Under the Community Stream Sampling and Salinity Mapping Project, the Australian Government through the Department of Agriculture, Fisheries and Forestry and the Department of Environment and Heritage, acting through Bureau of Rural Sciences, funded an airborne electromagnetic (AEM) survey to provide information in relation to land use questions in selected areas along the River Murray Corridor (RMC). The proposed study areas and major land use issues were identified by the RMC Reference Group at its inception meeting on 26th July, 2006. This report has been prepared to facilitate recommendations on the Lindsay-Walppolla study area. The work was developed in consultation with the RMC Technical Working Group (TWG) to provide a basis for the RMC Reference Group and other stake holders to understand the value and application of AEM data to the study area. This understanding, combined with the Reference Group's assessment of the final results and taking in account policy and land management issues, will enable the Reference Group to make recommendations to the Australian Government. The report is based on an assessment the application of AEM to the Reference Group's land management issues as specified by the TWG at its meeting on 16th August 2006 and out of session.

The conversion of data to conductivity for fixed wing transmitter loop ? towed bird receiver coil time-domain airborne electromagnetic (AEM) systems such as TEMPEST would ideally utilise complete knowledge of the system geometry and measurements for all 3 mutually perpendicular components of the received signal. In practice, not all of this information is available. A layered inversion formulation is described that integrates the supplied data from a TEMPEST survey with a priori conductivity information from the survey area. Total (primary plus secondary) field data from both the X (horizontal in-line) and Z (vertical) components are used. Receiver coil pitch angle and transmitter loop to receiver coil horizontal and vertical separation parameters are included as variable model parameters to be estimated. Borehole conductivity data are used to assign a reference conductivity model that acts as a constraint to stabilise the partitioning of the measured signal into primary field and ground response contributions. Smoothness constraints are applied to the conductivity values in the 1D model. The quality of the inversion output was assessed through comparison of the conductivity predictions with borehole conductivity values and shallow single-frequency ground EM measurements. An improvement in accuracy of the predictions was demonstrated compared with that of two previous sets of conductivity predictions.

The Frome Airborne Electromagnetic (AEM) Survey was designed to deliver reliable precompetitive AEM data and scientific analysis to aid research into the potential of energy and mineral resources in the Lake Frome region of South Australia. The Survey was the third regional AEM survey conducted within the Onshore Energy Security Program (OESP) at Geoscience Australia (GA), following the Paterson and Pine Creek AEM surveys. The Survey was flown by Fugro Airborne Surveys (FAS) for Geoscience Australia between 22 May and 2 November 2010, using the TEMPEST^TM time-domain electromagnetic (TEM) system. Survey lines were flown east-west at a nominal 100m above ground level, and spaced 2.5km or 5km apart. A total of 32 317 line km of new data were collected over an area of 95 450km2, approximately one tenth of the area of South Australia. The survey area extends from the South Australia-New South Wales border at Cameron Corner across to the Marree and Leigh Creek areas, skirts the highland of the northern Flinders Ranges, and includes the entire Lake Frome area, the Olary Spur between the towns of Yunta and Cockburn and the northwestern Murray-Darling Basin. The Lake Frome region contains a large number of sandstone-hosted uranium deposits with known resources of ~60 000 tonnes of U3O8, constituting ~45% of uranium resources of this type in Australia. The Survey was conducted with the aims of reducing exploration risk, stimulating exploration investment and enhancing prospectivity within the region primarily for uranium, but also for other commodities including copper, gold, silver, lead, zinc, iron ore, coal and groundwater. The Frome AEM Survey was designed to be a regional mapping program for imaging surface and subsurface geological features that may be associated with sandstone-hosted uranium systems. Interpretations of the Frome AEM Survey data provide a regional overview of the under-cover geology of the entire survey area, as well as providing detailed along-line information to give users a greater understanding of previous detailed investigations within small areas. The data have mapped features of fertile sandstone-uranium systems and have highlighted many new areas of prospectivity for uranium and other commodities.

This record reports on an AGSO/PIRSA/CRC LEME/Dominion Mining AEM Interpretation Workshop. The workshop focused on AEM data acquired over the Challenger Prospect in South Australia.

Presentation to minerals industry representatives at the Geological Survey of Western Australia, 4 May 2010.

Diagram produced for the Australian Fisheries Management Authority showing the vessel monitoring system positional data for MV Seawin Emerald 16//8/2006 to 27/8/2006. This diagram is restricted to internal use by AFMA and not for general release.

Geoscience Australia (GA) has implemented an Onshore Energy Security Program (OESP) to identify Australia's onshore energy resources. The objectives of the OESP are to provide essential pre-competitive geoscientific data to lower exploration risk and stimulate investment in exploration for Australia's uranium, thorium, geothermal and onshore petroleum resources. The program is funded under a new Energy Security Initiative announced by the Australian Government in August 2006. As a key component of the OESP GA will be conducting geophysical surveys across Australia for the next four years collecting the following data: deep seismic reflection, magnetotelluric, airborne magnetic, radiometric, electromagnetic and ground based gravity. The demand for resources, and increased funding by the Commonwealth, States and NT, have been the driving factors in the recent improvement in the regional geophysical coverage of Australia.

Diatoms are important primary producers within pelagic, benthic end epiphytic communities and their siliceous frustule leads to rapid sinking to the sediment. As a consequence, diatoms play a critical role in nutrient and carbon cycles in shallow and deep water environments. In this study, benthic nutrient and gas fluxes, water column and sediment properties were studied in a coastal lagoon of south-eastern Australia to identify control mechanisms coupling benthic and pelagic processes, in particular, how nutrients become fractionated by processes affecting benthic nutrient fluxes. During late spring, the water column of St. Georges Basin was oligotrophic, primary production was likely P limited and the phytoplankton community was dominated by cyanophytes. Molar ratios of TCO2 : Si benthic fluxes, however, were equal to the molar composition of diatoms suggesting that diatoms preferentially sink and deliver the most labile organic matter fraction to the sediment. The congruent release of Si and C implies a coupling of processes mobilizing Si and C. It is argued that extracellular polymeric substances surrounding the silicious frustule are the primary labile organic matter fraction and their rate of mineralization limits the dissolution of the silicious frustule. As decomposing biomass in sediments lead to net N2-production and very efficient burial of P, the fate of diatoms significantly contribute to the removal of bioavailable nutrients. High DIN:DIP benthic flux ratios of 290 to 900 promote P limitation particularly in shallow water bodies with long water residence times.

Ashmore Reef, 12°20 South, 123°0 E East, is a category one, Marine Protected Area administered by the Australian Government under the Environmental Protection and Biodiversity Conservation Act 1999. It is named after Irish, free mariner, Charles Samuel Ashmore, captain of the mercantile brig 'Hibernia'. He located, named and charted parts of Ashmore Reef on the 11th June, 1811. Since then there has been a range of Navy and research vessels who have continued the charting effort. Such traditional work has been supplemented by data from airborne laser bathymetric technology and Royal Australian Air Force photography. We present a maritime mapping history of Ashmore Reef and demonstrate the range of technologies which have influenced the progression of mapping processes over time. The advancement in sounding / data density and its presentation has been important for the management of Ashmore Reef as the Marine Protected Area is largely guided by the 50 metre contour and latitude and longitudinal references. Onsite compliance and enforcement of the EPBC Act 1999 is provided by personnel from the Australian Custom Service, National Marine Unit.

Presentation to minerals industry representatives at the Geological Survey of Western Australia, 4 May 2010