Dissertations / Theses on the topic 'Landscape regolith'

Construction of a 1:250,000 scale regolith-landform map of the Cobar area of central New South Wales (NSW) Australia, demonstrates the presence of a wide range of previously undescribed regolith materials, landforms and landscape features in the region. The map covers the east-west extent of the Cobar Basin, extends to the west onto the Darling River Floodplain, and east onto rocks of the Girilambone Group. The mapping area is centred on the Cobar township and covers -14,730 krn2 between 303113 and 446113 E and 6483184 and 6586183 N (AGO 66, MGA Zone 55). 48 regolithlandform units have been identified, including both transported (alluvial, colluvial, aeolian, lacustrine) and in situ materials. A range of siliceous, ferruginous and calcareous indurated materials are also present. Four major drainage types have been identified based on lithological, sedimentological and topographic differences in alluvial materials. The 4 drainage types include: 1) modern drainage; 2) maghemite and quartzose gravels elevated 1-2 m relative to the modern drainage; 3) higher topographically inverted, and at least partly silicified, gravels; and, 4) sediments of Cretaceous origin. Multiple phases of drainage stability and instability from the Cretaceous to the present are indicated within the sediments. Breaching of drainage divides and increased dissection of the modern drainage, especially to the south of Cobar, indicate possible tectonic movement across a major regolith-landform boundary in the southern map area. Colluvial materials are more widespread to the north of Cobar reflecting the increased landscape dissection to the south. Colluvial fans are preserved adjacent to major rangefronts. Aeolian and lacustrine materials include longitudinal dunefields of the Darling River floodplain, source bordering dunes, and small lunettes associated with the Barnato Lakes system. Regolith-landform mapping at Cobar has been used to assess the applicability of previously developed landscape evolution models of the Cobar Block and surrounding region, and to develop a new landscape evolution model for the region. The new landscape evolution model of Cobar indicates minimal deposition of Cretaceous sediments, succeeded by high-energy early Tertiary fluvial regimes across the Cobar landscape. Weathering and sediment deposition continued into the Miocene, coupled with deep valley incision on the Cobar Block associated with early Oligocene regression. By the close of the Miocene, the Cobar Block had eroded to predominantly bedrock terrain and widespread filling of previously incised valleys occurred. A decrease in erosion and fluvial activity led to the formation of the modern drainage during the Pliocene-early Quaternary, followed by the formation of alluvial, aeolian and lacustrine deposits in the later Quaternary. Regionally, Eromanga Basin sediments were not extensive over the Cobar Block, and low rates of erosion are recorded at Cobar from the Cretaceous to the present. Former northerly drainage did exist in this area in the Cretaceous, but was limited in distribution. By at least the Early Tertiary the Cobar area was a structural high and drainage systems of the region had assumed their current configuration. These findings do not support interpretations of AFTT data of significant cover and subsequent stripping over the Cobar Block in the Early Tertiary. Evidence of landscape evolution from the Cretaceous to the present suggests that the Cobar landscape has been responding to changes in the primary landscape forming factors of lithology, climate and to a lesser degree, tectonics. Variations in the these three primary landscape forming factors have contributed to ongoing weathering, relatively continuous deposition, and periods of relative stability and instability, particularly in response to climatic and baselevel fluctuations, within a dynamically evolving landscape throughout the entire Tertiary. Former landscape evolution models of peneplanation and pediplanation, based on correlation of palaeosurfaces including duricrusts, a deep weathering profile developed during extended planation in the Early Tertiary, and tectonism during the late Tertiary in the Cobar area, are not supported by evidence preserved in regolith-landform features at Cobar.

The study area extends from west of the Great Divide to the Broken Hill and Tibooburra regions of far western New South Wales, encompassing several important mining districts that not only include the famous Broken Hill lodes (Pb-Zn-Ag), but also Parkes (Cu-Au), Peak Hill (Au), Cobar (Cu-Au-Zn) and White Cliffs (opal). The area is generally semi-arid to arid undulating to flat terrain covered by sparse vegetation. ¶ During the Cretaceous, an extensive sea retreated across vast plains, with rivers draining from the south and east. After the uplift of the Great Divide associated with opening of the Tasman Sea in the Late Cretaceous, drainage swung to the west, cutting across the Darling River Lineament. The Murray-Darling Basin depression developed as a depocentre during the Paleogene. Climates also underwent dramatic change during the Cenozoic, from warm-humid to cooler, more seasonal climates, to the arid conditions prevalent today. Up until now, there has been very little temporal constraint on the development of this landscape over this time period. This study seeks to address the timing of various weathering and landscape evolution events in northwestern New South Wales. ¶ The application of various regolith dating methods was undertaken. Palaeomagnetic dating, clay δ18O dating, (U+Th)/He and U-Pb dating were all investigated. Palaeomagnetic and clay dating methods have been well established in Australian regolith studies for the last 30 years. More recently, (U+Th)/He dating has been successfully trialled both overseas and in Australia. U-Pb dating of regolith materials has not been undertaken. Each method dates different regolith forming processes and materials. Palaeomagnetic and clay dating were both successfully carried out for sites across northwestern New South Wales, providing a multi-technique approach to resolving the timing of weathering events. Although (U+Th)/He dating was unsuccessful, there is scope for further refinement of the technique, and its application to regolith dating. U-Pb dating was also unsuccessfully applied to late-stage anatase, which is a cement in many Australian silcretes. ¶ Results from this study indicate that the landscape evolution and weathering history of northwestern New South Wales dates back at least 60 million years, probably 100 million years, and perhaps even as far back as 180 million years. The results imply that northwestern New South Wales was continuously sub-aerially exposed for the last 100 Ma, indicating that marine sedimentation in the Murray-Darling and Eromanga-Surat Basins was separated by this exposed region. The ages also provide further evidence for episodic deep chemical weathering under certain climatic conditions across the region, and add to the data from across Australia for similar events. In particular, the palaeomagnetic ages, which cluster at ~60 ± 10 Ma and 15 ± 10 Ma, are recorded in other palaeomagnetic dating studies of Australian regolith. The clay ages are more continuous across the field area, but show older clays in the Eromanga Basin sediments at White Cliffs and Lightning Ridge, Eocene clays in the Cobar region, and Oligocene – Miocene clays in the Broken Hill region, indicating progressively younger clay formation from east to west across northwestern New South Wales, in broad agreement with previously published clay weathering ages from around Australia. ¶ These weathering ages can be reconciled with reconstructions of Australian climates from previously published work, which show a cooling trend over the last 40 Ma, following an extended period of high mean annual temperatures in the Paleocene and Eocene. In conjunction with this cooling, total precipitation decreased, and rainfall became more seasonal. The weathering ages fall within periods of wetness (clay formation), the onset of seasonal climate (clay formation and palaeomagnetic weathering ages) and the initiation of aridity in the late Miocene (palaeomagnetic weathering ages). ¶ This study provides initial weathering ages for northwestern New South Wales, and, a broad geochronology for the development of the landscape of the region. Building on the results of this study, there is much scope for further geochronological work in the region.

This study provides one of the first accounts of the relationships between termites, termitaria and the pedolith, towards developing their application as a biogeochemical sampling medium for mineral exploration. Mapping regolith–landforms, termitaria, and the associated termitaria biogeochemistry show that termites are an integral control on the organisation of trace metals in the landscapes of northern Australia. In particular, termites are important for transporting geochemical signatures from depth, through the pedolith and to the ground surface. This occurs by way of bioturbative and constructional activities of the mound-building termites, which in this study included Nasutitermes triodiae, Amitermes vitiosus, Drepanotermes rubriceps, Tumulitermes hastilis and T. pastinator. Termitaria from these species are mappable regolith– landform attributes at the local scale; this highlights their specific preferences for colony sites, such as access to vegetation, drainage, and the availability of construction materials. The mound-building termites featured in this study are also soil modifiers, altering the pedolith terms of both structure and chemistry. Developing an understanding of these processes has helped to refine a model for pedolith development through biotic processes, which is applicable to subtropical and tropical climatic regions, where termites act as important ecosystem engineers. This research project fills a niche for new scientific investigation of deeper regolith profiles and associated terrains; it moves away from theories of shallow soil development overlying an abiotic deep regolith, towards understanding pedolith development as wholly biotically driven. For mineral explorers this means that ore-related elements, such as Au, As and Zn, are re-organised and moved towards the land surface in settings such as buried Au-deposits and mineralisation in the Tanami region, and Pine Creek Orogen. A key finding within the study of the application of this technique is that the fine, silt-clay (>79 μm) from termitaria is capable of accurately delineating the surficial expression of buried Au mineralisation. Termitaria can therefore provide an accessible surficial biogeochemical sampling media that can be used in mineral exploration programs
http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1369217
Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009

The study area extends from west of the Great Divide to the Broken Hill and Tibooburra regions of far western New South Wales, encompassing several important mining districts that not only include the famous Broken Hill lodes (Pb-Zn-Ag), but also Parkes (Cu-Au), Peak Hill (Au), Cobar (Cu-Au-Zn) and White Cliffs (opal). The area is generally semi-arid to arid undulating to flat terrain covered by sparse vegetation. ¶ During the Cretaceous, an extensive sea retreated across vast plains, with rivers draining from the south and east. After the uplift of the Great Divide associated with opening of the Tasman Sea in the Late Cretaceous, drainage swung to the west, cutting across the Darling River Lineament. The Murray-Darling Basin depression developed as a depocentre during the Paleogene. Climates also underwent dramatic change during the Cenozoic, from warm-humid to cooler, more seasonal climates, to the arid conditions prevalent today. Up until now, there has been very little temporal constraint on the development of this landscape over this time period. This study seeks to address the timing of various weathering and landscape evolution events in northwestern New South Wales. ¶ ...

Regolith carbonate, especially when indurated (calcrete), has been widely adopted as a sampling medium by many Australian Au exploration companies. Rapid uptake of the medium in geochemical exploration programs, following its reported success in the South Australia Challenger Au deposit discovery, has resulted in poorly constrained sampling methodology with many inconsistencies. Results have therefore been equivocal. This study of regolith carbonates and their association with Au will improve this situation. Three aspects of regolith carbonate development and association with Au are investigated. These are based on variable spatial scales, ranging from the southern Australian continent, to local area, to individual profile. On a continental scale, regolith carbonates cover extensive areas of southern Australia. The primary component, Ca, is sourced from mineral weathering or atmospheric sources. Through the use of Sr isotopes to provide a surrogate expression for Ca sources, the source was identified as > 90% atmospheric or marine derived. A uniform inland signature is identified, which is due to the continual recycling and mixing of marine derived Ca with minimal bedrock input. An external Ca source means that Ca does not have a direct relationship with Au, which is locally sourced from mineralised areas. On a local scale, a Au-in-calcrete anomaly extending over 20 km² and lying over both mineralised (Tunkillia Au prospect) and barren bedrock was investigated. Regolith-landform mapping and geochemistry was used to further identify the zone of elevated Au-in-calcrete. The zone was found to correspond spatially with palaeo- and contemporary drainage systems that currently flow into ephemeral lakes. Geochemistry of the area shows that the majority of elements have been transported and enriched along these systems. This dispersion pattern and its contemporary landscape expression is complicated by dune fields over mineralisation that partially cover the palaeo-drainage. Millions of dollars have been spent drilling this anomaly with no significant mineralisation found beyond the discrete Tunkillia mineralized zones, yet with the aid of regolith-landform mapping an explanation of the anomaly spatial pattern and dispersion pattern has been provided at very low cost. On the profile scale, two regolith carbonate profiles from the White Dam Au-Cu prospect were analysed in detail. Mass balance calculations revealed chemical gains and losses for the soil horizon and total profile. The investigation quantified the extensive external Ca input and revealed the position and size of the Au particles. Gold in the profile prior to regolith carbonate development is concentrated at the top of what is presently the regolith carbonate horizon as calcite precipitation in void spaces reduces permeability. Ongoing calcite precipitation up the profile locks in the Au, resulting in a Au-in-calcrete anomaly. Exposure of Au-enriched calcrete horizons to chemical and physical weathering results in decomposition of the material. This material can then be transported in the form of surface lag, which may settle on top of existing and still developing regolith carbonates to form new Au-in-calcrete anomalies that are unrelated to underlying bedrock. The formation of Au-in-calcrete anomalies in relation to landscape processes is demonstrated. Additional information on landscape setting, gathered while sampling, can therefore improve interpretation of regolith carbonate geochemistry. Exploration companies that take time to understand the landscape setting in this way and react accordingly, can therefore expect improved results.
Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2009.

This work provides a landscape context and framework for the use of regolith and vegetation in mineral exploration on Kangaroo Island, South Australia. Regolith field observations and the production of a regolith–landform map have improved constraints on the ferricrete plateau formation and also on the landscape history of the Island. The ferricrete and ferruginous materials on Kangaroo Island have been found to be the result of continous formation but have been largely in place since the Eocene. Through field observations, microanalysis and a large scale geochemical survey, the nature of the ferruginous materials and the processes that form them have been examined. Ferrolysis and the movement of groundwater have been interpreted to play major roles in the formation of the ferruginous materials. These processes have a significant impact on the use of the weathered materials for mineral exploration as economic and indicator elements are leached early in the weathering process. Ferruginous materials do contain the signature of mineralisation over areas that contain known deposits, however, the apparent lack of dispersion halos makes these materials difficult to use for a large scale geochemical survey for mineral exploration as target zones may be missed by low sampling densities. Despite this, the ferricrete materials can be useful for mineral exploration, as although potentially only providing small target areas, they do highlight areas of mineralisation. Conversely, the underlying weathered bedrock potentially has less use for mineral exploration as the economic metals have been readily mobilised out of the bedrock during the weathering processes on Kangaroo Island. The biogeochemical surveys were successful in highlighting areas of mineralisation, and displayed a greater dispersion halo than observed in the ferruginous materials. The biogeochemical surveys also helped to provide further information into the processes occurring in the landscape. The eucalypts are interpreted to source groundwater from the weathering zone in the bedrock and effectively pick up elements as they are leached. While displaying a high degree of variability, even over areas of known mineralisation, this dataset was better suited to identifying signals of mineralisation at a larger scale than the ferricrete. A limiting factor on the use of eucalypt for biogeochemical surveys is the occurrence of systematic inter-species variations. This makes large, regional scale surveys difficult, as there is a high possibility that there will not be a consistent vegetation species, resulting in a dataset in which different species need to be compared and potentially excluded in order to correctly identify meaningful anomalies. The xanthorrhoea, overall, was less successful in taking up elements of interest, most likely due to its shallower root system, which is likely to tap into the already leached saprolite or groundwater that has only been recently recharged by meteoric water (diluting any chemical signature of the underlying bedrock). This thesis has been able to demonstrate the potential usefulness as well as challenges associated with utilising ferricrete and vegetation for geochemical and biogeochemical sampling for mineral exploration. In doing so it has also furthered understanding of the landscape evolution of Kangaroo Island, building on previous work, and providing a basis for future landscape evolution studies and mineral exploration on the island.
Thesis (Ph.D.) -- University of Adelaide, School of Physical Sciences, 2016.

This thesis documents previous research into the heavy mineral sands (HMS) of the Eucla Basin. It presents new research designed to incorporate previous work, and to then encourage a broadening of research into the future. Specifically, this thesis is dedicated to demonstrating the importance of encompassing all aspects of research within a mineral system rather than isolating system components. In order to understand the complex regolith geology expressed within the Eucla Basin and its contained HMS deposits, a multi-faceted approach is applied, targeting two broad research areas. The first research area addresses processes acting prior to deposition of the Eucla Basin sediments, including providing constraints on the source of the sediments using U-Pb zircon analysis. The conclusions of this area of the research are that the dominant U-Pb zircon population lies between 1100 and 1250 Ma. Further, that these zircon populations match with the ages of zircon growth events in two of the most proximal potential source regions, the Musgrave Province and the Albany-Fraser Province. This research has also shown that due to the similar magmatic and metamorphic history of the Musgrave Province and Albany-Fraser Province it is difficult to distinguish between the possible sources regions using the U-Pb zircon data alone, highlighting the need for other methods. This thesis also found that kyanite and staurolite, which are common minerals in the Eucla Basin HMS, do not have an identified source in the Musgrave Province but do have a potential source in the Mount Barren Group in the Albany-Fraser Province. Finally, this thesis clearly demonstrates that the recognition of a likely more western source of zircon, kyanite and staurolite requires a revision of existing models of Eucla Basin HMS provenance, which focuses on the Musgrave Province as the most likely source. The second research area concentrates on the syn- and post-depositional history of the sedimentary rocks inclusive of depositional processes, weathering and groundwater interactions, the combination of which are expressed in multi-element whole rock major, trace element and isotope geochemical data. These data can be combined with other components of the HMS mineral assemblage, together with an understanding of the denudation history of the possible source regions, to establish a landscape evolution model from source, through transport to the site of deposition. The conclusion of this section of research is that stratigraphy of the sequences hosting HMS deposits at Jacinth requires revision because stratigraphic boundaries were assigned to horizons that are the result of post-depositional acid-sulphate weathering and groundwater processes. Finally, differentiation of rock types into process related sub-groupings is vital for understanding exploration geochemical data but cannot be achieved using major element chemistry alone. A broad suite of trace elements and selected isotope data are required, including strontium/calcium and strontium isotope ratios for the purpose of discriminating between marine and pedogenic carbonates. This methodology has provided significant breakthroughs in the discrimination of carbonate materials, particularly for landscapes with a complex marine or marginal marine history.
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2015

This item is only available electronically.
South Australia hosts some of the world’s largest non-ferrous mineral deposits. Exploration for such mineralisation systems has so far been impeded by thick regolith that conceals much of the prospective regions throughout Australia. The project tenement studied here is on the Eyre Peninsula at the central northern edge of the Spencer Domain (Middleback Ranges) within the Gawler Craton. It considered highly prospective for mineralization, such as associated with Iron Ore Copper Gold (IOCG) mineralisation. This study provides a preliminary characterisation of the plant biogeochemistry in relation to potential mineralisation sources in the area, and evaluates the potential for plant biogeochemistry to provide an effective and efficient representation of the mineral prospectivity. Three different plant species (Marianna sedifolia, Acacia papyrocarpa and Casuarina pauper) were sampled along east-west transects. Regolith mapping was conducted from aerial imagery of the area and ground-proofing along transects. A landscape geochemical dispersion model was constructed to highlight material flow directions to further understand the regolith units, landform history and its relation to the biogeochemistry of the area. Multi-element plant biogeochemical results show elevated levels of the commodity elements (Cu, Au, U) over known fault structures, the western alluvial system, and surrounding the mineralised Hutchison Group. Three statistical methods were selected to analyse and interpret the data: 1) Normal distribution- two standard deviations; 2) Median absolute deviation; and 3) Normal probability plots & histograms. The median absolute deviation presented consistent parameters for isolating the natural (interpreted natural) uptake of the selected 19 elements. Threshold values displayed limits that were interpreted as showing minimal potential of inhibiting any interpretation of single points of interest or overshadowing any broad scale element trends. Thus this method was utilised in displaying the biogeochemical results. Proposed exploration models for the area include close spaced transect sampling of vegetation along fault structures. Results from this study have implications for the future of mineral exploration, both within this tenement and in other regions comprising similar species and regolith cover. Results demonstrate that biogeochemistry can assist in the exploration of mineral deposits at both the prospect and regional scale. The importance of regolith mapping and developing an understanding for the tenement and regional landscape are important components in identifying likely areas of mineralistion, the success of sampling and result analysis.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2011

In this dissertation, we have examined mineral assemblages and geomorphologic features in the Sisyphi Planum region of Mars, as well as examined the mineral assemblage of palagonite in Iceland. Chapter 2 is focused on the mineral assemblages detected on possible glaciovolcanic edifices in the Sisyphi Planum region of Mars. Minerals were identified utilizing visible/near-infrared orbital spectra from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). Analysis of eleven CRISM images located on the volcanic edifices revealed three distinct spectral classes in the region which are interpreted to be: gypsum-dominated, smectite-zeolite- iron oxide-dominated (possibly palagonite), and polyhydrated sulfate-dominated material. The possible palagonite detections on the volcanic edifices, the geomorphology of the region, and the analogous terrestrial mineralogy of subglacial eruptions strongly suggests the formation of these minerals during subglacial eruptions or associated hydrothermal systems. This implies that thick water ice sheets were present in this region in the late Noachian or early Hesperian, and that the subglacial hydrothermal systems could have supported habitable environments with excellent biosignature preservation potential. Chapter 3 is focused on evaluating the variability of the composition and crystallinity of palagonite on Earth in order to inform efforts to identify it on Mars. We hypothesized that variability in palagonite composition and crystallinity could occur due to differences in environmental conditions during formation. Palagonite samples were collected in Iceland at subglacial volcanic sites around Reykjavík in the Western Volcanic Zone, on the southern coast in the Eastern Volcanic Zone, and from the Herðubreið tuya and Askja volcano in the Northern Volcanic Zone. Visible/near-infrared reflectance spectroscopy, thermal-infrared emission spectroscopy, and quantitative XRD were used to assess the bulk mineralogy, crystallinity, and clay composition of all samples. Results show the sampled palagonites contain partially devitrified glass, unaltered glass, and secondary minerals including clay minerals, poorly crystalline ferric oxides, and zeolites. However, one sample (SCoast01) shows a vastly different mineral assemblage in all sample techniques, including well-crystalline Fe/Mg-clays as opposed to the poorly-crystalline Al-clays observed in our other samples. Based on previous studies of subaqueous palagonites and the location this sample was collected from, we hypothesize that the SCoast01 sample was formed in a submarine environment rather than subglacial. This suggests that it may be possible to differentiate submarine vs. subglacial palagonite on Earth based on composition and from remote sensing observations on Mars. Chapter 4 is a geomorphologic study of the Sisyphi Planum region of Mars where we identified and classified the tops of the Sisyphi Montes as well as geomorphologically mapped the Sisyphi Planum region. Here, we address an overarching question: What is the relationship between the Sisyphi Montes and the ice in this region? To do this, we identified 106 edifices in the region and classified them into five categories: 1) flat topped, 2) rounded tops, 3) sharp peaks, 4) cratered peaks, and 5) height less than 300 meters – a “catch-all” category for all features below the specified height, which exhibit less distinctive morphologies in MOLA topography. While many of the edifices could be sub-glacial in origin, we find that the only morphologic class that exhibits uniquely subglacial morphologies are the flat-topped edifices. These edifices are similar to terrestrial tuyas, which form when a subglacial volcano breaches an ice sheet and erupts a plateau of sub-aerial lavas. Based on the geomorphologic map and topographic data, we have shown that flat-topped edifices are all located outside of regions that we map as the Mantled Unit, which we infer to be related to the Dorsa Argentina Formation. The combination of the flat topped edifices and their location outside of the mapped ice-related regions strongly suggests that the ice in the region was once more extensive than what is currently observed. While this has been proposed in the past, it has not been documented how far the ice sheet could have extended. Here we show that the ice must have extended to at least as far as the flat topped edifices in the region. The combination of these chapters using both mineralogy and morphology suggest that the Sisyphi Planum region of Mars was subglacial in origin.

The regolith, or ‘critical zone’, forms a discontinuous layer that covers large areas of Earth’s terrestrial surface. It is a dynamic zone that forms and changes through time in response to interactions between air, rocks (minerals), water and biota. Knowledge of regolith is critical because of its key role in supporting terrestrial life, through physical, chemical and biological processes that operate at mineral-water interaction scales up to the regional scale through geological and tectonic activity. There are many disciplines or areas of applied integrated research that rely on an improved understanding of regolith formation and information on surface and sub-surface regolith properties at appropriate spatial scales. These areas of study include; agriculture, land use sustainability, hydrology, salinity management, ecology, mineral exploration, natural hazard risk assessment and civil engineering. Furthermore, mapping regolith is critical in understanding the origin and evolution of regolith through space and time. Mapping the regolith and formulation of associated robust process models are in their infancy compared with geological and soil mapping, which have had a long history of development and refinement. Regolith mapping can be seen as a hybrid approach combining elements from the existing mapping disciplines of geology, soil and geomorphology. The regolith-landform approach, used extensively in Australia, is broadly similar to soil-landscape mapping where landforms are used as the principal surrogate to map regolith. Regolith-landform and soil-landscape mapping are inherently empirical and qualitative. However, in the last ten years there has been a move from the qualitative land resource survey (i.e. soil-landscape mapping) approaches to quantitative, digital survey underpinned by statistical methods. These new quantitative approaches are enabling the prediction of specific soil properties with associated estimates of model confidence or uncertainty not possible using traditional approaches. The aim of the thesis is to demonstrate and assess the application of quantitative soil mapping approaches in predicting regolith properties. Four case studies are presented that illustrate the application of quantitative mapping approaches in predicting regolith across a range of spatial scales and within different landscape settings. These four investigations include: 1. A continent-wide prediction of weathering intensity using a step-wise multiple regression-based model using airborne gamma-ray imagery and terrain relief; 2. A continent-wide prediction of near-surface secondary carbonate using environmental correlation and regolith geochemistry; 3. A regional-scale prediction of soil-regolith thickness over the Mt Lofty Ranges in southern South Australia using environmental correlation, drilling and legacy data, and 4. A regional-scale 3D regolith-landscape evolution model of valley-fill deposits from the Jamestown area in South Australia based on dataset integration, regression analysis and optically stimulated luminescence dating. The investigations are interpreted within a landscape evolutionary framework and future research directions are discussed. Digital regolith mapping shows considerable potential in predicting regolith properties over different landscape scales. This mapping is also important for understanding the complex interaction of environmental factors that control regolith formation, removal and preservation. Addressing gaps in predictive datasets that describe or reflect properties within the sub-surface (i.e. 5–100 m depth interval) and systematic collection of quantitative regolith attributes such as weathering depth and geochemistry will greatly enhance the future applications of digital regolith mapping in Australia.
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2014

The post-orogenic history of the Appalachian Mountains, particularly the persistence of rough topography and the degree of river incision throughout the region, has been a longstanding focus of geomorphology studies. Numerous models have been developed to explain the evolution of this landscape, variously invoking episodic or continuous processes of uplift and erosion to drive the generation or reduction of topographic relief. Recently, late Cenozoic uplift has found favor as a mechanism for rejuvenating the topography of the southern and central Appalachians. This hypothesis has drawn on longitudinal river profiles, seismic tomography, and offshore sediment records as evidence of Neogene uplift.

Understanding climate-driven changes in global land-based ice volume is a critical component in our capability to predict how global sea level will rise as a consequence of the current human-driven climate change. At the last glacial maximum (LGM, which peaked around 20 ka), ephemeral ice sheets covered vast regions of the northern hemisphere while both the Greenland and Antarctic ice sheets were more extensive than at present. As global temperatures rose at the transition into the Holocene, driving the LGM deglaciation, eustatic sea level rose by approximately 125 m. The east Antarctic ice sheet (EAIS) is the largest ice sheet on Earth today, holding an ice volume equivalent to ca. 53 m rise in global sea level. Considering current trends in global climate, specifically rapidly increasing atmospheric CO₂ levels and global temperature, it is important to improve our understanding of how the EAIS will respond to global warming so that we can make better predictions of future sea level changes to guide community adaptation and planning efforts. Numerical ice sheet models which inform projections of future ice volume changes, and can, therefore, yield projections of sea level rise, rely on empirical data to test their ability to accurately represent former and present ice configurations. However, there is a general lack of data on the paleoglaciology of the EAIS along the western Dronning Maud Land (DML) margin. In order to address this situation, the paleoglaciology of western DML forms the focus of the work presented in this thesis.

Together with collaborators within the MAGIC-DML consortium (Mapping, Measuring and Modelling Antarctic Geomorphology and Ice Change in Dronning Maud Land) that provides the funding for this MS project, the author has performed geomorphological mapping across western DML; an area of approximately 200,000 km². The results of the mapping presented in this thesis will provide the basis for a detailed glacial reconstruction of the region. The geomorphological mapping was completed almost entirely by remote sensing using very high-resolution (sub-meter in the panchromatic) WordView-2 and WorldView-3 (WV) satellite imagery, combined with ground validation studies during field work. Compared to Landsat products, the improved spatial resolution provided by WV imagery has fundamentally changed the scale and detail at which remote sensing based geomorphological mapping can be completed. The mapping presented here is focused on the glacial geomorphology of mountain summits and flanks that protrude through the ice sheet’s surface (nunataks). In our study area of western DML these nunatak surfaces make up <0.2 % of the total surface area, and the landforms mapped here are generally smaller than can be identified from Landsat products (30 m spatial resolution). The detail achieved in our mapping, across such a vast, remote area that presents numerous obstacles to accessibility highlights the benefits of utilizing the new VHR WV data. As such an evaluation of the WV data, as applied to geomorphological mapping is presented here together with our mapping of the glacial geomorphology of western DML. The results of which provides evidence of ice having overridden sites at all elevations across the entire study area; from the highest elevation inland nunataks that form the coast-parallel escarpment, to low-elevation emerging nunataks close to the coast. Hence from our studies of the glacial geomorphology of this region we can ascertain that, at some point in the glacial history of western DML, ice covered all of the mountain summits that are exposed today, indicating an ice sheet surface lowering of up to 700 m in some places.