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).

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.

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.

Geomorphic banks were mapped in this study based on a GIS analysis of a 100 m bathymetry grid for the Great Barrier Reef produced by Beaman (2010). The bathymetric data were contoured at 5 m intervals and used to interpret the location of geomorphic bank features, defined as having at least one steep (i.e. greater than ~2 degrees) slope rising more than 15 m above the level of surrounding seafloor. All banks were digitised by hand aided using three-dimensional imagery. Bank polygons were created in ArcGIS with the base of slope taken as the outer edge of the bank. Mean bank elevation estimates thus include the bank slopes as well as planar bank-tops. Only banks occurring on the continental shelf of the Great Barrier Reef between the 20 and 200 m isobaths, and between the latitudes of 10 to 25° S were included. Disclaimer: Geoscience Australia gives no warranty regarding the data downloads provided herein nor the data's accuracy, completeness, currency or suitability for any particular purpose. Geoscience Australia disclaims all other liability for all loss, damages, expense and costs incurred by any person as a result of relying on the information in the data downloads.

The Lower Darling Valley (LDV) contains Cenozoic shallow marine, fluvial, lacustrine and aeolian sediments capped by a number of Quaternary fluvial units associated with the Darling River and its anabranches, which were poorly dated prior to this study. Recent investigations in the LDV area have used an Airborne Electromagnetic (AEM) survey, a new high-resolution LiDAR survey, sonic drilling, shallow hand-augering, examination of tractor-dug pits, sediment sample analyses, landform mapping, and river bottom profiling in combination with OSL and radiocarbon dating to provide new insights into the nature and chronology of Quaternary fluvial landscape evolution. The Quaternary sequence in the LDV consists of scroll-plain tracts of different ages incised into higher, older and more featureless floodplain sediments. Samples for OSL and radiocarbon dating were taken in tractor-excavated pits, from sonic cores and from hand-auger holes from a number of scroll-plain and older floodplain sediments. The youngest, now inactive, scroll-plain phase associated with the modern Darling River, was active in the period 5-2 ka. A previous anabranch scroll-plain phase has Last Glacial Maximum dates around 20 ka. Less distinct scroll-plain tracts, older than the anabranch system, have ages around 30ka. A poorly preserved scroll-plain phase with very indistinct scroll and channel traces is associated with the Darling River tract and has ages around 45-50 ka. Older dates of 85 ka and >150 ka have been obtained beneath the higher floodplain from lateral-migration sediments that lack visible scroll-plain traces. This chronologic sequence suggests regular recurrence of approximately 5 ka lateral-migration episodes separated by approximately 10 ka periods of quiescence. There is a lack of coincidence with the glacial-interglacial climate cycles. This suggests that the onset and termination of lateral-migration phases is probably a combination of changes in discharge and sediment regimes r

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.

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.

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.

A geological investigation was carried out by the writer. The aim was to check the previous mapping of the geology, and if necessary, to assist the Magnetician in locating a suitable site for magnetic observations. Some aspects of geomorphology, and the reconnaissance survey work carried out are discussed in this report.

During the summer of 1947, an expedition was despatched to Heard Island with the object of landing a party to spend about twelve months there. Geological work was undertaken by the writer. The results of this work are recorded in this report. These results include observations on the geomorphology of the island, and a description of the xenolithic ejectamenta collected from the tuffs of Rogers Head and Rogers Head Peninsula.