The upper Renmark Group is a widespread non-marine succession of Miocene age in the Murray Basin. Unlithified and nowhere exposed, it is a poorly understood unit that provides a lower confining horizon to important aquifers in the overlying Calivil succession, and includes deeper aquifers exploited for water for mineral sands mining. The use of sonic drilling has allowed extensive coring of the previously poorly sampled unit, documentation of its facies and collection of a diverse assemblage of spores and pollen. The upper Renmark Group was deposited on a low relief sedimentary plain dominated by anastomosing fixed channel streams, flowing southward into a complex low energy coastal plain with numerous lagoons and bays. Hydrological connection between the more (Renmark) and less saline (Calivil) aquifers is low, except where Renmark channel sands immediately underlie the Calivil. In these areas can be a distinct salinity gradient from the Calivil down into the Renmark, indicating mixing. High water tables during deposition facilitated preservation of an unusually detailed record of inland Australian vegetation from this period. Late Early to Middle Miocene climates were wet and warm with low seasonality. These conditions supported complex rainforest communities dominated by (1) Nothofagus (Brassospora) spp. and gymnosperms on floodplains inland of the palaeoshoreline, or (2) Myrtaceae (Syzygium-type) and unidentified mangrove angiosperms in areas subjected to a marine influence. Many of the latter pollen types are very small (<10 micron diameter), resulting in the 10 micron-filtered extracts being dominated by larger types such as Casuarinaceae and Nothofagus (Brassospora) spp.

Lithostratigraphy, grain sizes and down-hole logs of Site 1166 on the continental shelf, and Site 1167 on the upper slope, are analyzed to reconstruct glacial processes in eastern Prydz Bay and the development of the Prydz trough-mouth fan. In eastern Prydz Bay upper Pliocene-lower Pleistocene glaciomarine sediments occur interbedded with open-marine muds and grade upward into waterlaid tills and subglacial tills. Lower Pleistocene sediments of the trough-mouth fan consist of coarse-grained debrites interbedded with bottom-current deposits and hemipelagic muds, indicating repeated advances and retreats of the Lambert Glacier-Amery Ice Shelf system with respect to the shelf break. Systematic fluctuations in lithofacies and down-hole logs characterize the upper Pliocene-lower Pleistocene transition at Sites 1166 and 1167 and indicate that an ice stream advanced and retreated within the Prydz Channel until the mid Pleistocene. The record from Site 1167 shows that the grounding line of the Lambert Glacier did not extend to the shelf break after 0.78 Ma. Published ice-rafted debris records in the Southern Ocean show peak abundances in the Pliocene and the early Pleistocene, suggesting a link between the nature of the glacial drainage system as recorded by the trough-mouth fans and increased delivery of ice-rafted debris to the Southern Ocean.

For the first time, the distribution of seafloor geomorphic features has been systematically mapped over much of the Australian margin and adjacent seafloor. Each of 21 feature types was identified using a new, 250 m spatial resolution bathymetry model and supporting literature. The total area mapped was 48.9 million km2 and included the seafloor surrounding the Australian mainland and island territories of Christmas, Cocos (Keeling), Macquarie and Norfolk Islands. Of this total mapped area, the shelf is 41.9 million km2 (21.92%), the slope 44.0 million km2 (44.80%) and the abyssal plain/deep ocean floor 42.8 million km2 (32.20%). The rise covers 97 070 km2 or 1.08% of the mapped area. A total of 6702 individual geomorphic features were mapped. 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 55%. Reefs, which total 4172 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 seafloor geomorphology indicates that the Australian margin is relatively under-represented in shelf and rise and over-represented in slope area, a pattern that reflects the mainland being bounded on three sides by rifted continent ocean margins and associated large marginal plateaus. Significantly, marginal plateaus on the Australian margin cover 20% of the total world area of marginal plateaus. The mapped area can be divided into 10 geomorphic regions by quantifying regional differences in diagnostic assemblages of features, and these regions can be used as a starting-point to infer broad-scale seafloor habitat types.

An important aim of the comparative geomorphology of estuaries project was to increase understanding of the environmental characteristics of near-pristine estuaries and provide a reference dataset for quantifying changes in habitat patterns in modified systems. It was anticipated that this aim would be fulfilled by identifying key geomorphic characteristics of the near-pristine systems that may be used to benchmark the current condition of, and quantify change within, 'modified' waterways. Here we provide examples of some very promising results obtained from our preliminary analyses of the geomorphic habitat area information contained within the GIS maps available on OzEstuaries.

International efforts to protect the Vulnerable Marine Ecosystems (VMEs) that live on cold seeps and hydrothermal vents requires methods to predict where these features might be in advance of human activity. We suggest an approach to identifying seeps and vents in the CCAMLR region that uses existing data to highlight areas of possible seep and vent communities. These hierarchical criteria can be used to reduce the accidental disturbance of seep communities. We propose a 4 level classification of indicators: Class 1 Areas: VME confirmed by recovery of organisms or observation (video, stills). This level would qualify for VME status and high levels of protection. Class 2 Areas: Seepage/venting present but VME not confirmed. These locations would have a number of indicators of active seepage but VMEs have not been identified. Class 3 Areas: Seepage suspected from geophysical, geochemical or oceanographic observations. These areas have seismic indications of shallow gas or clathrates , structures suggesting fluid escape but where bubble flares or water column plumes have not been detected or where plume has been detected but not tied to an area of sea floor. Class 4 Areas: Area or geomorphic features associated with seepage and vents. These areas are large-scale geomorphic features such as Mid-Ocean Ridge rift valleys or volcanoes where vents are likely but not yet detected. Class 3 and Class 4 areas have been mapped from 45oE to 160oE using global bathymetry grids and seismic data from the SCAR Seismic Data Library.

This report contains the preliminary results of Geoscience Australia marine reconnaissance survey TAN0713 to the east margin of Australia. The survey, completed as part of the Federal Government's Offshore Energy Program, was undertaken between 7 October and 22 November 2007 using the New Zealand government's research vessel Tangaroa. Leg 1 departed Wellington on 7 October and returned to Lord Howe Island on 27 October. Leg 2 departed Lord Howe Island on 28 October and returned to Wellington on 22 November.

This report presents the geomorphology and sedimentology of the East Marine Region. The three main outputs of the report include: 1) a review of previous geological research undertaken in the East Marine Region (EMR); 2) the results of a quantitative study of seabed sediment texture and composition for these regions; and 3) a synthesis of this information characterizing regional trends in sedimentology, geomorphology and bathymetry. The study is a collaboration between Geoscience Australia and the Department of the Environment, Water, Heritage and the Arts (DEWHA) and is a continuation of similar work conducted for the North West Marine Region (Potter et al., in press; Baker et al., 2008) and the South West Marine Region (Richardson et al., 2005). By combining results of previous qualitative work and quantitative information generated from existing and new data, this report provides an improved understanding of sedimentology for the EMR. Information contained within this report will contribute to the Department of the Environment, Water, Heritage and the Arts national work program and will also assist in the marine bioregional planning for the East Marine Region. Previous sediment studies in the EMR have predominantly produced qualitative results at local scales. Geomorphic, sedimentary and biological information has previously been utilised to develop a National Bioregionalisation of Australia's Exclusive Economic Zone (EEZ) (Department of the Environment and Heritage (National Oceans Office), 2005; now the Department of the Environment, Water, Heritage and the Arts) and substantive geomorphic features of the eastern continental margins have already been identified and mapped (Heap and Harris, in press). This report adds significantly to these previous studies by incorporating the information in a sedimentological synthesis that includes a discussion of the implications for marine conservation in the EMR. The physical characteristics of the seabed in the EMR, as described by the sediment texture and composition data, can assist in determining the diversity of benthic marine habitats in the EMR. These data represent enduring features which are elements of the physical environment that do not change considerably and they are known to influence the diversity of biological systems. This is important for marine conservation by contributing to the better definition and characterisation of benthic habitats. Seabed texture and composition are easily measurable parameters that when combined with other physical features can be used to create "seascapes" that serve as broad surrogates for benthic habitats and biota (Whiteway et al., 2007). Seascapes have the potential to be used in informing the marine bioregional planning process.

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

The 2004 Sumatra-Andaman Earthquake and Indian Ocean Tsunami shattered the paradigm that guided our understanding of giant subduction zone earthquakes: that massive, magnitude 9+ earthquakes occur only in subduction zones experiencing rapid subduction of young oceanic lithosphere. Although this paradigm forms the basis of discussion of subduction zone earthquakes in earth sciences textbooks, the 2004 earthquake was the final blow in an accumulating body of evidence showing that it was simply an artefact of a sparse and biased dataset (Okal, 2008). This has led to the realization that the only factor known to limit the size of megathrust earthquakes is subduction zone length. This new appreciation of subduction zone earthquake potential has important implications for the southern Asia-Pacific region. This region is transected by many thousands of km of active subduction, including the Tonga-Kermadec, Sunda Arc, and the Makran Subduction zone along the northern margin of the Arabian Sea. Judging from length alone, all of these subduction zones are capable of hosting megathrust earthquakes of magnitude greater than 8.5, and most could host earthquakes as large as the 2004 Sumatra-Andaman earthquake (Mw=9.3). Such events are without historical precedent for many countries bordering the Indian and Pacific Oceans, many of which have large coastal populations immediately proximate to subduction zones. This talk will summarize the current state of knowledge, and lack thereof, of the tsunami hazard in the southern Asia-Pacific region. I will show that 'worst case' scenarios threaten many lives in large coastal communities, but that in most cases the uncertainty in these scenarios is close to 100%. Is the tsunami risk in SE Asia and the SW Pacific really this dire as the worst-case scenarios predict? The answer to this question relies on our ability to extend the record of tsunamis beyond the historical time frame using paleotsunami research.

The Lower Darling Valley (LDV) Cenozoic sequence contains Paleogene and Neogene shallow marine and shoreline as well as fluvial and shoreline sediments overlain by Quaternary lacustrine, aeolian and fluvial units. Recent investigations in the LDV using multiple datasets have provided new insights into the nature of post-Blanchetown Clay Quaternary fluvial deposition which differs to the Mallee and Riverine Plain regions elsewhere in the Murray Basin. In the LDV Quaternary fluvial sequence, multiple scroll-plain tracts are incised into higher, older and more featureless floodplain terrain. Prior to this study, these were respectively correlated to the Coonambidgal and Shepparton Formations of the Riverine Plain in the eastern Murray Basin. These formations were originally associated with the subsequently discarded Prior Stream/Ancestral River chronosequence of different climatically controlled depositional styles. In contrast to that suggestion, we ascribe all LDV Quaternary fluvial deposition to lateral-migration depositional phases of one style, though with variable stream discharges and channel and meander-scroll dimensions. Successively higher overbank-mud deposition through time obscures scroll traces and provides the main ongoing morphologic difference. A new morphostratigraphic unit, the Menindee Formation, refers to mostly older and higher floodplain sediments, where scroll traces are obscured by overbank mud which continues to be deposited by the highest modern floods. Younger inset scroll-plain tracts, with visible scroll-plain traces, are still referred to as the Coonambidgal Formation. Another new stratigraphic unit, the Willotia beds, refers to even older fluvial sediments, now above modern floodplain levels and mostly covered by aeolian sediments.