Geological Survey Of Queensland Research Articles

The British Geological Survey Rock Classification Scheme, its representation as linked data, and a comparison with some other lithology vocabularies

Controlled vocabularies are critical to constructing FAIR (findable, accessible, interoperable, re-useable) data. One of the most widely required, yet complex, vocabularies in earth science is for rock and sediment type, or ‘lithology’. Since 1999 the British Geological Survey has used its own Rock Classification Scheme in many of its workflows and products including the national digital geological map. This scheme pre-dates others that have been published, and is deeply embedded in BGS’ processes. By publishing this classification scheme now as a Simple Knowledge Organisation System (SKOS) machine-readable informal ontology, we make it available for ourselves and third parties to use in modern semantic applications, and we open the future possibility of using the tools SKOS provides to align our scheme with other published schemes. These include the IUGS-CGI Simple Lithology Scheme, the European Commission INSPIRE Lithology Code List, the Queensland Geological Survey Lithotype Scheme, the USGS Lithologic Classification of Geologic Map Units, and Mindat.org. The BGS lithology classification was initially based on four narrative reports that can be downloaded from the BGS website, although it has been added to subsequently. The classification is almost entirely mono-hierarchical in nature and includes 3454 currently valid concepts in a classification 11 levels deep. It includes igneous rocks and sediments, metamorphic rocks, sediments and sedimentary rocks, and superficial deposits including anthropogenic deposits. The SKOS informal ontology built on it is stored in a triplestore and the triples are updated nightly by extracting from a relational database where the ontology is maintained. Bulk downloads and version history are available on github. The RCS concepts themselves are used in other BGS linked data, namely the Lexicon of Named Rock Units and the linked data representation of the 1:625 000 scale geological map of the UK. Comparing the RCS with the other published lithology schemes, all are broadly similar but show characteristics that reveal the interests and requirements of the groups that developed them, in terms of their level of detail both overall and in constituent parts. It should be possible to align the RCS with the other classifications, and future work will focus on automated mechanisms to do this, and possibly on constructing a formal ontology for the RCS.

Geological Survey of Queensland: Current GSQ geophysics programmes and future work

Geological Survey of Queensland: Current GSQ geophysics programmes and future work

Geoscience Poster G12: Old basins, new seismic data – architecture of Proterozoic basins in Northwest Queensland

Poster G12 As part of the Strategic Resources Exploration Program and to complement surveys acquired under Geoscience Australia’s Exploring for the Future (EFTF) initiative, the Geological Survey of Queensland acquired the Camooweal 2D seismic survey in 2019. This survey was designed to support exploration for hydrocarbons in the Georgina and South Nicholson Basins and Isa Superbasin in Northwest Queensland (NWQ) by providing precompetitive sub-surface data to enable interpretation of basin and basement architecture and to examine structures interpreted in the 2018 North West Queensland SEEBASE Study. The Camooweal 2D seismic survey extends Geoscience Australia’s L210 South Nicholson Seismic Survey into an underexplored region of NWQ. It also ties into and complements the 1994 and 2004 Mount Isa seismic surveys, and the 2019 L212 Barkly Seismic Survey in the Northern Territory. The South Nicholson survey highlighted a significant thickness of sedimentary strata and identified a new depocenter of probable Proterozoic age, now referred to as the Carrara Sub-basin. The Camooweal and Barkly surveys extended the seismic coverage in this region and possibly increase the Carrara Sub-basin’s extent underneath the Georgina Basin. This work will present an interpretation of the basin architecture of the Camooweal 2D seismic in light of the recent drilling at NDI Cararra 1 and tie into interpretation of the Barkly Seismic Survey to provide a regional interpretation of NWQ’s Proterozoic basins in the region. To access the poster click the link on the right. To read the full paper click here

Old basins, new seismic data – architecture of Proterozoic basins in Northwest Queensland

As part of the Strategic Resources Exploration Program and to complement surveys acquired under Geoscience Australia’s Exploring for the Future (EFTF) initiative, the Geological Survey of Queensland acquired the Camooweal 2D seismic survey in 2019. This survey was designed to support exploration for hydrocarbons in the Georgina and South Nicholson Basins and Isa Superbasin in Northwest Queensland (NWQ) by providing precompetitive sub-surface data to enable interpretation of basin and basement architecture and to examine structures interpreted in the 2018 North West Queensland SEEBASE Study. The Camooweal 2D seismic survey extends Geoscience Australia’s L210 South Nicholson Seismic Survey into an underexplored region of NWQ. It also ties into and complements the 1994 and 2004 Mount Isa seismic surveys, and the 2019 L212 Barkly Seismic Survey in the Northern Territory. The South Nicholson survey highlighted a significant thickness of sedimentary strata and identified a new depocenter of probable Proterozoic age, now referred to as the Carrara Sub-basin. The Camooweal and Barkly surveys extended the seismic coverage in this region and possibly increase the Carrara Sub-basin’s extent underneath the Georgina Basin. This work will present an interpretation of the basin architecture of the Camooweal 2D seismic in light of the recent drilling at NDI Cararra 1 and tie into interpretation of the Barkly Seismic Survey to provide a regional interpretation of NWQ’s Proterozoic basins in the region.

Geological Survey of Queensland: Strategic Resources Exploration Program concludes, New Economy Minerals Initiative and geophysical programmes commence, and MT results released

In August the GSQ marked the conclusion of the 4-year (2017 - 21) Strategic Resources Exploration Program (SREP) with a workshop in Mount Isa to present all the final reports and datasets completed...

The Triassic insects of Denmark Hill, Ipswich, Southeast Queensland: the creation, use and dispersal of a collection

Type and additional fossil insects from the Late Triassic Denmark Hill locality in Southeast Queensland, Australia, are held in the collections of the Queensland Museum (Brisbane), the Australian Museum (Sydney) and the Natural History Museum of the United Kingdom (London). The history of these collections shows that they were the product of a concerted effort in the first two decades of the twentieth century to extract the fossils by Benjamin Dunstan, Queensland’s Chief Government Geologist, and to describe the fossils by Dunstan and Robin Tillyard, the foremost Australian entomologist of the time. They collaborated closely to document the late Triassic insects of Australia, at the same time as Dunstan carefully curated and organised both the official government collection of these insects for the Geological Survey of Queensland, and his own private collection. The death of the two men in the 1930s led to the sale by his widow of Dunstan’s private fossil collection (including type and type counterpart specimens) to the British Museum, and the donation of Tillyard’s by his widow to the same institution, in addition to some material that went to the Australian Museum. This paper documents the locations of all of the published specimens. The history of the Denmark Hill fossils (a site no longer accessible for collection) highlights the problems for researchers of the dispersal of holdings such as these, and in particular the separation of the part and counterpart of the same insect fossils. It also raises ethical questions arising from the ownership and disposal of private holdings of important fossil material collected in an official capacity.

Geological Survey of Queensland: New Economy Resources Initiative geophysics programmes and Cloncurry extension MT results released

The Department of Resources’ recent funding package, the New Economy Minerals Initiative (NEMI) aims to continue to drive exploration and understanding of the range of metals and minerals found in ...

Geological Survey of Queensland: Newly released airborne data and MT survey in the North West Mineral Province

Geological Survey of Queensland: Newly released airborne data and MT survey in the North West Mineral Province

Stratigraphic constraints on the Lower Cretaceous Orallo Formation, southeastern Queensland: U–Pb dating of bentonite and palynostratigraphy of associated strata

This study presents two chemical abrasion-thermal ionisation mass spectrometry (CA-TIMS) U–Pb zircon ages from tuffs as well as palynostratigraphic results from the embracing sedimentary succession of the Orallo Formation, Surat Basin, Queensland. Samples were taken from two Geological Survey of Queensland (GSQ) stratigraphic holes, GSQ DRD 26 and GSQ Roma 2. Palynological results assign the upper part of the Orallo Formation to the lower part of the Ruffordiaspora australiensis Interval Zone rather than the upper part of this zone as previously indicated. A late Valanginian isotopic date of 134.38 ± 0.04 Ma from GSQ DRD 26 and an early Hauterivian date of ≤132.46 ± 0.36 Ma from GSQ Roma 2 give the Orallo Formation a Berriasian?/Valanginian–Hautevarian age, rather than the previously inferred Berriasian–Valanginian age determined without any geochronological control. Additionally, when combined with previously published geochronological dates from the Westbourne Formation, these ages suggest that, in the Surat Basin succession, the Jurassic–Cretaceous boundary most likely lies within the Gubberamunda Sandstone. KEY POINTS Two U–Pb CA-TIMS ages of 134.38 ± 0.04 Ma and ≤132.46 ± 0.36 Ma have been found, based on zircons extracted Orallo Formation tuffs. Sediments surrounding the two tuffs the zircons were extracted from yielded palynofloras assignable to the lower part of the Ruffordiaspora australiensis Interval Zone. These dates, combined with earlier work, show the Orallo Formation to be of Berriasian?/Valanginian–Hautevarian age.

Approaches to data-driven exploration in Queensland

Queensland has a very significant petroleum resource endowment within 27 hydrocarbon basins spread across the state. Three of those basins already host Australia’s largest onshore gas supply industry, leaving significant opportunity to develop additional gas resources. To optimise the development of new resources, the Geological Survey of Queensland (GSQ) is implementing an integrated approach to exploration and appraisal called ‘data driven exploration’. Working in collaboration with industry, the research sector and relevant government agencies, GSQ is promoting data-driven exploration in four ways: by (1) optimising the type and quality of geoscience data collected and reported by industry; (2) improving data curation practices in government data repositories; (3) creating value-added opportunities for the use of geoscience data; and (4) improving industry capability and capacity through skills enhancement, collaborative mechanisms, and access to an expert capability network. The overarching objective of ‘data-driven exploration’ is to enable industry exploration and appraisal success by making best use of geoscience data coupled with supporting mechanisms to improve competency and capability to derive, interpret and employ geoscience information. The expression of success will vary depending on individual circumstances, but is intended to encompass a range of outcomes including improvements in the rate, cost and efficiency of discovery and appraisal.

Increasing prospectivity in a covered terrain – the southern Thomson Orogen, northwestern NSW

The Southern Thomson Project aims to advance understanding of tectonic history and mineral prospectivity of basement rocks of the southern Thomson Orogen beneath extensive Mesozoic and Cenozoic cover. The project area in northwestern New South Wales (NSW) and western Queensland is considered underexplored, with poor definition of structural corridors and mineral systems in the Palaeozoic rocks. This collaborative project between Geoscience Australia, the Geological Survey of New South Wales (GSNSW) and the Geological Survey of Queensland is acquiring and interpreting new geoscience data, including geophysical, geochemical, and isotopic investigations. Geophysical data interpretations and models have been tested through a program of stratigraphic drilling to provide basement cores for studies of petrology, geochronology, geochemistry, petrophysics and mineral systems. Downhole geophysical logging of the drillholes also aims to characterise the cover sequences and define depth to basement.Interpretation of regional aeromagnetic and gravity data and synthesis of existing mineral, water-bore and petroleum drillholes created a geological map of basement lithologies and structures. Stratigraphic drilling has targeted areas with no data to constrain lithologies or their ages, with four key areas selected for drilling in far northwestern NSW. Information on the thickness of cover sequences over resistive basement interpreted from AEM inversion models has proven useful during the selection of drilling locations.Seven stratigraphic drillholes were completed within NSW using a combination of mud rotary and diamond drilling. All holes penetrated surface regolith, as well as sedimentary rocks of the Eromanga Basin, to achieve approximately 50 metres of basement core for analyses. Resulting improvements to geological understanding and development of exploration techniques will be a keystone to progress future investigations in the southern Thomson Orogen.

Ultra-deep Permian coal gas reservoirs of the Cooper Basin: insights from new studies

There is a vast, untapped gas resource in deep coal seams of the Cooper Basin, where extensive legacy gas infrastructure facilitates efficient access to markets. Proof-of-concept for the 5 million acre (20 000km2) Cooper Basin Deep Coal Gas (CBDCG) Play was demonstrated by Santos Limited in 2007 during the rise of shale gas. Commercial viability on a full-cycle, standalone basis is yet to be proven. If commercial reservoirs in nanoDarcy matrix permeability shale can be manufactured by engineers, why not in deep, dry, low-vitrinite, poorly cleated coal seams having comparable matrix permeability but higher gas content? Apart from gas being stored in a source rock reservoir format, there is little similarity to other unconventional plays. Without an analogue, development of an optimal reservoir stimulation technology must be undertaken from first principles, using deep coal-specific geotechnical and engineering assumptions. Results to date suggest that stimulation techniques for other unconventional reservoirs are unlikely to be transferable. A paradigm shift in extraction technology may be required, comparable to that devised for shale reservoirs. Recent collaborative studies between the South Australian Department of State Development, Geological Survey of Queensland and Geoscience Australia provide new insight into the hydrocarbon generative capacity of Cooper Basin coal seams. Sophisticated regional modelling relies upon a limited coal-specific raw dataset involving ~90 (5%) of the total 1900 wells penetrating Permian coal. Complex environmental overprints affecting resource concentration and gas flow capacity are not considered. Detailed resource estimation and the detection of anomalies such as sweet spots requires the incorporation of direct measurement. To increase granularity, the authors are conducting an independent, basin-wide review of underutilised open file data, not yet used for unconventional reservoir purposes. Reservoir parameters are quantified for seams thicker than 10feet (3m), primarily using mudlogs and electric logs. To date, ~3750 reservoir intersections are characterised in ~1000 wells. Some parameters relate to resource, others to extraction. A gas storage proxy is generated, not compromised by desorption lost gas corrections. A 2016 United States Geological Survey resource assessment, based on Geoscience Australia studies, suggests that the Play remains a world-class opportunity, despite being technology-stranded for the past 10years. Progress has been made in achieving small but incrementally economic flow rates from add-on hydraulic fracture stimulation treatments inside conventional gas fields. Nevertheless, a geology/technology impasse precludes full-cycle, standalone commercial production. A review of open file data and cross-industry literature suggests that the root cause is the inability of current techniques to generate the massive fracture network surface area essential for high gas flow. Coal ductility and high initial reservoir confining stress are interpreted to be responsible. Ultra-deep coal reservoirs, like shale reservoirs, must be artificially created by a large-scale stimulation event. Although coal seams fail the reservoir ‘brittleness test’ for shale reservoir stimulation practices, the authors conclude from recent studies that pervasive, mostly cemented or closed coal fabric planes of weakness may instead be reactivated on a large scale, to create a shale reservoir-like stimulated reservoir volume (SRV), by mechanisms which harness the reservoir stress reduction capacity of desorption-induced coal matrix shrinkage.

1D depth burial history and thermal maturity modelling of the Toolebuc Formation, Queensland

The Toolebuc Formation in the Eromanga and Carpentaria basins in western Queensland shares many characteristics with successful tight oil plays in the US. A study by the Geological Survey of Queensland has examined key parameters for this formation, including depth, thickness, lithology, mineralogy, maturity (both vitrinite reflectance and Tmax), total organic carbon and mud gas compositions and identified a possible play fairway in the central Eromanga Basin. Mudgas wetness ratios indicate that in areas modelled to be more mature, oil may be present in the Toolebuc Formation. These areas are typically in the central Eromanga Basin where the Toolebuc Formation is deepest, though oil responses have been calculated for wells that are shallower. This is contradicted by the apparent maturity of the formation based on vitrinite reflectance and Tmax measurements. Initial burial history modelling of the six petroleum wells indicates that DIO Hammond–1, SSL Clinton–1, DIO Tanbar North–1 and DIO Marengo–1 are in main oil window (0.7–1.0 %Ro) while DIO Denley–1 and DIO Ingella–1 are in the early oil window (0.55–0.7 %Ro). A single erosional event of 550 m of the Winton Formation has been assumed for this modelling. These wells are the deepest intersections of the Toolebuc Formation where it has been modelled to have higher maturity, and mudgas wetness ratios indicate oil may be present. Further refinement of these models and examination of additional wells is needed to better understand the potential for the Toolebuc Formation to have generated petroleum.

Source rock characterisation of under-explored regions of Queensland

Historically, petroleum exploration in Queensland has focused on the Bowen-Surat and Cooper-Eromanga basins, with only cursory examination of other basins across the state. As part of the Queensland Industry Priorities Initiative, two projects (Round 1 and 2) were submitted to the Geological Survey of Queensland (GSQ) to examine the geochemical characteristics of potential petroleum source rocks throughout Queensland. The analysis conducted provides a better understanding of generative potential for petroleum, and predicts the timing, volume, composition, and physical state of hydrocarbons retained in and expelled from source rocks. It is an integral component to petroleum systems analysis used to identify the potential for undiscovered accumulations of petroleum from conventional and unconventional reservoirs. Of particular interest were the Georgina, Drummond, Eromanga, and Maryborough basins. Of these, the Georgina and Maryborough basins have known hydrocarbon shows identified through exploration drilling, though no commercial discoveries have yet been made. The Drummond Basin was targeted to identify a potential source for oil and gas shows encountered in drilling within the Galilee Basin. The Toolebuc Formation in the Eromanga Basin has been noted as having the potential for a shale oil play and this study is supporting further assessment to identify optimal areas for future exploration through predictive modelling. This report details the results from Round 1 of the study for samples taken from the Georgina Limestone and Scartwater, Ducabrook, Mount Hall, Toolebuc, and Maryborough formations, where limited analysis of source rock characteristics has historically been undertaken. Ninety-seven samples were chosen from nine wells and sent to Geos4 in Potsdam, Germany, for source rock analysis. All samples were screened for suitability of further analysis using Rock-Eval and TOC by LECO, with immature and organic-rich samples being preferentially selected for further testing. Screened samples were analysed using pyrolysis gas chromatography (n=27), thermovaporisation (n=23), bulk kinetics (n=5), compositional kinetics (n=4), late gas analysis (n=14), and biomarker and bulk isotope analysis (n=15). These results have been integrated with existing analyses to better understand the prospectivity of the under-explored basins of Queensland.

Carpentaria Conductivity Anomaly revisited with preliminary magnetotelluric results from the SE Mt Isa Survey 2014

SUMMARY The region to the east of Mt Isa has complex electrical conductivity, with conductive basin sediments overlying the deeper Carpentaria Conductivity Anomaly (CCA). Early magnetotelluric (MT) model results show alignment of the CCA with aeromagnetic, gravity and seismic features, together implying that they define the major structural edge of the Mt Isa Block. Profile MT data acquired during the previous 20 years have helped refine the position and depth of the CCA. New MT and deep seismic reflection data have recently been acquired in 2014 along a NW to SE profile, funded by the Geological Survey of Queensland’s Greenfields 2020 Program in conjunction with Geoscience Australia. These new data provide further evidence of the complex nature of the crustal conductivity in this region. Induction vectors indicate that the CCA itself is braided into several zones which may define deep-seated fracture systems.

An ancyloceratid ammonite from the Aptian Maryborough Formation, Queensland, Australia, and synonymy of Australiceras Whitehouse with Tropaeum Sowerby

McKENZIE, E.D., ROZEFELDS, A.C., DEACON, P., 2014. An ancycloceratid ammonite from the Aptian Maryborough Formation, Queensland, Australia, and synonymy of Australiceras Whitehouse with Tropaeum Sowerby. Alcheringa 38. ISSN 0311–5518.This first description and illustration of ammonites from the Maryborough Formation on Woody Island, Hervey Bay in Queensland shows that all known specimens are referable to Tropaeum jackii (Etheridge Jr 1880) comb. nov., for which a neotype is, herein, nominated to replace the missing lectotype. An analysis of comparative material from other eastern Australia Cretaceous basins, including the type specimens of Australiceras, illustrates that the variability of tuberculation can not be used to separate genera, nor species. Australiceras Whitehouse, 1926 is considered a junior synonym of Tropaeum J. de C. Sowerby. Two other Australiceras species are also transferred to Tropaeum; T. lampros (Etheridge Jr) comb. nov. and T. irregulare (Tenison Woods) comb. nov. The changing patterns, throughout ontogeny, of lateral rib densities (herein defined) and whorl shapes are useful for distinguishing these species. As the ammonites from the Maryborough Formation all fit within the present definition of Tropaeum jackii, and as this has been defined as a late Aptian taxon by faunal studies supported by extensive palynological work in adjacent Australian Cretaceous basins, the ammonites provide support for the assignment of a late Aptian age to this part of the formation.E.D. McKenzie [edmck@bigpond.com] and A.C. Rozefelds [andrew.rozefelds@qm.qld.gov.au] Queensland Museum, GPO Box 3300, South Brisbane, 4101, Queensland, Australia; Paula Deacon, [Paula.Deacon@dnrm.qld.gov.au] Geological Survey of Queensland, Department of Natural Resources and Mines (DNRM), PO Box 15216, City East, 4002, Queensland, Australia. Received 24.12.2012, revised 14.10.2013; accepted 28.10.2013.

Unconventional petroleum resource evaluation in Queensland

The search for unconventional petroleum resources requires a shift in the way the petroleum potential of sedimentary basins is assessed. Gas in source rocks and tight reservoirs has largely been ignored in preference for traditional conventional gas plays. Recent developments in technology now allow for the extraction of gas trapped in low-permeability reservoirs. Assessments of the unconventional petroleum potential of basins, including estimates of the potential resource are required to guide future exploration. The Geological Survey of Queensland is collaborating with Geoscience Australia (GA) and other state agencies to undertake regional assessments of several basins with potential for unconventional petroleum resources in Queensland. The United States Geological Survey methodology for assessment of continuous petroleum resources is being adopted to estimate total undiscovered oil and gas resources. Assessments are being undertaken to evaluate the potential of key formations as shale oil and gas and tight-gas plays. The assessments focus on mapping key attributes including depth, thickness, maturity, total organic carbon (TOC), porosity, gas content, reservoir pressure, mineralogy and regional facies patterns using data from stratigraphic bores and petroleum wells to determine play fairways or areas of greatest potential. More detailed formation evaluation is being undertaken for a regional framework of wells using conventional log suites and mudlogs to calculate porosity, TOC, maturity, oil and gas saturations, and gas composition. HyLoggerTM data is being used to determine its validity to estimate bulk mineralogy (clay-carbonate-quartz) compared with traditional x-ray diffraction methods. These methods are being applied to key formations with unconventional potential in the Georgina and Eromanga basins in Queensland.

Using self-organising maps to derive lithological boundaries from geophysically-derived data in the Mt. Isa region, Queensland

SUMMARY Susceptibility and density volumes, derived from the inversion of airborne magnetic and ground-based gravity measurements for a region of the Mt Isa inlier, Queensland, Australia, were analysed using a selforganizing map (SOM) approach. Three-dimensional sub-surface voxel distributions of susceptibility and density were derived from the inversion of magnetic and gravity data using the University of British Columbia (UBC) codes. These petrophysical volumes are often difficult to interpret because of their nebulous nature, with subtle differences between adjacent volume elements. As the SOM approach uses vector quantization, it is an ideal tool to identify subtle relationships in such volumes of disparate data. The CSIRO data-mining SOM tool (SiroSOM) was used here as it was designed specifically for the analysis of such spatially-located, diverse exploration data. Our SOM analysis of the petrophysical voxels has identified (1) some structural features that are evident on the previously constructed Geological Survey of Queensland (GSQ) model of the area; (2) anomalous voxels that form coherent patterns, which may be related to mineralisation and hence be exploration targets; and (3) explicit domains that relate to lithological packages. Further work is needed to validate the SOM results; however, our analysis has shown the value of the SOM approach for analysis of such data. By using SOM, we have been able to assess petrophysical volumes to extract information related to structure and lithological packages in addition to identifying geophysical targets with potential for mineralisation.

Geology in the Oceania region: A Preface

Guest Editors: KEITH M. SCOTT and PETER A. JELL Research School of Earth Sciences, The Australian National University and CSIRO Earth Sciences and Resource Engineering, PO Box 136, North Ryde, NSW 1670, Australia. E-mail: keith.scott@csiro.au Geological Survey of Queensland, Department of Natural Resources and Mines, GPO Box 15216, City East, QLD 4002, Australia. E-mail: peter.jell@deedi.qld.gov.au

The Millungera Basin—new geoscience supporting exploration

An unknown sedimentary sequence was first recorded during a Geoscience Australia/ Geological Survey of Queensland/ pmd*CRC deep seismic reflection survey in the Mount Isa Inlier and adjacent undercover terrains, during 2006/07. The sequence occurs unconformably underneath the Carpentaria Basin succession in the Julia Creek area, east of Cloncurry in north Queensland, and is named the Millungera Basin. A section through the basin is recorded along seismic line 07GA–IG1, recorded between north of Cloncurry to east of Croydon. In this section three internal sequences are noted—with two strongly reflective units separated by a poorly reflective unit. As well as deep crustal seismic reflection profiles, magnetotelluric profiles were collected along the same traverse. These data show a moderately conductive Millungera Basin underlying the strongly conductive Carpentaria Basin. Zones of limited reflectors beneath the basin in the seismic sections have been interpreted as granites, raising the possibility of raised geothermal gradients. The Millungera Basin may comprise a potential geothermal target. The Millungera Basin sequence is interpreted to overlie granites. Adjacent Proterozoic granites of the Williams Batholith are known to be high heat producing granites, containing high levels of potassium thorium and uranium. The hydrocarbon potential of the basin is similarly uncertain. Strong reflectors in the seismic sections may be coal beds. Although the depth of the basin in the seismic section is insufficient to have reached the oil window, interpretation of gravity profiles by Geoscience Australia suggest the basin deepens to the south, possibly reaching 4,000 m. If fertile beds have reached the oil window, the structurally more complex eastern side of the basin may contain petroleum traps. The age of the rocks in the Millungera Basin is not known. Constraints from the seismic suggest between the early Mesoproterozoic and the Middle Jurassic. Investigations into the nature of the basin are continuing. A more detailed magnetotellurc survey is being undertaken to better define the shape of the basin. In order to reliably describe the basins components, a deep drilling program is required.