This Record presents 40Ar/39Ar chronologic results acquired in support of collaborative regional geoscientific investigations and mapping programs conducted by Geoscience Australia (GA) and the Northern Territory Geological Survey (NTGS). Argon isotopic data and interpretations from hornblende, muscovite, and biotite from seven samples collected from the Aileron Province in ALCOOTA , HUCKITTA, HALE RIVER, and ILLOGWA CREEK in the Northern Territory are presented herein. The results complement pre-existing geochronological constraints from U–Pb zircon and monazite analyses of the same or related samples, and provide new constraints on the thermal and deformation history of the Aileron Province. Three samples (2003082017, 2003082021, 2003083040) were taken from ALCOOTA in the northeastern portion of the Aileron Province. Biotite in sample 2003082017 from the ca 1.81 Ga Crooked Hole Granite records cooling below 320–280°C at 441 ± 5 Ma. Biotite in sample 2003082021 from the ca 1.73 Ga Jamaica Granite records cooling below 320–280°C at or after 414 ± 2 Ma. Muscovite in sample 2003083040 from the Delny Metamorphics, which were deposited after ca 1.82 Ga and preserve evidence for metamorphism at ca 1.72 Ga and 1.69 Ga, records cooling below 430–390°C at 399 ± 2 Ma. The fabrics preserved in the samples from the Crooked Hole Granite and Delny Metamorphics are interpreted to have formed due to dynamic metamorphism related to movement on the Waite River Shear Zone, an extension of the Delny Shear Zone, during the Palaeoproterozoic. Portions of the northeastern Aileron Province are unconformably overlain by the Neoproterozoic–Cambrian Georgina Basin, indicating these samples were likely at or near the surface by the Neoproterozoic. Together, these data indicate that rocks of the Aileron Province in ALCOOTA were subjected to heating above ~400°C during the Palaeozoic. Two samples (2003087859K, 2003087862F) of exoskarn from an indeterminate unit were taken from drillhole MDDH4 in the Molyhil tungsten–molybdenum deposit in central HUCKITTA. The rocks hosting the Molyhil tungsten–molybdenum deposit are interpreted as ca 1.79 Ga Deep Bore Metamorphics and ca 1.80 Ga Yam Gneiss. They experienced long-lived metamorphism during the Palaeoproterozoic, with supersolidus metamorphism observed until at least ca 1.72 Ga. Hornblende from sample 2003087859K indicates cooling below 520–480°C by 1702 ± 5 Ma and may closely approximate timing of skarn-related mineralisation at the Molyhil deposit; hornblende from sample 2003087862F records a phase of fluid flow at the Molyhil deposit at 1660 ± 4 Ma. The Salthole Gneiss has a granitic protolith that was emplaced at ca 1.79 Ga, and experienced alteration at ca 1.77 Ga. Muscovite from sample 2010080001 of Salthole Gneiss from the Illogwa Shear Zone in ILLOGWA CREEK records cooling of the sample below ~430–390°C at 327 ± 2 Ma. This may reflect the timing of movement of, or fluid flux along, the Illogwa Shear Zone. An unnamed quartzite in the Casey Inlier in HALE RIVER has a zircon U–Pb maximum depositional age of ca 1.24 Ga. Muscovite from sample HA05IRS071 of this unnamed quartzite yields an age of 1072 ± 8 Ma, which likely approximates, or closely post-dates, the timing of deformation in this sample; it provides the first direct evidence for a Mesoproterozoic episode of deformation in this part of the Aileron Province.

This report provides a description of the activities completed during the Bynoe Harbour Marine Survey, from 3 May and 17 May 2016 on the RV Solander (Survey GA4452/SOL6432). This survey was a collaboration between Geoscience Australia (GA), the Australian Institute of Marine Science (AIMS) and Department of Land Resource Management (Northern Territory Government) and the second of four surveys in the Darwin Harbour Seabed Habitat Mapping Program. This 4 year program (2014-2018) aims to improve knowledge of the marine environments in the Darwin and Bynoe Harbour regions by collating and collecting baseline information and developing thematic habitat maps that will underpin future marine resource management decisions. The program was made possible through funds provided by the INPEX-led Ichthys LNG Project to Northern Territory Government Department of Land Resource Management, and co-investment from Geoscience Australia and Australian Institute of Marine Science. The specific objectives of the Bynoe Harbour Marine Survey GA4452/SOL6432 were to: 1. Obtain high resolution geophysical (bathymetry) data for the deeper areas of Bynoe Harbour (<5 m), including Port Patterson; and, 2. Characterise substrates (acoustic backscatter properties, sub-bottom profiles, grainsize, sediment chemistry) the deeper areas of Bynoe Harbour (<5 m), including Port Patterson. Data acquired during the survey included: 698 km2 multibeam sonar bathymetry, water column and backscatter; 102 Smith-McIntyre grabs, 104 underwater camera drops, 29 sub-bottom profile lines and 34 sound velocity profiles.

This report is the third of three reports that provide the scientific analyses and interpretations resulting from a four-year collaborative habitat mapping program undertaken within the Darwin and Bynoe Harbour region by Geoscience Australia (GA), the Australian Institute of Marine Science (AIMS) and the Northern Territory Government Department of Environment and Natural Resources (DENR). This program was made possible through offset funds provided by the INPEX-operated Ichthys LNG Project to DENR, and co-investments from GA and AIMS.

This report is the first of three reports that provide the scientific analyses and interpretations resulting from a four-year collaborative habitat mapping program undertaken within the Darwin and Bynoe Harbour region by Geoscience Australia (GA), the Australian Institute of Marine Science (AIMS) and the Northern Territory Government Department of Environment and Natural Resources (DENR). This 4 year program (2014-2018) aims to improve knowledge of the marine environments in the Darwin and Bynoe Harbour regions by collating and collecting baseline information and developing thematic habitat maps that will underpin future marine resource management decisions. This program was made possible through offset funds provided by the INPEX-operated Ichthys LNG Project to DENR, and co-investments from GA and AIMS.

<p>The Northern Territory Geological Survey (NTGS) designed the Mount Peake-Crawford survey to provide high resolution magnetic, radiometric and elevation data in the area. It is anticipated that the data from the survey would help attract explorers into ‘greenfield’ terranes and contribute to the discovery of the next generation of major mineral and energy deposits in the Northern Territory. A total of 120,000 line km of regional data (200m line spacing) and additional infill data (100m line spacing), flown at 60m flight height were acquired during the survey between July and October 2019. The survey was managed by Geoscience Australia. <p>Various grids were produced from the Mount Peake-Crawford Airborne Magnetic and Radiometric Survey dataset and simultaneously merged into a single grid file. The final grid retains all of the information from the input data and is levelled to the national map compilations produced by Geoscience Australia. The merged grids have a cell size of 20m. <p>The following merged 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>• NASVD-filtered potassium concentration grid (%). <p>• NASVD-filtered thorium concentration grid (ppm). <p>• NASVD-filtered uranium concentration grid (ppm).

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.

This report is the second of three reports that provide the scientific analyses and interpretations resulting from a four-year collaborative habitat mapping program undertaken within the Darwin and Bynoe Harbour region by Geoscience Australia (GA), the Australian Institute of Marine Science (AIMS) and the Northern Territory Government Department of Environment and Natural Resources (DENR). This program was made possible through offset funds provided by the INPEX-operated Ichthys LNG Project to DENR, and co-investments from GA and AIMS.

Building on newly acquired airborne electromagnetic and seismic reflection data during the Exploring for the Future (EFTF) program, Geoscience Australia (GA) generated a cover model across the Northern Territory and Queensland, in the Tennant Creek – Mount Isa (TISA) area (Figure 1; between 13.5 and 24.5⁰ S of latitude and 131.5 and 145⁰ E of longitude) (Bonnardot et al., 2020). The cover model provides depth estimates to chronostratigraphic layers, including: Base Cenozoic, Base Mesozoic, Base Paleozoic and Base Neoproterozoic. The depth estimates are based on the interpretation, compilation and integration of borehole, solid geology, reflection seismic, and airborne electromagnetic data, as well as depth to magnetic source estimates. These depth estimates in metres below the surface (relative to the Australian Height Datum) are consistently stored as points in the Estimates of Geophysical and Geological Surfaces (EGGS) database (Matthews et al., 2020). The data points compiled in this data package were extracted from the EGGS database. Preferred depth estimates were selected to ensure regional data consistency and aid the gridding. Two sets of cover depth surfaces (Bonnardot et al., 2020) were generated using different approaches to map megasequence boundaries associated with the Era unconformities: 1) Standard interpolation using a minimum-curvature gridding algorithm that provides minimum misfit where data points exist, and 2) Machine learning approach (Uncover-ML, Wilford et al., 2020) that allows to learn about relationships between datasets and therefore can provide better depth estimates in areas of sparse data points distribution and assess uncertainties. This data package includes the depth estimates data points compiled and used for gridding each surface, for the Base Cenozoic, Base Mesozoic, Base Paleozoic and Base Neoproterozoic (Figure 1). To provide indicative trends between the depth data points, regional interpolated depth surface grids are also provided for the Base Cenozoic, Base Mesozoic, Base Paleozoic and Base Neoproterozoic. The grids were generated with a standard interpolation algorithm, i.e. minimum-curvature interpolation method. Refined gridding method will be necessary to take into account uncertainties between the various datasets and variable distances between the points. These surfaces provide a framework to assess the depth and possible spatial extent of resources, including basin-hosted mineral resources, basement-hosted mineral resources, hydrocarbons and groundwater, as well as an input to economic models of the viability of potential resource development.

The Great Artesian Basin Research Priorities Workshop, organised by Geoscience Australia (GA), was held in Canberra on 27 and 28 April 2016. Workshop attendees represented a spectrum of stakeholders including government, policy, management, scientific and technical representatives interested in GAB-related water management. This workshop was aimed at identifying and documenting key science issues and strategies to fill hydrogeological knowledge gaps that will assist federal and state/territory governments in addressing groundwater management issues within the GAB, such as influencing the development of the next Strategic Management Plan for the GAB. This report summarises the findings out of the workshop.

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)