Drilling in the Geoscience Australia Exploring for the Future East Tennant project was conducted as part of the MinEx CRC National Drilling Initiative. Ten stratigraphic boreholes were drilled for scientific purposes in the region around the Barkly Roadhouse in the Northern Territory. Where possible, the boreholes were comprehensively wireline logged to obtain petrophysical data on the cover and basement rocks to help improve knowledge and geophysical models of the region. Formation density data obtained by wireline logging were validated using laboratory-based bulk density data obtained by Archimedes method on diamond drill core samples at Geoscience Australia. Results of the validation show that wireline-logged formation density data and Archimedes wet bulk density data are in good general agreement in the first five boreholes drilled (NDIBK01, NDIBK02, NDIBK03, NDIBK04 and NDIBK05). Difficult drilling and some lost drilling equipment meant that boreholes NDIBK06, NDIBK07 and NDIBK09 could not be cased properly, or could not be re-entered, and thus formation density wireline logs could not be obtained in these holes. Boreholes NDIBK08 and NDIBK10 were wireline logged, however formation density results from these last two holes were problematic. Wireline formation density results for borehole NDIBK08 are shown to be too high due to miscalibration of the wireline formation density tool, and results from borehole NDIBK10 cannot be robustly assessed because of a lack of sufficient Archimedes bulk density data needed to provide statistical relevance and validate the wireline formation density data.

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.

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

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

We present a resistivity model of the southern Tasmanides of southeastern Australia using Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) data. Modelled lower crustal conductivity anomalies resemble concentric geometries revealed in the upper crust by potential field and passive seismic data. These geometries are a key part of the crustal architecture predicted by the Lachlan Orocline model for the evolution of the southern Tasmanides, in which the Proterozoic Selwyn Block drives oroclinal rotation against the eastern Gondwana margin during the Silurian period. For the first time, we image these structures in three dimensions (3D) and show they persist below the Moho. These include a lower crustal conductor largely following the northern Selwyn Block margin. Spatial association between lower crustal conductors and both Paleozoic to Cenozoic mafic to intermediate alkaline volcanism and gold deposits suggests a genetic association i.e. fluid flow into the lower crust resulting in the deposition of conductive phases such as hydrogen, iron, sulphides and/or graphite. The 3D model resolves a different pattern of conductors in the lithospheric mantle, including northeast trending anomalies in the northern part of the model. Three of these conductors correspond to Cenozoic leucitite volcanoes along the Cosgrove mantle hotspot track which likely map the metasomatised mantle source region of these volcanoes. The northeasterly alignment of the conductors correlates with variations in the lithosphere-asthenosphere boundary (LAB) and the direction of Australian plate movement, and may be related to movement of an irregular LAB topography over the asthenosphere. By revealing the tectonic architecture of a Phanerozoic orogen and the overprint of more recent tectono-magmatic events, our resistivity model enhances our understanding of the lithospheric architecture and geodynamic processes in southeast Australia, demonstrating the ability of magnetotelluric data to image geological processes over time.

This set of explanatory notes provided the process of creating the 2019 National Gravity Grids released September 2020. This information provides a step by step guide to the processing sequence undertaken. The Notes provide: 1) the data sources for the grids, such as Geoscience Australia's National Airborne Geophysics Database (NAGD), the Australian National Gravity Database (ANGD), and Sandwell and Smith (v28p1) satellite gravity data. 2) Equations used to reduce gravity, gridding calculations, and observation surface for the "B" series grids, 3) Step by step processing sequence. There is also a section with a simple aid to interpreting the grids. The grids are available either as a complete set of grids, or individually, from the associated link. Links: https://ecat.ga.gov.au/geonetwork/srv/eng/catalog.search#/metadata/133023

<p>Eight hundred and seventy two km of gravity and deep crustal reflection data were collected for the Kidson Sub-Basin 2D seismic survey along a single transect: 18GA-KB1 during June to August 2018. <p>The purpose of the survey was to image basin and basement structures of the Kidson Sub-Basin of the onshore Canning Basin, and extending across the Paterson Orogen and on to the eastern margin of the Pilbara Craton. <p>The new data will help geological interpretations to determine the stratigraphy, lateral extent and stratigraphic relationships of the basin and adjoining terranes, and an assessment of the region for its oil and gas and mineral potential. <p>The project is a collaboration between Geoscience Australia (GA) and the Geological Survey of Western Australia (GSWA) and was funded by the Australian Government's Exploring for the Future program and the Western Australian Government's Exploration Incentive Scheme (EIS). <p>Raw data for this survey are available on request from clientservices@ga.gov.au - Quote eCat# 128284

The South Nicholson Basin and immediate surrounding region are situated between the Paleo- to Mesoproterozoic Mount Isa Province and McArthur Basin. Both the Mount Isa Province and the McArthur Basin are well studied; both regions host major base metal mineral deposits, and contain units prospective for hydrocarbons. In contrast, the South Nicholson Basin contains rocks that are mostly undercover, for which the basin evolution and resource potential are not well understood. To address this knowledge gap, the L210 South Nicholson Seismic Survey was acquired in 2017 in the region between the southern McArthur Basin and the western Mount Isa Province, crossing the South Nicholson Basin and Murphy Province. The primary aim of the survey was to investigate areas with low measured gravity responses (‘gravity lows’) in the region to determine whether they represent thick basin sequences, as is the case for the nearby Beetaloo Sub-basin. Key outcomes of the seismic acquisition and interpretation include (1) expanded extent of the South Nicholson Basin; (2) identification of the Carrara Sub-basin, a new basin element that coincides with a gravity low; (3) linkage between prospective stratigraphy of the Isa Superbasin (Lawn Hill Formation and Riversleigh Siltstone) and the Carrara Sub-basin; and (4) extension of the interpreted extent of the Mount Isa Province into the Northern Territory. <b>Citation:</b> Carr, L.K., Southby, C., Henson, P., Anderson, J.R., Costelloe, R., Jarrett, A.J.M., Carson, C.J., MacFarlane, S.K., Gorton, J., Hutton, L., Troup, A., Williams, B., Khider, K., Bailey, A.H.E. and Fomin, T., 2020. South Nicholson Basin seismic interpretation. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

This collection of documents detail various field techniques and processes that GA conduct. They are in conjunction with a series of Field Activity Technique Engagement Animations. The target audience are the communities that are impacted by our data acquisition activities. Field techniques in this collection include; • AEM fixed wing • AEM Helicopter • Borehole Geophysics • Goundwater sampling • Magnetotelluric (MT) surveys • Passive seismic surveys • Rapid Deployment Kits (RDKs) • Reflection seismic surveys • Surface Magnetic Resonance (SMR) surveys • Stratigraphic drilling

AusLAMP is a collaborative national project to cover Australia with long-period magnetotelluric (MT) data in an approximately 55 km spaced array. Signatures from past tectonothermal events can be retained in the lithosphere for hundreds of millions of years when these events deposit conductive mineralogy that is imaged by MT as electrically conductive pathways. MT also images regions of different bulk conductivity and can help to understand the continuation of crustal domains down into the mantle, and address questions on the tectonic evolution of Australia. The AusLAMP data presented here were collected as part of three separate collaborative projects involving several organisations. Geoscience Australia (GA), the Geological Survey of South Australia, the Geological Survey of New South Wales, the Geological Survey of Victoria, and the University of Adelaide all contributed staff and/or funding to collection of AusLAMP data; GA and AuScope contributed instrumentation. The data cover the Paleo-Mesoproterozoic Curnamona Province, the Neoproterozoic Flinders Ranges, and the Cambrian Delamerian Orogen, encompassing eastern South Australia and western New South Wales and western Victoria. This project represents the first electrical resistivity model to image the entire Curnamona Province and most of the onshore extent of the Delamerian Orogen, crossing the geographical state borders between South Australia, New South Wales and Victoria.