Colin F Pain

Abstract: The use of standard terminology for the characterisation of site attributes, such as landform and vegetation, and for the description of regolith has obvious benefits for the various organisations in Australia concerned with regolith investigations. Some uniformity in the description of regolith has been achieved over the years with the publication of RTMAP Regolith Database Field Book and Users Guide (Pain et al. 1991, 2007), Regolith landform mapping in the Yilgarn Craton, Western Australia: towards a standardised approach (Craig et al. 1999) and Genesis, classification and atlas of ferruginous materials, Yilgarn Craton (Anand et al. 2002). Because there are a number of possible approaches (for example, in setting class limits) for many attributes, the classes adopted here are taken, where possible, from Australian standards—and in particular The Australian Soil and Land Survey Field Handbook (McDonald et al. 1990, NCST 2008), which is considered to be most appropriate for Australian conditions. This Guide is based largely on the field component of Pain et al. (2007). It covers a range of field observations that are convenient to measure or observe, and are relevant both to practical problems of mineral exploration and natural resource management, and the scientific study of regolith. Improvements will depend to a degree on the use of more systematic methods in the recording of field observations, in order to test the underlying, often un-stated models that often guide the recording of such observations. It is hoped that the use of this Guide will allow the development of more concise, or more relevant, field observations than those recommended in it. Improvements will come only from knowledge of the precise needs of clients.

Abstract:

Abstract:

Abstract:

Abstract:

Abstract:

Abstract: Australia has numerous landforms and features, some unique, that provide a useful reference for interpreting the results of spacecraft orbiting Mars and exploring the martian surface. Examples of desert landforms, impact structures, relief inversion, long-term landscape evolution and hydrothermal systems that are relevant to Mars are outlined and the relevant literature reviewed. The Mars analogue value of Australia’s acid lakes, hypersaline embayments and mound spring complexes is highlighted along with the Pilbara region, where the oldest convincing evidence of life guides exploration for early life on Mars. The distinctive characteristics of the Arkaroola Mars Analogue Region are also assessed and opportunities for future work in Australia are outlined.

Abstract: Remotely sensed imagery has been used extensively in geomorphology since the availability of early Landsat data, with its value measurable by the extent to which it can meet the investigative requirements of geomorphologists. Geomorphology focuses upon landform description/classification, process characterization and the association between landforms and processes, while remote sensing is able to provide information on the location/distribution of landforms, surface/subsurface composition and surface elevation. The current context for the application of remote sensing in geomorphology is presented with a particular focus upon the impact of new technologies, in particular: (1) the wide availability of digital elevation models; and (2) the introduction of hyperspectral imaging, radiometrics and electromagnetics. Remote sensing is also beginning to offer capacity in terms of close-range ( 60;200 m) techniques for very high-resolution imaging. This paper reviews the primary sources for DEMs from satellite and airborne platforms, as well as briefly reviewing more traditional multispectral scanners, and radiometric and electromagnetic systems. Examples of the applications of these techniques are summarized and presented within the context of geomorphometric analysis and spectral modelling. Finally, the wider issues of access to geographic information and data distribution are discussed.

Abstract: The floodplain of the Lower Balonne River is in the upper reaches of the Murray-Darling Basin. The region has been extensively developed for agriculture, in particular irrigated cotton, and is highly productive. Multidisciplinary investigations to inform land management generated extensive sets of remotely sensed data including Landsat TM, airborne gamma-ray radiometrics, aerial photography, ASTER imagery and digital elevation models. These datasets provided the basis for regolith and geomorphic mapping. The wealth of data has allowed characterisation of the Lower Balonne River system, which is typical of many of the dryland rivers of southern Queensland. The geomorphic map of the Lower Balonne floodplain has eight major units based on landform and geomorphic processes. Bedrock consists of the slightly deformed and extensively weathered marine Cretaceous Griman Creek Formation. Coincident with erosion and weathering, Paleogene quartz gravels were deposited and are now extensively cemented and preserved as remnants forming zones of inverted relief. Much of the present landscape consists of a series of juxtaposed depositional units that have infilled an incised valley system. The different depositional units show the paleo-Balonne River migrating to the west. This is interpreted to be a result of tectonic depression and tilting to the west, causing avulsion and anastomosing of the paleochannels. The modern Balonne River system consists of a number of easily recognised segments. In the north, the modern channel is incised as a single channel. To the south the channel opens out onto an anastomosing plain with branching and reconnecting small-scale channels. Source-bordering dunes, currently inactive, have also formed along the western and eastern sides of the modern river and are prominent in large dunes in the south along the present Moonie River. Their absence in older landscape elements points to increasing aridity over time in the river system.

Abstract: The Apennines and the Dinarides consist of nappes thrust towards the Adriatic Sea, which is underlain by largely undisturbed rocks. Plate tectonic reconstructions are very varied, with supposed subduction in many different directions. Besides this there is an over-ruling concept that a plate called the Adriatic (or Adria) Plate moved north from Africa to Europe where its collision helped to create the Alps. Some think the plate is still moving. The total tectonic setting, together with palaeontological and seismic data, suggests that the older model of two converging nappe belts meeting a common foreland best fits the observed facts.

Abstract:

Abstract: Abstract: This paper describes the changes in soil water repellency and soil hydrological and erosional responses to rainfall at small-plot scale, arising from a prescribed fire immediately following burning and one year later in a Mediterranean heathland in the area of the Strait of Gibraltar (southern Spain). Very little research has been carried out about the modifications on the ground surface after fire immediately after burning. A prescribed fire was conducted to study short-term changes of the ground surface immediately and one year following burning. After a prescribed fire, a homogeneous charred litter layer and ash-bed covered the mineral soil surface. This cover stayed stable on the soil surface during a period of seven days, until strong winds redistributed litter and ashes. The hydrophobicity of the exposed surface (litter and ashes) decreased considerably in relation with the litter layer properties before the fire. Ponding, runoff coefficients and soil loss were determined using simulated rainfall over the litter layer, the ash-bed and the bare soil. Significant differences were not detected between pre- and post-fire soil loss rates while a charred litter and thick ash layer were present on the ground surface. Runoff and erosion rates increased and time to ponding and runoff decreased when the charred litter and ash layers were artificially removed and the bare soil was exposed. Although wildfires will increase soil erodibility, the trends observed in this study suggest that this increased susceptibility to erosion from rainsplash processes may be limited to some degree while an intact ash and charred litter layer is still present.

Abstract: Most research into the geomorphology of mountains since the 1970s accepts the plate tectonic explanation of mountains, that mountains are a result of collision along converging plate boundaries. For example, the first paragraph of Chapter 2 in Owens and Slaymaker (2004) states that mountain systems “are major belts of pervasive deformation”. But this is true only of some mountains – others such as the Drakensberg, are formed on horizontal strata. Equally, many of the Earth’s plains are formed in areas of pervasive deformation – those of the Amazon Basin, Western Australia and Uganda are good examples. There is no simple relationship between mountains and folding, or any other structure. Standard plate tectonics does little to explain most mountains (see Ollier and Pain, 2000, for a much more detailed treatment). Since many mountains are not on folded rocks and for those that are there is no relationship between the timing of folding and the timing of uplift, it seems clear that the folding did not make the mountains. We suggest mountains are formed by vertical uplift of originally flat areas with or without pre-existing folding to form plateaus, which may then be eroded to form mountains. Indeed there is one class of mountains, the Great Escarpments, such as the Drakensberg (South Africa) and theWestern Ghats (India) that are escarpments at the eroded edge of plateaus (Ollier, 2004). A lot of folding is caused by gravity sliding, well-known and documented since the days of van Bemmelen (1954). The Niger Delta has most of the fold and fault features of a classical mountain range such as the Apennines or European Alps, but has never been above sea level or ‘compressed’ between plates as in the standard model: the structures can only be created by gravity sliding. Gravity spreading can also affect any fault blocks raised by more than about a kilometre, as shown long ago by Jeffreys (1931). The Andes are not made by subduction of the Pacific under the South American Plate, as there are thrusts in the opposite sense on the eastern margin. A few have invoked subduction of Brazil in addition (by no means part of the regular plate tectonic paradigm) but perhaps it is more probable that the uplifted Andes block is spreading. Similarly the Tibet Plateau is bounded by the Himalayas in the south and the Kunlun in the north, with allegedly convergent subduction. The north-south trending Rocky Mountain Plateau is bounded by the Park Range on the east and the Front Range to the west, suggesting divergence. Other blocks in the region are similar, with a Precambrian core to an anticline, and divergent spreading, but some trend east-west (e.g. Uinta), others north-west-southeast (e.g. Wind River Mountains). It is geometrically impossible for bounding blocks to be moving in several directions simultaneously. Most mountain ranges of Europe are currently explained in terms of plate tectonic collision, but this too has many problems. To illustrate just one, the North Apennines are thought to be thrust north, and the Southern Alps to be thrust south. The two opposing nappe fronts are on a collision course, but there is no compression between them and no uplifted fold belt. Instead there is the Po Plain, underlain by essentially conformable and horizontal sediments in an area that has been quietly subsiding for the past 25 million years at least. Planation surfaces are described on many mountain chains of the world and most geomorphologists agree that they represent erosion surfaces created close to past base level (sea level) and later uplifted. The rocks affected by planation were previously folded, faulted and sometimes overthrust for tens of kilometres. Such is the case in the Andes of Ecuador (Coltorti and Ollier, 2000). The processes that folded and metamorphosed the rocks did not form the mountains, as mountain creation through uplift occurred much later. It cannot be overstressed that although some of the rocks are folded, the Andes are formed basically by vertical uplift after planation. It is also worth stressing that the Andes range includes the largest granite batholith in the world. This is mainly Cretaceous, and older than the Andes and their presumed subduction, and the batholith is also eroded to a plain. Similar planated granites are found in many other ranges, including the Eastern Highlands of Australia. A planation surface is an important feature in Earth history that marks the end of a tectonic regime. In elementary diagrams compression is shown as causing simultaneous folding and corrugation of the ground surface to make mountains. But in most mountains the ground surface is not folded, and commonly plateaus are preserved in almost horizontal position. Many planation surfaces can be dated, by a whole range of techniques including, for example, K/Ar dating of basalts. If it is accepted that the mountains are formed by vertical uplift of these areas to form plateaus, then we can estimate the age of uplift, and so the age of mountain building. These estimates led to a surprising discovery: most of the world’s mountains were uplifted in the last 8 million years and much of the uplift occurred in the last two million years (Ollier and Pain, 2000). The implications of this ‘Neotectonic Period” are still being evaluated, but one conclusion is clear: the time scale of mountain building is not that of plate tectonics, which has supposedly been active for at least 200 Million years. Owen (2004) presented the conventional plate tectonic account of mountain building at plate collisional boundaries, but he notes that some do not fit. He wrote: “These ‘ancient’ mountain systems generally have little or no relationship to the present lithospheric plate boundaries and may have begun to have formed many hundreds of millions ago.” This assumption that mountains that do not fit the plate tectonics pattern are all ancient is false. The mountains of deep continental interiors, rift valleys or passive continental margins all fit into the Neotectonic Period, and were formed essentially at the same time as mountains on so-called active continental margins.

Abstract: The Murray River forms the border between New South Wales and Victoria, before flowing into South Australia. It has been extensively investigated by state and national agencies as part of wide ranging environmental studies for management of floodplain, riparian, and riverine health (e.g. Hollingsworth 1990, Jolly et al. 1994, Overton et al. 2004, Overton and Jolly 2006). It is perhaps the most studied floodplain in Australia. Therefore it is ironic that the geomorphology of the floodplain has had almost no detailed investigation. High-resolution airborne LiDAR surveys allow geomorphic mapping at high hierarchic levels, these maps are useful for the interpretation of geophysical surveys and regolith landform maps, and, in conjunction with these additional data, the preparation of more derived products such as recharge and flush zone maps and groundwater and salt budget models (Tan et al. 2007). The Murray River in part occupies the Murray River Gorge (Twidale et al. 1978) a valley incised through a Late Cainozoic succession consisting of the Blanchetown Clay and the Loxton-Parilla Sands. These are mantled by Pleistocene aeolian sands of the Woorenin Formation (Brown and Stephenson 1991). The modern floodplain consists of three distinct generations of meander belt sediments composed of scroll bars and oxbow billabongs. These show distinct up and down-stream morphologies reflecting spill-over of sands during river floods. A conventional fine-grained floodplain is absent, because the meander belt sediments extend across the full width of the floodplain within the confines of the gorge. However, older meander deposits are draped by floodplain silty clays with thicknesses increasing to more than a metre with the older deposits. The oldest floodplain deposits also show distinctively longer meander wavelengths and wide channels than does the modern channel, indicating a diminished flow over time. Sinuous fixed anastomosing channels (anabranches) are related to drainage during high water levels. These channels and oxbow billabongs are mostly clay-lined. Distal to the river small clay pans abut against the cliffs forming the edge of the trench and are several metres lower than the rest of the floodplain. They form evaporation basins for water draining off the proximal floodplains along the fixed channels. Remnants of high level terraces of inferred Pleistocene age are correlated with those reported by Rogers and Gatehouse (1990) further south along the Murray River as being of Late Pleistocene age. The small size of the terraces makes it difficult to infer much about the depositional system that formed them. However, further upstream in the Lindsay-Wallpolla Islands reach of the river, similar terraces are mantled by aeolian silts and sands through which ghosts of channels and billabongs are visible in satellite imagery. Drilling has shown that the River Murray Gorge in South Australia is flat-floored and overlain by a coarse sand unit sometimes referred to as the “Monoman Sand” (Firman 1966). This unit, which has no formal stratigraphic status, is inferred to represent a braided stream facies deposited during the earliest phase of Late-Pleistocene to Early Holocene aggregation. The top of this facies is marked by a buried forest and palaeosol (Gill 1973) which may mark the transition from braided to meandering deposition that characterises the modern river. At Chowilla in South Australia the inferred latest Pleistocene to Holocene sediments are up to 40 m thick. Upstream the sediments thin markedly to less than 20 m in the Lindsay-Wallpolla region dur to thinning of the “Monoman Sand”.

Abstract: Following a long tradition of maps of physiography in the United States of America and Europe (e.g. Fenneman 1917, Lobeck 1922), Gentilli and Fairbridge (1951), with help from Lobeck, prepared a “Physiographic Diagram of Australia”. This was followed by a landform map (Loffler and Ruxton 1969), and then a map of Physiographic Regions by Jennings and Mabbutt (1977). Whereas in the United States physiographic regions are used as a basis for both geological mapping and natural resource management, in Australia they have not been used for these or any other purposes. Recently, however, a revised map of the Jennings and Mabbutt Physiographic Regions of Australia has been prepared for the Australian Soil Resources Information System (ASRIS). The revision was carried out by digitising the original map and then overlaying it on the Shuttle Radar Terrain Model (SRTM), which has a resolution of 90 m. The first step was to adjust the original boundaries to more closely reflect the landforms as depicted on the SRTM. This initial revision was then passed to state agencies for revision in light of more detailed information held at the state level. The final revision will be level 2 of the 6-level ASRIS hierarchy. Because of problems associated with aggregating data from small areas to large areas (the modifiable areal unit problem, discussed by Dark and Bram, 2007), and the problem of ensuring that digital data are at a scale commensurate with the scale of landscape processes (Pain 2005), it is important to have a regional framework of areas within which extrapolation of observations can be made with some confidence. The six-level ASRIS hierarchy provides such a framework. This paper will introduce the new map of physiographic regions, plus other national data sets including Groundwater Flow Systems, the ASRIS hierarchy, and other matters relating to scale, mapping and land unit characterisation. These regional maps provide a firm basis for more detailed digital soil mapping and modelling.

Abstract: Geomorphological mapping is the recording of surface form, materials and (inferred) processes. There was an original rise in interest in the late 1950’s, with an explosion in application in the 1960’s and 1970’s. There has been limited work since that time. However, the last decade has seen a resurgence in landform mapping using new technologies and tools such as remote sensing, geographic information systems (GIS), and digital elevation models (DEM). For this reason a Working Group on Applied Geomorphological Mapping (AppGeMa) of the International Association of Geomorphologists has been formed. The main goals of AppGeMa are to: • develop and deepen the theoretical basis of applied geomorphological mapping within the new technical context • develop standards, specific mapping procedures and legend systems • disseminate the importance and effectiveness of the use of geomorphological mapping as a basic tool for those working with the physical environment • help bridge scientific and professional communities Specific Objectives of AppGeMa are to: • develop a systematic, comparative study of different cartographic methodologies and applications, including different GIS legend systems • establish a strong dialogue with other IAG working groups such as theWorking Group on Planetary Geomorphology • help foster the inter-professional exchange of applied mapping experiences • promote standard mapping procedures amongst non-specialists. Outputs proposed by AppGeMa include: • A Professional Handbook of Landform Mapping, to be published in the Elsevier “Developments in Earth Surface Processes” book series. The table of contents has been developed, with the first full draft expected by the end of 2009. • A Digital Atlas of Applied Geomorphological Maps, to be published by the end of 2009. • A pamphlet on The Importance of Geomorphology in Land Planning and Natural Hazards Prevention (in the context of the International Year of Planet Earth initiative), to be published by the end of 2008. • A Special issue of the Journal of Maps to be published by summer 2008. The following web based outputs are also proposed: • A reference database, to be a multilingual collection of the most important references on geomorphic mapping. This is in progress with completion aimed to be by the end of 2008. • A Standardised set of symbols, GIS tools and palettes for the creation and use of mapping symbols, to be completed by the end of 2008. • A collection of digital mapping resources for open source and proprietary mapping software, to be completed by the end of 2008. • A multilingual Glossary of Geomorphological Mapping Terms by the end of 2009. Other outputs will include: • A collection of articles and book chapters on applied geomorphological mapping, where necessary translated into English (further language translations are being considered) • A collection/library of geomorphological maps to serve as a reference for AppGeMa members. • A session at the next IAG International Congress in Melbourne, June 2009. • Summer school/short course open to people working with the environment, to disseminate the understanding, importance, and use of geomorphological maps (2009 or later). Results achieved so far can be found on the AppGeMa web site (http://www.appgema.org), including access to the working group mailing list. AppGeMa meetings at the following conferences have been convened or are planned: • British Society for Geomorphology Annual Meeting, 4-6 July 2007, Birmingham (UK) • IAG Regional Meeting, Kota Kinabalu, Malaysia, 25-29 June 2007 • Regional IAG, 8-10 September 2008, Bra 184;sov, (Romania) • International Geomorphological Conference, June 2009, Melbourne (Australia). This will include a special session within the conference, as well as an AppGeMa meeting. For more information go to the AppGeMa web site, or contact one of the following: Colin Pain (Colin.Pain@ga.gov.au) Paolo Paron (paoloparon@yahoo.it) Mike Smith (michael.smith@kingston.ac.uk)

Abstract: Relief inversion has been invoked to explain a number of geomorphic features of the martian surface. Terrestrial relief inversion occurs when former depressions become elevated because their fill is more resistant to erosion than the surrounding terrain. It is a common product of long-term landscape evolution on Earth, especially in relatively stable intra-cratonic settings and flat, or near flat lying successions. The inverted relief will preserve relicts of former land surfaces and is therefore older than the surrounding terrain. Relief inversion can occur by a range of processes, including infill of depressions by intrinsically resistant material, selective secondary cementation via diagenesis and weathering, or surface armouring. We examine a number of possible cases of inverted relief on Mars that appear to have formed by these three processes. We suggest that the most likely cementing agents for surface induration are iron oxides, silica, and sulfates. Possible cementation mechanisms include fluid mixing during regional groundwater flow, cooling of hydrothermal or basinal fluids as they near the surface, and evaporation and sublimation of near surface water. Wind action appears the most common erosive process on Mars capable of the regional landscape lowering necessary for relief inversion to occur, unlike on Earth where both deflation and runoff are important. Preliminary crater densities of selected features show that the tops of the proposed inverted relief have considerably more craters than the surrounding plains, as is predicted by the inversion hypothesis. More accurate dating of inverted surfaces and the adjacent areas may provide a simple way of measuring the degree of erosion over time in at least some areas of Mars.

Abstract: The Lower Balonne Airborne Geophysics Project (LBAGP) is the largest (time domain) airborne electromagnetic (TEMPEST) survey acquired in Australia for salinity (and broader natural resource management) purposes. A total of 28,912 line km of data were acquired in 2001 under the auspices of the National Action Plan for Salinity and Water Quality, in a project undertaken by the Queensland Department of Natural Resources and Mines (QNR 38;M), the Cooperative Research Centre for Landscape, Environments and Mineral Exploration (CRC LEME), and the Bureau of Rural Sciences (BRS). The project also collected airborne magnetics and gamma radiometrics, digital elevation data, ground-based geophysical data, hydrological data from borehole investigations, soil site data and surface and sub-surface regolith data. The study area, part of the Lower Balonne catchment in the Darling Basin, southern Queensland, was selected to evaluate the use of airborne geophysics for salinity hazard and risk mapping and assessments in a flat inland alluvial floodplain landscape in an area of high agricultural value (cotton irrigation) and environmental sensitivity (Chamberlain 38; Wilkinson, 2004). Regolith landscape mapping in the project area has revealed that the present surface landscape in the study area consists of a mosaic of active and inactive low relief alluvial fans with anastomosing distributaries, including that of the modern Balonne River (Kernich et al., 2004). However, beneath the flood plain is a large, bedrock-incised palaeovalley system (Dirrinbandi palaeo-valley), eroded into weathered Cretaceous marine sediments (Clarke 38; Riesz, 2004). The trunk valley has been buried to depths of up to 200 m, and tributaries contain approximately 100 m of sediment. A change in depositional environment from confined to unconfined flood plains resulted in a change from anastomosing or braided channels to extensive braid plains when the valley sides were first over-topped (Clarke 38; Riesz, 2004). Aquifers occur in ‘nested’ groundwater flow systems concealed beneath the low relief landscape (Fitzpatrick et al., 2004). Three main salinity (land and groundwater) management units have been delineated in the study area (Chamberlain 38; Wilkinson, 2004). Groundwater flow paths are different in each of these zones. Management Unit A is characterized by areas where the bedrock either crops out, or underlies a relatively shallow cover of unconsolidated sediments. A dual-porosity, saline partial aquifer exists within the bedrock, however in most cases the water does is not free flowing due to generally low hydraulic conductivities. Within this unit, salinity risks occur at breaks of slope, and where perching of the water table occurs over shallow bedrock. There is also the potential for salinisation to develop as a result of rising water tables in areas of increased local recharge (Kellett et al. 2004, Grundy and Macaulay, 2004, Wilkinson et al. 2004). Management Unit B comprises areas where a thicker sequence (10-40m) of sediments overlies the basement. The original cotton irrigation area is located within this unit, and AEM data indicate an effect of irrigation on soil salt store, with an increased salt load in the top few (5 - 10) metres of the irrigated areas. Groundwater quality of the upper alluvial aquifer is highly variable in this area, however salt load in the near surface is not as high as in Unit A. A variety of salinity drivers have been identified in this unit, operating independently and interacting in various parts of the landscape. There is evidence for both vertical and horizontal groundwater flows, and sustainability of agricultural enterprises and the natural resources in this area will depend on continued monitoring and an increased investment in water use efficiency measures (Wilkinson et al. 2004). Management Unit C comprises deep alluvial materials (40 – 200 m) within which there are two alluvial aquifer systems, separated by a clay aquitard. Some newer cotton irrigation occurs in this unit, and exploitable groundwater resources occur in the north. Within the upper alluvial aquifer, water quality is highly variable, generally decreasing in quality from north to south and away from river recharge. In the lower alluvial aquifer, electrical conductivity increases gradually from north to south and the range of values is less than those in the upper aquifer. Short-term salinisation issues caused by rising groundwater are unlikely in this region. Recharge to the aquifer needs to be minimized, and monitoring of near-surface elevated salt loads is needed to ensure salts do not move downward into the aquifer. Overall, this project has been successful in developing new methodologies for data processing, analysis and integration that have produced valuable new insights for regolith mapping, and salinity risk mapping and management in the study area. Of particular note was the development of a new method for producing reliable constrained inversions of time-domain AEM data in areas of electrically conductive basement (Lane et al., 2004). This enabled

Abstract: The Lower Balonne River of southern Queensland is part of the greater Darling River drainage system. The region is extensively irrigated for cotton production, and understanding of the area’s geomorphology and subsurface regolith architecture is critical to keeping groundwater and salinity levels within acceptable limits. Recent research into the regolith and hydrogeology of the area has revealed new insights into the history of fluvial processes in the system. The current landscape consists of a mosaic of active and inactive low relief alluvial fans with anastomosing distributaries, including that of the modern Balonne River. Beneath the flood plain is a large, bedrock-incised palaeovalley system, eroded into weathered Cretaceous marine sediments. The trunk valley has been buried to depths of up to 200 m and tributaries contain approximately 100 m of sediment. Infill has occurred in two stages; an early phase in which deposition was confined by the sides of the palaeovalleys, and a later phase when sedimentation spilled across and buried the landscape. Sedimentation appears to have been essentially continuous during infill, however the change in depositional environment from confined to unconfined flood plains triggered a change from anastomosing or braided channels to extensive braid plains when the valley sides were first over topped. These braided systems later reformed as the present day set of anastomosing distributaries of the Balonne, Moonie, and Maranoa rivers. The date of incision is unknown. It must postdate erosion and weathering of the Early Cretaceous marine sediments and the deposition of quartzose conglomerates on the weathered surface, now preserved as silcreted remnants of inverted relief. This suggests is no older than Early Tertiary. Incision must also predate deposition of the infilling sediments. At present, the only age controls are provided by palynology, which suggests that the infill is no older than Pliocene. The trigger for incision is unknown, but is likely to be related to the Neogene uplift of the Eastern Highlands of Australia. The Dirranbandi palaeovalley and its fill represent what are, by Australian standards, an unusually rapid example of palaeovalley incision, infill, and eventual burial. This contrasts with other palaeovalley systems in Australia which are typically filled by Eocene, as in the case of those marginal to the Eucla Basin, or Oligocene sediments, as with those peripheral to the Murray Basin. The predominantly anastomosing nature of the channel sands within the sedimentary sequences imposes a high degree of anisotropy on groundwater flow. This in turn implies that hydrological responses to anthropogenic changes are also likely to be anisotropic. The “steers head” geometry of the sedimentary fill implies that changes in groundwater level from increased recharge or extraction will be non-linear due to the near-asymptotic increase in storage volume at shallower depths. Both these features have important implications for environmental management.

Abstract: The search for evidence of water on Mars has been a principal objective during NASA 039;s current 2003 - 2004 series of Mars Exploration Rover (MER) missions. The missions were designed to explore the Martian surface for signs, past or present, of liquid water. However, some attention has also been given to other erosional and landscape processes that may be inferred from the abundance of images now available. On Earth, the main physical weathering processes are frost weathering, salt weathering, and wetting and drying. These processes commonly result in exfoliation, spalling, and granular disintegration. Some of the forms present on the Martian surface also suggest that chemical weathering has taken place. There are also diverse aeolian processes that, in addition to dune forms, result in small abrasion forms on exposed rocks. NASA 039;s recent MER missions imaged numerous micro- and meso-scale features on the surface of the planet, many resembling the results of these terrestrial processes. Using imagery collected by NASA 039;s Spirit and Opportunity rovers, we describe and categorise features using a basic geomorphic classification and compare a number of these features with possible Earth analogues. Our comparisons show that many of the features on the surface of Mars could be formed by processes common on Earth. We conclude that in most cases it is not necessary to seek complex or exotic processes to explain Martian geomorphology.

Abstract: The floodplain of the lower Balonne River is in the upper reaches of the Murray Darling Basin and has significant agricultural value as cotton irrigation and cattle grazing land. The area faces water allocation issues and there have been reports of recent salinity hazards occurring in this heavily irrigated area. Consequently the region has undergone extensive and ongoing geoscientific investigations by many agencies. Groundwater flow systems and the presence of salinity hazards in the area are determined by regolith materials and their architecture at the surface and at depth. Landform, regolith and geomorphic mapping relied heavily on remotely sensed data, including Landsat TM, airborne gamma-ray radiometrics, aerial photography, Aster imagery, and digital elevation models (DEM). Mapping was carried out at 1:100,000 and 1:250,000 scale and individual units were validated. The Regolith Landform Map has 22 detailed units based on regolith materials and form, while the Geomorphic map is divided into the 8 major units based on landform and the geomorphic processes responsible for their formation. The Regolith Landform Map is useful for surface detail, especially in terms of salinity hazard identification and for assessing which data sources were most appropriate in its construction. For information on landscape evolution and for sub-surface interpretation, the more regional Geomorphic Units were considered. The landscape has a complex evolutionary history. Bedrock consists of the Griman Creek Formation, deposited as marine sediment in the Cretaceous. This unit has been slightly deformed and extensively weathered to form silcrete and ferricrete in varying amounts. The weathering profile is believed to strongly influence the groundwater characteristics in the area by forming an aquiclude for the overlying alluvial sediments. Coincident with the erosion and weathering quartz gravels were deposited and are now extensively duricrusted and preserved as remnants forming zones of inverted relief. These are inferred to be Early Tertiary in age. Much of the present landscape consists of a series of juxtaposed depositional surfaces. These are the surface expression of an incised and infilled valley succession formed from the Pliocene onwards by the palaeo-Balonne, Moonie, Maranoa and Condamine Rivers. The oldest of the depositional surfaces is the Maranoa surface. At present there is little active channel flow on the surface and it now has a slightly weathered and eroded form. The Maranoa surface is Pliocene – Early Pleistocene in age. At some point following the deposition of this feature, the Balonne River was diverted to its present course between two low rises upstream from the township of St George. After it changed course, the Balonne River flowed to the east of its present course. At the same time the Moonie River was bringing material from further east and presumably because it was blocked by sediments from the Balonne River, turned to the south to take up its present course. These changes in sedimentation patterns on the fluvial plain formed a series of different depositional surfaces. The Modern Balonne River system consists of a number of easily recognised segments. In the north, the modern Balonne River channel is deep and well established. To the south the modern channel opens out onto an anastomosing plain with branching and reconnecting small-scale channels. Source bordering dunes have also formed along the western and eastern sides of the modern Balonne River and are prominent in large dunes in the south along the present Moonie River. However, they are not apparent in older landscape elements. The surface distribution of regolith materials on most geomorphic units is a fair indication of the complexity of regolith materials at depth. Regolith distribution patterns of former channels in the major alluvial geomorphic units can be described, even if their actual location can not be predicted. Surface mapping unfortunately does little to characterise the sub-surface character of the Griman Creek formation which is present at depth throughout the study area and is a crucial factor in the ground water flow systems. Overall, however, knowledge of the surface distribution of regolith materials, their boundary character, and the processes that are responsible for that distribution, can be used as part of the input into models of the 3D regolith architecture, and of the evolution of the Lower Balonne landscape. Areas that may be a salinity hazard have also been identified through this study of the regolith and landforms of the Lower Balonne area. Predominantly these are located along the eastern boundary of the Maranoa surface. These are areas of concern because of their sodic soils, the potentially active seepage of saline water that the geomorphic evidence indicates to be going on in the area, and their proximity to the current Balonne River, which may receive some of the saline efflux.

Abstract: Munday, 2004). These flow systems may also be spatially nested, in effect containing local and intermediate types within the larger, slow moving regional flow systems (Fitzpatrick et al., 2004). This is considered to be a common occurrence in areas of fluvial buried landscapes, which occur in two thirds of the Murray-Darling Basin (Lawrie et al., 2003a). The critical attributes required for assisting salinity mapping, modelling and management in Australia’s depositional landscapes are (1) the connectivity of aquifers in different salt-water systems; (2) the existence and extent of by-pass flow (vertical and lateral); (3) the size of the salt store and its potential for mobilization; (4) the 3-D nature of the regolith (and adequate algorithms and models to depict this); (5) the need for a dynamic water balance (Lawrie et al., 2003a). In these landscapes, only geophysical techniques (e.g. airborne electromagnetics) can provide information on the spatial distribution of regolith materials and groundwaters (Spies 38; Woodgate, 2004). Presently, airborne are viewed as considerably more expensive than other airborne geophysical techniques for salinity and groundwater mapping. However, recent investigations by the Cooperative Research Centre for Landscape Environments and Mineral Exploration (CRC LEME) and Geoscience Australia suggest that substantial cost reductions in acquiring AEM datasets (up to an order of magnitude) may be achieved if the critical landscape elements that control salinity and groundwater in a target area can be identified prior to surveying (Lawrie et al., 2003b) Savings can be made if the spatial and geo-electrical characteristics of the elements allow relatively wide line spacings to be used. Preliminary work in the GILMORE Project area, NSW, has established many of the attributes listed above. The GILMORE survey area lies within a shallow inland basin, the Bland Creek palaeo-valley, a north-south-trending palaeo-valley system 60 km across, and 130 km long. The northern of two AEM surveys lies within the western flank of the palaeo-valley in an area of relatively flat alluvial plains with a few low hills (Lawrie et al., 2000; Chan 38; Gibson, 2001). The latter consist of granites or silicified hydrothermal alteration zones associated with Au and Au-Cu deposits (Lawrie et al., 2002b). NNW-trending, discontinuous topographic ridges consist of siliciclastic meta-sediments and/or granites. The streams flowing from the hills mostly disappear into alluvial fans or into the alluvium of the flood plains. The main north-flowing stream, Bland Creek, varies in salinity, receiving low salt waters from its left bank but, occasionally, very high salinity waters from the right bank (Lawrie et al., 2000). In the GILMORE project area a detailed picture of 3D regolith architecture has been established through analysis and interpretation of materials from several hundred boreholes, and integrating this analysis with airborne geophysics datasets and surface regolith landform mapping (Lawrie et al., 2000, 2002a). The MDBC Groundwater Flow Systems Map for this area is derived largely from surficial datasets and older geology maps that denote the Quaternary materials largely as one regional flow system. There is no sub-surface data incorporated in this construct. It shows a large part of the area as a regional GFS system. However, a very different picture of the regolith architecture and contained groundwaters emerges from the AEM survey data. Significant complexity is observed at sub-catchment scales, with compartmentalisation evident within this same area. Drilling has validated this compartmentalisation. Up to 120 m of sediment infill are recorded in the northeast of the AEM survey area. However, sediment thickness is markedly variable on account of complex bedrock palaeo-topography (Lawrie et al., 2000). Within this complex landscape there is considerable vertical and horizontal variability in landscape and salinity elements (Lawrie et al., 2003a). There are broadly four scales of features present: 1. First order features. At depth ( 62;20 m), bedrock-influenced elements such as variably weathered saprolith, and limited fresh bedrock (eg resistive silicified ridges). The structural dominance in the bedrock has partitioned the bedrock and its weathered equivalent into NNW-trending landscape elements that are between 1 and 6 km in width, and 10-50 km in strike length. These landscape elements provide the large scale controls on regolith architecture and have considerable influence on salt store and groundwater flow. In this landscape it is important to recognise and map these features for catchment and sub-catchment scale salinity mapping and management. Nearer surface ( 60;20 m), the bedrock influence is less, and Cainozoic sediments predominate. At these depths landscape elements of similar scale include a clay-dominated palaeo-lake that contains significant volumes of saline groundwater within clays of low hydraulic conductivity (salt store); 2. Second Order Features. Sedimentary basins developed through preferential erosion of weathered bedrock and subsequent infill. These form discrete basins at depth (15-60 m), and are between 1.5 and 6km in width, and 3-20 km in length. These features are important elements as they contain significant stores of saline groundwaters, and it is important to map these features at sub-catchment scales. At all depths colluvial fan deposits are important at different scales. However, at shallow depths ( 60;20 m) a colluvial fan apron around the Barmedman Granite is an important element, as significant recharge appears to occur within this unit. It is present as an apron around the exposed granite, extending up to 6 km from it; 3. Third Order Features. The sedimentary basins inter-connected downstream. They are sinuous features that represent palaeo-channel fill materials (not a single channel, but many stacked, small scale channels). They contain higher proportions of sand-sized materials than adjacent sediments, and in general appear to have higher hydraulic conductivities and water yields than adjacent finer grained sediments. These features form palaeo-gorges that cut through linear bedrock ridges that otherwise act as barriers to groundwater flow in this area. The palaeo-channels are generally less than 300 m in width, and can be traced for between 2 and 20 km. It is important to recognize and map these features at sub-catchment scales; 4. Fourth Order Features. Small-scale features are evident in the highest resolution AEM datasets. These features are mainly narrow ( 60;100 m wide, 500 m long) tributary palaeo-channels. These are probably of some significance at paddock (farm) scale only. These features are the key functional elements of the landscape that should enable targeted engineering and/or biological interventions in the landscape for salinity management at a range of scales. Pump tests in the different regolith materials in the survey area have demonstrated significant ( 62;5 orders of magnitude) differences in hydraulic conductivities in regolith materials in the GILMORE Project area (Grant Jones, pers com., 2002). Work is on-going to derive a hydrogeological model for the area. Analysis of the key functional elements of the landscapes in the GILMORE (New South Wales), Lower Balonne (Queensland) and Honeysuckle Creek (Victoria) TEMPEST AEM survey areas, suggest that 1km line spacing is adequate to map most landscape and salinity elements in these depositional landscapes (Lawrie et al., 2003b). Even 2 km-line spaced data provides catchment and sub-catchment scale salt store data, and this may be useful for broad scale planning and national audit purposes. For 1 km and 2 km line spacing, this means that significantly larger areas could be flow for the same cost, reducing the cost of AEM data per hectare as follows: 1 km line-spacing 60;$0.7/ha for acquisition 2 km line-spacing 60;$0.4/ha for acquisition This represents a very substantial cost saving, and could make AEM data affordable for many more NRM applications. The assumptions in the above calculations are that the total number of line km from the original surveys are maintained, that the line km costs are similar to those from recent surveys, and that all other survey mobilisation and operational costs remain similar to the original surveys (Lawrie et al., 2003b). Salinity and groundwater mapping in Australia’s complex regolith landscapes is greatly assisted by using an integrated geoscience approach that utilises a multi-scale, hierarchical approach to identify and map key functional elements. An approach that involves consideration of present landforms and buried landscapes can greatly assist with the design of cost-effective surveys for salinity mapping and broader NRM applications. This approach should also utilise GFS conceptual models and frameworks where possible.

Abstract: In Australia, the geological/geomorphological characterization of catchments relies mainly on the use of soil, surface landform (from regolith landform maps and digital elevation models), and surface geology maps. Constructs, such as the Groundwater Flow System (GFS) Map of Australia, and similar constructs at regional and catchment scales, rely on this approach to identify and map hydrogeomorphic units with similar geomorphological and hydrogeological characteristics (Coram et al., 2000). These constructs provide a useful basis for understanding groundwater flow systems that influence the recharge, transmission and discharge of groundwater involved in dryland salinity, and are a useful starting basis for large-scale salinity management planning and prioritization purposes (Coram et al., 2000). Unfortunately, the existing GFS frameworks are generally not adequate to underpin salinity management at sub-catchment scales. This has been due in large measure to the absence of 3-D data that is required to characterize the structural and hydraulic properties of sub-surface materials at the appropriate scales (Lawrie et al., 2002, 2003). However, over the last five years in particular, multi-disciplinary studies have provided new insights into regolith architecture, salt stores and the groundwaters that mobilize these salts in the sub-surface (Lawrie et al., 2000, 2002, 2003, 2004; Munday, 2004). These data are now being used to value-add to existing GFS frameworks. Value-adding to GFS maps in upland landscapes Bedrock influences tend to be greatest in upland (erosional) landscapes due to a thinner regolith veneer and the influence of fractured rock aquifers and near-surface constrictions in groundwater flow due to bedrock highs, faults, dykes, as well as lithology variations (Lawrie et al., 2004). In many of these landscapes, large-scale variability in bedrock textures and compositions (reflected in saprolith hydraulic properties), and structural geological information that is potentially of importance to groundwater flow, is not recorded on published maps of bedrock geology (Lawrie et al., 2002). A methodology has been developed to incorporate value-added mineral system data for groundwater and salinity studies in both depositional (Lawrie et al., 2000) and erosional landscapes (Lawrie et al., 2004). Also, it has been demonstrated that surface maps of soils and topography commonly used in GFS frameworks may not be a good guide for predicting sub-surface salt, and groundwater distribution and movement in upland landscape, particularly at subcatchment scales (Lawrie et al., 2004;Wilford, 2004). This is on account of significant landscape disequilibrium, where a long history of erosion and deposition results in the development of out-of-phase landscapes. This is particularly true in areas with a protracted landscape history and/or in areas where tectonic and volcanic activity has influenced landscape development. Landscape disequilibrium appears to be a common situation in Eastern and Southern Australia, where valley-fill sediments are preserved in erosional landscapes, and vice-versa. One consequence of this is a poor reliability in the use of present day landforms and models based on the use of digital elevation models (DEMs) and terrain indices to predict sub-surface regolith landscapes, salt stores and groundwater movements (Lawrie et al., 2004). Hence, in upland landscapes, a value-added approach to GFS that incorporates updated bedrock mineral system and regolith information is recommended to support targeted salinity management intervention, particularly at sub-catchment and/or farm scales. Importantly, a new approach for mapping salt stores and GFS down to subcatchment scales has been demonstrated (Lawrie et al., 2004). This methodology can be applied both to present day depositional and erosional landscapes. Value-adding to GFS maps in depositional landscapes Groundwaters within depositional landscapes are commonly mobilized along preferential pathways often determined by primary variations in sediment facies and/or changes in hydraulic conductivity wrought by overprinting weathering (Lawrie et al., 2000, 2002; Fitzpatrick et al., 2004; Munday, 2004). In these landscapes, including upland valleys where erosional landscapes may be buried by sedimentation, surface geomorphic processes will differ markedly from those associated with now-buried landscapes. In Australia’s subdued landscapes, the nature of sedimentary fill defines the response time of groundwater flow within a GFS. Hence significant value-adding to GFS frameworks can be achieved through incorporating information on landscape evolution, regolith architecture and sediment infill, and weathering and erosion distribution and processes. The ability to map and predict these properties in the sub-surface aids predictive models of groundwater and salt mobility (Lawrie et al., 2004). The critical attributes required for assisting salinity management in the regional depositional systems are (1) the connectivity of aquifers in different salt-water systems; (2) the existence and extent of by-pass flow (vertical and lateral); (3) the size of the salt store and its potential for mobilization; (4) the 3-D nature of the regolith (and adequate algorithms and models to depict this); (5) the need for a dynamic water balance (Lawrie et al., 2003). In these landscapes, only geophysical techniques (e.g. airborne electromagnetics) can provide information on the spatial distribution of regolith materials and groundwaters (Spies 38; Woodgate, 2004). Conclusions A value-added approach has the potential to address these issues both by determining the degree to which nested smaller GFS systems exist (Fitzpatrick et al., 2004), and by developing an understanding of the nature of the regolith landscape materials in terms of water fluxes and plant growth parameters. This approach has led to a demonstrated capacity to provide new salinity management options even in intermediate and regional flow systems (Fitzpatrick et al., 2004; Munday, 2004). The Groundwater Flow Systems GFS approach has enabled broad dissemination of specialist knowledge, highlighted diversity of processes and therefore management requirements, and has been very widely adopted within Australia as a conceptual framework for dryland salinity decision making, particularly at catchment scales. Its continued use and development as a decision platform to assist planning and prioritisation for salinity and groundwater management is encouraged, and its role indeed expanded to support a broader range of NRM issues. Significant value-adding to GFS frameworks can be achieved in all landscapes by incorporating information on regolith architecture and composition, salt store data, and up-dated bedrock mineral systems data (high resolution airborne geophysics, structural geology and mineral systems interpretations of bedrock geology).

Abstract: The palaeoplain is the terrestrial continental surface, little changed from the landsurface that existed before continental breakup. The basal unconformity occurs offshore, separating older continental rocks from younger post-rift sediments. This paper considers the palaeoplain and the basal unconformity to be the same surface. It presents a hypothesis for continental passive margins that integrates the geomorphology near the continental boundary with the offshore geomorphology. By recognising the identity of the palaeoplain with the basal unconformity the hypothesis links the terrestrial story to the offshore story. Many details that were separated in earlier models come together in a single model. Continental rifting starts with a rift valley stage. At this stage the pre-breakup landsurface, the palaeoplain at the edge of the continent, is downwarped. On the seaward side post-rift sediments accumulate on the submerged palaeoplain, which thus becomes the basal unconformity. This model explains the parallel structures of continental divide, present coast line, and continental edge. It also explains the creation of the basal unconformity in a short time, and the comparative volumes of onshore erosion and offshore sedimentation. Onshore, the model explains the modifications of drainage and the great escarpments that are characteristic of passive margins. It also explains oldlands observed near the coast.

Abstract: This paper briefly reviews the application of digital elevation models (DEMs) to the study of landscapes. Such studies can involve both the enhancement of DEM images to highlight particular patterns, and the use of DEMs to model attribute values of landscapes. Recognition of palaesurfaces is an example of the first use, while modelling hydrological properties based on slope attributes derived from a DEM is another. Following the review, the paper presents work on the character and scale of slopes and the processes that form them in a study area near Picton, NSW. These slope and process scales are then considered in the context of digital elevation models as a source of data about slopes. Slope angles are clustered around modal values that may be referred to as characteristic and threshold slopes. Characteristic slopes are those most commonly occurring in an area, and their inclination is controlled by the material on which they are formed and the processes that control their formation. They are closely related to threshold slope angles, which are those where sudden changes of slopes processes take place. Most DEMs have generalisations of the land surface built into them. If these generalisations are within the spatial range of the processes that are operating in the landscape of interest, there is no problem. However, if the generalisations are greater than the resolution of landscape processes, any results or indices derived from DEMs must be treated with caution. In the Picton study area only an original ground survey and to a lesser degree a 25m “DEM” give any indication of the shape of the ground surface. 50m and 100m DEMs barely resemble the ground surface, and values derived from these latter DEMs in no way reflect the original slope form. Moreover, they give no indication of the characteristic slope values, so they do not reflect the nature of the processes operating in this landscape. A SRTM 90m DEM over the same profile line similarly provides no real ground surface information. This study shows that, although DEMs are frequently used to derive values for slope angles, the accuracy of these derived values depends on the pixel resolution of the DEM from which they are derived. That accuracy of slope angle and shape depends on DEM resolution is obvious. What is not so obvious, and in many cases seems to be ignored, is that DEM resolution must be better than landsurface process scale if DEMs are to be used to predict spatial patterns of, say, soil attributes. Slope angles derived from most available DEMs are therefore limited as descriptions of real landscapes and processes unless the data are at a resolution that equals or is better than the scale of slope and regolith processes. The appropriate scale for a particular landscape can only be determined by geomorphic analysis of landform shape and processes; in most cases this will mean ground survey. In the Picton area a pixel resolution of 5m is adequate to capture the scale of surface processes and therefore likely variation of, say, soil attributes. In other areas the resolution required may be as small as 1m or as large of 100m. In other words, landscape process scale will dictate useful pixel resolution scale. And although this paper does not consider other raster image data, the results imply that the same conclusions apply to them as well.

Abstract:

Abstract:

Abstract:

Abstract: