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  • Map showing the Geomorphic Features of the Australian Margin and Island Territories. The features were interpreted from Geoscience Australia's 250 m horizontal bathymetry model and other published data, and include those specified in the International Hydrographic Office definitions.

  • Multibeam sonar mapping, underwater video and drill-cores have revealed the existence of widespread submerged coral reefs in the southern Gulf of Carpentaria, Australia. Seven reefs have been mapped to date using multibeam sonar and existing bathymetry data indicates as many as 50 other reefs may be present. The reefs are 14 to 30 m below present sea level and therefore invisible to optical remote sensing tools, which explains why they have only recently been identified. The time of colonisation and reef growth commenced in the early Holocene (11 to 10.5 kyr BP) and growth rates of 0.95 to 4 m kyr-1 were attained but reef growth had stopped in most locations by around 8.0 kyr BP, showing a classic "give-up" reef growth history. Reef growth in the late Holocene (2-3 kyr BP) was measured at only one of the reef sites. Our study reveals that the reefs in the southern Gulf of Carpentaria have some of the deepest Pleistocene foundations, the oldest framework coral and shortest-lived Holocene section known in Australia.

  • This record summarises the physical environments of the seabed for the Ceduna and Eyre Sub-basins.

  • This report describes the field survey carried out in Cockburn Sound, Western Australia by Geoscience Australia (GA) staff for the Coastal Geomorphology and Classification Subproject (CG) of the Coastal Water Habitat Mapping Project (CWHM). It documents the various sampling techniques and procedures used to collect surface and subsurface samples from the Sound; details of the vibracores and grab samples recovered and the proposed analyses to be performed on these samples. The results of the analysis of the grab samples will be used to classify the various surface sediment types encountered as well as map their distribution within Cockburn Sound. The analysis and interpretation of the vibracores will allow the reconstruction of the stratigraphic framework of Cockburn Sound. This information will be used in conjunction with the findings of the other subprojects in the CWHM Project. For example, it will assist in ground-truthing the results of the both the single and multi-beam sonar surveys that have and are to be carried out within Cockburn Sound by Curtin University. It will also provide key substrate information for incorporation into a more comprehensive benthic habitat classification for the sound.

  • Antarctic ice shelves and fast flowing ice streams are key drainage features of the Antarctic Ice Sheet and their behaviour determines the sensitivity of the ice sheet to climate change and sea level rise. Some fast flowing ice streams are thinning rapidly and could be the 'soft underbelly' of the East Antarctic Ice sheet. Processes across the grounding zone are important in understanding the retreat behaviour of ice streams but are poorly understood because of the difficulty of accessing the region. The Antarctic Shelf preserves geomorphic features and sedimentary structures left by ice retreat which can provide insights into processes in and close to the grounding zone. Sidescan sonar records from Prydz Bay image a range of features that reflect changes in processes across the Amery Ice Shelf grounding zone during retreat after the Last Glacial Maximum. The major features identified are: Mega-scale Glacial Lineations Linear ridges of sediment formed by moulding of mobile subglacial sediment parallel to ice flow. Flutes and Mega flutes - Smaller linear ridges moulded by ice flow. Inter-flute dunes - Large bedforms formed by bottom currents flowing the grounding zone in the sub-ice shelf cavity. Transverse steps - Ice flow parallel ridges that terminate in steps running oblique to normal to the ice flow direction. Sinuous ridges (Eskers) - Gently sinuous ridges that run generally parallel to obliquely across fluted surfaces. Polygonal crevasse infills - Irregular polygonal ridges on the crest of grounding zone wedges. The presence of fluted and mega-scale glacial lineations indicates that the ice moved over an unfrozen, deforming bed in the zone up stream of the grounding zone. For most of the Amery Ice Shelf, the inter-flute dunes reflect strong thermohaline circulation in the ice shelf cavity. Sand and gravel recovered in cores from beneath the Amery Ice Shelf indicate significant current speeds, possibly enhanced by tidal pumping.

  • The Australian continent is actively deforming in response to far-field stresses generated by plate boundary interactions and buoyancy forces associated with mantle dynamics. On the largest scale (several 103 km), the submergence of the northern continental shelf is driven by dynamic topography caused by mantle downwelling along the Indo-Pacific subduction system and accentuated by a regionally elevated geoid. The emergence of the southern shelf is attributed to the progressive movement of Australia away from a dynamic topography low. On the intermediate scale (several 102 km), low-amplitude (c. 100–200 m) long-wavelength (c. 100–300 km) topographic undulations are driven by (1) anomalous, smaller-scale upper mantle convection, and/or (2) lithospheric-scale buckling associated with plate boundary tectonic forcing. On the smallest scale (101 km), fault-related deformation driven by partitioning of far-field stresses has modified surface topography at rates of up to c. 170 m Ma-1, generated more than 30–50% of the contemporary topographic relief between some of Australia’s highlands and adjacent piedmonts, and exerted a first-order control on long-term (104–106 a) bedrock erosion. Although Australia is often regarded as tectonically and geomorphologically quiescent, Neogene to Recent tectonically induced landscape evolution has occurred across the continent, with geomorphological expressions ranging from mild to dramatic.

  • In this review we aim to synthesise physical and biological information on the Lord Howe Rise (LHR) region to describe its biogeography at a regional scale (100s of kilometres) and assess this in a national and global context. The LHR region is large (1.95 million km2), spans tropical and cool temperate latitudes (18.4oS to 40.3oS), and is topographically complex being formed of large expanses of soft sediment basins and plateaus (i.e. subdued bathymetric features), with scattered seamounts, guyots, knolls, and pinnacles (i.e. raised bathymetric features). Physical factors can vary between these two broad feature types, particularly regarding depth and substrate, although no clear relationship was detected between sediment texture and geomorphic features across the survey area. Biological data from two recent surveys (TAN0713 and NORFANZ) show differences in assemblages and species distribution between raised and subdued bathymetric features and suggest that biological communities are indeed influenced by substrate as well as depth-related variables, with some taxa such as demersal fish showing latitudinal gradients. There are only limited spatially-replicated studies and no time-series data available for most of the LHR region, but paleo-environmental processes and examples from other regions provide some indication of migration, speciation, and endemism in the LHR region.

  • Measurements of water turbidity, currents, seafloor sediment samples and geophysical data document the sedimentary processes and the Late Quaternary sedimentary history of a continental shelf valley system on the East Antarctic continental margin.

  • Salt lakes, also known as playa lakes, are a common feature of the Australian landscape, and are a strong indicator of our current and past climates. Despite their abundance they have not been extensively studied in Australia, with little research undertaken since the early benchmark work of the 1970s - 1980s (e.g. Bowler, 1971, 1981) which largely focussed on geomorphologic evolutionary patterns and trends. Notwithstanding, salt lakes contain some of the highest levels biological endemism in Australia (DeDecker, 1983) and their unique, and commonly extreme, chemistry offers the potential for distinctive saline mineralisation and potentially economic concentrations of Li, K, B, REEs, Br and U (e.g. Butt et al. 1984; Nissenbaum, 1993; Orris, 2011).