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  • Geoscience Australia carried out a marine survey on Carnarvon shelf (WA) in 2008 (SOL4769) to map seabed bathymetry and characterise benthic environments through colocated sampling of surface sediments and infauna, observation of benthic habitats using underwater towed video and stills photography, and measurement of ocean tides and wavegenerated currents. Data and samples were acquired using the Australian Institute of Marine Science (AIMS) Research Vessel Solander. Bathymetric mapping, sampling and video transects were completed in three survey areas that extended seaward from Ningaloo Reef to the shelf edge, including: Mandu Creek (80 sq km); Point Cloates (281 sq km), and; Gnaraloo (321 sq km). Additional bathymetric mapping (but no sampling or video) was completed between Mandu creek and Point Cloates, covering 277 sq km and north of Mandu Creek, covering 79 sq km. Two oceanographic moorings were deployed in the Point Cloates survey area. The survey also mapped and sampled an area to the northeast of the Muiron Islands covering 52 sq km. cloates_3m is an ArcINFO grid of Point Cloates of Carnarvon Shelf survey area produced from the processed EM3002 bathymetry data using the CARIS HIPS and SIPS software

  • This service has been created specifically for display in the National Map and the chosen symbology may not suit other mapping applications. The Australian Topographic web map service is seamless national dataset coverage for the whole of Australia. These data are best suited to graphical applications. These data may vary greatly in quality depending on the method of capture and digitising specifications in place at the time of capture. The web map service portrays detailed graphic representation of features that appear on the Earth's surface. These features include the administration boundaries from the Geoscience Australia 250K Topographic Data, including state forest and reserves.

  • It is proposed to acquire up to approximately 4000 km of deep crustal seismic data across the offshore Otway Basin in the period from early December 1994 to late January 1995. The principal goals of the survey (AGSO Survey 137) are to determine the deep crustal architecture of the offshore Otway Basin, to characterise the linkages between the Otway Basin and the flanking Bass Basin, Kanmantoo High and oceanic crust, and thereby to characterise the large scale extensional processes which led to the development of the Otway Basin as part of the larger Southern Rift System. In addition, the survey is designed to test many of the newer concepts which have arisen from the interpretation of AGSO's recently acquired aeromagnetic data. The integration of the deep crustal seismic and the aeromagnetic data sets should significantly enhance our understanding of the basin architecture, as well as provide new insights into the usefulness of high resolution aeromagnetic data in sedimentary basins. In order to constrain crustal velocities, seismic refraction data will be recorded on key lines. In line with recent AGSO deep-seismic surveys, the Otway Basin survey will use a 4800 m streamer, configured with 192 x 25 m active groups; data will be recorded with a 16 second record length, and a 2 millisecond sample interval; the seismic source will be tuned airgun arrays with a total capacity of 49 litres, and will be fired every 50 metres to give 48-fold CDP coverage. Navigation will be by differential GPS. Using these parameters on the North West Shelf and in the Gippsland Basin, AGSO has consistently obtained high-quality deep seismic data, with interpretable reflectors down to 8-12 s 'FWT, as well as obtaining good resolution in the upper 6 s of seismic data, which is normally the limit recorded by industry.

  • In 2010 the UN General Assembly appointed a Group of Experts to carry out the first cycle of the Regular Process from 2010 to 2014. The immediate tasks for the Group of Experts include preparing a draft outline for the First Global Integrated Marine Assessment (the Assessment) and to design a process for drafting and reviewing it. Producing the Assessment will be a major undertaking that will have to involve many hundreds of marine experts from around the world in order to succeed. The purpose of this paper is to describe the rationale behind the draft outline for the Assessment and to explain the process envisaged for producing it by the 2014 deadline. It is emphasised that the Assessment outline is a work in progress and that amendments will be made prior to the commencement of its drafting.

  • Recent field observations have identified the widespread occurrence of fluid seepage through the eastern Mediterranean Sea floor in association with mud volcanism or along deep faults. Gas hydrates and methane seeps are frequently found in cold seep areas and were anticipated targets of the MEDINAUT/MEDINETH initiatives. The study presented herein has utilized a multi-disciplinary approach incorporating observations and sampling of visually selected sites by the manned submersible Nautile and by ship-based sediment coring and geophysical surveys. The study focuses on the biogeochemical and ecological processes and conditions related to methane seepage, especially the anaerobic oxidation of methane (AOM), associated with ascending fluids on Kazan mud volcano in the eastern Mediterranean. Sampling of adjacent box cores for studies on the microbiology, biomarkers, pore water and solid phase geochemistry allowed us to integrate different biogeochemical data within a spatially highly heterogeneous system. Geophysical results clearly indicate the spatial heterogeneity of mud volcano environments. Results from pore water geochemistry and modeling efforts indicate that the rate of AOM is 6 mol m-2 year-1, which is lower than at active seep sites associated with conditions of focused flow, but greater than diffusion-dominated sites. Furthermore, under the non-focused flow conditions at Kazan mud volcano advective flow velocities are of the order of a few centimeters per year and gas hydrate formation is predicted to occur at a sediment depth of about 2 m and below. The methane flux through these sediments supports a large and diverse community of micro- and macrobiota, as demonstrated by carbon isotopic measurements on bulk organic matter, authigenic carbonates, specific biomarker compounds, and macrofaunal tissues...

  • Geoscience Australia is currently conducting a study under the National CO2 Infrastructure Plan (NCIP) to assess suitability of the Vlaming Sub-basin for CO2 storage. It involves characterisation of the potential seal, the Early Cretaceous South Perth Shale (SPS), by integrating seismic and well log interpretation into a sequence stratigraphic framework. The SPS, conventionally described as a regional seal deposited during a post-rift thermal subsidence phase, consists of a series of prograding units deposited in a deltaic to shallow marine setting. Mapping of the SPS has revealed differences in the geometries of progradational sequences between the northern and southern areas, related to the type and distance to the sediment source as well as the seafloor morphology. In the northern area, deltaic progradation and aggradation occurred over a flat topography between the two uplifted blocks. The succession is composed of prograding sequences commonly exhibiting sigmoidal to oblique geometries, prograding from the north-east to south-west. In the southern area the topography is more complex due to the presence of several paleotopographic highs associated with pre-existing structures. These sequences are sigmoidal to oblique in cross section. They were deposited in fan shaped lobes, successively infilling paleotopographic lows. Direction of the progradation is from southwest to northeast. The thickness of the SPS varies from 200 m between topographic highs to 700 m in the lows. Sedimentary facies are interpreted to vary from sandy delta front to muddy slope and prodelta deposits. These findings will be used in a 3D geological model for assessing CO2 storage potential.

  • Project 121.30 - "Lord Howe Rise and Norfolk Ridge 'Law of Sea' Study" -was initiatedto improve our understanding of the geological framework of the southern part of theLord Howe Rise region, in the vicinity of the Australia/New Zealand seabed boundary zone. The major objectives of the project are: To investigate the structure, stratigraphy and basin development of the southern LordHowe Rise, southern New Caledonia Basin and the West Norfolk Ridge. To assess the resource potential of the major structural features within the region. To determine the tectonic framework, crustal characteristics and evolution of the region, and attempt to understand the processes that have produced narrow strips of thinned and extended continental lithosphere ("ribbon continents") separated bynarrow ocean basins. To acquire data to assist with the definition of Australia's 'legal' Continental Shelf on the southwestern margin of the Lord Howe Rise. Because of the presence of Lord Howe Island and Norfolk Island, Australia has laid claim to a large part of the seabed in the region, enveloped by a 200 nautical mile Exclusive Economic Zone (EEZ) around each island, plus areas of 'legal' ContinentalShelf beyond the EEZ. The total area of Australia's 'legal' Continental Shelf in the Lord Howe Rise region would be about 1.65 million km2. While the seabed boundary in the northern part of the region has been negotiated between Australia and France, there is not, as yet, a negotiated boundary between Australia and New Zealand in the southernLord Howe Rise/West Norfolk Ridge region. The proposal for Survey 114 was to acquire approximately 3250 km of multichannelseismic and associated geophysical data. The data was acquired mainly on longregional lines, two of which extended from the Tasman Basin to the Norfolk Basin, using a 3000 m streamer (120 x 25 m groups), 49 litre sleeve gun arrays, 16 secondrecords, and 30-fold coverage. The ship departed Sydney at 2000 hrs on Friday, 6 November 1992, and, after transitingthrough rough seas, arrived in the study area on the evening of 9 November. The cablewas deployed and balanced by midnight, 10 November. The next twenty one days wasspent shooting deep crustal (16 sec.) seismic . During this period a total of 3191 km ofseismic was shot, over 70% with two gun arrays operating. This was achieved in spiteof 3.5 days loss as a result of bad weather and 20 hours loss for cable repairs as a resultof fish bites. Seismic acquisition ceased on the afternoon of 1 December. The shipreturned to Sydney at 1730 hrs on Thursday, 3 December. Overall, the quality of the seismic data was very good. When shooting the two verylong lines, the weather remained reasonably calm, and so noise levels were withinspecifications.

  • The Perth Basin formed as part of an obliquely-oriented extensional rift system on Australia's southwestern margin during the Paleozoic to Mesozoic breakup of eastern Gondwana. The Houtman Sub-basin is situated in the offshore portion of the northern Perth Basin, located about 200 km northwest of Perth. It is an elongate, northwest-southeast trending depocentre containing up to 14 km of Early Triassic to Late Jurassic sedimentary strata. A detailed sequence stratigraphic study has been undertaken on the three wells in the Houtman Sub-basin: Gun Island 1, Houtman 1 and Charon 1. The purpose of this study was to investigate facies variations between the wells to gain a better understanding of potential source, reservoir and seal distribution and to assist regional palaeogeographic reconstructions of the Perth Basin. The study focussed on the Early-Late Jurassic succession comprising the Cattamarra Coal Measures, Cadda Formation and Yarragadee Formation. Wireline log character, cuttings, sidewall core and conventional core lithologies and palynological data were used to identify facies and paleoenvironments. Palynology for all wells has been reviewed, including new data collected by Geoscience Australia for Gun Island 1 and Charon 1. Facies stacking patterns were used to define systems tracts and subsequently ten third-order depositional sequences. Collectively these sequences define a larger scale, second-order (supersequence) transgressive-regressive cycle. The Cattamarra Sequence Set forms a regional transgression which culminates in an extensive marine maximum flooding event within the Cadda Sequence Set. These sequence sets are followed by the regressive highstand Yarragadee Sequence Set. The third-order sequences characterised in this study overprint this supersequence and control the local distribution of facies. The combined influence of these third- and second-order sequences on facies distribution has significant implications for the distribution of potential reservoirs and seals, particularly in the northern Houtman Sub-basin where well and seismic data are relatively sparse.

  • The Tasmante cruise (AGSO Cruise 125) started in Auckland on 12 February 1994, and ended in Adelaide on 29 March 1994 (Fig. 1). The cruise used the French research vessel l'Atalante on an exchange basis. The French vessel was used rather than Rig Seismic because of the wide-angleswath-mapping capability of its SIMRAD EM12D system. Data were recorded on transits, as well as off Tasmania, our main area of interest (Figs. 1 & 2). The swath-mapping system functioned well throughout. The maps produced are mostly at 1:250 000 scale, and cover the transit from New Zealand (T1-77), the detailed survey off Tasmania (C1-C7), and the transit to Adelaide (T8-T9). The suite of maps generally includes ship tracks, sonar imagery, detailed and less detailed contour maps (25 and 50 m contours), and an overlay of sonar imagery on the less detailed contours. In addition, 1:1 000 000 scale maps of the entire Tasmanian survey area were produced of bathymetry (50 m contours) and imagery. Finally, 1:100 000 scale maps were provided of two fisheries areas off Tasmania: 20 m contours and imagery in thesouth, and 20 m contours in the west.

  • Map showing the offshore petroleum blocks in the Shared Area of the Perth Treaty. Also supplied was 1 Excel spreadsheet containing the listing of the blocks within this area. Requested by NOPTA 5th December 2012. LOSAMBA register 675.