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.

Geoscience Australia has the primary role in the delineation of Australia's domestic and international maritime limits and boundaries. An output of this activity is the development of the Australian Maritime Boundaries (AMB) data. AMB is a GIS data product, replacing AMBIS 2006, providing access to the data for Australia's maritime zones. AMB is a digital representation of Australia's limits and boundaries as established under the Seas and Submerged Lands Act 1973 and associated proclamations. The data also include a representation of the limits by which the scheduled and offshore areas of each of the States and of the Northern Territory are determined under the Offshore Petroleum and Greenhouse Gas Storage Act 2006 (OPGGSA). In the event of an inconsistency between AMB data and the limits under any legislation, the latter prevails. The data have been published by Geoscience Australia in consultation with other relevant Commonwealth Government agencies including the Attorney-General's Department, the Department of Foreign Affairs and Trade and the Australian Hydrographic Office. AMB data comprise the territorial straight baselines and the outer limits of each zone, together with maritime boundaries determined by treaties between Australia and neighbouring countries. All data coordinates are supplied in the GDA94 datum. The data reflects the location of the coastline within the constraints of available source material at the time of production. AMB Data can also be viewed on-line via AMSIS (http://www.ga.gov.au/marine/jurisdiction/amsis.html). Product Specifications Coverage: Australia including all external territories Currency: May 2014. Coordinates: Geographical Datum: GDA94 (functionally equivalent to WGS84). Format: ESRI Geodatabase and REST web service - free online.

Geoscience Australia undertook seabed mapping surveys in the eastern Bonaparte Gulf in 2009/2010 to deliver integrated information relevant to marine biodiversity conservation and offshore infrastructure development. The survey objectives were to characterise the physical, chemical and biological properties of the seabed, document potential geohazards and to identify unique or sensitive benthic habitats and collect baseline information on these habitats. Different clustering methods were applied to a 124 sample dataset comprising 74 physical and geochemical variables which describe organic matter (OM) reactivity/quantity/source and geochemical processes relevant to biodiversity. Infauna data were used to assess different groupings because they are an important food source for epibenthic crustaceans and fish and purveyors of ecosystem services including nutrient cycling and mineralisation. Clusters based on physical/geochemical data discriminated infauna better than geomorphic features. Major variations amongst clusters included grainsize and a cross-shelf transition in from authigenic-Mn /As enrichments (inner shelf) to authigenic-P enrichment (outer shelf) which relate to energy levels and sediment oxygen status. Groups comprising raised features had the highest reactive OM concentrations (e.g. based on low chlorin indices and C:N-ratios, and high k) and benthic algal -13C signatures. Surface area normalised OM concentrations higher than continental shelf norms were observed in association with: (i) low -15N, inferring Trichodesmium input; and (ii) pockmarks. The pockmarks are shown to impart bottom-up controls on seabed chemistry and cause inconsistencies between bulk and pigment OM pools. The geochemical data and clustering methods provide insight into ecosystem processes which influence biodiversity patterns in the region. Low Shannon-Wiener diversity occurred in association with low porewater pH and evidence for low sediment redox status and high energy levels, while the highest beta-diversity was observed at euphotic depths. Pair-wise ANOSIM results for infauna are brought together in a summary model which highlights the influence of the clusters on beta diversity.

Legacy product - no abstract available

No product available. Removed from website 25/01/2019

The Australian Government formally releases new offshore exploration areas at the annual APPEA conference. These areas are located across various offshore hydrocarbon provinces ranging from mature basins with ongoing oil and gas production to exploration frontiers. In support of the annual acreage release, Geoscience Australia (GA) provides a variety of technical information with an emphasis on basin evolution, stratigraphic frameworks and overviews of hydrocarbon prospectivity. In recent years, GA's petroleum geological studies have significantly high graded the prospectivity of large underexplored offshore regions such as the Ceduna Sub-basin and the Northern Perth Basin. A new program is now targeting areas that lie adjacent to producing regions with the aim to delineate the occurrence and distribution of petroleum systems elements in less explored or in unsuccessful areas and to provide a comprehensive overview of the regional geological evolution. Updates to the stratigraphic framework and new results from geochemical studies are already available and are used for prospectivity assessments. Furthermore, the Australian government continues to assist offshore exploration activities by providing free access to a wealth of geological and geophysical data.

The global ocean absorbs 30% of anthropogenic CO2 emissions each year, which changes the seawater chemistry. The absorbed CO2 lowers the pH of seawater and thus causes ocean acidification. The pH of the global ocean has decreased by approximately 0.1 pH units since the Industrial Revolution, decreasing the concentration of carbonate ions. This has been shown to reduce the rate of biological carbonate production and to increase the solubility of carbonate minerals. As more CO2 is emitted and absorbed by the oceans, it is expected that there will be continuing reduction in carbonate production coupled with dissolution of carbonate sediments. This study was undertaken as part of a program to collect baseline data from Australia's seabed environments and to assess the likely impacts of ocean acidification on continental shelf sediments. Over 250 samples from four continental shelf areas of northern Australia (Capricorn Reef, Great Barrier Reef Lagoon, Torres Strait, Joseph Bonaparte Gulf) were analysed to characterise the surface sediment mineral and geochemical composition. Of particular importance was the quantification of carbonate minerals (calcite, aragonite, high-magnesium calcite) and the magnesium content in high-magnesium calcite. The latter determines the solubility of high-magnesium calcite, which is most soluble of all common carbonate minerals. The thermodynamic stability of carbonate minerals as referred to the state of saturation was calculated using the current and predicted equatorial ocean water composition [1]. Northern Australian continental shelf sediments are largely dominated by carbonate. High-magnesium calcite had the highest abundance of all carbonate minerals followed by aragonite in all areas. The average mol% MgCO3 in high-magnesium calcite varied from 13.6 to 15.5 mol% for the different areas, which is in agreement with the global average magnesium concentration in high-magnesium calcite in tropical and subtropical regions [2].

Legacy product - no abstract available

Legacy product - no abstract available