later' Newer Volcanic age often contain water of low salinity, particularly in the intake areas which are located in the ‘stony rises' or near the volcanic cones. The intake area water of the Mt. Warrion basalts is a low salinity calcium-magnesium-bicarbonate water, having an unusually high nitrate content. As the salinity of the water increases away from the intake area the chemical nature of the water approaches that of a dilute sea water. This has been interpreted as being the result of a release of 'oceanic' connate salts by weathering of the calcareous material found in the tuffs and scoria beds of the volcanic cones. The material has been derived from the underlying marl sequence and has been incorporated into the igneous rocks during eruption. The high nitrate concentration has been attributed to the effects of pollution, since there is some evidence that the nitrate values have increased over the last sixty years, but there is also probably an increased rate of fixation in the intake area due to the effects of cultivation. The high bicarbonate values are probably due to a high rate of absorption of carbon dioxide from the atmosphere in the intake areas. The hydraulic characteristic of the basalts ensures the rapid distribution at the high nitrate and bicarbonate waters of the intake area over large areas, hence the effects of pollution are more readily noticeable. The groundwater regime plays an important role in the transfer of dissolved salts in the mainly saline water domain of the Corangamite Region. The study of the water and salt content of some of the lakes of the area indicates that a balance exists that results in the maintenance of a specific lake salinity within narrow limits, and in which the groundwater regime is often involved. By considering the salt balance and water balance of a system as one parameter, referred to as the Hydro Salinity Factor, a simple mathematical model can be postulated to determine some of the unknown factors involved in the maintenance of an equilibrium salinity in a lake. The drilling programme and groundwater investigation outlined an important water resource located in the Warrion area. Already 40 bores have been drilled in this area and they produce 6.6 x 105m3 /year (800 acre feet/year). There is an annual underflow of about 1.5 x 107 m3 (12,000 acre feet). This quantity is well within the 'safe yield' of the area and further development should be encouraged, but because of the presence of the large number of saline lakes in the area, saline water intrusion into the basalts would rapidly occur if the groundwater levels are lowered beneath the lake levels.
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    The geology and petrology of the Lower Devonian Buchan Group, Victoria
    Husain, Farhat ( 1981)
    This study is devoted to a detailed examination of the stratigraphy and petrology of the late Lower Devonian (Emisan) Buchan Group, an essentially carbonate sequence. The Buchan Group begins with the lenticular Spring Creek member of the Buchan Caves Limestone. This consists of terrigenous clastic sediments derived from erosion of the underlying Snowy River Rhyodacites. Lithologies range from conglomerates and breccias with rhyodacite pebbles, through arkosic sandstones to quartz sandstones and shales. Pyroclastics, previously identified in this unit, are absent. The Spring Creek member changed from non-marine to marine as the main transgression became established and was followed by a change to carbonate deposition.