The northern Houtman Sub-basin is an under-explored region of Australia’s western continental margin. It is located at the transition between the non-volcanic margin of the northern Perth Basin and the volcanic province of the Wallaby Plateau, and lies adjacent to the Wallaby-Zenith Transform Margin. In 2014-15, Geoscience Australia acquired new 2D seismic data (GA-349) across the northern Houtman Sub-basin to assess its hydrocarbon prospectivity. This study integrated interpretation of the recently acquired GA-349 survey, with Geoscience Australia’s existing regional interpretation of the Houtman and Abrolhos sub-basins, to develop a 2D structural and stratigraphic interpretation for the study area. As there are no wells in the northern Houtman sub-basin, the age and lithologies of the mapped sequences were derived from regional mapping, stratal relationships and seismic facies. The new data clearly images a large depocentre, including a much thicker Paleozoic section (up to 13 km) than previously recognised. Extending the length of the inboard part of northern sub-basin are a series of large half-graben (7-10 km thick), interpreted to have formed as a result of Permian rifting. Overlying these half-graben, and separated by an unconformity, is a thick succession (up to 6 km) interpreted to represent a subsequent late Permian to Early Jurassic phase of the thermal subsidence. A second phase of rifting started in the Early Jurassic and culminated in Early Cretaceous breakup. The sedimentary succession deposited during this phase of rifting is highly faulted and heavily intruded in the outboard part of the basin, adjacent to the Wallaby Saddle, where intrusive and extrusive complexes are clearly imaged on the seismic. In contrast to the southern part of the Houtman Sub-basin, which experienced rapid passive margin subsidence and regional tilting after the Valanginian breakup, the northern sub-basin remained mostly exposed sub-aerially until the Aptian while the Wallaby Zenith Fracture Zone continued to develop. Poster/Extended Abstract presented at the Australian Exploration Geoscience Conference (AEGC) 2018 (https://www.aig.org.au/events/first-australian-exploration-geoscience-conference/)

Browse Shelf reef polygons were manually digitized from multibeam echosounder datasets collected on marine survey GA0345/GA0346/TAN1411 in October/November 2014. Reef areas were defined as exposed, hard substrate that are often raised above the surrounding seafloor. The continental shelf was defined using the 200 m depth contour. They were mapped using bathymetry and backscatter data along with bathymetric derivatives including; slope, hillshaded bathymetry and contours. Features were mapped at a scale of 1:10 000. This dataset is published with the permission of the CEO, Geoscience Australia.

Interpretation of newly acquired seismic data in the northern Houtman Sub-basin (Perth Basin) suggests the region contains potential source rocks similar to those in the producing Abrolhos Sub-basin. The regionally extensive late Permian–Early Triassic Kockatea Shale has the potential to contain the oil-prone Hovea Member source interval. Large Permian syn-rift half-graben, up to 10 km thick, are likely to contain a range of gas prone source rocks. Further potential source rocks may be found in the Jurassic-Early Cretaceous succession, including the Cattamarra Coal Measures, Cadda shales and mixed sources within the Yarragadee Formation. This study investigates the possible maturity and charge history of these different source rocks. A regional pseudo-3D petroleum systems model is constructed using new seismic interpretations. Heat flow is modelled using crustal structure and possible basement composition determined from potential field modelling, and subsidence analysis is used to investigate lithospheric extension through time. The model is calibrated using temperature and maturity data from 9 wells in the Houtman and Abrolhos sub-basins. Source rock properties are assigned based on an extensive review of TOC, Rock Eval and kinetic data for the offshore northern Perth Basin. Petroleum systems analysis results show that Permian, Triassic and Early Jurassic source rocks may have generated large cumulative volumes of hydrocarbons across the northern Houtman Sub-basin, whilst Middle Jurassic‒Cretaceous sources remain largely immature. However the timing of hydrocarbon generation and expulsion with respect to trap formation and structural reactivation is critical for the successful development and preservation of hydrocarbon accumulations.

Lithified, drowned coastal dunes preserved below sea-level on continental shelves are rarely observed. Here we present new insights into the evolution of the Rottnest Shelf, southwestern Australia, where drowned parabolic dunes have been identified in high-resolution multibeam bathymetry (Figure 1). In 2012 Geoscience Australia undertook a marine survey of the warm temperate, carbonate-dominated, sediment-starved Rottnest Shelf, overlying the Vlaming Sub-basin, southwest Australia. This work supports an assessment of the CO2 storage potential of the basin, part of the Australian Government's National CO2 Infrastructure Plan. The survey acquired a range of data for sedimentological, geochemical and biological characterisation of the seabed, including multibeam sonar bathymetry and backscatter, side-scan sonar, acoustic sub-bottom profiles, towed underwater video and grab samples. Two areas were surveyed, one each north and south of Rottnest Island. The seabed surface comprised plains, ridges, and nested parabolic dunes, as well as high-relief mounds, shallow depressions, sediment waves, rhodolith beds and fault scarps. The seabed is dominantly a hard carbonate surface thinly veneered with biogenic carbonate sediment. Parabolic and crescent shaped ridges, with steep landward-facing slopes, form the most conspicuous features, with up to 10 m of relief above the seabed (water depths of 29-54 m). The ridges are interpreted to be the remnants of Late Quaternary coastal barriers and dunefields. Annular ridges are present within fields of parabolic ridges, the latter supporting high densities of sessile biota including hard corals, macroalgae, red algae, massive sponges and bryozoans. Here we propose a model to account for the geomorphic development of the Rottnest Shelf that relates the formation of the relict barrier dune system to eustatic changes in sea-level, prevailing winds and sediment supply. Additional factors considered include local variability in hydrodynamic regime and its interaction with geomorphic features.

The product consists of 5,291 line kilometres of time-domain airborne electromagnetic (AEM) geophysical data acquired in the Fitzroy River Catchment of the West Kimberley region, the electrical conductivity models derived from the dataset, and the survey operations and processing report. The data were acquired using the heliborne SkyTEM-312 AEM system. A locality diagram for the survey is shown below. The survey was funded by the Government of Western Australia, as part of its Water for Food Initiative, through the Department of Water (WA DoW). The survey was managed by Geoscience Australia as part of a national collaborative framework project agreement with WA DoW. The aim of the survey was to map the electrical properties of the top 200-300 metres of the sub-surface geology and hydrogeology within the study area. Geoscience Australia contracted SkyTEM Australia Pty Ltd to acquire the AEM data using the SkyTEM-312 system in September and October 2015. The data were also processed by SkyTEM Australia Pty Ltd using its in-house processing and inversion techniques. The Kimberley Region in north-west Australia is a priority area for the development of irrigated agriculture. The hydrogeology of the area is poorly understood, hence the primary aim of the AEM survey was to provide geophysical data in support of groundwater investigations. Specific objectives of the AEM survey included mapping the extent of regional Canning Basin aquifers to aid assessment of groundwater resources and sustainable yield estimates for agricultural development; provide AEM data in transects to underpin studies of surface-groundwater interactions (groundwater discharge and recharge potential) associated with the major rivers, and permanent river pools in particular; detect and assess potential groundwater salinity hazards within proposed irrigation areas; and map the seawater intrusion (SWI) interface. Very specific mapping objectives were developed for each sub-area, and the survey was designed with these detailed local objectives in mind. The survey design reflects two scales of investigation: 1. Two areas (Knowsley-Mowanjum and GoGo-Fitzroy Crossing) with higher density flight line spacing (400 m) in areas with advanced plans for development of irrigated agriculture; 2. Irregular grid of regional transects and lines acquired along river tracts reflecting the reconnaissance nature of regional investigations in a frontier hydrogeological area. Much of the area lies underneath cover of sedimentary basins and is a poorly-understood element of Australia¿s geology. The Fitzroy Trough is also host to a number of mineral systems including diamonds and base metal mineralisation, as well as shale gas resources. The survey data should assist with understanding of the basin geology and neotectonics, while lamproite pipes have also been intersected in a number of flight lines. The survey data will also add to the knowledge of the thickness and character of alluvium and regolith cover and will inform future geological mapping in the region. The data will be available from Geoscience Australia¿s web site free of charge. The data release package includes: 1. Point-located electromagnetic line data with associated position, height, orientation, transmitter current, and derived ground elevation data. These data are in ASCII column format with associated ASEG-GDF2 header files. All regular survey, repeat lines and high altitude lines are included in the dataset. The dataset is split into Parts 1 and 2 based on the differences in the receiver gate times for each part. 2. Point-located magnetic line data with associated position, height, orientation, and derived ground elevation data. These data are in ASCII column format with associated ASEG-GDF2 header files. All regular survey, repeat lines and high altitude lines are included in the dataset. 3. Point-located line data for conductivity estimates derived by SkyTEM Australia Pty Ltd using its Automated Laterally Constrained Inversion (aLCI) algorithm with associated position, height, orientation, and derived ground elevation data. Data include the conductivity estimate for each of the 30 inversion model layers, the layer elevation, estimated depth of investigation, and data fit residuals. These data are in ASCII column format with associated ASEG-GDF2 header files. All regular survey and repeat lines are included in the dataset. 4. Gridded data for the derived ground elevations, total magnetic intensity, and the conductivity of the 30 aLCI inversion model layers. The grids are in ER Mapper® binary raster grid format with associated header files. The grids have a cell size of 100 m. For the aLCI inversion layer conductivity grids, there are versions that are masked (set to undefined) below the estimated depth of investigation and unmasked. 5. Graphical multiplots and spatial images derived from the aLCI inversion. The multiplots show the derived aLCI conductivity depth sections and selected data panels for each individual flight line in Portable Network Graphics (PNG) and Portable Document Format (PDF) formats. The spatial images show colour images of the conductivity for each aLCI model layer and are in PNG, PDF and geo-located Tagged Image Format (TIF) files suitable for use in MAPINFO. 6. The survey Operations and Processing Report, which provides the details of the AEM system, logistics, data acquisition, data processing and the aLCI inversion parameters. 7. ESRI shapefiles and KML files of flight lines. Summary Survey Name West Kimberley Airborne EM Survey, WA, 2015 (Water for Food) State Western Australia Sub Region West Kimberley Area 20,314 km2 Line km 5,291 km Survey Completed 17 October 2015 AEM system SkyTEM-312 Processing SkyTEM Australia Pty Ltd

AusAEM 02 Airborne Electromagnetic Survey, NT /WA, 2019-2020: TEMPEST® AEM data and conductivity estimates The accompanying data package, titled “AusAEM 02 WA/NT, 2019-20 Airborne Electromagnetic Survey: TEMPEST® airborne electromagnetic data and conductivity estimates”, was released on 10 August 2020 by Geoscience Australia (GA), the Geological Survey of Western Australia and the Northern Territory Geological Survey. The package contains processed data from the“AusAEM 02 WA/NT, 2019-20 Airborne Electromagnetic Survey" that was flown over the North-West part of the Northern Territory across the border and all the way to the coast into Western Australia. The regional survey was flown at a 20-kilometre nominal line spacing and entailed approximately 55,675 line kilometres of geophysical data. The survey was flown in two tranches during 2019, by CGG Aviation (Australia) Pty. Ltd. under contract to Geoscience Australia, using the TEMPEST® airborne electromagnetic system. CGG also processed the data. The survey also includes a further 6,450 line kilometres of infill flying that was funded by private exploration companies, acquired in certain blocks within the survey area. The data from these infill blocks have been processed in the same manner as the regional lines and are part of this release. Geoscience Australia commissioned the AusAEM 02 survey as part of the Exploring for the Future (EFTF) program, flown over parts of the Northern Territory and Western Australia. Geoscience Australia (GA) leads the EFTF program, in collaboration with the State and Territory Geological Surveys of Australia. The program is designed to investigate the potential mineral, energy and groundwater resources of Australia driving the next generation of resource discoveries. GA managed the survey data acquisition, processing, contract, the quality control of the survey and generating two of the three inversion products included in the data package. The data release package comntains 1. A data release package summary PDF document. 2. The survey logistics and processing report and TEMPEST® system specification files 3. ESRI shape files for the regional and infill flight lines 4. Final processed point located line data in ASEG-GDF2 format 5. Conductivity estimates generated by CGG’s EMFlow conductivty-depth transform -point located line data output from the inversion in ASEG-GDF2 format -graphical (PDF) multiplot conductivity sections and profiles for each flight line -Grids generated from CGG's inversion conductivty-depth transform in ER Mapper® format (layer conductivities) 6. Conductivity estimates generated by Geoscience Australia's inversion -point located line data output from the inversion in ASEG-GDF2 format -graphical (PDF) multiplot conductivity sections and profiles for each flight line -georeferenced (PNG) conductivity sections (suitable for pseudo-3D display in a 2D GIS) -GoCAD™ S-Grid 3D objects (suitable for various 3D packages)

Refined wind vulnerability curves for residential houses in Western Australia. The dataset contains heuristic vulnerability curves for individual communities in WA, initially provided by Geoff Boughton (JCU), and modified by Martin Wehner (GA), in line with commentary from Geoff that the curves are representative of individual houses. The vulnerability would increase in a community situation due to debris generation from upwind houses. An additional curve for the reinforced masonry/concrete roof houses observed in Exmouth is also included.

<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

Carnarvon Shelf reef polygons were manually digitized from multibeam echosounder datasets collected on marine survey GA0308 in August/September 2008. Reef areas were defined as exposed, hard substrate that are often raised above the surrounding seafloor. They were mapped using bathymetry and backscatter data along with bathymetric derivatives including; slope, hillshaded bathymetry and contours. Features were mapped at a scale of 1:10 000. This dataset is published with the permission of the CEO, Geoscience Australia.

<div>AusAEM Western Resources Corridor Survey: Logistics Report, AEM Data, and GALEI conductivity estimates.</div><div><br></div><div>From&nbsp;May to October 2022, an airborne electromagnetic (AEM) survey was flown over parts of Western Australia, Northern Territory and South Australia. Geoscience Australia commissioned the survey in collaboration with the Geological Surveys of Western Australia (GSWA) and South Australia (GSSA)&nbsp;as part of the Australian Government's Exploring for the Future program and the Western Australian Government's Exploration Incentive Scheme.</div><div><br></div><div>A total of 58,858 line kilometres of new data were acquired. GA managed all aspects of the acquisition, quality control and processing of the AEM data.</div><div><br></div><div>The survey was flown by Xcalibur Aviation (Australia)&nbsp;Pty Ltd using its TEMPEST AEM system. The survey was flown in variable line directions and line spacings ranging from 20km to&nbsp;5km apart. Skytem Australia Pty Ltd also processed the data. This data package includes the acquisition and processing report, the final processed AEM data, and the results of the contractor's conductivity-depth estimates. The data package also contains the results and derived products from a 1D inversion by Geoscience Australia with its own inversion software.</div><div><br></div><div>Geoscience Australia's Exploring for the Future program provides pre-competitive information to inform decision-making by Government, community and industry on the sustainable development of Australia's mineral, energy and groundwater resources. We are building a national picture of Australia's geology and resource potential by gathering, analysing and interpreting new and existing precompetitive geoscience data and knowledge. This leads to a strong economy, resilient society and sustainable environment for the benefit of all Australians. This includes supporting Australia's transition to a low emissions economy, strong 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.</div><div><br></div><div>The survey will become part of the national AusAEM airborne electromagnetic acquisition program, which aims to provide geophysical information to support investigations of the regional geology and groundwater system and better characterise the salinity, recharge and architecture of the aquifers within the upper few hundred metres of the subsurface. It will also provide data to allow for the study of trends in regolith thickness and variability, variations in bedrock conductivity, the conductivity of key bedrock (lithology-related) conductive units under cover; and (d) the groundwater systems of the region at a reconnaissance scale.</div>