Geological Survey Of Western Australia Research Articles

A preliminary assessment of regional CO2 storage potential in the onshore northern Perth Basin

The Geological Survey of Western Australia (GSWA) is creating a new carbon dioxide (CO2) geological storage atlas for Western Australia. The atlas will incorporate the latest state-wide datasets to provide a regional assessment of the potential for CO2 sequestration across the Perth, Southern Carnarvon, Northern Carnarvon (onshore and State waters), Canning and Officer basins. Multi-1D modelling of subsurface temperature in the northern Perth Basin incorporates newly collated temperature data, updated regional depth maps, and stratigraphic revisions. This modelling captures lateral subsurface temperature variations that are incorporated into isothermal depth and temperature maps identifying reservoir units within the optimum temperature–pressure window for CO2 storage. Isopach maps of associated sealing units indicate where they are of adequate thickness to contain CO2. Modelled present-day temperature maps of seven key reservoir units reveal promising CO2 storage prospectivity, with all postulated reservoir units having significant extents within optimum CO2 storage temperature and pressure ranges. Whereas older reservoir units are prospective for CO2 storage towards the margins of the basin, younger reservoir units in the shallower part of the succession are only prospective in or near the Dandaragan Trough, the deepest part of the basin. The critical upper temperature limit of 31.1°C is shallower in the north and west of the basin, where the modelled geothermal gradient is higher. All state-wide raw and interpreted datasets including temperature and depth maps will be published and available for download on the GSWA Western Australian Petroleum and Geothermal Information Management System website.

Early Ordovician trilobites from Barnicarndy 1 stratigraphic well of the southern Canning Basin, Western Australia

Twenty-three trilobite taxa are described here from the Early Ordovician (Tremadocian to Floian) Nambeet Formation retrieved from the Barnicarndy 1 drillcore, Canning Basin, Western Australia. This includes one new genus, Veeversaspis gen. nov., and six new species: Asaphellus zheni sp. nov., Madiganaspis lauriei sp. nov., Norasaphus (Norasaphus) jagoi sp. nov., Rodingaia leggi sp. nov., Sanbernardaspis excalibur sp. nov., and Veeversaspis jelli gen. et sp. nov. This fauna can be divided into three stratigraphically distinct assemblages, the Apatokephalus sp.–Veeversaspis jelli gen. et sp. nov. Assemblage (2177.50–2382.94 m depth), Asaphellus trinodosus Assemblage (2030.07–2177.52 m depth), and Asaphellus zheni sp. nov. Assemblage (1595.83–2001.88 m depth). The two stratigraphically lowest assemblages are consistent with a late to latest Tremadocian age (both within the Paroistodus proteus Zone). The third, and highest, assemblage is consistent with a mid-Floian age (within the Oepikodus communis Zone). This systematic contribution refines previous biostratigraphic work based on an age-diagnostic conodont fauna and demonstrates the stratigraphic utility of using multiple taxonomic groups for more robust biostratigraphic age estimates. P.M. Smith [ Patrick.Smith@austmus.gov.au ], Palaeontology Department, Australian Museum Research Institute, Sydney, New South Wales, 2010, Australia, and Department of Biological Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia. H.J. Allen [ heidi.allen@dmirs.wa.gov.au ], Geological Survey of Western Australia, Department of Mines, Industry Regulation and Safety, Mineral House, 100 Plain Street, East Perth, Western Australia, 6004, Australia.

Geological Survey of Western Australia: Western Officer and Perth Basins SEEBASE reports

Geological Survey of Western Australia: Western Officer and Perth Basins SEEBASE reports

Geological Survey of Western Australia: Regional geophysical data acquisition in GSWA 2022–23

Geological Survey of Western Australia: Regional geophysical data acquisition in GSWA 2022–23

Geological Survey of Western Australia: WA-ARRAY announced

Geological Survey of Western Australia: WA-ARRAY announced

Early Ordovician conodonts from Barnicarndy 1 stratigraphic well of the Southern Canning Basin, Western Australia

Documented here is the systematic description of conodonts from 10 samples collected within the Nambeet Formation in Barnicarndy 1, a deep stratigraphic drillhole located within the Barnicarndy Graben on the southwestern margin of the Canning Basin, Western Australia. The fauna is represented by 22 identifiable species including a new species, Juanognathus? denticulatus sp. nov., and several age-diagnostic taxa. Three biozones extending from the upper Tremadocian to upper Floian (Lower Ordovician) are recognized in these assemblages, including the Jumudontus gananda Biozone, the Oepikodus communis Biozone and the Paroistodus proteus Biozone, all previously recorded from the Samphire Marsh Member of the Nambeet Formation. Identification of this conodont succession has enabled both precise age constraints for this sequence and correlation to other occurrences of the Samphire Marsh Member, and indicates that this unit reaches an apparent thickness of 925 m (from 1345 to 2270 m depth) in Barnicarndy 1. This newly recovered fauna can be well correlated across the basin, such as with Nambeet Formation faunas intersected in the Olympic 1 petroleum well in the northwestern Broome Platform, and from correlative carbonates on the Lennard Shelf along the northern margin of the Canning Basin. Yong Yi Zhen [ yong-yi.zhen@planning.nsw.gov.au ], Geological Survey of New South Wales, W.B. Clarke Geoscience Center, 947-953 Londonderry Road, Londonderry NSW 2753, Australia; Heidi J Allen [ heidi.allen@dmirs.wa.gov.au ]; Sarah K Martin [ sarah.martin@dmirs.wa.gov.au ], Geological Survey of Western Australia, Department of Mines, Industry Regulation and Safety, Mineral House, 100 Plain Street, East Perth WA 6004.

Geological Survey of Western Australia: Forging a pathway for geoscience – a review of GSWA Open Day 2021

Geological Survey of Western Australia: Forging a pathway for geoscience – a review of GSWA Open Day 2021

Geological Survey of Western Australia: Closing in on AusAEM–WA

Geological Survey of Western Australia: Closing in on AusAEM–WA

Geological Survey of Western Australia: Geological Survey of Western Australia’s Accelerated Geoscience Program

During 2020–21, the Geological Survey of Western Australia (GSWA) reprioritized its work programme due to the impact of travel and operational restrictions imposed by the COVID-19 pandemic. By usin...

Barnicarndy Graben, southern Canning Basin: stratigraphy defined by the Barnicarndy 1 stratigraphic well

Funded by Geoscience Australia’s Exploring for the Future initiative and operated by the Geological Survey of Western Australia, the Waukarlycarly 1 deep stratigraphic drillhole was designed to investigate the geology of the little-known Waukarlycarly Embayment and assess the petroleum, mineral, groundwater and CO2 storage potential of the area. Based on consultation with the Western Desert Lands Aboriginal Corporation on the cultural significance of the name, Waukarlycarly, it has been agreed to change the name of the well to Barnicarndy 1 and the tectonic subdivision to the Barnicarndy Graben. This and all future publications will now refer to the Barnicarndy 1 stratigraphic drillhole (previously Waukarlycarly 1) and the Barnicarndy Graben (previously Waukarlycarly Embayment). Drilling commenced on 1 September 2019 and reached a total depth (TD) of 2680.53m on 30 November 2019, recovering more than 2km of continuous core. The cored interval extended from 580m to TD in Neoproterozoic Yeneena Basin dolostone, which was unconformably overlain by a thick, lower Canning Basin Ordovician stratigraphy, including richly fossiliferous marine mudstones with common volcanic ash beds. A major unconformity is located at the top of the Ordovician section where it is overlain by sandstones and muddy diamictites of the Carboniferous–Permian Grant Group, followed by a Cenozoic succession near surface. Ditch cuttings were collected from surface to 580m at 3m intervals. The pre-Grant Group Paleozoic succession is unique within the Canning Basin, indicating that the Barnicarndy Graben’s depositional history is markedly different when compared with adjacent structural subdivisions, such as the Munro Arch and Kidson Sub-basin. Detrital zircon geochronology, biostratigraphy and borehole imaging interpretation assisted in the definition of two new geological units within the Ordovician stratigraphy of Barnicarndy 1: the Yapukarninjarra and Barnicarndy formations. Preliminary routine core analysis data indicates the potential for CO2 storage within the Barnicarndy Formation beneath a Grant Group seal. The well also provides new insights into the structural interpretation of the Barnicarndy Graben.

Petrophysical and geochemical interpretations of well logs from the pre-Carboniferous succession in Barnicarndy 1, Canning Basin, Western Australia

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 (855–2585mRT) unconformably overlying Neoproterozoic metasedimentary rocks. Three informal siliciclastic intervals were defined based on core lithology, well logs, chemical and mineral compositions: the Upper Sandstone (855–1348.1mRT), Middle Interval (1348.1–2443.4mRT) and Lower Sandstone (2443.4–2585mRT). 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 464.5mD in the Upper Sandstone and 6.75% and 10mD in the Lower Sandstone. The Middle Interval claystone has an average porosity and permeability of 4.17% and 0.006mD, and average TOC content and S2 value of 0.17wt% and 0.047mgHC/g rock, with maximum values of 0.66wt% and 0.46mgHC/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.

Geological Survey of Western Australia: SWAN takes off - a new seismic monitoring project in Western Australia

The Geological Survey of Western Australia, in collaboration with the Australian National University, Macquarie University, the Department of Fire and Emergency Services and Geoscience Australia, h...

Geological Survey of Western Australia: AusAEM20–WA Stage 1 underway

Data acquisition in Stage 1 of the AusAEM20-WA project is underway. This project (see Preview 205 April 2020, https://doi.org/10.1080/14432471.2020.1751781) is funded by the Western Australian Gove...

Bayesian geological and geophysical data fusion for the construction and uncertainty quantification of 3D geological models

Traditional approaches to develop 3D geological models employ a mix of quantitative and qualitative scientific techniques, which do not fully provide quantification of uncertainty in the constructed models and fail to optimally weight geological field observations against constraints from geophysical data. Here, using the Bayesian Obsidian software package, we develop a methodology to fuse lithostratigraphic field observations with aeromagnetic and gravity data to build a 3D model in a small (13.5 ​km ​× ​13.5 ​km) region of the Gascoyne Province, Western Australia. Our approach is validated by comparing 3D model results to independently-constrained geological maps and cross-sections produced by the Geological Survey of Western Australia. By fusing geological field data with aeromagnetic and gravity surveys, we show that 89% of the modelled region has >95% certainty for a particular geological unit for the given model and data. The boundaries between geological units are characterized by narrow regions with <95% certainty, which are typically 400–1000 ​m wide at the Earth’s surface and 500–2000 m wide at depth. Beyond ~4 ​km depth, the model requires geophysical survey data with longer wavelengths (e.g., active seismic) to constrain the deeper subsurface. Although Obsidian was originally built for sedimentary basin problems, there is reasonable applicability to deformed terranes such as the Gascoyne Province. Ultimately, modification of the Bayesian engine to incorporate structural data will aid in developing more robust 3D models. Nevertheless, our results show that surface geological observations fused with geophysical survey data can yield reasonable 3D geological models with narrow uncertainty regions at the surface and shallow subsurface, which will be especially valuable for mineral exploration and the development of 3D geological models under cover.

The Mineral Systems Atlas — delivering greater value from precompetitive geoscience data

The Mineral Systems Atlas and Guide are recent online systems developed and curated by the Geological Survey of Western Australia (GSWA). The objective of the Atlas and Guide is to more effectively...

Regional airborne gravity surveys in Western Australia: Considerations for the end user

Regional airborne gravity surveys are being acquired over much of the State of Western Australia by the Geological Survey of Western Australia (GSWA) and Geoscience Australia (GA) to provide covera...

Driving the paradigm shift of near surface exploration geochemistry using ultrafine soils

SummarySoils are widely used as a geochemical sample medium. These samples are sieved to <250 μm or <180 μm to remove larger gravels and coarse sand and later pulverized for analysis, but no other refinement is commonly used. Why is this the case? In transported cover, the soils that host/adsorb the mobile element signature are the smallest size fractions, so we should consider concentrating the clay size fraction (<2 μm) as an improved sample medium. Industry is unlikely to fully adopt these changes without proof of the benefit of refining the size fraction so a series of experiments were conducted to demonstrate the value of using <2 μm fractions for exploration geochemistry. Twenty-seven composite reference soils were collected in the vicinity of known mineral deposits (including background areas) that reflect the common soil types of Western Australia. These soils were used in replicate testing to assess differences in particle size, sample weight, dispersants and how this relates to the geochemistry with intent to optimise the extraction and speed of ultra-fine fraction recovery. Following the refinement of the technique, we commercialised and then applied the new UltraFine+ workflow to numerous orientation site studies, including reprocessed archived regional soil samples from the Geological Survey of Western Australia. Orientation results were promising. Analysing fine fractions (<2 μm) generated reproducible, reliable results, with bigger concentrations. Key benefits were the removal of nugget effects (for Au) and the challenges with detection limits in materials that are dominantly quartz sand. Importantly, the study revealed a marked decrease in censored results for Au (63% to 10% below detection limit) and less variation with sampling depth in soil profiles. The UltraFine+ workflow demonstrates the additional value from (re-) assaying regional soil and sediment samples to generate new targets and improve regional geochemical maps.

Computer vision-based framework for extracting tectonic lineaments from optical remote sensing data

ABSTRACT The extraction of tectonic lineaments from digital satellite data is a fundamental application in remote sensing. The location of tectonic lineaments such as faults and dykes are of interest for a range of applications, particularly because of their association with hydrothermal mineralization. Although a wide range of applications have utilized computer vision techniques, a standard workflow for application of these techniques to tectonic lineament extraction is lacking. We present a framework for extracting tectonic lineaments using computer vision techniques. The proposed framework is a combination of edge detection and line extraction algorithms for extracting tectonic lineaments using optical remote sensing data. It features ancillary computer vision techniques for reducing data dimensionality, removing noise and enhancing the expression of lineaments. The efficiency of two convolutional filters are compared in terms of enhancing the lineaments. We test the proposed framework on Landsat 8 data of a mineral-rich portion of the Gascoyne Province in Western Australia. To validate the results, the extracted lineaments are compared to geologically mapped structures by the Geological Survey of Western Australia (GSWA). The results show that the best correlation between our extracted tectonic lineaments and the GSWA tectonic lineament map is achieved by applying a minimum noise fraction transformation and a Laplacian filter. Application of a directional filter shows a strong correlation with known sites of hydrothermal mineralization. Hence, our method using either filter can be used for mineral prospectivity mapping in other regions where faults are exposed and observable in optical remote sensing data.

Geological Survey of Western Australia: Data released from Eastern Goldfields 2019 seismic survey

Geological Survey of Western Australia: Data released from Eastern Goldfields 2019 seismic survey

Application of ultrafine fraction soil extraction and analysis for mineral exploration

The need to innovate to advance exploration success is ongoing and, while regional geochemical surveys are common, increasing the data we collect and improving survey results has stagnated. A new adaption of existing methods known as UltraFine+™ extracts the &lt;2 µm fraction of soils and sediments, which is then analysed and combined with spectral mineralogy proxies and physicochemical properties to improve targeting for Au and base-metal exploration. We applied the UltraFine+™ workflow to three small orientation site studies in Western Australia, and reprocessed archived regional soil samples from the Geological Survey of Western Australia to test the method. The orientation programme ( c . 200 samples) involved samples from the Leonora and Sir Samuel 1:250 000 map sheets, an area that hosts known major Au and base-metal deposits. We then applied this approach to the Kingston 1:250 000 map sheet area, analysing a further 300 samples in a region on the Yilgarn Craton margins that is essentially greenfields, as there has been little exploration and the original geochemical survey data were heavily censored due to the abundance of transported regolith dominated by quartz-rich sand. The archived samples were specifically selected soils (sheetwash or sandplain) with a component of Quaternary–Tertiary transported cover. Results at the orientation test sites (Telfer West, Tooting Bec and DeGrussa) were promising. Importantly, the study revealed a marked decrease in censored results for Au (from 63% to 10% below detection limit). Geochemistry and some example indices for mineral exploration and lithology mapping, as well as example maps using the additional spectral mineralogy proxies or particle-size variation, are presented. The application of the &lt;2 µm particle-size separation and the UltraFine+™ workflow importantly demonstrate the additional value from (re-)assaying regional soil and sediment samples to generate new targets and improve regional geochemical maps. This is an exercise that can be applied to new greenfields surveys and, when exploration budgets are lean, to archived samples.