The Paleo-Mesoproterozoic Isa Superbasin is located in northwestern Queensland and is part of the geologically complex and resource rich Mount Isa Province. Over the last five years, the Northern Lawn Hill Platform (NLHP) in the northern part of the Isa Superbasin has become a focus for frontier conventional and unconventional hydrocarbon exploration. Thick and extensive organic-rich shale units in the River and Lawn supersequences are of particular interest for unconventional shale gas exploration following a gas discovery in 2014 from the Lawn Shale at Egilabia-2 DW1. Potential shale gas resources in these stratigraphic intervals include 22.1 Tcf of prospective gas and 0.15 Tcf of contingent (2C) gas resources (Armour Energy, 2014 and 2015). Other conventional and unconventional plays may also occur in overlying stratigraphic units within the Isa Superbasin. However despite the increased interest in the region’s petroleum prospectivity, the data coverage across the Isa Superbasin is sparse and aspects of the regional geological framework remain ambiguous. This report presents an update to seismic and well interpretation in the Isa Superbasin originally undertaken in the late 1990’s as part of the North Australian Basins Resource Evaluation (NABRE) Project in the NLHP, the area with the greatest concentration of data and petroleum exploration activity. The NABRE Project focussed on developing an integrated structural and stratigraphic framework for the NLHP in the context of understanding and predicting sediment-hosted mineral deposits. However, the project did not produce depth-converted structure or isopach maps, which are required for assessing and mapping conventional and unconventional petroleum plays. Assessments of the area’s resource potential would also benefit by incorporating some key recently acquired data sets and published research with the original NABRE work. The original NABRE work has therefore been updated to include interpretations from new seismic and well data, and to generate depth-converted structure and isopach maps for eight key stratigraphic horizons of interest for petroleum exploration in the NLHP. Major sub-surface structures are also formally defined and named based on the depth-structure maps. The review of the Isa Superbasin geological framework presented here underpins work on two major federal government initiatives, the Exploring For The Future Program and Geological and Bioregional Assessment Program. Recommendations are included in this report on further value adding work that could supplement these programs to better inform prospectivity assessment.

Exploring for the Future (EFTF) is a four-year $100.5 million initiative by the Australian Government conducted by Geoscience Australia in partnership with state and Northern Territory government agencies, CSIRO and universities to provide new geoscientific datasets for frontier regions. As part of this program, Geoscience Australia acquired two new seismic surveys that collectively extend across the South Nicholson Basin (L120 South Nicholson seismic line) and into the Beetaloo Sub-basin of the McArthur Basin (L212 Barkly seismic line). Interpretation of the seismic has resulted in the discovery of new basins that both contain a significant section of presumed Proterozoic strata. Integration of the seismic results with petroleum and mineral systems geochemistry, structural analyses, geochronology, rock properties and a petroleum systems model has expanded the knowledge of the region for energy and mineral resources exploration. These datasets are available through Geoscience Australia’s newly developed Data Discovery Portal, an online platform delivering digital geoscientific information, including seismic locations and cross-section images, and field site and well-based sample data. Specifically for the EFTF Energy project, a petroleum systems framework with supporting organic geochemical data has been built to access source rock, crude oil and natural gas datasets via interactive maps, graphs and analytical tools that enable the user to gain a better and faster understanding of a basin’s petroleum prospectivity. <b>Citation:</b> Henson Paul, Robinson David, Carr Lidena, Edwards Dianne S., MacFarlane Susannah K., Jarrett Amber J. M., Bailey Adam H. E. (2020) Exploring for the Future—a new oil and gas frontier in northern Australia. <i>The APPEA Journal</i><b> 60</b>, 703-711. https://doi.org/10.1071/AJ19080

This Record presents new Sensitive High Resolution Ion MicroProbe (SHRIMP) U-Pb zircon results from the Mount Isa Orogen obtained under the auspices of the Geological Survey of Queensland-Geoscience Australia (GSQ-GA) National Collaboration Framework (NCF) geochronology project between July 2016 and June 2017. New results are presented from eight samples collected as part of ongoing regional mapping and geoscientific programs in the Mount Isa Orogen. GA work presented here represents part of the federally funded Exploring for the Future Program. As a part of ongoing geological mapping in the Mount Isa Orogen, the Geological Survey of Queensland (GSQ) and Geoscience Australia (GA) have undertaken a geochronology program to enhance the understanding of the geological evolution of the province. There are two focus areas as a part of this Record. The first focus area is north of Mount Isa, in the Kalkadoon-Leichhardt and Sybella domains (Figure i), and includes geochronology results from three mafic to intermediate rocks. The second focus area is south of Cloncurry, in the Kuridala–Selwyn and Marimo–Staveley domains (Figure i), and includes geochronology results from one leucogranite and four sedimentary rocks. For ease of reporting, these two focus areas are split into two themes 1) ‘mafic rocks’ for the three geochronology results north of Mount Isa; and 2) ‘Kuridala–Selwyn corridor’ for the five geochronology results south of Cloncurry. <b>Bibliographic Reference:</b> LEWIS, C.J., WITHNALL, I.W., HUTTON, L.J., BULTITUDE, R.J., SLADE, A.P., SARGENT, S., 2020. Summary of results. Joint GSQ–GA geochronology project: Mount Isa region, 2016–2017. <i>Queensland Geological Record</i><b> 2020/01</b>.

<div>The Canobie Airborne Gravity Gradiometer (AGG) survey of Northern Queensland was flown between 24 November and 3 December 2021. </div><div>Contracted to Xcalibur Multiphysics, Geoscience Australia undertook the project management, contract management and quality control on behalf of the Geological Survey of Queensland. </div><div>The located data, gridded data and quality control reports are contained within this record. </div><div><br></div><div>Survey area was centered on latitude 19° 31’ 04” S and longitude 140° 44’ 14” E to the north of Cloncurry. A total of 8 production flights were flown for a combined total of 4,712.4 </div><div>line kilometers of data and acquired on 1000 m line spacing at 80 m nominal terrain clearance</div><div>Quality control was performed by airborne gravity consultant Dr Mark Dransfield on behalf of Geoscience Australia, with his report included here.</div><div><br></div><div>The survey was designed to supplement the regional legacy ground gravity data and improve the definition of gravimetric anomalies in a region deemed highly prospective for base metals exploration. </div><div>In addition, the AGG survey will provide better understanding of the cover sequence thickness (estimated to be less than 100 m) and characteristics of the underlying basement geology. </div><div><br></div><div>The data was released by the Geological Survey of Queensland on March 29 and can be found at https://geoscience.data.qld.gov.au/dataset/gg100099/resource/geo-spa460972-gg100099. </div><div><br></div><div>Survey Name: Canobie airborne gravity gradiometery survey,2021</div><div>Datasets Acquired: Gravity gradiometry, digital terrain model</div><div>Geoscience Australia Project Number: P5021</div><div>Acquisition Start Date: 24/11/2021</div><div>Acquisition End Date: 03/12/2021</div><div>Flight line spacing: 1000 m</div><div>Flight line direction: East-West (090-270)</div><div>Total distance flown: 4,712 line-km</div><div>Nominal terrain clearance: 80 m</div><div>Blocks: 1</div><div>Data Acquisition: Xcalibur Multiphysics</div><div>Project Management: Geoscience Australia</div><div>Quality Control: Mark Dransfield on behalf of Geoscience Australia</div><div>Dataset Ownership: Geological Survey of Qld and Geoscience Australia</div><div><br></div><div>Included in this release:</div><div>1. Point-located Data</div><div>ASCII-column data with accompanying description and definition files.</div><div>• Gravity gradiometry data including the various corrections</div><div>• Gravity gradiometry data noise estimates</div><div>• Vertical gravity estimate including various reduction and levelled corrections</div><div>• Digital terrain model</div><div><br></div><div>2. Grids</div><div>Gridded data in ERMapper (.ers) format (GDA2020):</div><div>• Gravity gradiometry</div><div>• Free-air corrected vertical gravity</div><div>• Terrain and bouguer corrected vertical gravity</div><div>• Digital terrain model</div><div><br></div><div>3. Reports</div><div>• Contractors Logistics Report</div><div>• Quality Control Report (Mark Dransfield)</div><div><br></div><div>4. Location</div><div>• ARCGIS shape file</div><div><br></div><div><br></div><div>© Geological Survey of Queensland and Commonwealth of Australia (Geoscience Australia) 2021. With the exception of the Commonwealth Coat of Arms and where otherwise noted, this product is provided under a Creative Commons Attribution 4.0</div>

From June 23rd to November 4th 2016 Geotech Ltd. carried out a helicopter-borne geophysical survey over part of East Isa in Queensland (figure 1). Operations were based at Cloncurry, Queensland. The traverse lines were flown in an east to west (N 90° E azimuth) direction with 2km and 2.5km traverse line spacings, with three Tie lines flown perpendicular to the traverse lines. During the survey the helicopter was maintained at a mean altitude of 76 metres above the ground with an average survey speed of 90 km/hour. This allowed for an actual average EM Transmitter-receiver loop terrain clearance of 38 metres and a magnetic sensor clearance of 68 metres. The principal geophysical sensors included a versatile time domain electromagnetic (VTEMTMPlus) full receiver-waveform system, and a caesium magnetometer. Ancillary equipment included a GPS navigation system, laser and radar altimeters, and inclinometer. A total of 15697 line-kilometres of geophysical data were acquired during the survey. The electromagnetic system is a Geotech Time Domain EM (VTEMplus) with full receiver-waveform streamed data recording at 192 kHz. The "full waveform VTEM system" uses the streamed half-cycle recording of transmitter current and receiver voltage waveforms to obtain a complete system response calibration throughout the entire survey flight. The VTEM transmitter loop and Z-component receiver coils are in a concentric-coplanar configuration and their axes are nominally vertical. An X-component receiver coil is also installed in the centre of the transmitter loop, with its axis nominally horizontal and in the flight line direction. The receiver coils measure the dB/dt response, and a B-Field response is calculated during the data processing. In-field data quality assurance and preliminary processing were carried out on a daily basis during the acquisition phase. Preliminary and final data processing, including generation of final digital data products were undertaken from the office of Geotech Ltd. in Aurora, Ontario. A set of Conductivity Depth Images (CDI) were generated using EM Flow version 3.3, developed by Encom Technologies Pty Ltd. A total of forty-five (45) dB/dt Z component channels, starting from channel 4 (21 µsec) to channel 48 (10667 µsec), were used for the CDI calculation. An averaged waveform at the receiver was used for the calculation since it was consistent for the majority of the flights with minor deviation from the average. Digital data includes all electromagnetic and magnetic data, conductivity imaging products, mulitplots plus ancillary data including the waveform.

Interpretation of 2014–2015 deep crustal seismic reflection and magnetotelluric data has revised the architecture and geodynamic framework of western Queensland, with implications for the assembly and dispersal of the supercontinents Nuna, Rodinia and Gondwana. In the Mount Isa Province, crustal-scale boundaries of the Leichhardt River Domain, Kalkadoon-Leichhardt Domain and Eastern Subprovince are mapped in the third dimension. The Leichhardt River and Kalkadoon-Leichhardt domains have similar Nd isotopic T 2DM model ages to provinces to the west, indicating they were part of ancestral North Australian Craton (NAC); the Eastern Subprovince is a separate terrane, with the Pilgrim Fault a collisional suture. The Gidyea Suture Zone separates the Mount Isa Province from the subsurface Numil Seismic Province. To the east, the west-dipping Yappar Fault separates east-dipping structures in the west from west-dipping structures in the east, forming a classic doubly vergent orogen within the upper plate of a convergent margin. The northwestern boundary of the Bernfels Seismic Province, the Kynuna Fault, truncates the Gidyea Suture Zone, implying this seismic province was welded to the NAC prior to initial deposition of the Etheridge Province. The Cork Fault truncates the north-south grain of the Mount Isa Province; the easternmost part of the NAC has been excised, presumably during breakup of Nuna. The subsurface Brighton Downs Seismic Province, formerly part of the northern Thomson Orogen, is a discrete seismic province, located between the NAC and the Thomson Orogen, and welded to the NAC during the accretion of Rodinia. Basement to the Thomson Orogen is a collage of microplates, accreted to the Brighton Downs Seismic Province during the assembly of Gondwana. By 530 Ma, eastern Australia faced an open Pacific Ocean, with the Thomson Orogen in a backarc setting. Thus, northeastern Australia contains a record of repeated continental accretion and breakup over at least three supercontinent cycles. <b>Citation: </b>Russell J. Korsch, Michael P. Doublier, Dominic D. Brown, Janelle M. Simpson, Andrew J. Cross, Ross D. Costelloe, Wenping Jiang, Crustal architecture and tectonic development of western Queensland, Australia, based on deep seismic reflection profiling: Implications for Proterozoic continental assembly and dispersal, <i>Tectonophysics</i>, Volume 878, 2024, 230302, ISSN 0040-1951, https://doi.org/10.1016/j.tecto.2024.230302.

This record presents nine new Sensitive High Resolution Ion Micro Probe (SHRIMP) U–Pb zircon results obtained under the auspices of the Exploring for the Future (EFTF) Programme, a four year, federally funded initiative to better understand the mineral, energy and groundwater potential of northern Australia. The results presented here are derived from eight sedimentary samples and one probable tuffaceous sample together belonging to the Mount Isa Province, South Nicholson Basin and Georgina Basin.

Magnetotelluric (MT) measures the natural variations of the Earth' magnetic and electrical (telluric) fields. The Audio-Magnetotelluric method (AMT) samples signal frequencies in the range of 20k Hz down to ~1Hz and provides data pertaining to the upper few kilometres of the Earth' crust. Broadband MT (BBMT) measures frequencies ranging from ~400 Hz down to periods of ~5000 s, providing measures of the conductivity of the crust. AMT and BBMT data were acquired at 138 stations with an interval of 2.5-5.0 km along a 690 km transect extending from Four Ways to Longreach in the South-eastern Mount Isa region. Full-waveform time series data were acquired and processed into frequency-domain transfer functions. Remote reference was applied to eliminate uncorrelated noise. After quality assurance, processed data were exported to industry-standard EDI files containing site info, impedance tensor, apparent resistivity, phase and vertical transfer function.

Zircon and xenotime U–Pb SHRIMP geochronology was conducted on samples from the South Nicholson Basin, and western Mount Isa Orogen. These samples were collected from outcrop and core from the Northern Territory and Queensland. The age data indicate the South Nicholson Basin was deposited after ca 1483 Ma but deposition most likely had ceased by ca 1266 Ma; the latter age likely represents post-diagenetic fluid flow in the area, based on U–Pb xenotime data. Geochronology presented here provides the first direct age data confirming the South Nicholson Group is broadly contemporaneous with the Roper Group of the McArthur Basin, which has identified facies with high hydrocarbon prospectivity. In addition, geochronology on the Paleoproterozoic McNamara Group provides new age constraints that have implications for the regional stratigraphy. The data obtained in this geochronological study allow for a comprehensive revision of the existing stratigraphic framework, new correlations and enhances commodity prospectivity in central northern Australia.

An important finding of this study is the presence of Williams-Naraku Batholith ages (i.e. ca 1500 Ma) east and (well) north of the currently known extent. Sample 2804770/DPMI013 is a leucocratic biotite granite collected from unnamed unit PLg/k ca 30 km southwest of Burke and Wills Roadhouse at the far northern outcropping extent of the Mary Kathleen Domain. This unit intrudes the Corella Formation and Boomarra Metamorphics as small pods and dykes that likely represent the upper portions of a larger pluton. The results from this sample are complex but indicate a minimum crystallisation age of 1500 ± 6 Ma. This is within error of units assigned to the Williams and Naraku Batholiths (e.g. Mavis Granodiorite, Malakoff Granite, Wimberu Granite – see geochronology compilation of Jones et al., 2018). A similar but more certain age of 1511 ± 4 Ma was determined for an unnamed amphibole granite farther south near Kajabbi (2804772/DPMI049b). It is likely that this intrusion also represents the upper parts of a pluton that is more extensive at depth. Together, these two new ages greatly expand the known extent of magmatism at ca 1500 Ma. The Mount Godkin Granite forms a prominent, topographically high range ca 45km northwest of Cloncurry. It intrudes the Corella Formation and has a distinct ellipsoid mapped extent. On the basis of geochemistry, Budd et al. (2001) included the Mount Godkin Granite in the Burstall Suite. The crystallisation age reported here (1739 ± 3 Ma) for sample 2804771/DPMI041 is within error of the most recent published ages from the Burstall Granite and Lunch Creek Gabbro (i.e. 1740 ± 3 Ma, 1737 ± 3 Ma, 1739 ± 3 Ma; Neumann et al., 2009) confirming broadly synchronous emplacement. We also sampled a fine-grained, leucocratic and miarolitic biotite granite from the far northern tip of the Burstall Granite (mapped as subunit l). Despite being lithologically and texturally distinct from the main body of Burstall Granite, this sample (2804773/DPMI054) yielded a similar crystallisation age (1736 ± 4 Ma) to the main Burstall Granite and Lunch Creek Gabbro bodies (Neumann et al., 2009). A lithologically similar, unfoliated, miarolitic leucogranite was sampled from Exco Resources drill core EMCDD094 (534.85–536.07 m) at Mount Colin mine near the contact between the Burstall Granite and Corella Formation. In drill core, this granite contains large xenoliths of Corella Formation and locally transitions to a crystallised hydrothermal phase. It appears intimately associated with copper mineralisation and the crystallisation age of 1737 ± 3 Ma determined here (2804792/DPMI080) may be similar to the mineralisation age. The Myubee Igneous Complex and Overlander Granite intrude the Corella Formation in the southern part of the Mary Kathleen Domain. They were thought to have been emplaced at about the same time as the nearby Revenue Granite, the Mount Erle Igneous Complex farther south, and the Burstall Granite to the north, based on lithological and chemical similarities (e.g., Bultitude et al., 1978, 1982; Blake et al., 1984). These last three units have yielded U–Pb zircon (SHRIMP) ages in the 1735–1740 Ma range (Neumann et al., 2009; Geoscience Australia, 2011; Kositcin et al., 2019). However, Bierlein et al. (2011) reported slightly younger SHRIMP zircon emplacement ages in the 1718–1722 Ma range for parts of the Revenue Granite and Mount Erle Igneous Complex, suggesting the units are composite. The 1740 ± 5 Ma age yielded by the Overlander Granite as part of the current study is similar to ages recorded for the units listed above and, therefore, supports the interpretations of earlier workers. The granite is associated spatially with several small Cu–Au deposits in nearby country rocks (Corella Formation) including the Overlander group of mines (abandoned) and prospects, and the Andy’s Hill (Cu–Au–Co–La) and Scalper (Cu–Au) prospects (Denaro et al., 2003), but a genetic relationship between the granite and mineralisation has yet to be unequivocally demonstrated. Granite of the Myubee Igneous Complex yielded a slightly younger age of 1727 ± 5 Ma. We interpret this as a minimum age for igneous crystallisation of the granite, because most of the SHRIMP zircon analyses preserve evidence of post-crystallisation isotopic disturbance. However, it does support the conclusion of Passchier (1992) who deduced that the Myubee Igneous Complex is slightly younger than the nearby Revenue Granite, based on structural criteria. According to Passchier D1 (local) structures in the Revenue Granite are not present in the Myubee Igneous Complex. The significance of the anomalously young SHRIMP, zircon age of 1722 ± 5 Ma subsequently reported by Bierlein et al. (2011) for the Revenue Granite has yet to be resolved. The dated sample of Wimberu Granite is from a relatively small lobe, separated from the main outcrop area to the east by an extensive cover of younger Georgina Basin rocks. The lobe is located ~11 km east of the Pilgrim Fault Zone, which marks the eastern boundary of the Mary Kathleen Domain. The analysed sample yielded a U–Pb zircon age of 1518 ± 5 Ma, which is similar to the U–Pb (SHRIMP) zircon ages reported previously for different parts of the main body of Wimberu Granite east of Devoncourt homestead—namely 1508 ± 4 Ma (Page & Sun, 1998) and 1512 ± 4 (Pollard & McNaughton, 1997). <b>Bibliographic Reference: </b>Bodorkos, S., Purdy, D.J., Bultitude, R.J., Lewis, C.J., Jones, S.L., Brown, D.D. and Hoy, D., 2020. Summary of Results. Joint GSQ–GA Geochronology Project: Mary Kathleen Domain and Environs, Mount Isa Inlier, 2018–2020. <i>Queensland Geological Record</i><b> 2020/04</b>.