Science Collected Works - Theses
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ItemThe sedimentary and tectonic structures of the Lower Devonian Liptrap formation, Victoria, Australia(University of Melbourne, 1978)The shore-platform and cliff exposures of the (Lower Devonian) Liptrap Formation were mapped around Cape Liptrap. In all, 3200 metres of interbedded sandstones and mudstones together with occasional slump beds were examined and the tectonic and sedimentary structures contained within them described in detail. In addition, the overall sedimentary and tectonic environments are discussed. The sediments were derived from two sources; a more distant provenance located on a granitic� metamorphic terrain in eastern Victoria and a local prevenance across the Waratah Fault located in Cambrian greenstones and Devonian sediments. The direction of overfolding of slumped beds indicates a palaeoslope from east to west, while current direction indicators show movement from the east. The sequence of sedimentary structures developed within sandstone-mudstone couples indicates emplacement of the sediments chiefly by bottom traction. Rapid deposition is suggested by structures indicating post-depositional instability with a variety of water-escape structures being developed. The overall sedimentary environment is interpreted as being that of a small-scale shallow water submarine fan deposit. Tectonic structures were developed under a low cover during a single phase of folding and regional cleavage formation - the Middle Devonian Tabberabberan deformation. Chevron folds plunge at low angles to the.north or south, while minor parasitic folds have a different but predictable orientation relative to major fold axes in that they diverge from the major anticlinal axes and converge on the synclines. This is caused by local reorientation of the overall stress field on the limbs of the major folds which have an initial plunge. Folds show evidence for generation at and migration from point sources with consequent rapid changes in plunge both between different folds and within individual folds. In the profile plane a cyclical change in fold form can be seen with single hinged chevron folds giving way to box folds which have two diverging hinges. These style changes are thought to reflect packing difficulties encountered during tightening of the folds. The regional cleavage is statistically axial planar to the folds and is developed as a penetrative differentiated layering best seen in the mudstones. Mica rich M foliae and quartz rich Q zones indicate pressure solution of the more soluble minerals (chiefly quartz) with concentration of less soluble minerals (chiefly mica) at the solution surfaces. Mechanical rotation and deformation of larger clastic flakes attended the shortening which accompanied this pressure solution process. The geometrical and spatial relationship between certain post-depositional soft sediment structures and certain hard rock tectonic structures is noted and a possible link between tectonic and sedimentary structures is suggested, in that they may have developed at the same time.
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ItemSevere weather forecasting in coastal East Antarctica(University of Melbourne, 1999)
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ItemNo Preview AvailableThe chemistry of the ethylene sulphides and some related topics(University of Melbourne, 1948)
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ItemGeological investigations in the Murray Basin in New South Wales(University of Melbourne, 1962)
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ItemBonding and anharmonic vibration in some high symmetry crystals(University of Melbourne, 1977)
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ItemFire and soil interactions in a Mallee heathland : the generation of heterogeneity in an homogeneous landscape(University of Melbourne, 1999)The soils of Australian heathlands are considered to be markedly nutrient-deficient, with some of the lowest concentrations of nitrogen, phosphorus and other essential nutrients ever recorded. The flora is strongly adapted to nutrient conservation and efficiency of use. Yet these same heathlands are often subject to invasion by tall woody shrubs that eventually come to dominance, at the expense of the presumably �better-adapted� typical heathland species. In an attempt to understand and characterize this change in dominance and species composition, the changes in soil nutrient supply and storage were tracked thru a semi-arid heathland in north-western Victoria. Different species used the available nutrients differently, and their impacts on the soil nutrient pool varied with size and age. Some (such as the dominant Casuarina pusilla) augmented the meagre soil nitrogen supply by nitrogen fixation, particularly when younger. Such fixation decreased or even disappeared as the shrubs aged (�senesced�). In August-September 1992 the �available� ammonium concentration in soil from under C. pusilla canopies (at 4.4 ppm) was over double that from under canopies of Callitris verrucosa (at 1.7 ppm) or from the inter-canopy gaps (1.4 ppm). Available ammonium also varied seasonally (with peaks in the moist soils of early spring, August-September, and troughs in desiccated soils early in autumn, April-May), and with stand age. Vigorous N fixation of young C. pusilla and others contributed to relatively high soil ammonium concentrations in 11-year old regrowth when compared with much lower concentrations in 34-year old regrowth, or older. Other species, notably the deep-rooted C. verrucosa, added to the low capital of circulating phosphorus by accessing supplies deep in the profile and bringing some of this to the surface. The litter of some species was richer in these limiting nutrients than the litter of others - again affecting the nutrient return to the surface soil pool and differential accumulation of nutrients under different species. In particular, long-term nutrient enrichment in surface soils enabled annuals formerly absent from these heathlands to establish and grow, in very old stands only (at least greater than 35 years post-fire). Individual species characteristics affected nutrient use and supply to the soils. The markedly sclerophyllous and nutrient deficient leaf litter from Banksia ornata added little of these nutrient s to the soil in the first few years after fire, in contrast with the nitrogen-rich litter from Casuarina pusilla. There was a post-fire flush of nutrients to the surface soil - assisting regrowth and establishment of seedlings. Nitrogen availability and transformations in the soil soon returned to the pre-bum situation, probably within a year. However, the increased soil concentrations of mineral phosphorus immediately after fire, declined much sooner and there was evidence of a subsequent decline in phosphorus availability, to significantly below that of soils in unburnt heathland. The soil nutrient availability in the community is characterized by relative stasis punctuated by short-term flushes deriving from rainfall events, seasonal changes in ambient temperature and occasional fires. Variability in nutrient availability also has a spatial component, deriving from the different architecture, tissue nutrient concentrations, growth stage and internal recycling capacities of the various dominant species present. The landscape was apparently remarkably uniform. Nevertheless, significant habitat heterogeneity was generated by these differences in nutrient use. There was a variety of regeneration strategies adopted by the component species. Some regenerated successfully in the absence of fire - some by seed and others by vegetative means. Small epacrids and myrtles (such as Astroloma and Brachyloma, Baeckea and Calytrix) successfully established from seed in unburnt heathland. Regeneration of many other shrubs and sclerophyllous monocots appeared to require fire and they were unable to regenerate successfully without the opportunities presented by the post-fire environment. The regeneration strategies adopted by four prominent dominants, Banksia ornata, Callitris verrucosa, Casuarina pusilla and Hakea mitchellii (all serotinous shrubs) were investigated. In spite of this apparent similarity, each had a unique response to fire and the opportunities it provided for seed regeneration. The variability of growth and nutrient responses of the many component species, and their interactive effects with the habitat, produced a far more heterogeneous landscape than might have been expected from the remarkably uniform soils and landscape profile. This heterogeneity enabled many species to co-exist, each exploiting a particular, site- specific combination of features and, in turn, producing a site-specific (even �unique�) set of habitat features. The biological components of the ecosystem generated habitat heterogeneity, permitting many species to co-exist. In return, this biodiversity enabled further micro-habitat specialization and habitat heterogeneity. The heathlands did not reach a �steady state� or climax, but continued to change in the continued absence of fire. Species gradually disappeared from the community (either �retreated� to the soil seed bank or truly disappeared as the few remnant adults, with their elevated seed bank, died without replacement). Other species entered the community as the formerly subordinate and then co-dominant C. verrucosa assumed complete dominance - mimicking the invasion and establishment of woody shrubs in heathlands elsewhere. By this stage, the successional change was irreversible. Whether the change is described as �senescence� or �maturation� is subjective. It depends on the perceptions of the particular observer. Although land management has recently come to recognize the importance of heterogeneity in biodiversity maintenance, it has traditionally had difficulty with managing for heterogeneity in time and space. The problems of managing for habitat heterogeneity are considered and a practical conceptual context is provided for future land management.
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ItemNo Preview AvailablePartition chromatography and its applications(University of Melbourne, 1949)
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ItemNo Preview AvailableSome physico-chemical aspects of naturally occurring pigments(University of Melbourne, 1948)
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ItemNo Preview AvailableBases of mathematical theories of plasticity(University of Melbourne, 1951)