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.

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.

<div>An airborne gravity survey was conducted over the North East Canning area in the Kimberley region of Western Australia as a part of the Tanami-NE Canning Western Australia Airborne Gravity Survey 2017. The survey was part of a collaborative research project between Geoscience Australia (GA) and the Geological Survey of Western Australia. Gravity data was collected at 5 km wavelength resolution with the purpose to help characterise key undercover geological elements of the region. The survey was conducted by Thomson Aviation Pty Ltd with a GT-2A gravimeter and managed by Geoscience Australia. A total of 23,953.65 line km of data were acquired over an area of 53,346 km².</div><div><strong>Survey details</strong></div><div>Survey Name: Tanami North East Canning Airborne gravity survey</div><div>State/Territory: Western Australia (WA)</div><div>Datasets Acquired: Airborne gravity</div><div> Geoscience Australia Project Number: P1291A</div><div> Acquisition Start Date: 17 August 2017</div><div> Acquisition End Date: 15 November 2017</div><div> Flight line spacing: 2.5 km</div><div> Flight line direction: 180deg / NS</div><div> Tie line spacing: 25km</div><div> Tie line direction: 270 deg / EW</div><div>Total line kilometers: 23,953.65</div><div> Nominal terrain clearance (above ground level): 710 m</div><div> Aircraft model: GippsAero GA-8 Airvan</div><div>Data Acquisition: Thomson Aviation Pty Ltd</div><div> Project Management: Geoscience Australia</div><div> Quality Control: CMG Operations Pty Ltd and Geoscience Australia</div><div> Dataset Ownership: GSWA and Geoscience Australia</div><div><br></div><div><strong>Files included in this download </strong></div><div>&nbsp;</div><div>This data package release contains the final survey deliverables received from the contractor Thomson Aviation, with an initial QC by CMG Operations Pty Ltd, then peer reviewed by Dr Jack McCubbine (Geoscience Australia).</div><div>&nbsp;</div><div>The horizontal datum and projection for all the data are GDA94 and MGA51, respectively.</div><div>&nbsp;</div><div><strong>1.</strong> <strong><em>Point-located Data / line data</em></strong></div><div>ASCII column XYZ and ASEG-GDF2 format with accompanying description and definition files. </div><div><br></div><div> <strong><em>2.Grids</em></strong> –</div><div> Datum:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;GDA94</div><div>Projection:&nbsp;&nbsp;MGA51</div><div>Grid cell size:&nbsp;500m</div><div>Format: ERMapper (.ers)</div><div>Gravity datum: AAGD07. </div><div>&nbsp;</div><div>There are 24 gridded data supplied in ERMapper (.ers) format. The grid cell size is 500 metres. The gravity datum used is AAGD07.</div><div><br></div><div> <strong>3. Reports</strong> </div><div> • Final survey logistic report delivered to Geoscience Australia by the survey contractor - <em>TNC-NE-CANNING-FINAL-REPORT.PDF</em></div><div>• QC report from the peer reviewing the data package: <em>Tanami - North East Canning QC report.pdf</em></div><div> </div><div>The data from this Tanami North East Canning survey can also be downloaded from the Geological Survey of Western Australia’s MAGIX platform at https://magix.dmirs.wa.gov.au and GeoVIEW.WA web mapping application at https://geoview.dmp.wa.gov.au/GeoView under reference number 71201.&nbsp;</div><div><br></div>

<div>The Tanami–King Leopold survey was part of a collaborative research project between Geoscience Australia (GA) and the Geological Survey of Western Australia. Gravity data was collected at 5 km wavelength resolution with the purpose to help characterise key undercover geological elements of the region. The project area extends approximately from the Balgo Hills region near the border with the Northern Territory through to Derby in the west. The survey was conducted by Thomson Aviation Pty Ltd with a GT-2A gravimeter and managed by GA. A total of 25,869.36 line km of data were acquired over an area of 58,040 km².</div><div>&nbsp;</div><div><strong>Survey details</strong></div><div>Survey Name: Tanami-King Leopold WA airborne gravity survey 2017</div><div>State/Territory: Western Australia (WA)</div><div>Datasets Acquired: Airborne gravity</div><div> Geoscience Australia Project Number: P1291B</div><div> Acquisition Start Date: June 16, 2017</div><div> Acquisition End Date: August 12, 2017</div><div> Flight line spacing: 2.5 km</div><div> Flight line direction: 180deg / NS</div><div> Tie line spacing: 25km</div><div> Tie line direction: 270 deg / EW</div><div>Total line kilometers: 25,869.36</div><div> Nominal terrain clearance (above ground level): 477 m</div><div> Aircraft type: GippsAero GA-8 Airvan</div><div>Data Acquisition: Thomson Aviation </div><div> Project Management: Geoscience Australia</div><div> Quality Control: CMG Operations Pty Ltd and Geoscience Australia</div><div> Dataset Ownership: GSWA and Geoscience Australia</div><div>&nbsp;</div><div><strong>Files included in this download</strong></div><div>This data package release contains the final survey deliverables received from the contractor Thomson Aviation. Quality control and data processing services were provided by CMG Operations Pty Ltd and peer reviewed by Dr Jack McCubbine (Geoscience Australia).</div><div>&nbsp;</div><div>The horizontal datum and projection for all the data are GDA94 and MGA52, respectively.</div><div>&nbsp;</div><div><strong>1.</strong> <strong><em>Point-located Data / line data</em></strong></div><div>ASCII column XYZ and ASEG-GDF2 format with accompanying description and definition files.</div><div><br></div><div> <strong><em>2.Grids</em></strong> </div><div> </div><div>Datum:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;GDA94</div><div>Projection:&nbsp;&nbsp;MGA52</div><div>Grid cell size:&nbsp;500m</div><div>Format: ERMapper (.ers)</div><div>Gravity datum: AAGD07. </div><div>&nbsp;</div><div>There are 24 gridded data supplied in ERMapper (.ers) format. The grid cell size is 500 metres. The gravity datum used is AAGD07. </div><div><br></div><div> <strong>3. Reports</strong> </div><div> • Final survey logistic report delivered to Geoscience Australia by the survey contractor: <em>TNC-TANAMI-FINAL-REPORT.pdf</em></div><div>• QC report from the peer reviewer of the data package: <em>Tanami King Leopold QC report.pdf</em></div><div> </div><div>The data from this Tanami King Leopold survey can also be downloaded from the Geological Survey of Western Australia’s MAGIX platform at https://magix.dmirs.wa.gov.au and GeoVIEW.WA web mapping application at https://geoview.dmp.wa.gov.au/GeoView under reference number 71200.&nbsp;</div><div><br></div>

CGG Aviation (now Xcalibur Multiphysics) collected airborne gravity data in the Kidson area covering parts of the Gibson and Great Sandy Deserts in central Western Australia as part of a collaborative project between Geoscience Australia (GA) and the Geological Survey of Western Australia (GSWA). The aim of the project was to collect airborne gravity gradiometry data in the region at 2500 m wavelength resolution to help characterise key undercover geological elements of the region. The survey consisted of a Main block and an Extension block. Data were acquired from North/South flight lines (Main block) and East-West flight lines (Extension block) with an average target ground clearance of 120m. Tie lines at 25,000m line spacing were flown only for the Main block. A total of 78,700 line kilometres of data were collected during the survey. <b>Survey details</b> Survey Name: Kidson WA airborne gravity gradiometer survey 2017 State/Territory: Western Australia Datasets Acquired: Airborne gravity gradiometer Geoscience Australia Project Number: Acquisition Start Date: July 21, 2017 Acquisition End Date: May 3, 2018 Number of blocks: 2 Flight line spacing: 2,500m Flight line direction: Area 1 - 180 deg/ NS; Area 2 - 270 deg/EW Tie line spacing: 25,000m Tie line direction: Area 1 only - 270 deg / EW Total distance flown: 78,700 line kilometres Nominal terrain clearance (above ground level): 120m Clearance method: Drape Aircraft type: 2 aircrafts with different Falcon AGG system installed - Cessna Grand Caravan 208B / Full spectrum Falcon system Kepler/Newton Data Acquisition: CGG Aviation Australia Pty Ltd Project Management: Geoscience Australia Quality Control: Dr Mark Dransfield contracted by Geoscience Australia Dataset Ownership: Western Australia and Geoscience Australia <b>Files included in this download</b> The original agreement with CGG Aviation Australia Pty Ltd (CGG) stated that gradient point located data was available for purchase on non-exclusive terms from CGG until 30 June 2027, after which date the gradient data would be made public. In July 2021, the terms of the agreement changed after Xcalibur Multiphysics acquired CGG Aviation Pty Ltd. Xcalibur authorised the release of the gradient data. A new final dataset and report was generated by Xcalibur and delivered to Geoscience Australia. This data release contains the gradient point located data. <b>1. Point-located Data / line data</b> ASEG-GDF2 and Geosoft GDB format with accompanying description and definition files. The sample frequency is 8Hz. <b>2. Grids</b> Datum: GDA2020 Projection: MGA 51 Grid cell size: 500m Formats: Geosoft GRD and ERMapper (.ers) with accompanying description files. <b>3. Reports</b> • Final survey logistic report delivered to Geoscience Australia by the survey contractor. • Kidson QC report from Dr Mark Dransfield The data from this Kidson airborne gravity gradiometry survey has been released and can be downloaded from the Geological Survey of Western Australia’s MAGIX platform at https://magix.dmirs.wa.gov.au and GeoVIEW.WA web mapping application at https://geoview.dmp.wa.gov.au/GeoView under reference number 71234.

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)

<div>The Yilgarn Craton of Western Australia represents one of the largest pieces of Precambrian crust on Earth, and a key repository of information on the Meso-Neoarchean period. Understanding the crustal, tectonic, thermal, and chemical evolution of the craton is critical in placing these events into an accurate geological context, as well as developing holistic tectonic models for the Archean Earth. In this study, we collected a large U-Pb (420 collated samples) and Hf isotopic (2163 analyses) dataset on zircon to investigate the evolution of the craton. These data provide strong evidence for a Hadean-Eoarchean origin for the Yilgarn Craton from mafic crust at ca. 4000 Ma. This ancient cratonic nucleus was subsequently rifted, expanded and reworked by successive crustal growth events at ca. 3700 Ma, ca. 3300 Ma, 3000-2900 Ma, 2825-2800 Ma, and ca. 2730-2620 Ma. The <3050 Ma crustal growth events correlate broadly with known komatiite events, and patterns of craton evolution, revealed by Hf isotope time-slice mapping, image the periodic break-up of the Yilgarn proto-continent and the formation of rift-zones between the older crustal blocks. Crustal growth and new magmatic pulses were focused into these zones and at craton margins, resulting in continent growth via internal (rift-enabled) expansion, and peripheral (crustal extraction at craton margins) magmatism. Consequently, we interpret these major geodynamic processes to be analogous to plume-lid tectonics, where the majority of tonalite-trondhjemite-granodiorite (TTG) felsic crust, and later granitic crust, was formed by reworking of hydrated mafic rocks and TTGs, respectively, via a combination of infracrustal and/or drip-tectonic settings. While this process of crust formation and evolution is not necessarily restricted to a specific geodynamic system, we find limited direct evidence that subduction-like processes formed a major tectonic component, aside from re-docking the Narryer Terrane to the craton at ca. 2740 Ma. Overall, these 'rift-expansion' and 'craton margin' crustal growth process led to an intra-cratonic architecture of younger, juvenile terranes located internal and external to older, long-lived, reworked crustal blocks. This framework provided pathways that localized later magmas and fluids, driving the exceptional mineral endowment of the Yilgarn Craton.</div> This Abstract/Poster was submitted to & presented at the 2023 6th International Archean Symposium (6IAS) 25 - 27 July (https://6ias.org/)

<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>Komatiites are extinct volcanic rocks that formed by partial melting of 20-50% of their mantle source – a unique feature that allows us to understand the composition of the mantle in the early Earth. Due to their high temperature, komatiites incorporate proximal rock types on their way to, and on, the Earth’s surface. In this craton-scale study, we looked to use this property of komatiite magmas to track their interaction with the crust of the Yilgarn Craton. The results yielded Hf and Nd isotope arrays (Figure 1), that potentially have three components. The first likely represents the depleted mantle source of the magmas, and most plot in the region between +2 and +6 εHfi and 0 to +3.3 εNdi. The second source represents a more unradiogenic component, most likely 3.5-3.3 Ga continental crust (minimum). This component is more notable in the 2.8 and 2.9 Ga events with values trending to CHUR and negative εNd. The 2.8 Ga dataset, and particularly the komatiitic basalts from the Marda region, appear to show the most contamination with old crust. This is likely due to this area representing the old nucleus of the craton, as shown in Hf-isotope mapping. The final component represents an ultra-depleted source. Data from Ravensthorpe, Mt Clifford, and Wiluna show trends towards this source referred to as the Early Refractory Reservoir (ERR)(Nebel et al. 2014). We suggest that the 2.7 and 2.9 Ga plumes interacted with refractory Hadean plume residues, which constitute the ERR, within the Yilgarn lithosphere. Isotopic data on crustal rocks suggests the Yilgarn may have formed in the Hadean to Eoarchean, and hence the ERR could represent the residue of the Hadean crust generation process that formed the low Lu/Hf Jack Hills zircons. If correct, this suggests that the ERR survived for much longer than previously thought, as a rare component within the Earth’s oldest cratons.</div> This Abstract was submitted/presented to the 2023 6th International Archean Symposium (6IAS) 25 - 27 July (https://6ias.org/)

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.