Geoscience Australia first sought feedback on a metadata standard for magnetotelluric (MT) time-series data in 2018 with the publication of a Preview article (Kirkby, 2019) outlining suggestions for metadata fields that should be collected when running an MT survey. This was the first step in standardising the MT formats used by the Australian MT community to ensure a cohesive community approach moving forward. Intrepid Geophysics was subsequently contracted by Geoscience Australia to investigate the current community sentiment around a metadata standard and report on the community’s requirements for a standardised data format. Intrepid Geophysics was chosen as an independent party that had no significant stake in the magnetotellurics discussion. This report is the third made to Geoscience Australia in a series investigating the needs of the Australian magnetotelluric community, with a focus on the definition of the metadata that should be collected along with the raw data of an MT survey. The findings were collated from interviews conducted in the preliminary stage of the project as well as an online questionnaire that was sent to those who had agreed to be contacted. Feedback was constructive, centring on standardisation of parameter naming schemes, adding parameters that were missing and could add value, and misclassification of parameters. Future work should focus on a more widespread community engagement program that involves system manufacturers as well as building the metadata structure around the chosen data format.

<p>The Barkly 2D Seismic Survey was acquired during September to November 2019 and commenced near the town of Camooweal on the border of Queensland and Northern Territory. This project is a collaboration between Geoscience Australia (GA) and the Northern Territory Geological Survey (NTGS), and was funded by the Australian Government's Exploring for the Future program and the Northern Territory Geological Survey under Northern Resourcing the Territory initiative. <p>The Barkly seismic survey extends the 2017 South Nicholson seismic survey and links with the existing Beetaloo Sub-basin seismic data. The total length of acquisition was 812.6 km spread over five lines 19GA-B1 (434.6 km), 19GA-B2 (45.9 km), 19GA-B3 (66.9 km), 19GA-B4 (225.8 km) and 19GA-B5 (39.4 km). The Barkly seismic project provides better coverage and quality of fundamental geophysical data over the region from the southern McArthur Basin to northern Mt Isa western succession. The Barkly seismic data will assist in improving the understanding of basins and basement structures and also the energy, mineral and groundwater resource potential in Northern Australia. The new reflection seismic data and derivative information will reduce the risk for exploration companies in this underexplored area by providing information for industry to confidently invest in exploration activities. <b>Raw data for this survey are available on request from clientservices@ga.gov.au - Quote eCat# 132890</b>

<p>The accompanying data package, was released on 30 April 2020 by the Geological Survey of New South Wales (GSNSW) and Geoscience Australia (GA). <p>The package contains processed data from the “MinEx CRC Cobar Airborne Electromagnetic Survey” that was flown over the Cobar–Lake Cargelligo area of Central West New South Wales . The regional survey was flown at 2.5 and 5 km nominal line spacings and entails approximately 5,900 line kilometres of new geophysical data. The survey was flown in 2019 by New Resolution Geophysics Pty. Ltd. (NRG) using the XCITE® airborne electromagnetic system. NRG also processed the data. <p>The survey also included a further 800 line kilometres of infill flying that was funded by private exploration companies, in certain blocks within the survey area. The data from these infill blocks are not part of this data release due to confidentiality agreements but will be released to the public after a 12 month moratorium. <p>GSNSW commissioned the survey as part of the MinEx Cooperative Research Centre’s (MinEx CRC), the world’s largest mineral exploration collaboration. It brings together industry, government, research organisations and universities to further our understanding of geology, mineral deposits and groundwater resources in areas where rocks aren’t exposed at Earth’s surface. GSNSW is a major participant in the NDI program, committing $16 million to the program over 10 years. In NSW, the program focuses on five areas in the state’s central and far west, where metallic minerals potentially exist under a layer of younger barren geology. These areas are North Cobar, South Cobar, Broken Hill (Mundi), Forbes and Dubbo. <p>GA managed the survey data acquisition and processing contract and the quality control of the survey on behalf of GSNSW. GA also contributed by generating one of the two inversion products included in the data package. <p>The data release package comntains <p>1. A data release package summary PDF document. <p>2. The survey logistics and processing report and XCITE® system specification files <p>3. ESRI shape files for the flight lines and boundary <p>4. KML (Google Earth) files of the flight lines <p>5. Final processed point located line data in ASEG-GDF2 format -final processed dB/dt electromagnetic, magnetic and elevation data -final processed BField electromagnetic, magnetic and elevation data <p>6. Conductivity estimates generated by NRG’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 -graphical (JPEG) conductivity sections for each line -georeferenced (PNG) conductivity sections (suitable for pseudo-3D display in a 2D GIS) -GoCAD™ S-Grid 3D objects (suitable for various 3D packages) -Curtain image conductivity sections (suitable 3D display in GA’s EarthSci) -Grids generated from the NRG inversion in ER Mapper® format (layer conductivities, depth slices, elevation slices) -Images generated from the grids above (layer conductivities, depth slices, elevation slices) <p>7. Conductivity estimates generated by Geoscience Australia's inversion -point located line data output from the inversion in ASEG-GDF2 format -graphical (JPEG) conductivity sections for each line -georeferenced (PNG) conductivity sections (suitable for pseudo-3D display in a 2D GIS) -GoCAD™ S-Grid 3D objects (suitable for various 3D packages) -Curtain image conductivity sections (suitable 3D display in GA’s EarthSci) -Grids generated from Geoscience Australia's inversion in ER Mapper® format (layer conductivities, depth slices, elevation slices) -Images generated from the grids above (layer conductivities, depth slices, elevation slices) <p>Directory structure <p>├── report <p>│   ├── line_data <p>│   ├── shapefiles <p>│   ├── kml <p>│   ├── contractor_inversion <p>│   │   ├── line_data <p>│   │   ├── multiplots <p>│   │   ├── sections <p>│   │   ├── georeferenced_sections <p>│   │   ├── gocad_sgrids <p>│   │   ├── earthsci <p>│   │   │   └── MinExCRC_Cobar_AEM_Contractor_Regional <p>│   │   ├── images <p>│   │   │   ├── layers <p>│   │   │   ├── depth_slice <p>│   │   │   └── elevation_slice <p>│   │   └── grids <p>│   │   ├── layers <p>│   │   ├── depth_slice <p>│   │   └── elevation_slice <p>│   └── ga_inversion <p>│   ├── line_data <p>│   ├── sections <p>│   ├── georeferenced_sections <p>│   ├── gocad_sgrids <p>│   ├── earthsci <p>│   │   └── MinExCRC_Cobar_AEM_GA-Inversion_Regional <p>│   ├── images <p>│   │   ├── layers <p>│   │   ├── depth_slice <p>│   │   └── elevation_slice <p>│   └── grids <p>│   ├── layers <p>│   ├── depth_slice <p>│   └── elevation_slice

As part of the Exploring For the Future program 2022 showcase, Geoscience Australia (GA) in collaboration with the Australian Institute of Geoscientists held an Airborne Electromagnetics (AEM) workshop in Perth on 11th August 2022. The workshop comprised the following: - An introduction to GA's 20 km spaced continent-wide AusAEM program, by Karol Czarnota - How the Western Australia government has successfully used 20 km spaced AEM data, by Klaus Gessner - An introduction to AEM, surveying, and quality control given by Yusen Ley-Cooper - An introduction to inverse theory presented by Anandaroop Ray - Hands-on AEM modeling and inversion using HiQGA.jl by Anandaroop Ray - Integrating geophysics and geology in subsurface interpretation, by Sebastian Wong - Avoiding the 10 most common pitfalls in AEM interpretation according to Neil Symington YouTube video from the workshop, as well as data and code to follow along with the videos can be found on GA's GitHub at <a href=https://github.com/GeoscienceAustralia/HiQGA.jl/tree/workshop><u>this link.</u></a>

Barnicarndy 1 is a stratigraphic well drilled in the southern part of the Canning Basin’s Barnicarndy Graben under Geoscience Australia’s Exploring for the Future program in collaboration with the Geological Survey of Western Australia to provide stratigraphic data for this poorly understood tectonic component. The well intersects a thin Cenozoic section, Permian–Carboniferous fluvial clastics and glacial diamictites and a thick pre-Carboniferous succession (855–2585 mRT) unconformably overlying Neoproterozoic metasedimentary rocks. Three informal siliciclastic intervals were defined based on core lithology, well logs, chemical and mineral compositions: the Upper Sandstone (855–1348.1 mRT), Middle Interval (1348.1–2443.4 mRT) and Lower Sandstone (2443.4–2585 mRT). The Middle Interval was further divided into six internal zones. Both conventional methods and artificial neural network technology were applied to well logs to interpret petrophysical and elastic properties, total organic carbon (TOC) content, pyrolysis products from the cracking of organic matter (S2) and mineral compositions. Average sandstone porosity and reservoir permeability are 17.9% and 464.5 mD in the Upper Sandstone and 6.75% and 10 mD in the Lower Sandstone. The Middle Interval claystone has an average porosity and permeability of 4.17% and 0.006 mD, and average TOC content and S2 value of 0.17 wt% and 0.047 mg HC/g rock, with maximum values of 0.66 wt% and 0.46 mg HC/g rock, respectively. Correlations of mineral compositions and petrophysical, geomechanical and organic geochemical properties of the Middle Interval have been conducted and demonstrate that these sediments are organically lean and lie within the oil and gas window. Published in The APPEA Journal 2021 <b>Citation:</b> Wang Liuqi, Edwards Dianne S., Bailey Adam, Carr Lidena K., Boreham Chris J., Grosjean Emmanuelle, Normore Leon, Anderson Jade, Jarrett Amber J. M., MacFarlane Susannah, Southby Chris, Carson Chris, Khider Kamal, Henson Paul, Haines Peter, Walker Mike (2021) Petrophysical and geochemical interpretations of well logs from the pre-Carboniferous succession in Barnicarndy 1, Canning Basin, Western Australia. <i>The APPEA Journal</i><b> 61</b>, 253-270. https://doi.org/10.1071/AJ20038

The Geoscience Australia Rock Properties database stores the result measurements of scalar and vector petrophysical properties of rock and regolith specimens and hydrogeological data. Oracle database and Open Geospatial Consortium (OGC) web services. Links to Samples, Field Sites, Boreholes. <b>Value:</b> Essential for relating geophysical measurements to geology and hydrogeology and thereby constraining geological, geophysical and groundwater models of the Earth <b>Scope:</b> Data are sourced from all states and territories of Australia

Orogenic gold deposits provide a significant source of the world’s gold, but their depth of formation is contentious. One hypothesis is that orogenic gold deposits formed along crustal faults over a wide range of depths spanning sub-greenschist to granulite facies. Other authors suggest that the source is restricted to a smaller range of crustal depths (~20-30 km) and temperatures (~550⁰C) that correspond to the transition from greenschist to amphibolite metamorphic facies. Rapid burial of C and S-rich oceanic sediments and amphibolite-grade metamorphism leads to the production of large amounts of fluid in a short amount of time. In order to help discriminate between these competing hypotheses, we compiled thirty years of magnetotelluric (MT) and geomagnetic depth sounding (GDS) data across western Victoria and south-eastern South Australia. This region contains one of the world’s foremost and largest orogenic gold regions that has produced 2% of historic worldwide gold production. Three-dimensional inversion of the MT and GDS data shows a remarkable correlation between orogenic gold deposits with >1 t production and a <20 ohm.m low-resistivity region at crustal depths >20 km. Such depths are at the pressures and temperatures of greenschist to amphibolite-grade metamorphism that releases HS- ligands for Au from C and pyrite (FeS2) rich sediment interbedded with mafic oceanic rocks. Carbon is then precipitated through retrograde hydration reactions with CO2 precipitating as conductive flake graphite. Thus, our model indicates that orogenic gold in western Victoria is most likely sourced from C and FeS2 rich oceanic sediments at amphibolite-grade facies. Citation: Heinson, G., Duan, J., Kirkby, A. et al. Lower crustal resistivity signature of an orogenic gold system. Sci Rep 11, 15807 (2021). https://doi.org/10.1038/s41598-021-94531-8

Nuclear Magnetic Resonance data may be used to estimate physical properties such as water content, NMR relaxation time, and porosity of formations penetrated by boreholes. These data were acquired as part of the Exploring for the Future (EFTF) program at field sites within the East Kimberley and Southern Stuart Corridor field areas.

Modern magnetotellurics (MT) offers a multiscale capability to image the electrical properties of Earth’s crust and upper mantle. The data it provides and the models derived from it are important geophysical contributions to understanding Earth’s geology and resource potential. In Australia, MT data is acquired by the resource exploration industry, university-based research groups, and Federal, State and Territory geological surveys. To ensure this data can be used to its full potential, including by groups and individuals who may not have been responsible for its acquisition, it is important that community-agreed standards be adopted for the acquired data and its associated metadata. <b>Citation: </b>Jingming Duan, Alison Kirkby, Darren Kyi, Wenping Jiang, Marina Costelloe & Adrian Hitchman (2021) Metadata standards for magnetotelluric time-series data, <i>Preview</i>, 2021:215, 61-63. DOI: 10.1080/14432471.2021.2012035

<p>The Roebuck Basin is considered a new and relatively untested hydrocarbon province in the central North West Shelf of Australia. Inconsistent results from drilling for hydrocarbons highlights the need to better understand the deep structures along this rifted margin that initially formed as an intra-continental, failed rift during Late Permian. Recent wells penetrated the previously unknown Lower-Middle Triassic fluvio-deltaic sedimentary package in the Bedout Sub-basin (inboard part of the Roebuck Basin), including intervals with major oil and gas discoveries. Another two wells, Anhalt 1 and Hannover South 1, only penetrated the top of this succession and they encountered volcanics in the Rowley Sub-basin (outboard part of the Roebuck Basin). Steeply dipping clinoforms observed in the seismic data in the Rowley Sub-basin have been interpreted either as a lava delta complex associated with a failed triple junction; or as a series of back-stepping, Late Permian carbonate ramps and banks, interpreted to have developed on a thermally subsiding rift flank. The implication for prospectivity between the two scenarios is significant. Geoscience Australia undertook a Triassic regional basin analyses, including potential field modelling to validate whether the two proposed models are a plausible solution. A combination of magnetic and gravity 2.5D modelling along nine key regional seismic lines, considered the distribution of potential intrabasinal volcanic rocks and the crustal structure, including Moho depth and depth to top crystalline basement. <p>New seismic interpretation correlated to recent wells, including 2D and 3D seismic reflection surveys was integrated with deep seismic reflection and refraction data resulting in an improved geometry and lithology model that was input into the potential field analyses. The results show that the combined Jurassic and Triassic successions reach up to 16 km deep in the central North West Shelf. The Lower-Middle Triassic sediment package in the Rowley Sub-basin correlates with up to 10 km of dense material (about 2.7 g/cm3 density) and contains magnetic features partially sourced from basalts at the top of the section, as intersected in Anhalt 1 and Hannover South 1. Combined with other causative sources within basement, the basalts correlate with a spatially large positive magnetic anomaly that extends north onto the Scott Plateau and into the Barcoo Sub-basin; in the offshore southwest part of the Browse Basin, where Warrabkook 1 intersected Late Jurassic volcanoclastics at its total depth. The presence of high density and high positive magnetic anomalies in the Lower-Middle Triassic and basement supports the presence of a large igneous province in this area. This interpretation in the outer Rowley Sub-basin downgrades the petroleum prospectivity in this area for this Lower-Middle Triassic interval. Petroleum prospectivity remains in the area due to the overlying sediments containing good source rocks which have been identified to have good to excellent generative potential. <p>The Lower-Middle Triassic sediment package in the adjacent northern Carnarvon Basin has been intersected only on the Lambert Shelf; encountering fluvio-deltaic sediments. In the offshore part of the northern Carnarvon Basin, the nature of this sediment package still remains enigmatic. It correlates with low density sediments (about 2.5 g/cm3 density) that include magnetic bodies on the outboard Exmouth Plateau. The basement and crust show crustal thinning with the presence of a thick layer of interpreted hyper-extended continental crust or exhumed lithospheric mantle. This crustal domain is overlain by thick onlapping Lower-Middle Triassic sediments which form a triangular shape depocentre in the inboard northern Carnarvon Basin, wrapping around the edge of the Pilbara Craton. The location of this initial thick sediment package suggests that it was controlled by the inherited thermal structure of the Late Permian-early Triassic rift architecture that is associated with some volcanics related to a large igneous province extending across the central North West Shelf. As described in the Rowley Sub-basin, the petroleum prospectivity of the northern Carnarvon Basin remains in the overlying sediments showing similar characteristics and indicating good to excellent hydrocarbon generative potential.