Letteratura scientifica selezionata sul tema "Geomorphology South Australia"

This article provides a review of the study and geomorphology of Australia's fluvial systems by offering comment on the development, concerns and future of the subject. Trends in the history of fluvial landform studies in Australia are traced from the observations and comments of the early explorers and visiting scientists through to the emergence and growth of fluvial geomorphology as a study discipline. Subsequent development of the idea of a distinctive geomorphology of Australian fluvial systems that often contrast with Anglo-American observations is outlined and illustrated with particular reference to fluvial studies in south-east Australia. Key features of the Australian setting include low long-term denudation rates, the absence of extensive Quaternary glaciation and the predominance of low gradient fluvial systems over much of the continent. Some of the most important themes in contemporary Australian fluvial research are discussed and include long-term landscape evolution, thresholds and riverine response to secular trends in climate, Quaternary environmental change, arid-environment systems, bedrock channels and applied approaches to study. Consideration is also given to present deficiencies in research and to future priorities. Particular attention is focused on the need firstly to collect additional process data, secondly to shift the bias in research away from south-east Australia, and thirdly to develop links between fluvial process and alluvial stratigraphy/chronology. It is concluded that, given the variety of hydrogeomorphological environments in Australia and the diversity of approaches to study, ongoing research will provide further indications of the unusual nature of many of the continent's fluvial systems.

This study examines landscape rehabilitation treatments installed 20–40 years ago in the Western Catchment of NSW. Treatment outcomes were assessed using geomorphic criteria, because geomorphic processes are fundamental to ecological permanence. Contour furrowing creates artificial runoff-runon sets which intercept runoff (resistance to flow by windrows microrelief and surface roughness) and promote infiltration (artificial permeability by ripping). As originally conceived, after windrows subside, flow resistance would be afforded by surface roughness under belts of vegetation. This study shows that rehabilitation treatments have a more complex relationship with the landscape than this would suggest, and that the final effect of the treatment depends on the geomorphic processes natural to the site. Treatment design should therefore be site-specific. The relevant aspects of treatment design are site location, runoff : runon ratio (expressed as furrow spacing and furrow length), furrow placement, and post-treatment management. Some long-term successes are documented. In ironstone ridge country affected by impermeable hard-setting soils, furrowing creates artificial permeability, allowing plant germination; plant material in the soil reverses hard-setting and establishes self-sustaining permeability. In stony gilgai country furrowing through vegetated patches can aid in re-establishing vegetation, but furrowing through stony runoff patches only diminishes, rather than improves, landscape function. Other landscape types will have different key attributes. In all cases, selection of appropriate sites for rehabilitation treatment is of primary importance. The 1990s NSW Soil Conservation Service best-practice included a specialised furrower, surveying techniques for accurate furrow placement along the contour, staggered gaps along each furrow line to reduce risks of gullying by windrow breakthrough, and post-treatment management of total grazing pressure. New guidelines for treatment design developed from this study include determining for each site the optimum runoff:runon ratio (which varies according to climate, gradient, vegetation, and regolith), and matching furrow spacing and furrow/gap length to local runoff:runon ratios. In stony gilgai country, furrow placement should be along the contour but within non-stony patches; elsewhere, placement should be rigorously along the contour. In ironstone ridge country, a greater runoff:runon ratio, commensurate with the area’s apparently larger patch scale, can be achieved by having more gap than furrow along each furrow line. No single rehabilitation technique will fit all landscape types, and these guidelines will ideally be developed further with investigation of other landscapes.

The received wisdom was and is that landscapes cannot be more than a few millions of years old. Nevertheless, consideration of local geology and age of sediments in adjacent basins convinced Paul S. Hossfeld that the summit surface of low relief preserved on the northern Mount Lofty Ranges of South Australia resulted from long-continued planation and that it is of Cretaceous age; that is, some 70 million years old. Hossfeld's apparently intuitive suggestion that very old landscapes exist, recorded in his graduate thesis but not further pursued by him, is the earliest known statement of this idea.

Abstract. Here we present the results of a multi-proxy investigation – integrating geomorphology, ground-penetrating radar, and luminescence dating – of a high-elevation lunette and beach berm in northern New South Wales, eastern Australia. The lunette occurs on the eastern shore of Little Llangothlin Lagoon and provides evidence for a lake high stand combined with persistent westerly winds at the Last Glacial Maximum (LGM – centring on 21.5 ka) and during the early Holocene (ca. 9 and 6 ka). The reconstructed atmospheric circulation is similar to the present-day conditions, and we infer no significant changes in circulation at those times, as compared to the present day. Our results suggest that the Southern Hemisphere westerlies were minimally displaced in this sector of Australasia during the latter part of the last ice age. Our observations also support evidence for a more positive water balance at the LGM and early Holocene in this part of the Australian sub-tropics.

The invasion of northern Australia by the poisonous cane toad is well recognised, as is its devastating impacts on numerous local native species. However, there is little recognition that the toads are spreading into south-western Queensland. Utilising local knowledge, a limited survey was undertaken within the Cooper Creek catchment to locate the invasion front. Dispersal during 2010–11 floods has established cane toads as far south as Jundah. Integrating this information with landform mapping indicates that cane toad invasion can continue south-west down the Cooper Creek. Though arid, Cooper Creek’s geomorphology renders it partially independent of local climate, and permanent and semipermanent waterholes (including RAMSAR-listed wetlands) are found downstream from Windorah and into the Strzelecki Desert. Natural landforms provide potential daytime shelter and breeding sites, and additional suitable habitat created by human activity is also widespread. Even unsuccessful attempts at breeding may be detrimental to regional ecology, especially fish populations, at critical stages of their boom/bust cycle. We conclude that there is no reason why cane toads cannot penetrate further down the Cooper Creek, threatening wetlands in north-eastern South Australia. Published models of cane toad expansion, which conclude that north-eastern South Australia is too dry for cane toad populations to establish, are based on climatic parameters that significantly under-represent true habitat availability.

Phylogeographic patterns in the cp genome of Eucalyptus marginata Don ex Sm., a species common in the mesic region of south-western Australia, were investigated by using RFLP analysis. The chloroplast diversity was structured into two geographically distinct lineages and nested clade analysis inferred historical fragmentation as the major influence on the phylogeographic pattern. The lineages were separated along the geomorphological boundary of the Darling Scarp, which separates the Coastal Plain from the Darling Plateau. The divergence between the lineages is consistent with uplifting of the Darling Plateau in the late Neogene. Further geographic structuring in haplotype distributions was evident in the forest lineage on the Darling Plateau, where one sublineage was present in the central forest region and another was restricted to the south-eastern region. The level of divergence between these sublineages was similar to that between divergent lineages that have been identified in comparative phylogeographic studies of cpDNA variation in three species widespread throughout south-western Australia. In these species, divergence was attributed to the influence of significant changes in climatic oscillations across the semi-arid region during the mid-Pleistocene. The divergence identified in this study indicates that the influence of climatic change was widespread throughout south-western Australia, including the mesic, higher-rainfall region.

The distribution and productivity of mangroves is directly affected by a wide range of climatic drivers, including temperature, frost, rainfall, evaporation and storm activity, which, in turn, influence a suite of secondary drivers, including changes in freshwater run-off and sediment supply, groundwater dynamics and inter-species competitiveness. The highest-latitude expression of mangroves globally is at Millers Landing, Victoria (38°45′S), and because the vigour and productivity of mangroves across much of Victoria is thought to be limited by low winter temperatures and the incidence and severity of frosts, it is likely that mangroves will be among the first plant communities to be affected by climate change in coastal south-eastern Australia. An increase in plant vigour is likely, but there are almost no historical data with which to compare current rates of primary production. An extension of mangroves to higher latitudes on the mainland is impossible because of the geomorphology of the land that lies further to the south. Small-scale changes in distribution, including the progressive encroachment of mangroves into coastal saltmarsh, are likely to be among the clearest indications of the response of mangroves to a warming climate. Increased effort into tracking changes in mangrove vigour, productivity and distribution is clearly warranted.

Recent erosion in arid regions of western NSW has exposed large areas that are scattered with stone artefacts manufactured by Aboriginal people in prehistory. These exposures offer an opportunity for archaeologists to study the artefacts abandoned by Aboriginal people through time and to compare those artefacts that accumulate in different parts of the landscape. To reconstruct the nature of prehistoric behaviour in the rangelands, two approaches are needed. First, the geomorphological context of the artefacts needs to be considered since exposure of the artefacts is a function of landscape history. Second, large areas (measured in thousands of square metres) and large numbers of artefacts need to be considered if patterns reflecting long-term abandonment behaviour by Aboriginal people are to be identified. This paper reports on the Western New South Wales Archaeological Program (WNSWAP) which was initiated in 1995 to study surface archaeology in the rangelands. Geomorphological studies are combined with artefact analysis using geographic information system software to investigate Aboriginal stone artefact scatters and associated features such as heat retainer hearths, in a landscape context. Results suggest that apparently random scatters of stone artefacts are in fact patterned in ways which inform on prehistoric Aboriginal settlement of the rangelands. Key words: Aboriginal stone artefacts; rangelands; landscape archaeology; geomorphology; GIs

Healthy riparian vegetation has a positive impact on the adjacent river. Unfortunately, riparian vegetation is often threatened by human impacts such as dam construction and clearing. To gain the knowledge underlying the effects of such impacts and to aid riparian rehabilitation, the objective of this thesis was: to determine riparian vegetation association with, and response to, variation in fluvial geomorphology over several scales and consequently to fluvial disturbance. Only woody riparian plant species were considered. Flood disturbance was the unifying theme of this thesis. Linked to this theme and arising from the main objective was the supposition that plant interactions with the abiotic environment, but not biotic interactions between species, control riparian species distribution because of frequent fluvial disturbances. Woody riparian vegetation and riverine environmental variables were recorded along the upper Murrumbidgee River at three spatial scales based on a geomorphic hierarchy for Chapter 2. Multivariate analysis was used to group species and to associate environmental variables with vegetation at the three spatial scales. Observations at the two larger scales, of river segment (site) and riparian reach (transect), identified a river-longitudinal speciescomposition gradient associated with geology, river width and stream channel slope. Observations at the smallest scale of geomorphic units (plot) identified a lateral riparian gradient and also the longitudinal gradient; these gradients were associated with geomorphic variation, land use, plot elevation and also river longitudinal variables. Using the same data set, but varying the spatial scale of analysis caused the species composition pattern to change between scales. Increase in scale of observation, that is from geomorphic unit to reach and segment scales, resulted in disproportionate importance of rarer species and decreased importance of some key riparian species at the larger scales. It would appear that in this instance the geomorphic unit scale best described patches of different species composition because this scale had high spatial resolution and was also able to identify multiple gradients of environmental variation. It was recommended that riparian sampling take place at scales that represent dominant gradients in the riparian zone. These gradients are represented by geomorphic scales, indicating the appropriateness of using geomorphic based scales for observation of riparian vegetation. Chapter 3 considered whether there is a geomorphic template upon which riparian vegetation is patterned and whether it is associated with process variables, such as flooding and soil type. This question was investigated at different spatial scales in three ways: i) by an experiment to determine whether soil nutrient condition affects plant growth; ii) by graphical analysis of trends between geomorphic units, species and process variables; and iii) by analysis of vegetation distribution data. The smallest scale (meso) found experimental differences in plant growth because of soil type. Plants growing in sand had the lowest performance, with an average plant Relative Growth Rate (RGR) of 0.01, compared to plants growing in soils with small amounts of silt or clay particles, with an average plant RGR of 0.04. This pattern was attributed to differences in nutrients. Clear relationships were demonstrated at the larger geomorphic unit scale between species distribution and process variables. For example, hydrology and substratum type were found to be associated with geomorphic units and species. The largest scale considered in Chapter 3 was the riparian reach scale. At this scale species were clearly grouped around reach type. Therefore, geomorphology was considered to be a template for riparian species distribution. Findings in this chapter suggested that geomorphic variables should be good predictors of riparian species distribution. This hypothesis was tested and supported in Chapter 6. The experiments reported in Chapter 4 aimed to determine whether inundation depth and duration affected plant performance and survival for five common riparian zone species. Riparian seedling patterns in the field were also compared with experimental results to test whether species performance was reflected by field distribution. The experiments that were conducted included an inundation period and depth experiment, and a survival period test whilst under complete inundation. Biomass and height relative growth rates were determined, and the results were analysed using factorial Analysis of Variance. Obligate riparian species (Callistemon sieberi, Casuarina Cunninghamiana, Leptospermum obovatum) were found to be tolerant of inundation duration and depth, to the point where inundation provided a growth subsidy. On the other hand, non-obligate riparian species (Acacia dealbata, Kunzea ericoides) were either just tolerant of inundation or showed a negative growth response. For instance, C. sieberi demonstrated an average height RGR of 0.04 after complete inundation and 0.007 when not inundated, while A. dealbata had an average height RGR of 0.001 after complete inundation and 0.01 when not inundated. These experimental findings were found to closely reflect both seedling and adult plant distribution in the field such that inundation tolerant species were found close to the river and intolerant species further away. Thus, the conclusion was drawn that riparian species establishment and distribution is affected by inundation and that change to the flood regime could have serious impacts on riparian zone plant composition. The other aim of this chapter was to determine whether optimum germination temperatures were associated with flood or rainfall. Growth chamber germination trials were conducted at air temperatures of 15�C, 20�C and 25�C to determine the 'best' germination temperature. These germination patterns at different temperatures were then related to annual variation in field temperature, flooding period and rainfall. No evidence was found to suggest a relationship between ideal germination temperature and flood season, rather it was suggested that germination was patchy through time and may simply reflect recent rainfall. Investigations that were reported in Chapter 5 aimed to elucidate relationships between species and flow velocity variables. Two experiments were conducted: i) a flume experiment to determine the effect of flow velocity on plant growth; and ii) an experiment to observe the response of plants to damage (imitating flood damage) and inundation. Field observations of species distribution and flow velocity related variables were also conducted to put the flume results into a real-world context. Treatments for the flume experiment were fast flow velocity (0.74 m s-1), slow velocity (0.22 m s-1) and no velocity (control) but still inundated. All treatments were flooded completely for four days. Subsequent biomass and height relative growth rates were determined, and the results were analysed using factorial Analysis of Variance. Results were unexpected, given that obligate species exposed to the fastest velocity had the highest growth rate with an average height RGR of 0.046, compared to plants in still water, which grew the least with an average height RGR of 0.013. It was hypothesised that this response was because relatively greater carbon dioxide and oxygen levels were available in the moving water compared to the still water. With regard to shoot damage, the species that were nonobligate riparian species lost more leaves from velocity treatment than the obligate riparian species. The cut and flood experiment found growth of the obligate species (Casuarina cunninghamiana) to be greater after cutting than the non-obligate species. Flooding was not found to have an effect in the cut and flood experiment, probably because the period to sampling after flood treatment was longer (4 weeks) than other flooding experiments (3 weeks). Field observations were found to support the experimental findings, with a gradient of species across the riparian zone that reflected potential flood velocities. Therefore, velocity is one of a suite of riparian hydrological factors that are partially responsible for the gradient of species across the riparian zone. Potentially the absence of flooding could result in a homogeneous mix of species, rather than a gradient, except on the very edge of the river. The study that was reported in Chapter 6 investigated a technique for predicting riparian vegetation distribution. One of the aims of this investigation was to address a current riparian rehabilitation shortfall, which was how to objectively select species to plant for rehabilitation. Field data were collected from three confined river valleys in south-eastern New South Wales. Using data on plant species occurrence and site and plot measures of soils, hydrology and climate, an AUSRIVAS-style statistical model, based on cluster and discriminant analysis, was developed to predict the probability of species occurrence. The prediction accuracy was 85 % when tested with a separate set of plots not used in model construction. Problems were encountered with the prediction of rarer species, but if the probability of selection was varied according to the frequency of species occurrence then rarer species would be predicted more often. Various models were tested for accuracy including three rivers combined at the geomorphic unit (plot) scale and riparian reach (transect) scale in addition to a Murrumbidgee River plot scale model. Surprisingly, the predictive accuracy of the all rivers and single river models were approximately the same. However, the difference between the large scale and small scale models pointed to the importance of including small scale flood-related parameters to predict riparian vegetation. When these riparian predictions were compared to predictive outcomes from a hill slope model, which was assumed to be affected by fewer disturbances (i.e. flooding), predictive accuracies were not very different. Overall though, predictive accuracy for riparian vegetation was high, but not good enough to support the supposition that riparian vegetation is abiotically controlled because of frequent flood disturbance. Nevertheless, geomorphology and consequently flood effects are still important for the determination of the riparian community composition. Overall, riparian vegetation was found to be closely linked to its environment (evidenced in Chapters 2, 3, 4, 5) in a predictable manner (Chapter 6). Species pattern relied on flood disturbance affecting species distribution. Some riparian species were found to be highly tolerant of flooding and gained a growth advantage after flooding (Chapters 4 and 5). Therefore, flood tolerance was important for the formation of a species gradient across the riparian zone. These species tolerances and growth requirements reflect riparian geomorphic pattern (Chapter 3), which was suggested to form a template on which riparian vegetation is structured.

[Truncated abstract] Land clearing is known to increase runoff, and in many dryland landscapes is also associated with rising saline watertables, causing increased stream salinity and degrading riparian vegetation. The limited understanding of how river morphology responds to these changes and the potential for vegetation-based strategies to offer river management options under these conditions, has prompted this research. In southwestern Australia the severity of salinity and recent nature of land clearing provides an appropriate setting to investigate river response. A data-based, multidisciplinary methodology was applied to determine how land clearing and landscape salinisation has altered landscape sensitivity through changes in erosive potential, system connectivity and material threshold mechanisms, and how these affect patterns of river response. The study investigated the responses of morphologically similar reaches across fifty two study sites in the Kent River and Dalyup River catchments, in the south coastal rivers region of Western Australia. Land clearing was found to have significantly altered the hydrologic regime and erosive potential in both frequency and magnitude, with flow becoming more perennial, and increased annual discharge, flood peaks and bankfull flow frequency. While sediment transport rates have also increased since land clearing, they remain low on a global scale. Human response to a reduced rainfall regime and related water security pressures has caused large hillslope areas to be decoupled from the main channels by bank and farm dam construction, and have reduced downstream transmission of change. ... By contrast, steeper-sloped mid-catchment areas with minimal vegetation degradation caused by salinity are associated with higher erosive potential. A more erosive response is observed in these reaches where floodplains have been cleared for agricultural purposes. A conceptual model of vegetation growth across the salinity gradient observed in the study catchments was developed, and applied to selected river styles to assess the potential that vegetation-based strategies offer for river management. This work identifies the unsuitability of river restoration strategies, but the potential for river restoration or remediation in a saline landscape. Hydraulic modelling demonstrated that river rehabilitation strategies such as improving the vegetation condition of the riparian buffer using native or commercial species on areas elevated above saline flow can stabilise reaches. For river styles in wide and flat valleys, there is limited potential for vegetation-based river rehabilitation under the current salinity gradient. Field observation and modelling suggest that river remediation may offer geomorphic management options in salt-affected reaches through channelisation to lower watertables, and further research on this is warranted. This work found a consistent response for river styles across the two study catchments. Based on the understanding of river response and the potential for vegetation-based river management for each style, this research offers a regional-scale tool for river management in a saline landscape.

Thesis (PhD)--Macquarie University, Division of Environmental & Life Sciences, Graduate School of the Environment, 2002.
Includes bibliographical references: p. 228-232.
Geomorphology, archaeology and geoarchaeology: introduction and background -- Surface stone artefact scatters: why can we see them? -- Geomorphic controls on spatial patterning of the surface stone artefact record -- A temporal framework for interpreting surface artefact scatters in Western NSW -- Synthesis: stone artefact scatters in a dynamic landscape.
Surface scatters of stone artefacts are the most ubiquitous feature of the Australian Aboriginal archaeological record, yet the most underutilized by archaeologists in developing models of Aboriginal prehistory. Among the many reasons for this are the lack of understanding of geomorphic processes that have exposed them, and the lack of a suitable chronological framework for investigating Aboriginal 'use of place'. This thesis addresses both of these issues. -- In arid western NSW, erosion and deposition accelerated as a result of the introduction of sheep grazing in the mid 1800s has resulted in exposure of artefact scatters in some areas, burial in others, and complete removal in those parts of the landscape subject to concentrated flood flows. The result is a patchwork of artefact scatters exhibiting various degrees of preservation, exposure and visibility. My research at Stud Creek, in Sturt National Park in far western NSW, develops artefact and landscape survey protocols to accommodate this dynamic geomorphic setting. A sampling strategy stratified on the basis of landscape morphodynamics is presented that allows archaeologists to target areas of maximum artefact exposure and minimum post-discard disturbance. Differential artefact visibility at the time of the survey is accommodated by incorporating measures of surface cover which quantify the effects of various ephemeral environmental processes, such as deposition of sediments, vegetation growth, and bioturbation, on artefact count. -- While surface stone artefact scatters lack the stratigraphy usually considered necessary for establishing the timing of Aboriginal occupation, a combination of radiocarbon determinations on associated heat-retainer ovens, and stratigraphic analysis and dating of the valley fills which underlie the scatters, allows a two-stage chronology for huntergatherer activity to be developed. In the Stud Creek study area, dating of the valley fill by OSL established a maximum age of 2,040±100 y for surface artefact scatters. The heatretainer ovens ranged in age from 1630±30 y BP to 220±55 y BP. Bayesian statistical analysis of the sample of 28 radiocarbon determinations supported the notion, already established from analysis of the artefacts, that the Stud Creek valley was occupied intermittently for short durations over a relatively long period of time, rather than intensively occupied at any one time. Furthermore, a gap in oven building between about 800 and 1100 years ago was evident. Environmental explanations for this gap are explored, but the paiaeoenvironmental record for this part of the Australian arid zone is too sparse and too coarse to provide explanations of human behaviour on time scales of just a few hundred years. -- Having established a model for Stud Creek of episodic landscape change throughout the late Pleistocene and Holocene, right up to European contact, its veracity was evaluated in a pilot study at another location within the region. The length of the archaeological record preserved in three geomorphically distinct locations at Fowlers Gap, 250 km south of Stud Creek, is a function of geomorphic dynamics, with a record of a few hundred years from sites located on channel margins and low terraces, and the longest record thus far of around 5,000 years from high terrace surfaces more remote from active channel incision. But even here, the record is not continuous, and like Stud Creek, the gaps are interpreted to indicate that Aboriginal people moved into and out of these places intermittently throughout the mid to late Holocene. -- I conclude that episodic nonequilibrium characterizes the geomorphic history of these arid landscapes, with impacts on the preservation of the archaeological record. Dating of both archaeological and landform features shows that the landscape, and the archaeological record it preserves, are both spatially and temporally disjointed. Models of Aboriginal hunter-gatherer behaviour and settlement patterns must take account of these discontinuities in an archaeological record that is controlled by geomorphic activity. -- I propose a new geoarchaeological framework for landscape-based studies of surface artefact scatters that incorporates geomorphic analysis and dating of landscapes, as well as tool typology, into the interpretation of spatial and temporal patterns of Aboriginal huntergatherer 'use of place'.
Mode of access: World Wide Web.
vii, 232 p. ill., maps

Coastal wetlands are dynamic ecosystems that are highly susceptible to change due to natural and human factors. The study area, located within the Native Dog Creek sub-catchment of the Logan River - which drains into Moreton Bay, south east Queensland - holds a detailed history of environmental change spanning most of the Holocene epoch. This history is preserved in the estuarine sedimentary record and is a valuable indicator of natural environmental change. More recently, human-induced changes within the study area have been superimposed on the natural process of environmental change. In order to develop a conceptual bio-geomorphic model of the coastal wetlands of Native Dog Creek, this thesis examined - on an integrated catchment basis - the evolution and connectivity of four coastal wetland community types (Melaleuca, Casuarina, saltmarsh and mangroves). The research consisted of four discrete studies within the study area: a geomorphic investigation that provided a framework for understanding how the wetlands evolved during the Holocene epoch; an acid sulfate soil (ASS) study that surveyed the distribution and concentration of sulfides; a palynological study that examined the natural directions of ecosystem change; and an investigation of the impact of specific human activities on these ecosystems. Detailed stratigraphic modelling found that the Logan River system (and its Native Dog Creek sub-catchment) has evolved from an infilling estuary since the peak of the Holocene transgression 6500 years before present. Recognition of the major controls that influenced geomorphic coastal development during the Holocene, provided important insights into the distribution and genesis of estuarine pyritic sediments which strongly influence the soils within the study area. In general, the estuarine central basin and fluvial delta sediments posed the greatest risk to the environment from acidification if disturbed. The major focus of the ASS study was to survey the distribution of ASS and to identify other areas most vulnerable to acidification. A predictive approach that combined chemical and stratigraphic analysis was used. Results showed that these areas are intrinsically related to their environment of deposition. The study found, for example, that the alternation of excessively wet and dry conditions - combined with high organic carbon levels and variations in microtopography - provided ideal conditions for the re-formation of pyrite in the stream channel within the Melaleuca wetlands. The palaeo-environmental study reconstructed the evolution of Holocene coastal wetland vegetation during the marine transgression and subsequent shoreline progradation. Pollen records from the four representative wetland communities (previously mentioned) were examined. The results found the mid-late Holocene vegetation history was controlled by the development of geomorphic features that have affected freshwater input, drainage and salinity. In response to the progradation of the shoreline after sea level stabilised, changes in fossil pollen from mangroves and saltmarsh taxa during the early-mid Holocene, to freshwater taxa during the late Holocene, are estimated to have taken 800 years. Thus, pollen analysis when used in combination with stratigraphic modelling, provided an important point of reference for rates of natural ecological change in response to evolutionary changes to the physical environment. The wetlands within the study area have suffered varying degrees of disturbance since European settlement in the 1820s. The most significant changes occurred during early European settlement, when vast areas of coastal lowlands were cleared for timber, sheep and cattle grazing and for agricultural purposes. A second period of change occurred from 1989 to 1995, when the Melaleuca community suffered dieback in response to hydrological modifications to Native Dog Creek for the development of a golf course. Results indicate that human-induced changes over the past 170 years have occurred at a rate far beyond the ability of the natural ecosystem to adapt or move to a more ecologically sustainable state, at least in the short-term. Hence the current environment is experiencing degradation through both decline in health and loss of indigenous species. The development of a conceptual bio-geomorphic model was based on the integration of results from all four studies, in an effort to provide a holistic understanding of the coastal wetland environment and of the impact of human-induced changes upon that environment. If these vulnerable ecosystems are to be maintained, successful and sustainable coastal management strategies must rely on a sound scientific understanding of the response of a coastal ecosystem to both human and environmental changes.

Le plateau sud-africain (ou Kalahari) est le plateau anorogénique le plus grand au monde. Sa très grande longueur d’onde (×1000 km) et son altitude moyenne élevée (1000-1500 m) impliquent des processus mantelliques. La cinétique et l’origine de ce relief sont mal comprises. D’un côté, les études géomorphologiques le considèrent comme un relief mis en place à la fin de l’intervalle Cénozoïque (<30 Ma). A l’inverse, les données thermochronologiques montrent deux phases de dénudation pendant l’intervalle crétacé, corrélées à des phases d’accélération du flux silicoclastique sur les marges, qui suggèrent qu’il s’agirait d’un relief plus ancien hérité du Crétacé supérieur. Peu d’études ont porté sur l’évolution du système terre-mer depuis le bassin versant en érosion aux marges en sédimentation. Ce travail de thèse repose donc sur une double approche : une analyse géomorphologique des formes du relief (surfaces d’aplanissement) à terre, basée sur leur (i) cartographie, (ii) chronologie relative, (iii) relation avec les profils d’altération et (iv) datation au moyen des placages sédimentaires et du volcanisme datés qui les fossilisent ; une analyse stratigraphique de l’intervalle post-rift des marges, basée sur l’interprétation de données de sub-surface (lignes sismiques et puits), réévaluées en âge (biostratigraphie), pour (i) identifier, dater et mesurer les déformations des marges et de leur relief amont , (ii) mesurer les flux silicoclastiques, produits de l’érosion continentale. Un calendrier et une cartographie des déformations ont été obtenus sur les marges et mis en relation avec les différentes générations de surfaces d’aplanissement étagées qui caractérisent le relief du plateau sud-africain. Au moins deux périodes de déformation ont été identifiées au Crétacé supérieur (92-70 Ma) et à l’Oligocène (30-15 Ma). L’évolution est la suivante : 100 - 70 Ma (Cénomanien à Campanien) : plateau à très grande longueur d’onde, peu élevé (0-500 m), bordé à l’est par des reliefs plus hauts et plus anciens le long des marges indiennes, qui agissent comme une ligne de partage des eaux entre l’océan Atlantique et l’océan Indien. La déformation est initiée à l’est avec une flexuration brève, à grande longueur d’onde, des marges indiennes aux alentours de ~92Ma. Cette première surrection marque un paroxysme d’érosion enregistré par la mise en place d’un delta géant sur la marge atlantique (delta de l’Orange). La déformation migre ensuite vers l’ouest avec la croissance du bourrelet marginal atlantique entre 81 et 70 Ma. Le relief acquiert sa configuration actuelle comme l’indique une diminution du flux silicoclastique sur la marge atlantique qui traduit un changement majeur du système de drainage ; 70-30 Ma (Crétacé terminal-Paléogène) : période d’apparente non déformation. Le relief est fossilisé et intensément altéré (latérites) ; 30-15 Ma (Oligocène - Miocène inférieur) : deuxième surrection du plateau sud-africain qui acquière sa topographie actuelle. La déformation semble plus importante à l’est du plateau - flexure des marges nord indiennes initiée à ~25 Ma qui alimente les grands deltas de l’océan Indien (Zambèze, Limpopo, Tugela) ; le relief est fossilisé à partir du Miocène moyen, synchrone d’une aridification majeure de l’Afrique australe
The South African (Kalahari) Plateau is the world's largest non-orogenic plateau. It forms a large-scale topographic anomaly (×1000 km) which rises from sea level to > 1000 m. Most mechanisms proposed to explain its elevation gain imply mantle processes. The age of the uplift and the different steps of relief growth are still debated. On one hand, a Late Cretaceous uplift is supported both by thermochronological studies and sedimentary flux quantifications. On the other hand, geomorphological studies suggest a Late Cenozoic uplift scenario (<30 Ma). However few attentions were paid to the evolution of the overall geomorphic system, from the upstream erosional system to the downstream depositional system. This study is based on two different approaches : onshore, on the mapping and chronology of all the macroforms (weathering surfaces and associated alterites, pediments and pediplains, incised rivers, wave-cut platforms) dated by intersection with the few preserved sediments and the volcanics (mainly kimberlites pipes) ; offshore, on a more classical dataset of seismic lines and petroleum wells, coupled with biostratigraphic revaluations (characterization and dating of vertical movements of the margins - sediment volume measurement). The main result of this study is that the South African Plateau is an old Upper Cretaceous relief (90-70 Ma) reactivated during Oligocene (30-15 Ma) times. Its evolution can be summarized as follows : 100-70 Ma (Cenomanian to Campanian): low elevation plateau (0-500 m) with older and higher reliefs located along the Indian side, acting as a main divide between the Atlantic and the Indian Oceans. First uplift occurred in the east at ~92 Ma, with a fast flexuration of the Indian margins. This initiates a paroxysm of the erosion (90-80 Ma) with the growth of a large delta along the Atlantic margin (Orange delta). Deformation migrated progressively westward and resulted on the growth of the Atlantic marginal bulge between 81 and 70 Ma. Most of the present-day relief was probably created at this time. This is supported by the decrease of the sedimentary flux which suggests a reorganisation of the interior drainage pattern ; 70-30 Ma (Uppermost Cretaceous-Paleogene): most of the relief is fossilized and weathered - relative tectonic quiescence ; 0-15 Ma (Oligocene-Early Miocene): second period of the South African Plateau uplift. Most of the deformation took place along the Indian side of the Plateau (strike flexure) feeding the Zambezi, Limpopo and Tugela deltas ; since at least Middle Miocene times, all those reliefs have been fossilized, with very low erosion rates (x1m/Ma), in response to the major aridification of southern Africa

Bibliography: leaves 291-315.
x, 315 leaves, [9] leaves of plates : ill. (chiefly col.), maps ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1998?

Processed.
Bibliography: leaves 92-105 (1st sequence)
xix, 105, c. 100 leaves : ill. (some col.), maps (some folded) ; 30 cm. + 1 map : col. ; 100 cm. x 74 cm. folded to 25 x 19 cm. ; in envelope inside back cover.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--Dept. of Geography and the Dept. of Geology and Geophysics, University of Adelaide, 1991

Bird Island is a former flood tide delta occurring in the mouth of the River Murray, Encounter Bay, South Australia. The island has experienced a rapid development history; in around 60 years the formerly ephemeral deltaic deposits have rapidly become stabilised, forming a permanent island approximately 1 km in diameter.
It has been possible to place tight time restraints on the progressive development of Bird Island over this 60 year period. Its sand dunes and marshes of different ages can be distinguished clearly from an analysis of successive aerial photographs. Evidence suggests they represent different phases in the growth and development of the island, resulting from an interplay of factors including the position and migration of the Murray Mouth relative to the island as well as the availability of sediment and conditions conducive to aeolian sand transport.
The landforms of Bird Island present a unique opportunity for the assessment and study of progressive plant colonisation and succession on a pristine landscape in a coastal/estuarine setting. Bird Island comprises 19 different dune and marsh vegetation types. Research has identified several trends suggesting that the environmental gradients associated with the marsh-dune landforms has influenced some characteristics of species distribution. It also appears that in a general way, species distributions may represent succession on the sand dunes, but this was not as clearly demonstrated across the marshes of different ages on Bird Island.
Research suggests that the construction of the lower River Murray barrages in 1940, which has reduced the median annual flow to the estuary by nearly 75%, and has reduced the tidal prism by up to 90%; has facilitated the development of Bird Island. Bird Island contributed to the closure of the mouth of the River Murray in 1981; inlet behaviour not demonstrated in the 100 years prior to barrage construction according to the results of this research.
The continuing development of Bird Island suggests considerable potential for more blockages in the future. The continuing sedimentation in the Murray Mouth reflects the inability of the current flow regime and marine processes in maintaining the mouth as they did prior to the construction of regulatory works on the Lower River Murray.
Thesis (MApSc(EnvironmentRecreationMg))--University of South Australia, 2004

This book provides readers with a unique understanding of the ways in which Aboriginal people interacted with their environment in the past at one particular location in western New South Wales. It also provides a statement showing how geoarchaeology should be conducted in a wide range of locations throughout Australia. One of the key difficulties faced by all those interested in the interaction between humans and their environment in the past is the complex array of processes acting over different spatial and temporal scales. The authors take account of this complexity by integrating three key areas of study – geomorphology, geochronology and archaeology – applied at a landscape scale, with the intention of understanding the record of how Australian Aboriginal people interacted with the environment through time and across space. This analysis is based on the results of archaeological research conducted at the University of New South Wales Fowlers Gap Arid Zone Research Station between 1999 and 2002 as part of the Western New South Wales Archaeology Program. The interdisciplinary geoarchaeological program was targeted at expanding the potential offered by archaeological deposits in western New South Wales, Australia. The book contains six chapters: the first two introduce the study area, then three data analysis chapters deal in turn with the geomorphology, geochronology and archaeology of Fowlers Gap Station. A final chapter considers the results in relation to the history of Aboriginal occupation of Fowlers Gap Station, as well as the insights they provide into Aboriginal ways of life more generally. Analyses are well illustrated through the tabulation of results and the use of figures created through Geographic Information System software. Winner of the 2015 Australian Archaeology Association John Mulvaney Book Award