The Australian National Marine Data Group was formed by the Heads of Marine Agencies (HOMA) to promote improved interchange of marine data in Australia. The ANMDG held a workshop of practitioners in May 2002 with the intention of identifying major areas of interest and tasks for working groups to address in order to make progress with development of marine data interchange in Australia. This Proceedings CD contains the presentations by speakers in the form of PowerPoint slides and a few Acrobat documents. It was distributed to participants in the workshop.

Legacy product - no abstract available

Map showing Australia's Maritime Jurisdiction in the Timor Sea. One of the 27 constituent maps of the "Australia's Maritime Jurisdiction Map Series" (GeoCat 71789). Depicting Australia's extended continental shelf approved by the Commission on the Limits of the Continental Shelf in April 2008, treaties and various maritime zones. Background bathymetric image is derived from a combination of the 2009 9 arc second bathymetric and topographic grid by GA and a grid by Smith and Sandwell, 1997. Background land imagery derived from Blue Marble, NASA's Earth Observatory. A0 sized .pdf downloadable from the web.

Map showing Australia's Maritime Jurisdiction off the Northwest Shelf. One of the 27 constituent maps of the "Australia's Maritime Jurisdiction Map Series" (GeoCat 71789). Depicting Australia's extended continental shelf approved by the Commission on the Limits of the Continental Shelf in April 2008, treaties and various maritime zones. Background bathymetric image is derived from a combination of the 2009 9 arc second bathymetric and topographic grid by GA and a grid by Smith and Sandwell, 1997. Background land imagery derived from Blue Marble, NASA's Earth Observatory. A0 sized .pdf downloadable from the web.

Slope failures with associated submarine slides, sediment accumulation along contourite drifts and focus seepage features have been interpreted from new sub-bottom profiler, multibeam bathymetry, side-scan sonar, echo-sounder data together with geochemical analyses of sediment samples along the continental slope off Western Australia. The processes recognised show the implication of slope instability and hydrocarbon seepage in shaping the continental slope geomorphology. The spatial correlation between regional seafloor features and reactivation of pre-existing faults suggests tectonics and seismic activity being the main potential triggering parameters for slope processes offshore northern Perth Basin. Geomechanical models have been used to test potential up-fault leakage using the present-day stress field and the results correlate with the seepage features observed in the study area. The marine survey results provide additional support for the presence of an active petroleum system in the northern Perth Basin; and combined with geomechanical models, the study helps reducing petroleum exploration and geohazards riks.

Australia's marine jurisdiction is one of the largest and most diverse in the world and surprisingly our knowledge of the biological diversity, marine ecosystems and the physical environment is limited. Acquiring and assembling high resolution seabed bathymetric data is a mandatory step in achieving the goal of increasing our knowledge of the marine environment because models of seabed morphology derived from these data provide useful insights into the physical processes acting on the seabed and the location of different types of habitats. Another important application of detailed bathymetric data is the modelling of hazards such tsunami and storms as they interact with the shelf and coast. Hydrodynamic equations used in tsunami modelling are insensitive to small changes in the earthquake source model, however, small changes in the bathymetry of the shelf and nearshore can have a dramatic effect on model outputs. Therefore, accurate detailed bathymetry data are essential. Geoscience Australia has created high resolution bathymetry grids (at 250, 100, 50 and 10 metres) for Christmas, Cocos (Keeling), Lord Howe and Norfolk Islands. An exhaustive search was conducted finding all available bathymetry such as multibeam swath, laser airborne depth sounder, conventional echo sounder, satellite derived bathymetry and naval charts. Much of this data has been sourced from Geoscience Australia's holdings as well as the CSIRO, the Australian Hydrographic Service and foreign institutions.Onshore data was sourced from Geoscience Australia and other Commonwealth institutions. The final product is a seamless combined Digital Bathymetric Model (DBM) and Digital Elevation Model (DEM).The new Geoscience Australia grids are a vast improvement on the existing publicly available grids.

Geoscience Australia Marine Survey 302: Final Survey Report. by Fugro Robertson Inc, Nov. 2006 - Jan. 2007.

The Australian Geological Survey Organistaion (AGSO) has produced a set of digital bathymetry, gravity and magnetic grids for the southwest quadrant of Australia (24 - 46S, 106-140E), using all available land, marine and satellite data. The work was done in cooperation with Desmond Fitzgerald & Associates (DFA), and with significant bathymetric data input from the Australian Hydrographic Office (AHO). The results were obtained by performing a network adjustment on marine ship-track data, and combining these with onshore and satellite-derived data.

This paper presents a new style of bedload parting from western Torres Strait, northern Australia. Outputs from a hydrodynamic model identified an axis of bedload parting centred on the western Torres Strait islands (~142°15"E). Unlike bedload partings described elsewhere in the literature, those in Torres Strait are generated by incoherence between two adjacent tidal regimes as opposed to overtides. Bedload parting is further complicated by the influence of wind-driven currents. During the trade wind season, wind-driven currents counter the reversing tidal currents to a point where peak currents are directed west. The eastwards-directed bedload pathway is only active during the monsoon season. Satellite imagery was used to describe six bedform facies associated with the bedload parting. Bedform morphology was used to indicate sediment supply. Contrary to bedload partings elsewhere, sand ribbons are a distal facies within the western bedload transport pathway despite peak currents directed toward the west throughout the year. This indicates that sediment is preferentially trapped within sand banks near the axis of parting and not transported further west into the Gulf of Carpentaria or Arafura Sea.

The Murray Canyons are a group of deeply-incised submarine canyons on a steep 400-km section of the continental slope off Kangaroo Island, South Australia. Some of the canyons are amongst the largest on Earth. The canyons, some 80 km long, descend from the shelf edge to abyssal plain 5200 m deep. Sprigg Canyon, the deepest and one of the largest, has walls 2 km high. The thalwegs of the larger canyons are concave in profile, steepest on the upper continental slope (15?-30?), with about 4?gradient on the mid slope, then level out on the lower slope to merge with the 1? continental rise. Between canyons, the continental slope is slightly convex to linear with a gradient of about 5?-6?. Canyon walls commonly slope at 15?-22?. The passive continental margin narrows to 65-km at the Murray Canyons and links the Bight and Otway Basins. WNW-trending Jurassic-Cretaceous rift structures control the irregular shape of the central canyons. At the western end, large box canyons 1 km deep are incised into thick sediments of the Ceduna Sub-basin. Formed by headscarp erosion, some of these canyons have coalesced by canyon capture. The upper parts of most canyons are cut into Cretaceous sediments and in some places are floored by basement rocks. Large holes, spaced about 5 km apart and up to several hundred metres deep, along the outlet channels of the larger and steeper canyons were probably gouged by turbidity currents resulting from major slope failures at the shelf edge. Quaternary turbidites were deposited on the abyssal plain more than 100 km from the foot of slope. Canyon down-cutting was episodic since the latest Cretaceous, with peak activity since the Oligocene due to strong glacioeustatic fluctations and cycles, with canyon development occurring during lowstands and early transgressions when sediment input at the shelf edge was usually highest. The timing of canyon development is linked to major unconformities within adjacent basins, with down-cutting events recorded or inferred during early Paleocene, Middle Eocene, Early Oligocene, Oligocene/Miocene transition (~24 Ma), mid Miocene (~14 Ma) and latest Miocene-Pleistocene. The early phases involved only siliciclastic sediments, while post-early Eocene canyon cutting was dominated by biogenic carbonates generated on the shelf and upper continental slope. The Murray River dumped its sediment load directly into Sprigg Canyon during extreme lowstands of the Late Pleistocene when the Lacepede Shelf was dry land.