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  • Validation of spectral remote sensing data for geological mapping and detection of hydrothermal footprints in the Mount Isa Inlier

  • A new digital surface geology dataset covering Australia at 1:1 million scale was released recently by Geoscience Australia. The digital map, which depicts geological units and structures seamlessly across state and territory borders, will provide an invaluable baseline dataset for national and regional evaluation of resources as well as environmental management and land use decision-making. This national project was undertaken with the full co-operation of the geological surveys of each Australian state and the Northern Territory who provided their most recent map data for the national compilation as well as their advice in resolving stratigraphic issues.

  • The Leeuwin Current has significant ecological impact on the coastal and marine ecosystem of south-western Australia. This study investigated the spatial and temporal dynamics of the Leeuwin Current using monthly MODIS SST dataset between July 2002 and December 2012. Topographic Position Index layers were derived from the SST data for the mapping of the spatial structure of the Leeuwin Current. The semi-automatic classification process involves segmentation, 'seeds' growing and manual editing. The mapping results enabled us to quantitatively examine the current's spatial and temporal dynamics in structure, strength, cross-shelf movement and chlorophyll a characteristic. It was found that the Leeuwin Current exhibits complex spatial structure, with a number of meanders, offshoots and eddies developed from the current core along its flowing path. The Leeuwin Current has a clear seasonal cycle. During austral winter, the current locates closer to the coast (near shelf break), becomes stronger in strength and has higher chlorophyll a concentrations. While, during austral summer, the current moves offshore, reduces its strength and chlorophyll a concentrations. The Leeuwin Current also has notable inter-annual variation due to ENSO events. In El Niño years the current is likely to reduce strength, move further inshore and increase its chlorophyll a concentrations. The opposite occurs during the La Niña years. In addition, this study also demonstrated that the Leeuwin Current has a significantly positive influence over the regional nutrient characteristics during the winter and autumn seasons. Apart from surface cooling and advection, the Leeuwin Current's sizable cross-shelf movement may be another contributing factor to the seasonal and inter-annual variations of its chlorophyll a concentrations.

  • Reliable marine benthic habitat maps at regional and national scales are needed to enable the move towards the sustainable management of marine environmental resources. The most effective means of developing broad-scale benthic habitat maps is to use commonly available marine physical data due to the paucity of adequate biological data and the prohibitive cost of directly sampling benthic biota over large areas. A new robust method of mapping marine benthic habitats at this scale was developed based on a stratified approach to habitat classification. This approach explicitly uses knowledge of marine benthic ecology to determine an appropriate number of stratification levels, to choose the most suitable environmental variables for each level, and to select ecologically significant boundary conditions (i.e. threshold values) for each variable. Three stratification levels, with nine environmental variables, were created using a spatial segmentation approach. Each level represents major environmental processes and characteristics of the Australian marine benthic environment. The finest scale of benthic habitat is represented by seafloor physical properties of topography, sediment grain size and seabed shear stress. Water-column nutrient parameters and bottom water temperature depicted the intermediate scale, while the broadest scale was defined by seabed insolation parameters derived from depth data. The classifications of the three stratified levels were implemented using an object-based fuzzy classification technique that recognises that habitats are largely homogenous spatial regions, and transitions between habitats are often gradual. Classification reliability was indicated in confidence maps. Physical habitat diversity was evaluated for the final benthic habitat map that combines the three classifications. The final benthic habitat map identifies the structurally complex continental shelf break as an area of relatively high habitat diversity. Continental Shelf Research

  • Hyperspectral airborne images from the Eastern Fold Belt of the Mount Isa Inlier, were validated as new tool for the detection of Iron oxide Cu-Au (IOCG) related alteration. High resolution mineral maps derived from hyperspectral imaging (4.5m/pixel) enables the recognition of various types of hydrothermal alteration patterns and the localisation of fluid pathways. Four different types of hydrothermal alteration patterns were identified with the hyperspectral mineral maps: (1) Metasomatic 1: White mica mineral maps were applied to map the spatial distribution of regional sodic-calcic alteration in metasedimentary successions of the Soldiers Cap Group in the Snake Creek Anticline. (2) Metasomatic 2: Alteration zoning is evident from albitised granites, assigned to the Williams-Naraku Suite, along the Cloncurry Fault show characteristic absorption features in the shortwave infrared range (SWIR) and can be detected with white mica mineral maps (white mica composition, white mica content, white mica crystallinity index).

  • This report documents the findings of the Ord Valley Airborne Electromagnetics (AEM) Interpretation Project. The project was co-funded by the Australian and Western Australian Governments to provide information in relation to salinity and groundwater management in the Ord Valley, Western Australia. The project involved the acquisition of airborne electromagnetic (AEM) and Light Ranging and Detection (LiDAR) surveys, and complementary drilling, borehole geophysics, laboratory analysis and interpretation services. The project was undertaken under the auspices of the National Action Plan for Salinity and Water Quality, and managed by Ord Irrigation Cooperative (OIC) for the WA Rangelands NRM Group.

  • This is a promotional flyer for the Austrlian Mines Atlas that is handed out at conferences and other events. The flyer explains what is available through the Australian Mines Atlas website.

  • The Joseph Bonaparte Gulf (JBG) is an offshore area in northern Australia, with active petroleum exploration and infrastructure development. The Van Diemen Rise, an area of raised banks and channels in the northeastern region of the JBG, has been proposed for protection as part of the Oceanic Shoals Commonwealth Marine Reserve. However, baseline information for much of this area is lacking, including spatial and environmental patterns of biological communities. This study uses still imagery of the sea floor in four study areas across the Van Diemen Rise, collected during two seabed mapping surveys conducted by Geoscience Australia and the Australian Institute of Marine Science, in 2009 and 2010. Based on these analyses benthic communities are characterised, and important species and morphological groups are compared with a number of abiotic variables. In so doing, a preliminary assessment is given as to which abiotic variables make the most appropriate surrogates for characterising benthic communities in the region. A number of variables are found to correlate significantly and strongly with some of the biological groups determined in this study. Pheophytin, Si/Al and mud content correlate with the large habitat forming species Mopsella sp., Ianthella sp. and Xestospongia sp. respectively. Backscatter signals from multibeam sonar surveys correlate very strongly with depth and also to some degree with a number of the functional growth forms of sponges. Based on the positive results of this preliminary data investigation, it is recommended that non-linear modelling and robust multivariate analyses be applied to the data set to investigate more complex relationship. This study provides baseline information on the ecology and morphology of key habitat-forming organisms in the northeastern Joseph Bonaparte Gulf which will be facilitate marine monitoring programs for reserve management and environmental impact assessments for industry activity.