The magnetotelluric (MT) method is increasingly being applied to a wide variety of geoscience problems. However, the software available for MT data analysis and interpretation is still very limited in comparison to many of the more mature geophysical methods such as the gravity, magnetic or seismic reflection methods. MTPy is an open source Python package to assist with MT data processing, analysis, modelling, visualization and interpretation. It was initiated at the University of Adelaide in 2013 as a means to store and share Python code amongst the MT community (Krieger and Peacock 2014). Here we provide an overview of the software and describe recent developments to MTPy. These include new functionality and a clean up and standardisation of the source code, as well as the addition of an integrated testing suite, documentation, and examples in order to facilitate the use of MT in the wider geophysics community.

Australia’s Energy Commodity Resources (AECR) provides estimates of Australia’s energy commodity reserves, resources, and production as at the end of 2019. The 2021 edition of AECR also includes previously unpublished energy commodity resource estimates data compiled by Geoscience Australia for the 2018 reporting period. The AECR energy commodity resource estimates are based primarily on published open file data and aggregated (de identified) confidential data. The assessment provides a pre COVID 19 baseline for the production and remaining recoverable resources of gas, oil, coal, uranium and thorium in Australia, and the global significance of our nation’s energy commodity resources.

This resource includes backscatter data for Arafura Marine Park (Arafura Sea) collected by Geoscience Australia (GA) and the Australian Institute of Marine Science during the period 2 – 15 November 2020 on the RV Solander. The survey was undertaken as a collaborative project funded through the National Environmental Science Program Marine Biodiversity Hub, with co-investment by GA and AIMS. The purpose of the project was to build baseline information for benthic habitats in Arafura Marine Park that will support ongoing environmental monitoring within the North Marine Park Network as part of the 10-year management plan (2018-2028). Data acquisition for the project included multibeam bathymetry and backscatter for two areas (Money Shoal and Pillar Bank), seabed samples and underwater imagery of benthic communities and demersal fish. This backscatter dataset contains two 32-bit geotiff files of the backscatter mosaic for two survey areas produced from the processed EM2040C Dual Head system using the CMST-GA MB Process v15.04.04.0 (x64) toolbox software co-developed by the Centre for Marine Science and Technology at Curtin University and Geoscience Australia. A detailed report on the survey is provided in: Picard, K. Stowar, M., Roberts, N., Siwabessy, J., Abdul Wahab, M.A., Galaiduk, R., Miller, K., Nichol, S. 2021. Arafura Marine Park Post Survey Report. Report to the National Environmental Science Program, Marine Biodiversity Hub (https://www.nespmarine.edu.au/node/4505).

Geoscience Australia is Australia’s Earth science public sector organisation, recognised for its expert data capabilities and high level of expertise. As the nation’s trusted advisor on geology and geography the organisation is the premium provider of data, science and analysis for decision makers. Internally, Geoscience Australia is currently targeting and refining its core capabilities in order to establish and clearly articulate our value proposition and service offering to stakeholders.

This Record presents new U–Pb geochronological data, obtained via Sensitive High Resolution Ion Micro Probe (SHRIMP), from 43 samples of predominantly igneous rocks collected from the East Riverina region of the central Lachlan Orogen, New South Wales. The results presented herein correspond to the reporting period July 2016–June 2020. This work is part of an ongoing Geochronology Project, conducted by the Geological Survey of New South Wales (GSNSW) and Geoscience Australia (GA) under a National Collaborative Framework agreement, to better understand the geological evolution and mineral prospectivity of the central Lachlan Orogen in southern NSW (Bodorkos et al., 2013; 2015; 2016, 2018; Waltenberg et al., 2019).

An assessment of tight, shale and deep coal gas prospectivity of the Cooper Basin has been undertaken as part of the Australian Government’s Geological and Bioregional Assessment Program. This aims to both encourage exploration and understand the potential impacts of resource development on water and the environment. This appendix presents a review of the regional petroleum prospectivity, its exploration, and the characterisation and analysis of shale, deep coal and tight gas in Carboniferous–Permian Gidgealpa Group of the Cooper Basin. The Cooper Basin is Australia’s premier onshore conventional hydrocarbon-producing province providing domestic gas for the East Coast Gas Market. As of December 2014, the Cooper and Eromanga basins have produced 6.54 Tcf of gas since 1969. The basins contain 256 gas fields as well as 166 oil fields that are currently in production. Gas is predominantly reservoired in the Cooper Basin, whereas the overlying Eromanga Basin hosts mainly oil. Hydrocarbon shows are found in the reservoir units throughout the succession. Recently, exploration targeting a range of unconventional plays has gained momentum. Unconventional play types within the mainly Permian Gidgealpa Group include shale gas associated with the Patchawarra Formation and the Roseneath and Murteree shales, tight and deep coal gas accumulations within the Toolachee, Epsilon and Patchawarra formations and additional tight gas plays in the Daralingie Formation and Tirrawarra Sandstone. To date, at least 80 wells have been drilled to test shale, tight and deep coal gas plays. Given the basin’s existing conventional production, and its processing and pipeline infrastructure, these plays are well placed to be rapidly commercialised, should exploration be successful. A prospectivity confidence mapping workflow was developed to evaluate the regional distribution of key unconventional gas plays within the Gidgealpa Group. For each play type, key physical properties were identified and characterised. The specific physical properties evaluated include formation extents, source rock properties (net thickness, TOC, quality and thermal maturity), reservoir characteristics (porosity, permeability, gas saturation and brittleness), regional stress regime and overpressure. Parameters for mappable physical properties were individually classified to assign prospectivity rankings. Individual properties were then multiplied together produce formation and play-specific prospectivity confidence maps. Non-mappable criteria were not integrated into the prospectivity mapping but were used to better understand the geological characteristics of the formations. Overall, both source and reservoir characteristics were found to be moderately to highly favourable for all play types assessed. Abundant source rocks are present in the Gidgealpa Group across the Cooper Basin. The Toolachee and Patchawarra formations are the richest, thickest and most extensive source rocks, with good to excellent source potential across their entire formation extents. Net shale, coal and sand thicknesses also demonstrate an abundance of potential reservoir units in the Gidgealpa Group across the basin. The predominantly fluvial Toolachee Formation is thickest in the Windorah Trough and Ullenbury Depression. Average effective porosity for assessed tight gas plays ranges from 6.7 % in the fluvio-deltaic to lacustrine Epsilon Formation to 7.8% in the Toolachee Formation. Based on an assessment of the brittleness of the shales and coaly shales, the Patchawarra Formation appears to be most favourable for hydraulic stimulation with an average Brittleness Index of 0.695, indicative of brittle rocks. This compares to the less brittle lacustrine Roseneath and Murteree shales have brittleness indices of 0.343 and 0.374, respectively. As-received total gas content is favourable, with averages ranging from 1.3 scc/g in the Patchawarra Formation to 1.6 scc/g for the Murteree Shale. The regional stress regime has an approximately east-west oriented maximum horizontal stress azimuth, resulting in predominantly strike-slip faulting to reverse faulting, depending on the depth, lithology and proximity of structures, e.g. GMI ridge. Significant overpressure is present at depths greater than 2800 m, especially in the Nappamerri and Patchawarra troughs. Overpressures are generally constrained to the Gidgealpa Group, with the Toolachee Formation being the youngest formation in which significant overpressure has been achieved. Based on a review of the geomechanical properties of the Cooper Basin sedimentary succession, it was found that stress variations within and between lithologies and formations are likely to provide natural barriers to fracture propagation between the gas saturated Permian sediments and the overlying Eromanga Basin. Prospectivity confidence maps were generated for six individual shale and deep coal plays and one combined tight gas play across the Gidgealpa Group. Comparison with key wells targeting shale, tight and deep coal gas plays, indicates that the prospectivity confidence mapping results are largely consistent with exploration activity to-date, with the highest prospectivity confidence for tight, shale and deep coal gas plays mapped in the Nappamerri, Patchawarra, Windorah, Allunga and Wooloo troughs and the southern Ullenbury Depression. Consequently, there is more confidence in the resultant maps in the southern Cooper Basin as more data was available here. Prospectivity confidence maps are relative, therefore a high prospectivity confidence does not equate to 100 % chance of success for a particular formation or play. The outputs of this regional prospectivity assessment identify areas warranting more detailed data collection and exploration and the assessment of potential impacts of resource development on water and the environment. The results also have the potential to encourage further exploration investment in underexplored regions of the Cooper Basin.

Assessing the regional prospectivity of tight, shale and deep coal gas resources in the Cooper Basin is an integral component of the Australian Government’s Geological and Bioregional Assessment Program, which aims to encourage exploration and understand the potential impacts of resource development on water and the environment. The Permo-Triassic Cooper Basin is Australia’s premier onshore conventional hydrocarbon-producing province, yet is relatively underexplored for unconventional gas resources. A chance of success mapping workflow, using rapid integration of new and existing data, was developed to evaluate the regional distribution of key gas plays within the Gidgealpa Group. For each play type, key physical properties (e.g. lithology, formation depths and extents, source rock and reservoir characteristics, and rock mechanics) were identified and criteria were used to assign prospectivity rankings. Parameter maps for individual physical properties were classified, weighted and then combined into prospectivity confidence maps that represent each play’s relative chance of success. These combined maps show a high chance of success for tight, shale and deep coal gas plays in the Nappamerri, Patchawarra and Windorah troughs, largely consistent with exploration results to-date. The outputs of this regional screening process help identify additional areas warranting investigation, and may encourage further exploration investment in the basin. This methodology can be applied to other unconventional hydrocarbon plays in frontier and proven basins.

GA publication: Flyer AEIP, ELVIS, EM-LINK 2021

AusAEM (WA) 2020-21, Earaheedy & Desert Strip Airborne Electromagnetic Survey The accompanying data package, titled “AusAEM (WA) 2020-21,Earaheedy & Desert Strip Airborne Electromagnetic Survey Blocks: TEMPEST® airborne electromagnetic data and GALEI conductivity estimates”, was released on 25 March 2021 by Geoscience Australia (GA) and the Geological Survey of Western Australia. The data represents the first phase of the AusAEM2020 (WA) survey flown with a fixed-wing aircraft by CGG Aviation (Australia) Pty. Ltd. under contract to Geoscience Australia, using the TEMPEST® airborne electromagnetic system. The survey was flown at a 20-kilometre nominal line spacing over the most eastern part of the state and down to the southern coast of Western Australia. The total area encompasses close to 32,680 line kilometres of newly acquired airborne electromagnetic geophysical data. CGG also processed the data. This package contains 14,279 line kilometres of the survey data, which have been quality-controlled, processed and inverted. The Earaheedy Block entailed approximately 6,407 line kilometres and the Desert Strip 7,870 line kilometres. The remaining data will be released as a separate package. Geoscience Australia and Western Australia (Department of Mines, Industry Regulation and Safety) commissioned the AusAEM 2020 survey as part of the national airborne electromagnetic acquisition program, to complete 20km line separation AEM coverage over WA. The program is designed to deliver freely available pre-competitive geophysical data to assist in the investigation and discovery of potential mineral, energy and groundwater resources within Australia. Funding for the survey came from the Western Australian government’s Exploration Incentive Scheme. GA managed the survey data acquisition, processing, contracts, quality control of the survey and generated the inversion products included in the data package. The data release package contains 1. A data release package summary PDF document. 2. The survey logistics and processing report and TEMPEST® system specification files 3. ESRI shapefiles 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 conductivity-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 conductivity-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)

This document sets out the five year strategy for the marine geoscience program at Geoscience Australia, for the period 2018-2023. This strategy delivers to Geoscience Australia's Strategy 2028 in the area of 'Managing Australia's marine jurisdictions to support sustainable use of our marine environment.' The strategy includes four key activities: (1) National Coordination of Seabed Mapping; (2) Data Acquisition for Marine and Coastal Baselines and Monitoring; (3) Marine Geoscience Data Accessibility, and; (4) Marine Geoscience Advice.