Several different techniques have recently been developed to rapidly map and characterise surface landforms and materials for groundwater recharge studies in Australia. In this example, in the Darling Floodplain of western New South Wales, regional landform mapping was carried out primarily using Google Earth imagery with hill-shaded LiDAR DEM and SPOT images as visual guide and some field validation. A second, more detailed map (compiled: 1:25,000; final usable scale: 1:30,000) included landform elements such as borrow pits, individual scrolls and oxbow lakes was compiled using LiDAR DEM. Prior to landform delineation, the LiDAR DEM required levelling to eliminate tilting in the landscape, by subtracting the floodplain trend surface from the DEM. This is particularly important in floodplains and river profiles where there can be as much as a 20 m difference between the upper and lower reaches. A best-fit trend surface, which provides an average estimation of change in slope along a single plane, was required to level the data. Once the LiDAR was levelled, an interactive contour tool in ArcGIS was used to generate graphic outlines of particular features at identified breaks in elevation using hill-shading, e.g. channel banks and dune bases. Slope and 3-D DEM visualisation also facilitated identification of these breaks. Further editing was required to assemble line work, convert it into polygons, and assign landform attributes. A greater number of landform classes were developed at this finer scale than for the regional scale. In many cases, specific landforms are characterised by particular surface materials, though sediment type can vary within a single landform class. SPOT imagery has been used to delineate surface materials. In summary, the combination of the two datasets - landforms and surface materials - has allowed for the identification of potential recharge site

Geomorphic landscape features and associated surface materials are fundamental to groundwater recharge processes as they form the first layer through which surface water passes before it becomes groundwater. Different surface materials exhibit different water-holding capacity and hence permeability characteristics. In the Broken Hill Managed Aquifer Recharge project, surface-materials mapping in conjunction with geomorphic mapping, has assisted hydrogeological investigations, including recharge predictions, salinity hazard and the identification of potential infiltration basins. Prior to landform identification, LiDAR DEM data was levelled using trend surfaces to eliminate regional slope (~20m). As a consequence of this, an ArcGIS interactive contour tool could be used to identify specific breaks in elevation associated with landform features. Multivariate image analysis of elevation, high resolution SPOT and Landsat-derived wetness further enhanced the contrast between geomorphic elements to confirm mapping boundaries. While specific landforms can be characterised by particular surface materials, these sediments can vary within a single geomorphic feature. Consequently, SPOT multispectral satellite imagery was used to identify surface materials using principal component analysis and unsupervised classification. This approach generated 20 classes; each assigned a preliminary cover/landform attribute using SPOT imagery. Field data (surface and borehole sample, and observations at shallow pits) were used to refine the classification approach. Interactive mapping using a de-trended DEM provided a rapid, effective and accurate alternative to time consuming manual landform digitisation. The combination of these two new products - surface-materials and geomorphic maps - has assisted in the identification of potential recharge sites and naturally occurring infiltration sites.

An examination of regionally extensive hill-shaded SRTM 90m resolution and DLI 10 m resolution digital elevation data and discussions with government and industry geologists familiar with the local geology has resulted in the identification of thirty eight previously unrecognised linear topographic scarps in the southwest and central west of Western Australia. I contend that most of these relate to Quaternary surface-rupturing earthquakes. If validated, this more than doubles the number of Quaternary fault scarps known from this area, bringing the total to sixty. The newly recognised scarps average between 25 km and 50 km in length and from ~1.5 m to 20 m in height. The geometric, recurrence and spatial attributes of these features makes it possible to propose a model describing the causative seismicity. The model contends that uniform contractional strain in the ductile lithosphere manifests as localised, transient and recurrent brittle deformation in zones of pre-existing crustal weakness in the upper lithosphere. The data presented allow for ready calculation of the maximum probable magnitude earthquake for the southwest of Western Australia, and identify 'earthquake prone' regions of interest to seismic hazard assessors.

This is a compilation of all the processed multibeam bathymetry data that are publicly available in Geoscience Australia's data holding for the Macquarie Ridge.

This report is one of a series of environmental summaries of frontier basins, which are scheduled for acreage release during the timeframe of the 'Energy Security Initiative' (2007-2011). The aim of these reports is to synthesise the available environmental information to adequately equip the exploration industry to anticipate as many as possible of the environment-related issues that may impact on exploration and potential future production activities. The environmental information for the Vlaming Sub-basin and Mentelle Basin has been compiled and presented in a manner consistent with the Geographic Information System (GIS) provided with this report. The GIS includes the results of an analysis to obtain representative seascapes. Seascapes are the principal environmental output and in recent years assisted Department of Environment, Water, Heritage and the Arts with the design and implementation of a National Representative System of Marine Protected Areas for Australia (Section 1.1). The following section summarises the geological history of the Vlaming Sub-basin and Mentelle Basin and provides a tectonic and depositional context for the geophysical data and geomorphology of the sub-basin, which are discussed in Sections 3 and 4, respectively. The surface sediment properties are described in Section 5. These sections provide all of the information necessary to characterise benthic habitats. Section 6 discusses the oceanographic processes operating in the sub-basin, which influence both the benthic and pelagic ecology described in Section 7. Section 8 synthesises the information contained in the first seven sections into a seascape map of the Vlaming Sub-basin and Mentelle Basin.

The overarching theme of this book (and for the GeoHab organisation in general) is that mapping seafloor geomorphic features is useful for understanding benthic habitats. Many of the case studies in this volume demonstrate that geomorphic feature type is a powerful surrogate for associated benthic communities. Here we provide a brief overview of the major geomorphic features that are described in the detailed case studies (which follow in Part II of this book). Starting from the coast we will consider sandy temperate coasts, rocky temperate coasts, estuaries and fjords, barrier islands and glaciated coasts. Moving offshore onto the continental shelf we will consider sandbanks, sandwaves, rocky ridges, shallow banks, coral reefs, shelf valleys and other shelf habitats. Finally, on the continental slope and deep ocean environments we will review the general geomorphology and associated habitats of escarpments, submarine canyons, seamounts, plateaus and deep sea vent communities.

The late Quaternary ice sheet/ice shelf extent in the George V Basin (East Antarctica) has been reconstructed through analyses of Chirp sub-bottom profiles, integrated with multi-channel seismic data and sediment cores. Four glacial facies, related to the advance and retreat history of the glaciated margin, have been distinguished: Facies 1 represents outcrop of crystalline and sedimentary rocks along the steep inner shelf and comprises canyons once carved by glaciers; Facies 2 represents moraines and morainal banks and ridges with a depositional origin along the middle-inner shelf; Facies 3 represents glacial flutes along the middle-outer shelf; Facies 4 is related to ice-keel turbation at water depths <500 m along the outer shelf. A sediment drift deposit, located in the NW sector of the study area, partly overlies facies 2 and 3 and its ground-truthing provides clues to understanding their age. We have distinguished: a) an undisturbed sediment drift deposit at water depth >775 m, with drape/sheet and mound characters and numerous undisturbed sub-bottom sub-parallel reflectors (Facies MD1); b) a fluted sediment drift deposit at water depth <775 m, showing disrupted reflectors and a hummocky upper surface (Facies MD2). Radiocarbon ages of sediment cores indicate that the glacial advance producing facies MD2 corresponds to the Last Glacial Maximum (LGM) and that during the LGM the ice shelf was floating over the deep sector of the basin, leaving the sediment drift deposit undisturbed at major depths (Facies MD1). This observation further implies that: a) glacial facies underneath the sediment drift were the result of a grounding event older than the LGM, b) this sector of the East Antarctic fringe was sensitive to sea-level rise at the end of the LGM; thus potentially contributing to meltwater discharge during the last deglaciation.

In 1946 and 1947 the writer had excellent opportunities to study the effect of lateritisation in the course of geological reconnaissances in Northern Australia. From field evidence which has been collected on several aspects of lateritisation - origin, products and relationship to geomorphological processes - a detailed account of lateritisation in Australia can be given. Lateritisation and the occurrence of opal are discussed in this report.

This record is a review and synthesis of geological research undertaken along the south western margin of Australia. The record has been written in support of regional marine planning and provides fundamental baseline scientific information for the South Western Marine Planning Area.

For the first time, the distribution of seabed geomorphic features has been systematically mapped over the Australian margin. Each of 21 feature types was identified using a new, 250 m spatial resolution bathymetry model and supporting literature. The total area mapped was >8.9 million km2 and included the seabed surrounding the Australian mainland and island territories of Christmas, Cocos (Keeling), Macquarie and Norfolk Islands. Of this total, the shelf is >1.9 million km2 (21.92%), the slope >4.0 million km2 (44.80%), and the abyssal plain/deep ocean floor >2.8 million km2 (32.20%). The rise covers 97,070 km2 or 1.08% of the margin. A total of 6,702 individual geomorphic features were mapped on the Australian margin. Plateaus have the largest surface area and cover 1.49 million km2 or 16.54%, followed by basins (714,000 km2; 7.98%), and terraces (577,700 km2; 6.44%), with the remaining 14 types each making up <5%. Reefs, which total 4,172 individual features (47,900 km2; 0.54%), are the most numerous type of geomorphic feature, principally due to the large number of individual coral reefs of the Great Barrier Reef. The geomorphology of the margin is most complex where marginal plateaus, terraces, trench/troughs and submarine canyons are present. Comparison with global seabed geomorphology indicates that the Australian margin is relatively under-represented in shelf, rise and abyssal plain/deep ocean floor area and over-represented in slope area, a pattern that reflects the mainland being bounded on three sides by passive continent-ocean rifted margins and associated numerous subsided marginal plateaus. Significantly, marginal plateaus on the Australian margin cover 20% of the total world area of marginal plateaus. The Australian margin can be divided into 10 geomorphic regions by quantifying regional differences in diagnostic features that can be used to infer broad-scale seabed habitats. The present study has application for the future management of Australia's ocean resources.