<div>Geoscience Australia’s Exploring for the Future program provides precompetitive information to inform decision-making by government, community and industry on the sustainable development of Australia's mineral, energy and groundwater resources. By gathering, analysing and interpreting new and existing precompetitive geoscience data and knowledge, we are building a national picture of Australia’s geology and resource potential. This leads to a strong economy, resilient society and sustainable environment for the benefit of all Australians. This includes supporting Australia’s transition to net zero emissions, strong, sustainable resources and agriculture sectors, and economic opportunities and social benefits for Australia’s regional and remote communities. The Exploring for the Future program, which commenced in 2016, is an eight year, $225m investment by the Australian Government. This work contributes to building a better understanding of the Australian continent, whilst giving the Australian public the tools they need to help them make informed decisions in their areas of interest.</div><div><br></div><div>As part of the Australia's Resources Framework Project, in the Exploring for the Future Program, Geoscience Australia and CSIRO undertook a magnetic source depth study across four areas, with the objectives of generating cover model constraints from magnetic modelling to expand national coverage, and to improve our subsurface understanding of these areas. During this study, 2005 magnetic estimates of depth to the top of magnetization were generated, with solutions derived using a consistent methodology (targeted magnetic inversion modelling, or TMIM; also known as ‘sweet-spot’ modelling). The methodology for these estimates are detailed in a summary report by Foss et al (2024), and is available for download through Geoscience Australia’s enterprise catalogue (https://pid.geoscience.gov.au/dataset/ga/149239). </div><div><br></div><div>The new points were generated over four areas: 1) the western part of Tasmania that is the southernmost extension of the Darling-Curnamona-Delamerian (DCD) project area; 2) northeastern Queensland; 3) the Officer Basin area of western South Australia and southeastern West Australia; and 4) the Eastern Resources Corridor (ERC), covering eastern South Australia, southwest Queensland, western New South Wales and western Victoria. These depth estimates have been released, together with a summary report detailing the data and methodology used to generate the results, through Geoscience Australia's product catalogue (ecat) at https://pid.geoscience.gov.au/dataset/ga/149239.</div><div><br></div><div>This supplementary data release contains the chronostratigraphic attribution of the new TMIM magnetic depth estimates, which range in depth from at surface to 13,294 m below ground. To ensure that the interpretations took into account the local geological features, the magnetic depth estimates were integrated and interpreted with other geological and geophysical datasets, including borehole stratigraphic logs, potential fields images, surface and solid geology maps, and airborne electromagnetic interpretations (where available). </div><div><br></div><div>Each depth-solution is interpretively ascribed to either a chronostratigraphic boundary with the stratigraphic units above and below the depth estimate, or the stratigraphic unit that the depth estimate occurs within, populated from the Australian Stratigraphic Units Database (ASUD). Stratigraphic attribution adds value and informs users of the depth to certain stratigraphic units in their areas of interest. Each solution is accompanied by confidence estimates. The depth estimate points are formatted for compliance with Geoscience Australia’s (GA) Estimates of Geological and Geophysical Surfaces (EGGS) database, the national repository for standardised depth estimate points. </div><div><br></div><div>Results from these interpretations provided some support to stratigraphic drillhole targeting, as part of the Delamerian Margins NSW National Drilling Initiative campaign, a collaboration between GA’s EFTF program, the MinEx CRC National Drilling Initiative and the Geological Survey of New South Wales. The magnetic depth-estimate solutions produced within this study provide important depth constraints in data-poor areas. These data help to construct a better understanding of the 3D geometry of the Australian continent and aid in cover thickness modelling activities. The availability of the depth-estimate solutions via the EGGS database through Geoscience Australia’s Portal creates enduring value to the public.</div>

Geoscience Australia is the custodian of the most comprehensive publicly available Australian airborne magnetic, gamma-ray, seismic, electromagnetic and gravity data sets. The airborne geophysics data set contains approximately 34 million line kilometres of data, which, at current prices, would cost approximately $197 million to acquire. The gravity data set contains more than 1.57 million reliable onshore stations gathered during more than 1800 surveys. The collection also includes a large number of seismic surveys from Australia's offshore basins. The onshore component of this data set was previously approved for RDSI for 8 TB. This proposal extends the collection to 150TB. The data types and access methods for the Offshore and Onshore data are identical Certain holdings are additionally hosted at the NCI (see downloads)

This service provides Estimates of Geological and Geophysical Surfaces (EGGS). The data comes from cover thickness models based on magnetic, airborne electromagnetic and borehole measurements of the depth of stratigraphic and chronostratigraphic surfaces and boundaries.

<p>The Geological Survey of South Australia commissioned the Gawler Craton Airborne Survey (GCAS) as part of the PACE Copper initiative. The airborne geophysical survey was flown over parts of the Gawler Craton in South Australia. The program was designed to capture new baseline geoscientific data to provide further information on the geological context and setting of the area for mineral systems (http://energymining.sa.gov.au/minerals/geoscience/pace_copper/gawler_craton_airborne_survey). <p>The survey design of 200 m spaced lines at a ground clearance of 60 m can be compared with the design of previous regional surveys which generally employed 400 m line spacing and a ground clearance of 80 m. The new survey design results in ~2 x the data coverage and ~25% closer to the ground when compared to previous standards for regional surveys in South Australia. <p>Survey blocks available for download include: <p>Streaky Bay, block 5 <p>Gairdner, block 6A <p>Spencer, block 7 <p>Kingoonya, block 9B <p>The following grids are available in this download: <p>• Laser-derived digital elevation model grids (m). Height relative to the Australian Height Datum. <p>• Radar-derived digital elevation model grids (m). Height relative to the Australian Height Datum. <p>• Total magnetic intensity grid (nT). <p>• Total magnetic intensity grid with variable reduction to the pole applied (nT). <p>• Total magnetic intensity grid with variable reduction to the pole and first vertical derivative applied (nT/m). <p>• Dose rate concentration grid (nGy/hr). <p>• Potassium concentration grid (%). <p>• Thorium concentration grid (ppm). <p>• Uranium concentration grid (ppm). <p>• NASVD processed dose rate concentration grid (nGy/hr). <p>• NASVD processed potassium concentration grid (%). <p>• NASVD processed thorium concentration grid (ppm). <p>• NASVD processed uranium concentration grid (ppm). <p>The following point located data are available in this download: <p>• Elevation. Height relative to the Australian Height Datum. Datum: GDA94 <p>• Total Magnetic Intensity. Datum: GDA94 <p>• Radiometrics. Datum: GDA94

Over 8,200 line kilometres of gravity and magnetic data, acquired during the 2020 Otway Basin Seismic Program (OBSP), were combined with public domain survey and satellite data to produce seamless maps of the NW-SE trending deep-water Otway Basin. These data provide valuable information on the geometry and spatial extent of igneous rocks in the deep-water basin. While the top of basement can effectively be imaged from seismic reflection datasets onshore in the Otway Basin, it remains problematic in parts of the deep-water offshore region due to variable seismic data quality. Modelling of the magnetic line data provides an estimate of the depth to the top of basement, an important interface for understanding hydrocarbon prospectivity because it plays a key role in characterising the tectonic evolution of the basin, and thus the thermal maturation history of hydrocarbons. Magnetic modelling was performed using a profile-based curve matching technique producing a depth estimate to the top of the magnetic body that is assumed to be the top of the basement. However, this assumption is flawed where there are volcanic or igneous intra-sedimentary rocks in the basin, as is the case for the Otway Basin where the interpretation of seismic reflection data shows highly reflective events corresponding to igneous features. In most parts of the basin, the modelling results show two layers: a shallow layer (depths < 1000m) corresponding to near surface volcanics, and a deeper layer (depths > 1000m) attributed to the top of the magnetic basement. Magnetic basement shows some similarities with basement picked on seismic reflection data, though in some areas the magnetic basement is shallower. The results also show that the depth to basement is not well resolved in areas with abundant intra-sedimentary igneous rocks. Further investigation is needed in such areas. Presented at the 2024 Australian Society of Exploration Geophysicists (ASEG) Discover Symposium

This service provides Estimates of Geological and Geophysical Surfaces (EGGS). The data comes from cover thickness models based on magnetic, airborne electromagnetic and borehole measurements of the depth of stratigraphic and chronostratigraphic surfaces and boundaries.

<div>Geoscience Australia (GA), in collaboration with the New South Wales (NSW) Government’s Geological Survey of NSW, undertook a horizontal magnetic gradient and radiometric survey in the Yathong area of NSW. This survey was fully funded by the NSW Government as part of a project to find deep groundwater for use in times of drought.</div><div><br></div><div>Survey Name: Yathong</div><div>Datasets Acquired: Horizontal Magnetic Gradient, Radiometrics, and Elevation</div><div>Geoscience Australia Project Number: P5023</div><div>Acquisition Start Date: 21/05/2023</div><div>Acquisition End Date: 14/09/2023</div><div>Flight line spacing: 200 m</div><div>Flight line direction: East-West (090-270 degrees)</div><div>Total distance flown: 65,503.75 line-km's</div><div>Nominal terrain clearance: 80 m</div><div>Data Acquisition: Magspec Airborne Surveys Pty Ltd</div><div>Project Management: Geoscience Australia</div><div>Quality Control: Geoscience Australia</div><div>Dataset Ownership: Geological Survey of New South Wales</div><div>Datum: Geocentric Datum of Australia 2020 (GDA2020)</div><div>Projection: Map Grid of Australia Zone 55 (MGA55)</div><div><br></div><div>Included in this release:</div><div><br></div><div>1. Point-located Data - ASCII-column (.dat) and NetCDF (.nc) format.</div><div>• Magnetic diurnal;</div><div>• Magnetic gradient raw-edited;</div><div>• Magnetic gradient reduced;</div><div>• Radiometrics raw-edited;</div><div>• Radiometrics reduced.</div><div><br></div><div>2. Gridded data - ERMapper (.ers) format.</div><div>• Gradient enhanced Total Magnetic Intensity (TMI);</div><div>• Gradient enhanced TMI Reduced to Pole (RTP);</div><div>• Gradient enhanced TMI RTP with First Vertical Derivative (1VD);</div><div>• Dose rate (with NASVD and standard processing);</div><div>• Potassium concentration (with NASVD, standard processing);</div><div>• Thorium concentration (with NASVD, standard processing);</div><div>• Uranium concentration (with NASVD, standard processing);</div><div>• Radar-derived digital elevation model (geoidal).</div><div><br></div><div>3. Reports.</div><div>• Calibration report;</div><div>• Operations and processing summary report.</div>

<p>Geoscience Australia (GA) generated a series of gravity and magnetic grids and enhancements covering Northern Australia. Several derivative gravity datasets have been generated 1) for the North-West Shield Western Australia region (approximately between latitudes 7‒26⁰ S and longitudes 110‒130⁰ E), 2) for the Northern Territory (approximately between latitudes 7‒26⁰ S and longitudes 125.5‒141⁰ E) and for Queensland (approximately between latitudes 7‒30⁰ S and longitudes 135‒160⁰ E). The magnetic dataset has been generated only for the North-West Shield Western Australia region (approximately between latitudes 7‒26⁰ S and longitudes 110‒130⁰ E). The magnetic and gravity data were downloaded from the Geophysical Archive Data Delivery System (GADDS), website (http://www.geoscience.gov.au/cgi-bin/mapserv?map=/nas/web/ops/prod/apps/mapserver/gadds/wms_map/gadds.map&mode=browse). Satellite Free-air (FA) gravity v27.1 (released March 11, 2019) and Satellite Topography v19.1 (released January 14, 2019) data were sourced from Sandwell et al. (2014) and downloaded from the Scripps Institution of Oceanography (SIO), National Oceanic and Atmospheric Administration (NOAA), U.S. Navy and National Geospatial-Intelligence Agency (NGA) (SIO Satellite Geodesy, website, http://topex.ucsd.edu/WWW_html/mar_grav.html). The Satellite Bouguer gravity grid with onshore correction density of 2.67 gcm-3 and offshore correction density of 2.20 gcm-3 was derived from the Free-air gravity v27.1 and Topography data V19.1. This Bouguer gravity grid was used for filling areas of data gaps in the offshore region. <p>Data evaluation and processing of gravity and magnetic data available in the area of interest resulted in the production of stitched onshore-offshore Bouguer gravity grid derived from offshore satellite Bouguer gravity grid and GA’s onshore ground and airborne gravity survey data and a stitched Total Magnetic Intensity (TMI) grid derived from airborne and shipborne surveys (Tables 1 and 5). A Reduction to the Pole (RTP) grid was derived from the stitched TMI grid. The TMI, RTP, FA and terrain corrected Bouguer gravity anomalies are standard datasets for geological analysis. The free-air gravity anomaly provides the raw and basic gravity information. Images of free-air gravity are useful for first-pass interpretation and the data is used for gravity modelling. Magnetic anomalies provide information on numerous magnetic sources, including deep sources as arising from the structure and composition of magnetic basement and shallow sources such as intra-sedimentary magnetic units (e.g. volcanics, intrusions, and magnetic sedimentary layers). A standard TMI image will contain information from all these sources. Geosoft Oasis montaj software was used throughout the data processing and enhancement procedure and the montaj GridKnit module was used to generate the stitched gravity and magnetic grids. <p>Enhancement techniques have been applied to the final processed Bouguer gravity and RTP magnetic grids to highlight subtle features from various sources and to separate anomalies from different source depths. These enhancement techniques are described in the next section. <p>Enhancement processing techniques and results <p>A summary of image processing techniques used to achieve various outcomes is described in Table 1. <p>Data type Filter applied Enhancement/outcome <p>Gravity/Magnetic First vertical derivative (1VD) Near surface features (e.g. intrabasinal) <p>Gravity/Magnetic Upward continuation Noise reduction in data <p>Gravity/Magnetic Low pass filter, or large distance upward continuation Enhancement of deep features (e.g. basement) <p>Gravity/Magnetic High pass filter Enhancement of shallow features (e.g. surface anomalies) <p>Gravity/Magnetic Tilt filter and 1VD Enhancement of structure (e.g. in basement) <p>Gravity/Magnetic ZS-Edgezone and ZS-Edge filters Enhancement of edges <p>Gravity/Magnetic horizontal modulus / horizontal gradient Enhancement of boundaries <p>Magnetic RTP (reduction to the pole), Compound Anomaly, and Analytic Signal filter Accurate location of sources

<div>This document defines the technical standards set by Geoscience Australia for the acquisition, processing and supply of airborne magnetic, horizontal magnetic gradient and radiometric (gamma-ray spectrometric) data. The technical standards cover the requirements for equipment, calibrations, quality control checks, reporting and data formats for airborne surveys.</div><div><br></div><div><br></div><div><strong>Table of Contents</strong></div><div><br></div><div>Attachment 1A – Data Acquisition and Processing</div><div><br></div><div>1 Aircraft</div><div>2 Flight and Tie Lines</div><div>3 Global Navigation Satellite System (GNSS)</div><div>4 Parallax Correction</div><div>5 Altimeter</div><div>6 Barometer</div><div>7 Digital Elevation Model</div><div>8 Magnetic System Equipment</div><div>9 Magnetic Gradient System Equipment</div><div>10 Magnetic / Gradient Calibration and Quality Tolerances</div><div>11 Magnetic Base Station (Diurnal Monitoring)</div><div>12 Magnetic Data Reduction</div><div>13 Magnetic Gradient Data Reduction</div><div>14 Radiometric System Equipment</div><div>15 Radiometric Calibration and Quality Tolerances</div><div>16 Radiometric Data Reduction</div><div><br></div><div>Attachment 1B – Reporting and Data Supply</div><div><br></div><div>1 General</div><div>2 Calibration Report</div><div>3 Daily Acquisition Report</div><div>4 Weekly Acquisition Report</div><div>5 Operations and Processing Summary Report</div><div>6 Supply Schedule</div><div><br></div><div>Attachment 1C – Data Formats</div><div><br></div><div>1 General</div><div>2 Point-Located Data Files</div><div>3 Definition Files</div><div>4 Description Files</div><div>5 Raw-Edited Magnetic Data File</div><div>6 Reduced Magnetic Data File</div><div>7 Diurnal Magnetic Data File</div><div>8 Raw-Edited Magnetic Gradient Data File</div><div>9 Reduced Magnetic Gradiometry Data File</div><div>10 Raw-Edited Radiometric Data File</div><div>11 Reduced Radiometric Data File</div><div>12 Gridded Data Files</div><div>13 Image Enhanced GeoTIFF Files

<div>This report contains information about the operation of Geoscience Australia’s ten permanent geomagnetic observatories, repeat stations and other relevant information covering the period from 2017 to 2021.</div><div>Information regarding the activities and services of Geoscience Australia’s Geomagnetism program, distribution of geomagnetic data, geomagnetic instrumentation and data processing procedures is also provided.</div><div><br></div>