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    Gravity data measure small changes in gravity due to changes in the density of rocks beneath the Earth's surface. The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This National Gravity Compilation 2019 includes airborne DGIR 1VD image is produced from the 2019 Australian National Gravity Grids B series. These gravity data were acquired under the project No. 202008. The grid represented in this image has a cell size of 0.00417 degrees (approximately 435m). The data are derived from ground observations stored in the Australian National Gravity Database (ANGD) as at September 2019, supplemented by offshore data sourced from v28.1 of the Global Gravity grid developed using data from the Scripps Institution of Oceanography, the National Oceanic and Atmospheric Administration (NOAA), and National Geospatial-Intelligence Agency (NGA) at Scripps Institution of Oceanography, University of California San Diego. Airborne gravity and gravity gradiometry data were also included to provide better resolution to areas where ground gravity data was not of a suitable quality. Out of the approximately 1.8 million gravity observations, nearly 1.4 million gravity stations in the ANGD together with Airborne Gravity surveys totaling 345,000 line km and 106,000 line km of Airborne Gravity Gradiometry were used to generate this grid. The ground and airborne gravity data used in this grid has been acquired by the Commonwealth, State and Territory Governments, the mining and exploration industry, universities and research organisations from the 1940's to the present day. Station spacing for ground observations varies from approximately 11 km down to less than 1 km, with major parts of the continent having station spacing between 2.5 and 7 km. Airborne surveys have a line spacing ranging from 0.5 km to 2.5 km. The image shows the first vertical derivative of the de-trended global isostatic residual (DGIR) anomalies over Australia and its continental margins. The DGIR grid was obtained by subtracting 3 quantities (i.e., the near-field isostatic correction, the far-field isostatic correction, and a first order trend correction) from Complete Bouguer Anomaly data (CBA) of the 2019 Australian National Gravity Grids B series. A first vertical derivative was calculated by applying a fast Fourier transform (FFT) process to the DGIR grid of the 2019 Australian National Gravity Grids to produce the grid represented in this image.

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    Gravity data measure small changes in gravity due to changes in the density of rocks beneath the Earth's surface. The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This National Gravity Compilation 2019 DGIR tilt grid is produced from the 2019 Australian National Gravity Grids A series. These gravity data were acquired under the project No. 202008. The grid has a cell size of 0.00417 degrees (approximately 435m). The data are derived from ground observations stored in the Australian National Gravity Database (ANGD) as at September 2019, supplemented by offshore data sourced from v28.1 of the Global Gravity grid developed using data from the Scripps Institution of Oceanography, the National Oceanic and Atmospheric Administration (NOAA), and National Geospatial-Intelligence Agency (NGA) at Scripps Institution of Oceanography, University of California San Diego. Out of the approximately 1.8 million gravity observations, nearly 1.4 million gravity stations in the ANGD together with marine data were used to generate this grid. The ground gravity data used in the national grid has been acquired by the Commonwealth, State and Territory Governments, the mining and exploration industry, universities and research organisations from the 1940's to the present day. Station spacing for ground observations varies from approximately 11 km down to less than 1 km, with major parts of the continent having station spacing between 2.5 and 7 km. The DGIR was obtained by subtracting 3 quantities (i.e., the near-field isostatic correction, the far-field isostatic correction, and a first order trend correction) from Complete Bouguer Anomaly data (CBA) of the 2019 Australian National Gravity Grids A series. The grid shows a tilt of the de-trended global isostatic residual (DGIR) anomalies (A series) over Australia and its continental margins. A tilt filter was calculated by applying a fast Fourier transform (FFT) process to the DGIR grid of the 2019 Australian National Gravity Grids A series. A tilt filter is a ratio of the vertical derivative to the total horizontal derivative and is used for detection of edges of geological units.

  • Bathymetry is the study and mapping of the sea floor. It involves obtaining measurements of the depth of the ocean and is the equivalent to mapping topography on land. Bathymetric data is collected in multiple ways: 1. Satellite data can be used to produce maps showing general features over a large area at low resolution. Satellite altimetry measures the height of the ocean surface. If there are hills/mountains on the sea floor, the gravitational pull around that area will be greater and hence the sea surface will bulge. This measurement can be used to show where the seafloor is higher, and this can be used to produce maps showing general features over a large area at low resolution. 2. Single beam echosounders produce a single line of depth points directly under the equipment. These measurements are usually made while a vessel is moving to identify general sea floor patterns and/or schools of fish. 3. Equipment that captures swathes of data by acquiring multiple depth points in each area, such as multibeam echosounders (or swath echosounders) and airborne laser measurements (LADS). These datasets are very high resolution, with data down to better than one metre accuracy. This bathymetry dataset is a collection of singlebeam data sourced from seismic navigation lines, multibeam data, satellite and LADS data acquired by GA and by other government and non-government agencies.

  • <p>Australia has established a network of 58 marine parks within Commonwealth waters covering a total of 3.3 million square kilometres, or 40 per cent of our exclusive economic zone (excluding Australian Antarctic Territory). These parks span a range of settings, from near coastal and shelf habitats to abyssal plains. Parks Australia manages the park network through management plans that came into effect for all parks on 1 July 2018. Geoscience Australia is contributing to their management by collating and interpreting existing environmental data, and through the collection of new marine data. “Eco-narrative” documents are being developed for those parks, where sufficient information is available, delivering collations and interpretations of seafloor geomorphology, oceanography and ecology. Many of these interpretations rely on bathymetric grids and their derived products, including those in this data release. <p>Bathymetry grids <p>The bathymetry of the marine parks was created by compiling and processing Geoscience Australia’s bathymetry data holding gridded at the optimum resolution depending of the vessel’s sonar system. <p>The bathymetry of the park is illustrated by a panchromatic geotiff image, developed by combining the bathymetric data with a hillshade image. <p> Morphological Surfaces <p>Geoscience Australia has developed a new marine seafloor classification scheme, which uses the two-part seafloor mapping morphology approach of Dove et al (2016). This new scheme is semi-hierarchical and the first step divides the slope of the seafloor into three Morphological Surface categories (Plain, <2°; Slope, 2-10°; Escarpment, >10°). <p>Dove, D., Bradwell, T., Carter, G., Cotterill, C., Gafeira, J., Green, S., Krabbendam, M., Mellet, C., Stevenson, A., Stewart, H., Westhead, K., Scott, G., Guinan, J., Judge, M. Monteys, X., Elvenes, S., Baeten, N., Dolan, M., Thorsnes, T., Bjarnadóttir, L., Ottesen, D. (2016). Seabed geomorphology: a twopart classification system. British Geological Survey, Open Report OR/16/001. 13 pages. <p>This research is supported by the National Environmental Science Program (NESP) Marine Biodiversity Hub through Project D1.<p><p>This dataset is not to be used for navigational purposes.

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    Gravity data measure small changes in gravity due to changes in the density of rocks beneath the Earth's surface. The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This National Gravity Compilation 2019 DGIR grid is produced from the 2019 Australian National Gravity Grids A series. These gravity data were acquired under the project No. 202008. The grid has a cell size of 0.00417 degrees (approximately 435m). The data are given in units of um/s^2, also known as 'gravity units', or gu. The data are derived from ground observations stored in the Australian National Gravity Database (ANGD) as at September 2019, supplemented by offshore data sourced from v28.1 of the Global Gravity grid developed using data from the Scripps Institution of Oceanography, the National Oceanic and Atmospheric Administration (NOAA), and National Geospatial-Intelligence Agency (NGA) at Scripps Institution of Oceanography, University of California San Diego. Out of the approximately 1.8 million gravity observations, nearly 1.4 million gravity stations in the ANGD together with marine data were used to generate this grid. The ground gravity data used in this grid has been acquired by the Commonwealth, State and Territory Governments, the mining and exploration industry, universities and research organisations from the 1940's to the present day. Station spacing for ground observations varies from approximately 11 km down to less than 1 km, with major parts of the continent having station spacing between 2.5 and 7 km. The grid shows de-trended global isostatic residual anomalies (A series) over Australia and its continental margins. This National Gravity Compilation 2019 DGIR grid (DGIR) was obtained by subtracting 3 quantities (i.e., the near-field isostatic correction, the far-field isostatic correction, and a first order trend correction) from Complete Bouguer Anomaly data (CBA) of the 2019 Australian National Gravity Grids A series.

  • <p>Australia has established a network of 58 marine parks within Commonwealth waters covering a total of 3.3 million square kilometres, or 40 per cent of our exclusive economic zone (excluding Australian Antarctic Territory). These parks span a range of settings, from near coastal and shelf habitats to abyssal plains. Parks Australia manages the park network through management plans that came into effect for all parks on 1 July 2018. Geoscience Australia is contributing to their management by collating and interpreting existing environmental data, and through the collection of new marine data. “Eco-narrative” documents are being developed for those parks, where sufficient information is available, delivering collations and interpretations of seafloor geomorphology, oceanography and ecology. Many of these interpretations rely on bathymetric grids and their derived products, including those in this data release. <p>Geoscience Australia has developed a new marine seafloor classification scheme, which uses the two-part seafloor mapping morphology approach of Dove et al (2016). This new scheme is semi-hierarchical and the first step divides the slope of the seafloor into three Morphological Surface categories (Plain, <2°; Slope, 2-10°; Escarpment, >10°). This classification was applied to the portion of the Beaman and Spinnocia (2018) 30 m grid within the marine park. <p>Beaman, R.J. and Spinoccia, M. (2018). High-resolution depth model for Northern Australia - 30 m. Geoscience Australia. <p>Dove, D., Bradwell, T., Carter, G., Cotterill, C., Gafeira, J., Green, S., Krabbendam, M., Mellet, C., Stevenson, A., Stewart, H., Westhead, K., Scott, G., Guinan, J., Judge, M. Monteys, X., Elvenes, S., Baeten, N., Dolan, M., Thorsnes, T., Bjarnadóttir, L., Ottesen, D. (2016). Seabed geomorphology: a twopart classification system. British Geological Survey, Open Report OR/16/001. 13 pages. <p>This research is supported by the National Environmental Science Program (NESP) Marine Biodiversity Hub through Project D1.

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    Gravity data measure small changes in gravity due to changes in the density of rocks beneath the Earth's surface. The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This National Gravity Compilation 2019 includes airborne DGIR image is produced from the 2019 Australian National Gravity Grids B series. These gravity data were acquired under the project No. 202008. The grid The grid represented in this image has a cell size of 0.00417 degrees (approximately 435m). The data are given in units of um/s^2, also known as 'gravity units', or gu. The %%MV_DATASETS/SURVEY_NAME% are derived from ground observations stored in the Australian National Gravity Database (ANGD) as at September 2019, supplemented by offshore data sourced from v28.1 of the Global Gravity grid developed using data from the Scripps Institution of Oceanography, the National Oceanic and Atmospheric Administration (NOAA), and National Geospatial-Intelligence Agency (NGA) at Scripps Institution of Oceanography, University of California San Diego. Airborne gravity and gravity gradiometry data were also included to provide better resolution to areas where ground gravity data was not of a suitable quality. Out of the approximately 1.8 million gravity observations, nearly 1.4 million gravity stations in the ANGD together with Airborne Gravity surveys totaling 345,000 line km and 106,000 line km of Airborne Gravity Gradiometry were used to generate this grid. The ground and airborne gravity data used in this grid has been acquired by the Commonwealth, State and Territory Governments, the mining and exploration industry, universities and research organisations from the 1940's to the present day. Station spacing for ground observations varies from approximately 11 km down to less than 1 km, with major parts of the continent having station spacing between 2.5 and 7 km. Airborne surveys have a line spacing ranging from 0.5 km to 2.5 km. The image shows de-trended global isostatic residual anomalies over Australia and its continental margins. This National Gravity Compilation 2019 includes airborne DGIR image (DGIR) was obtained by subtracting 3 quantities (i.e., the near-field isostatic correction, the far-field isostatic correction, and a first order trend correction) from Complete Bouguer Anomaly data (CBA) of the 2019 Australian National Gravity Grids B series.

  • The Darwin Harbour bathymetry survey, GA-0333 was acquired by Geoscience Australia (GA), iXSurvey Australia Pty Ltd, and the Darwin Port Corporation (DPC) onboard the vessel 'Matthew Flinders' from 17 October to 07 November 2010 using GA's Kongsberg EM3002D multibeam sonar system and DPC's The specific objectives of the survey were to: 1. Obtain high resolution geophysical (bathymetry) data for Darwin Harbour; 2. Characterise substrates (acoustic backscatter properties, grainsize, sediment chemistry) for Darwin Harbour; and 3. Collect tidal data for the survey area. This V0 dataset contains a 1m resolution 32-bit geotiff of the Darwin Harbour survey area produced from the processed EM3002D sonar bathymetry data. This dataset is published with the permission of the CEO, Geoscience Australia Not to be used for navigational purposes.

  • Australia has established a network of 58 marine parks within Commonwealth waters covering a total of 3.3 million square kilometres, or 40 per cent of our exclusive economic zone (excluding Australian Antarctic Territory). These parks span a range of settings, from near coastal and shelf habitats to abyssal plains. Parks Australia manages the park network through management plans that came into effect for all parks on 1 July 2018. Geoscience Australia is contributing to their management by collating and interpreting existing environmental data, and through the collection of new data. This includes compiling existing bathymetry datasets for select marine parks. This dataset includes a compilation of multibeam sonar bathymetry (gridded to 100 m spatial resolution) for Bremer Marine Park, in the South-west Marine Park Network. The park incorporates Bremer Canyon and adjacent smaller canyons that incise the continental slope and outer shelf. This research is supported by the National Environmental Science Program (NESP) Marine Biodiversity Hub through Project D1.<p><p>This dataset is not to be used for navigational purposes.

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    Gravity data measure small changes in gravity due to changes in the density of rocks beneath the Earth's surface. The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. This National Gravity Compilation 2019 DGIR 0.5VD grid is produced from the 2019 Australian National Gravity Grids A series. These gravity data were acquired under the project No. 202008. The grid has a cell size of 0.00417 degrees (approximately 435m). The data are derived from ground observations stored in the Australian National Gravity Database (ANGD) as at September 2019, supplemented by offshore data sourced from v28.1 of the Global Gravity grid developed using data from the Scripps Institution of Oceanography, the National Oceanic and Atmospheric Administration (NOAA), and National Geospatial-Intelligence Agency (NGA) at Scripps Institution of Oceanography, University of California San Diego. Out of the approximately 1.8 million gravity observations, nearly 1.4 million gravity stations in the ANGD together with marine data were used to generate this grid. The ground gravity data used in this grid has been acquired by the Commonwealth, State and Territory Governments, the mining and exploration industry, universities and research organisations from the 1940's to the present day. Station spacing for ground observations varies from approximately 11 km down to less than 1 km, with major parts of the continent having station spacing between 2.5 and 7 km. The grid shows the half vertical derivative of the de-trended global isostatic residual anomalies (A series) over Australia and its continental margins. The original DGIR was obtained by subtracting 3 quantities (i.e., the near-field isostatic correction, the far-field isostatic correction, and a first order trend correction) from Complete Bouguer Anomaly data (CBA) of the 2019 Australian National Gravity Grids A series. A half vertical derivative was calculated by applying a fast Fourier transform (FFT) process to the DGIR grid of the 2019 Australian National Gravity Grids to produce this grid.