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  • <p>This data package contains three airborne geophysical datasets that have been acquired and processed from the Lower Macquarie River TEMPEST AEM survey flown in 2007, located to the north-west of Dubbo in the Central West region of New South Wales. The datasets are: a new Geoscience Australia layered earth inversion (GA-LEI) of the 2007 Lower Macquarie River TEMPEST Airborne Electromagnetic (AEM) survey; an airborne magnetic survey; and a digital elevation model (DEM). These data include enhancements of previously available datasets using more recent geophysical processing software advances. <p>This metadata briefly describes the contents of the data package. The user guide included in the package contains more detailed information about the individual datasets and available technical reports. <p>The AEM dataset comprises the final Geoscience Australia layered earth inversion (GA-LEI) of the Lower Macquarie River TEMPEST AEM survey data, produced in 2008. The main data products from the GA-LEI inversion are: point located inversion output data; horizontal layer conductivity grids below ground surface; horizontal conductivity-depth slice grids of various regular depth intervals below ground surface; vertical conductivity-depth sections along each flight line; AEM survey outline and flight line vector GIS data; and borehole comparison logs. The GA-LEI AEM data are derived from the 'Lower Macquarie River TEMPEST AEM Survey, NSW, 2007 Final Data (P1140)', available as Geoscience Australia product number 67211 (GeoCat #67211). The GA-LEI has been demonstrated to generate more accurate conductivity predictions than other algorithms for similar TEMPEST surveys. <p>The airborne magnetics and DEM data in this data package includes the corresponding data from GeoCat #67211, with additional raster and image formats to facilitate accessibility on a range of geographic information system platforms. <p>The point located data are stored in ASCII files (.asc) formatted with space-delimited columns with an associated comprehensive header (.hdr) file. The gridded data are stored in ER Mapper and ESRI grid formats as binary floating point raster grid files. The image data are stored in GeoTIFF format with associated world (.tfw) files and (.png) legends. The vector data are stored in ESRI shapefiles (.shp) Technical reports are stored in Portable Document Format (.pdf). The datasets are compressed in ZIP files. <p>The TEMPEST time domain airborne electromagnetic (AEM) survey was flown by Fugro Airborne Surveys over the Lower Macquarie River catchment in 2007. The survey was commissioned by the Australian Government Department of Agriculture, Fisheries and Forestry through the Bureau of Rural Sciences (BRS), now known as the Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES) and funded under the National Action Plan for Salinity and Water Quality. Geoscience Australia (GA) provided several geophysical services in relation to the survey including survey planning, technical system selection, data quality control and layer earth inversion of the resultant data. Format conversion of the magnetics and DEM data in this product was performed by ABARES from data provided by GA.

  • <p>This data package contains three airborne geophysical datasets processed from the Billabong Creek Geophysical survey, southern New South Wales, flown in 2001. The datasets are: a new Geoscience Australia layered earth inversion (GA-LEI) of the Billabong Creek TEMPEST Airborne Electromagnetic (AEM) survey; an airborne magnetic, gamma-ray and elevation (MAGSPEC) survey; and an extract of the Australian National Gravity Database (GRAVITY). The additional processing and enhancement of the 2001 geophysical survey data has significantly improved previous conductivity predictions as well as enabling the extraction of geologically significant information to support salinity and natural resource management. <p>This metadata briefly describes the contents of the data package. The user guide included in the package contains more detailed information about the individual datasets and available technical reports. <p>The AEM dataset comprises the final Geoscience Australia layered earth inversion (GA-LEI) of the 2001 Billabong Creek TEMPEST AEM survey, produced in 2008. The main data products from the GA-LEI inversion are: point located inversion output data; horizontal layer conductivity grids below ground surface; horizontal conductivity-depth slice grids of various regular depth intervals below ground surface; vertical conductivity-depth sections along each flight line; horizontal conductance distribution grids; interpreted grids of the depth and elevation of the base of the conductive unit; and images of the above datasets produced using standard image enhancement techniques. The GA-LEI AEM data are derived from the 'Billabong Creek TEMPEST AEM Survey, NSW, 2001 Final Located Data (P904)', available as Geoscience Australia product number 65385 (GeoCat #65385). The GA-LEI has been demonstrated to generate more accurate conductivity predictions than other algorithms for similar TEMPEST surveys. The MAGSPEC datasets are: airborne magnetic data comprising grids of total magnetic intensity (TMI), TMI reduced to pole (TMI-RTP), TMI-RTP first vertical derivative data and a range of enhanced magnetic images derived from the data; airborne gamma-ray data comprising grids of dose rate, concentration of potassium (K), thorium (Th) and uranium (U) and a range of enhanced gamma-ray images derived from the data; and elevation data comprising grids and images of the digital elevation model (DEM) derived from the MAGSPEC survey. <p>The GRAVITY dataset includes point located data, grids and enhanced images of data extracted from the Australian National Gravity Database. <p>The point located data are stored in ASCII files (.asc) formatted with space-delimited columns with an associated comprehensive header (.hdr) file. The gridded data are stored in ER Mapper and ESRI grid formats as binary raster grid files. The image data are stored in JPG format with associated world (.jgw) files. Technical reports describing the data processing techniques are stored in Portable Document Format (.pdf). The datasets are compressed in ZIP files. <p>The Billabong Creek airborne geophysics survey was commissioned by the Murray-Darling Basin Commission in 2001. Fugro Airborne Surveys Pty Ltd (Fugro) was contracted to acquire and process the AEM survey utilising the TEMPEST time domain airborne electromagnetic system. Kevron Geophysics Pty Ltd (Kevron) was contracted to acquire and process the MAGSPEC survey utilising an industry standard system. The project was administered by the Australian Government Department of Agriculture, Fisheries and Forestry through the Bureau of Rural Sciences (BRS), now known as the Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES). Geoscience Australia (GA) managed and quality controlled the work of Kevron and Fugro. Additional processing and enhancements of the 2001 airborne geophysics data was undertaken by GA in 2007-08, with funding from the National Action Plan for Salinity and Water Quality.

  • <p>This data package contains three airborne geophysical datasets processed from the Honeysuckle Creek Geophysical survey, Victoria, flown in 2001. The datasets are: a new Geoscience Australia layered earth inversion (GA-LEI) of the Honeysuckle Creek TEMPEST Airborne Electromagnetic (AEM) survey; an airborne magnetic, gamma-ray and elevation (MAGSPEC) survey; and an extract of the Australian National Gravity Database (GRAVITY). The additional processing and enhancement of the 2001 geophysical survey data has significantly improved previous conductivity predictions as well as enabling the extraction of geologically significant information to support salinity and natural resource management. <p>This metadata briefly describes the contents of the data package. The user guide included in the package contains more detailed information about the individual datasets and available technical reports. <p>The AEM dataset comprises the final Geoscience Australia layered earth inversion (GA-LEI) of the 2001 Honeysuckle Creek TEMPEST AEM survey, produced in 2008. The main data products from the GA-LEI inversion are: point located inversion output data; horizontal layer conductivity grids below ground surface; horizontal conductivity-depth slice grids of various regular depth intervals below ground surface; vertical conductivity-depth sections along each flight line; horizontal conductance distribution grids; a grid and images of conductance distribution; grids and images of interpreted bedrock topography and regolith thickness; and images of the above datasets produced using standard image enhancement techniques. The GA-LEI AEM data are derived from the 'Honeysuckle Creek TEMPEST AEM Survey, Victoria, 2001 Final Located Data (P903)', available as Geoscience Australia product number #65384. The GA-LEI has been demonstrated to generate more accurate conductivity predictions than other algorithms for similar TEMPEST surveys. <p>The MAGSPEC datasets are: airborne magnetic data comprising grids of total magnetic intensity (TMI), TMI reduced to pole (TMI-RTP), TMI-RTP first and second vertical derivative data and a range of enhanced magnetic images derived from the data; airborne gamma-ray data comprising grids of dose rate, concentration of potassium (K), thorium (Th) and uranium (U) and a range of enhanced gamma-ray images derived from the data; and elevation data comprising grids and images of the digital elevation model (DEM) derived from the MAGSPEC survey. <p>The GRAVITY dataset includes point located data, polygon location data, grids and enhanced images of data extracted from the Australian National Gravity Database. <p>The point located data are stored in ASCII files formatted with space-delimited columns with an associated comprehensive header file. The gridded data are stored in ER Mapper and ESRI grid formats as binary floating point raster grid files. The image data are stored in JPG format with associated world files. Polygon and other point location data are stored in ESRI shapefiles. Technical reports describing the data processing techniques are stored in Portable Document Format. <p>The survey was commissioned by the Murray-Darling Basin Commission in 2001. Fugro Airborne Surveys Pty Ltd was contracted to acquire and process the AEM survey utilising the TEMPEST time domain airborne electromagnetic system. Kevron Geophysics Pty Ltd was contracted to acquire and process the MAGSPEC survey utilising an industry standard system. The project was administered by the Australian Government Department of Agriculture, Fisheries and Forestry through the Bureau of Rural Sciences), now known as the Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES). Geoscience Australia managed and quality controlled the work of Kevron and Fugro. Additional processing and enhancements of the 2001 airborne geophysics data was undertaken by GA in 2007-08, with funding from the National Action Plan for Salinity and Water Quality.

  • Within the coming decade it is anticipated that GNSS will be capable of providing pseudorange-based positioning services with an uncertainty (1-sigma) of 3 cm (open sky) and 15 cm (tree covered) while carrier-phase positioning services supported by GNSS ground networks with an inter-station spacing of 100-200 km should achieve uncertainties of 1-2 cm in real-time. These capabilities will improve business processes and national productivity but are also likely to encourage spatial-data collection by a broad community of users, including those without strong spatial expertise. From a spatial-data management perspective, a challenge will emerge in that these new global services will support positioning in the International Terrestrial Reference Frame (ITRF), which is a dynamic and time dependent coordinate system, and not directly in any individual national datum, including the Geocentric Datum of Australia 1994 (GDA94). GDA94 established in the 1990s, has relatively poor internal accuracy, weak linkages to the ITRF, and is held static at an epoch date nearly 2 decades ago. Recognising that GDA94 will be incompatible with these future positioning capabilities and that the national datum will need to directly serve a wider-community of users, the Intergovernmental Committee for Surveying and Mapping (ICSM) - Permanent Committee for Geodesy (PCG) in collaboration with the CRC for Spatial Information (CRCSI) is currently examining options for revision of the datum. This presentation will overview the drivers for further developing Australia's datum, initial concepts and indicative timeframes for implementation.

  • The national measurement system in Australia ensures a basis for legally traceable, consistent and internationally recognised measurements. With the growing societal dependency on GPS, the need for the legal traceability of GPS positions with respect to the Australian Datum - the Geocentric Datum of Australia 1994 (GDA94) -- has become increasingly apparent. In the interest of ensuring consistency of positions derived from private and government Continuously Operating Reference Stations (CORS),Geoscience Australia maintains an appointment as a legal metrology authority in accordance with the National Measurement Act 1960 and provides legally traceable positions. This presentation will overview Geoscience Australia's approach to the legal traceability of GPS positions, the process of legal certification including: (1) the basic requirements for requesting certification; (2) quality standards and the quality management system of the position verification processes. The structured maintenance and continual improvement program for the verifying laboratory will also be introduced.

  • 1. Band ratio: B11/(B10+B12) Blue is low quartz content Red is high quartz content Geoscience Applications: Use in combination with Silica index to more accurately map "crystalline" quartz rather than poorly ordered silica (e.g. opal), feldspars and compacted clays.

  • Band ratio: B3/B2 Blue is low content Red is high content Use this image to help interpret the amount of "obscuring/complicating" green vegetation cover.

  • 1. Band ratio: (B5+B7)/B6 Blue is low abundance, Red is high abundance potentially includes: phengite, muscovite, paragonite, lepidolite, illite, brammalite, montmorillonite, beidellite, kaolinite, dickite Useful for mapping: (1) exposed saprolite/saprock (2) clay-rich stratigraphic horizons; (3) lithology-overprinting hydrothermal phyllic (e.g. white mica) alteration; and (4) clay-rich diluents in ore systems (e.g. clay in iron ore). Also combine with AlOH composition to help map: (1) exposed in situ parent material persisting through "cover" which can be expressed as: (a) more abundant AlOH content + (b) long-wavelength (warmer colour) AlOH composition (e.g. muscovite/phengite).

  • 1. Band ratio: B5/B7 Blue is well ordered kaolinite, Al-rich muscovite/illite, paragonite, pyrophyllite Red is Al-poor (Si-rich) muscovite (phengite) useful for mapping: (1) exposed saprolite/saprock is often white mica or Al-smectite (warmer colours) whereas transported materials are often kaolin-rich (cooler colours); (2) clays developed over carbonates, especially Al-smectite (montmorillonite, beidellite) will produce middle to warmers colours. (2) stratigraphic mapping based on different clay-types; and (3) lithology-overprinting hydrothermal alteration, e.g. Si-rich and K-rich phengitic mica (warmer colours). Combine with Ferrous iron in MgOH and FeOH content products to look for evidence of overlapping/juxtaposed potassic metasomatism in ferromagnesian parents rocks (e.g. Archaean greenstone associated Au mineralisation) +/- associated distal propyllitic alteration (e.g. chlorite, amphibole).

  • 1. Band ratio: (B10+B12)/B11 Blue is low gypsum content. Red is high gypsum content. Accuracy: Very Low: Strongly complicated by dry vegetation and often inversely correlated with quartz-rich materials. Affected by discontinuous line-striping. Use in combination with FeOH product which is also sensitive to gypsum. Geoscience Applications: Useful for mapping: (1) evaporative environments (e.g. salt lakes) and associated arid aeolian systems (e.g. dunes); (2) acid waters (e.g. from oxidising sulphides) invading carbonate rich materials including around mine environments; and (3) hydrothermal (e.g. volcanic) systems.