The Oceanic Shoals Commonwealth Marine Reserve (CMR) (>71,000 km2) is located in the Timor Sea and is part of the National Representative System of Marine Protected Areas of Australia. The Reserve incorporates extensive areas of carbonate banks and terraces that are recognised in the North and North West Marine Region Plans as Key Ecological Features (KEFs). Although poorly studied, these banks and terraces have been identified as potential biodiversity hotspots for the Australian tropical north. As part of the National Environment Research Program Marine Biodiversity Hub, Geoscience Australia in collaboration with the Australian Institute of Marine Science undertook a marine biodiversity survey in 2012 to improve the knowledge of this area and better understand the importance of these KEFs. Amongst the many activities undertaken, continuous high-resolution multibeam mapping, video and still camera observations, and physical seabed sampling of four areas covering 510 km2 within the western side of the CMR was completed. Multibeam imagery reveals a high geomorphic diversity in the Oceanic Shoals CMR, with numerous banks and terraces, elevated 30 to 65 m above the generally flat seabed (~105 m water depth), that provide hard substrate for benthic communities. The surrounding plains are characterised by fields of depressions up to 1 m deep (pockmarks) formed in soft silty sediments that are generally barren of any epibenthos (Fig .1). A distinctive feature of many pockmarks is a linear scour mark that extends several tens of metres (up to 150 m) from pockmark depressions. Previous numerical and flume tank simulations have shown that scouring of pockmarks occurs in the direction of the dominant near-seabed flow. These geomorphic features may therefore serve as a proxy for local-scale bottom currents, which may in turn inform on sediment processes operating in these areas and contribute to the understanding of the distribution of biodiversity. This study focused on characterising these seabed scoured depressions and investigating their potential as an environmental proxy for habitat studies. We used ArcGIS spatial analyst tools to quantify the features and explored their potential relationships with other variables (multibeam backscatter, regional modelled bottom stress, biological abundance and presence/absence) to provide insight into their development, and contribute to a better understanding of the environment surrounding carbonate banks. Preliminary results show a relationship between pockmark types, (i.e. with or without scour mark) and backscatter strength. This relationship suggests some additional shallow sub-surface control, mainly related to the presence of buried carbonate banks. In addition, the results suggest that tidal flows are redirected by the banks, leading to locally varied flow directions and 'shadowing' in the lee of the larger banks. This in turn is likely to have an influence on the observed density and abundance of benthic assemblages.

We undertook a biological data acquisition program as part of the transit of the R.V. Southern Surveyor between Darwin and Cairns 15-24 October 2012. The overarching aim of this program was to use an ROV and benthic sled to collect benthic marine information and specimens for biodiversity and biodiscovery research in areas previously mapped by Geoscience Australia during survey GA-276, including a bank (Area I) and terrace/hole feature within the proposed Wessel Islands CMR (Area II). This study focuses on sessile invertebrates such as sponges and octocorals due to their ecological importance as habitat providers and their chemical importance as sources of marine natural products and medicines. In less than 24 hours of sampling effort, survey SS2012/t07 resulted in 261 voucher specimens which will be used for biodiversity and natural products research. A total of 49 samples are to be lodged at the ABL, and samples with weights larger than 300 g will be sent to the NCI for screening of active compounds against cancer and HIV. Sponges were the most abundant group collected based on both biomass (~ 139 kg) and number of voucher specimens (93), followed by cnidarians (30 kg, 73 vouchers), particularly hard corals (23 kg, 11 vouchers). As expected the top of the bank in Area I had a seemingly diverse and abundant sessile invertebrate community, with consistent patchy occurrence of sponges, octocorals, and hard corals. The terrace at in Area II supports moderate densities of sponges and octocorals, while the adjacent deep hole at ~ 100 m seems to be covered with muddy gravel and supports scattered mobile and sedentary invertebrates, of which crinoids dominate, as well as skates and numerous small demersal fish.

The Natural Variability Sub-program of the Co-operative Research Centre for Antarctic and Southern Ocean Environments aims to study past environmental change by examining ice core and sedimentary records in Antarctica and the Southern Ocean. As the first stage in marine sedimentological studies, Voyage 7 of the Australian National Antarctic Research Expeditions (ANARE) 1992/1993 shipping season included a geoscience program comprising echo sounder traverses, gravity coring and grab sampling of the Antarctic continental shelf and slope on the Mac. Robertson Shelf and in Prydz Bay. This record describes the preliminary results of the voyage and presents location information for core and grab samples and preliminary descriptions of grab samples and lists of subsamples taken by associated research programs.

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This record is a summary of the preliminary results of the second AGSO/Antarctic Co-operative Research Centre/ANARE marine geoscience program in Prydz Bay, the Mac.Robertson Shelf, Antarctica and the Kerguelen Plateau (Fig.1). The cruise program consisted of activities aimed at understanding modern sedimentary processes on the Antarctic margin, understanding the Plio-Pleistocene environmental history of the region and obtaining samples from the Kerguelen Plateau to illuminate the history of water mass reorganisation in the Southern Ocean during Quaternary climate change episodes. The cruise is designated AGSO survey 149 in AGSO's data bases and has the acronym BANGSS (Big ANtarctic Geology and Seismic Survey) in Antarctic Division data sets. The cruise program set out in O'Brien et al., (1995) was to meet the common goal of the Antarctic CRC Natural Variability (sediments) sub-program and the ASAC strategic plan for Antarctic Geosciences which is to promote a better understanding of global climate change by providing statements of the Antarctic and Southern Ocean palaeoenvironments over the following time intervals: (A)0-10,000 years (post-glacial warming) (B)0-160,000 years (last glacial cycle) (C) 0-5,000,000 years (Pliocene "warming" of Antarctica). Studies of modern sediment transport and modern organisms that contribute to Quaternary sediments were designed to aid the understanding of the ancient sedimentary record and the modern Antarctic environment. Seismic lines and sampling on this cruise were also expected to provide insights into the tectonic and stratigraphic development of the parts of the Antarctic margin. The three features targeted for study during the cruise were: (A) the trough-mouth fan deposits adjacent to Prydz Bay; (B) sediment traps associated with deep, shelf-basins on the Mac.Robertson Shelf; and (C) sediments on the Kerguelen Plateau. These features were selected because in anticipation that they should provide insights into Antarctic environmental history. Sediments deposited in Prydz Bay should contain a record of ice sheet fluctuations because of their location at the downstream end of the largest outlet glacier draining from the East Antarctic Ice Sheet, the Lambert Glacier. The Mac.Robertson Shelf, in contrast, was glaciated by ice originating entirely in the adjoining coastal region. It also contains deep basins that contain thick Holocene sediments that are useful in the detailed study of post-glacial environmental change. The Southern Ocean is a major component of the global climate system. Its water masses play a pivotal role by absorbing, transporting and releasing heat and by transferring oxygen, nutrients and CO2 to and from the deep ocean. In this context, the Kerguelen Plateau has accumulated sedimentary sequences that will contain records of how the Polar Front and its associated water masses have varied between glacial and interglacial periods.

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Geoscience Australia is custodian of ship-track magnetic and gravity data from close to 700 marine surveys conducted between 1960 and 2009. These data were last combined and levelled in the late 1990s. New levelling has been motivated by specific requirements within projects being conducted as part of the Australian Government's Energy Security Program (2006-2011). These projects rely on marine potential-field datasets to help constrain sediment thickness and basement architecture in remote offshore basins. Recently-levelled datasets cover: 1) the Capel and Faust basins, deepwater basins about 800 km off the east coast, and 2) the southwest margin of the Australian continent. The levelling involved the following steps: consistent computation of gravity anomalies; splitting lines into straight-line segments to facilitate cross-over computations; low-pass line filtering where necessary; editing to remove problematic ship-tracks; and levelling to minimise cross-over misties. Using methods developed by Intrepid Geophysics for the late-1990s Australia-wide work, magnetic data were levelled by minimising misclosures around loops and then gridded and merged with aeromagnetic data in onshore and near-shore areas. Gravity data were levelled using a polynomial technique and satellite-altimeter-derived gravity data as a reference surface. The resulting levelled datasets provide information at a higher-resolution than is available from satellite-derived gravity measurements or from global compilations of magnetic data. Despite this, the levelled datasets are limited to areas of specific scientific or exploration interest, which highlights the need for levelled datasets that cover the whole of Australia's marine jurisdiction.

Geoscience Australia has recently completed a marine survey in the offshore northern Perth Basin, off Western Australia (Jones et al., 2011b; Jones, 2011c, Upton and Jones, 2011). One of the principal aims of the survey was the collection of evidence for natural hydrocarbon seepage. The survey formed part of a regional reassessment of the basin's petroleum prospectivity in support of frontier exploration acreage Release Area W11-18. This reassessment was initiated under the Australian Government's Offshore Energy Security Program and formed part of Geoscience Australia's continuing efforts to identify a new offshore petroleum province. The offshore northern Perth Basin was identified as a basin with new frontier opportunities. New data demonstrated that proven onshore-nearshore petroleum system is also effective and widespread in the offshore (Jones et al., 2011a). Evidence for a Jurassic petroleum system was also demonstrated in the Release Area W11-18 (Jones et al., 2011a). The marine survey results provide additional support for the presence of an active petroleum system in the northern Perth Basin.