Enhancing NSW statewide geophysics with high resolution company data

Matthews, Sam1

1Geological Survey of New South Wales, Department of Regional NSW, Maitland, NSW, Australia

The Geological Survey of New South Wales (GSNSW) has released an updated suite of magnetic grids and imagery which improve the existing images through the inclusion of high-resolution, open-file company data. The foundation of this product comprises over 60 regional government surveys flown at 200 to 400 m line-spacings. The addition of about 150 private company surveys flown at 50 to 200 m line-spacings increases the resolution of the grids in these areas. The higher-resolution surveys also allow the data to be gridded with a 25 m cell size rather than the previous 50 m, which provides better definition of anomalies.

The project commenced with the quality assurance (QA) of about 650 airborne magnetic surveys flown in New South Wales since the late 1950s. An algorithm was derived to quantitatively assess each survey on the merits of the survey metadata. The algorithm applied a weighted score to various parameters such as line-spacing, flight height, sampling interval, and survey area. A baseline score was calculated for the previous statewide merge based on the regional government surveys, which became the cut-off for the company data. All surveys falling below that score were excluded. A final manual QA of the remaining surveys was performed to ensure only the best data filtered through the algorithm before being included in the new merges.

The boundaries of each survey were placed into a shapefile and where any overlap occurred, the survey with the lower score from the algorithm was clipped using the boundaries of the higher scoring survey. An external buffer of 500 m was added to the survey boundaries, creating a small overlap to allow the software to align features when merging. After clipping, all surveys were re-sampled and re-projected into a unified grid cell size and projection. A base layer of total magnetic intensity (TMI) for the merge was created using the regional government surveys, which were levelled to the Australia-wide 70 km spaced magnetic traverses (AWAGS) to retain the long spatial wavelengths. Holes were clipped into this grid and buffered to the shapes of the company surveys. The final merge with the company data was then performed to create the high resolution statewide TMI grid.

The TMI grid became the foundation to create a series of enhancements. Reduction to the Pole, First and Second Vertical Derivative, and Tilt Angle filters were applied to the TMI data, which were then reprojected into a suite of projections relevant for NSW. The final high-resolution imagery is now available on MinView, the GSNSW web-based data portal. The improvements are immediately visible, with far higher resolution of magnetic anomalies across the state, especially in regions with extensive company surveys. The additional resolution provides precise definition of geophysical signatures and geological structures at all scales and will lead to improved image interpretation for geological mapping and exploration targeting.


Sam Matthews works as a geophysicist within the Geological Survey of NSW. He earnt his PhD from Macquarie University studying the geophysical signatures of sequestered CO2 and is now responsible for maintaining and enhancing all geophysical data within NSW.

How the GSNSW is helping to preserve data from the NSW infrastructure boom

Adewuyi, David1

1Geological Survey of New South Wales, Department of Regional NSW, Maitland, Australia

Geotechnical data provide information about rock/soil characterisation, strength and stability and subsurface hazard identification that is critical to infrastructure planning, design and construction, and asset protection and maintenance. These data also provide information about the volume and quality of construction materials that, when enough data is collated, can be used to assess available resources for possible extraction. Due to the vast recent and forecast increase in public construction infrastructure spending, including a New South Wales (NSW) Government commitment of $93 billion over four years to 2022–23, responsible NSW agencies that procure geotechnical services have been tasked with maintaining the integrity of their geotechnical data assets. Keeping a corporate record of geotechnical reports and re-using the information has been a key challenge for these agencies.

In January 2020, the NSW Department of Planning, Industry and Environment (including the Geological Survey of NSW (GSNSW), Sydney Water and Public Works Advisory NSW) signed a Memorandum of Understanding (MoU) with Transport for New South Wales (comprising Sydney Metro, Sydney Trains, and Roads and Maritime Services) and the Australian Rail Track Corporation, to collaborate in the development of a whole-of-government single repository for NSW geotechnical information – the Government Geotechnical Report Database (GGRD). Presently, there are over 3450 Public Works reports available in the GSNSW’s DiGS document archive and geo-located in the online spatial viewer, MinView. Industry professionals in both the private and public sector have attested to the usefulness of the database in the initial planning stages of projects for informing desktop studies, gaining preliminary understanding of subsurface conditions and identifying potential risks while scoping geotechnical investigations, which enables a more robust estimation of project costs.

To demonstrate how the geotechnical data can be used, GSNSW is working on the construction of a 3D geotechnical model as a proof-of-concept planning tool for the Western Sydney Aerotropolis area. As well as modelling the strength of the subsurface, the project will also give insights on the extraction potential of construction resources in the area.

The GGRD will also support the ongoing digital transformation in NSW that is being applied in the creation of a NSW Spatial Digital Twin, launched by NSW Spatial Services in early 2020. The NSW Spatial Digital Twin will provide 3D and 4D digital spatial models of built and natural environments. It allows visualisation of amenities even before construction begins to enable better planning of infrastructure and communities in the state.


David Adewuyi is a Senior Geoscientist Special Projects in the Geoscience Information unit of the Geological Survey of New South Wales (GSNSW), where he manages the Government Geotechnical Reports Database (GGRD) project. The GGRD is a whole of government single repository for government procured geotechnical reports and data.

Mapping the geology that matters – the role of Australia’s geological surveys in supporting mineral discovery in the 21st century

Yeats, Chris1

1Geological Survey of New South Wales, Department of Regional NSW, Maitland, Australia

During the late 20th century, Australia’s geological survey organisations (GSOs) completed 1:250,000 scale surface geological mapping of the continent. This work provided a framework for mineral exploration that led to the discovery of most of the surface and near-surface deposits in areas of outcropping basement that form the basis of the country’s current mineral production. From the 1970s, geological mapping was augmented by regional geophysical data and from the mid-1990s increased geochronological analysis, which supported a second generation of higher resolution mapping under the National Geoscience Mapping Accord into the early 21st century. However, this second wave of mapping, which often focused on areas of good quality outcrop with known mineral potential, did not lead to many significant discoveries and over 80% of the country’s current mineral production now comes from deposits discovered prior to 1980.

In order to provide a framework for mineral discovery in the 21st century, Australian GSOs need to change the search space and provide the exploration industry with the data they need to successfully explore deeper and step out into the 75% of the Australian continent where prospective basement is buried under younger, non-prospective cover. Essentially, GSOs must map “the geology that matters” – defining the structural architecture, temporal evolution and lithologies of potentially prospective geological terranes, regardless of whether they are exposed at the surface, or not.

This work has already started in New South Wales (NSW), with the NSW Seamless Geology providing an interpreted lithotectonic framework for the state, based primarily on surface mapping and potential field geophysical data. However, further geological data is required to support this model, particularly in undercover terranes. As participants in the ten-year MinEx CRC National Drilling Initiative (NDI), Australia’s GSOs will generate new precompetitive geoscientific data over several underexplored, undercover regions across the continent. Equally importantly, the NDI will support development of cheaper, faster drilling technologies, real-time sensing technologies and new concepts and decision-making tools that will aid mineral exploration in deep and/or covered terranes, thereby making large parts of the continent more accessible to mineral exploration.

Concurrently, Australia’s GSOs are deploying new technologies to augment existing national datasets. The ~55km-spaced stations of the collaborative Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) is delivering a lithospheric-scale conductivity model that can be used to define areas of anomalous fluid flow for further investigation. Completion of the AusAEM electromagnetic survey across Australia over the next four years will deliver a near-surface conductivity model that can be used to define depth to basement, as well as potential for mineral and groundwater resources. New geochemical and isotopic datasets are also being used to define fluid sources and crustal evolution at a continental scale.

As we enter the third decade of the 21st century, Australia’s GSOs face a watershed moment. We must and are transitioning from mapping the surface geology, to mapping prospective geology and delivering new types of data, to create a framework for the discovery of the new deposits needed to support Australia’s mineral industry into the second half of the century.


Chris was Executive Director of the Geological Survey of NSW from June 2015 to December 2020. Prior to this, he spent 17 years as a researcher and manager at CSIRO, where his work focussed on the formation of and exploration for gold and base metal deposits in ancient and modern terranes.

Geoheritage significance of three contiguous Holocene wetlands 161, 162, & 163 in the Becher Wetland Suite, south-western Australia

Semeniuk, Christine1, Semeniuk, Vic1,2

1V & C Semeniuk Research Group, , , 2Notre Dame University, Fremantle, Australia

The Becher Wetland Suite comprises a series of wetland basins located in inter-dune depressions on a Holocene prograded beach-ridge plain.  With progradation, the wetlands formed by the regional water table naturally rising into the inter-dune depressions.  As beach-ridge progradation is westerly, the inter-dune depressions (becoming wetland basins) generally young towards the west, with the oldest basins some 4500 years old, and the youngest < 900 years old.  Through the Becher region, the insertion of wetlands on the prograded beach-ridge plain, through generally younging westwards, in detail, is staggered because of the uneven topography of the depressions along their length.  For instance, wetlands 161, 162, & 163, the subject of this paper, all occur along an inter-dune depressions located on the 4500-year beach-ridge isochron (the oldest part of the beach-ridge plain) and, as such, ideally should be the same age and show the same history. However, they have a staggered history, with wetland 161 commencing accretion some 4350 years ago, wetland 162 commencing 4110 years ago, and wetland 163 commencing 2920 years ago.  All three basins filled with calcilutite.  However, with different ages and longevity of accretional history, and subject to differing small-scale temporal climate changes (in the order o 100 years of less) they exhibit different sedimentary history in terms of thickness of calcilutite, the relationship of calcilutite to underlying sand, diagenetic effects (such as dissolution of underlying carbonate sand, dissolution of Chara and sponge spicules, and patchy cementation of calcilutite), and the responses to fire.  This sequence of wetlands illustrates the complexities of wetland basin sedimentation.   As such, the contiguous wetlands 161, 162, & 163 are a system of international geoheritage significance.


Christine Semeniuk is a Director of VCSRG, a Research & Development Corporation.    Graduated from the University of Sydney in 1969, she was awarded a PhD from Murdoch University in 2003. Christine arrived in Western Australia 50 years ago, undertaking research into wetlands of Western Australia, and has over 30 peer-reviewed publications in wetland science and geoheritage, including the geoheritage values of wetlands of the Swan Coastal Plain. Christine is a founding member of the NGO the Wetlands Research Association inaugurated in 1999.

Patina: A microscopic feature of palaeo-environmental and geoheritage significance

Clifford, Penelope1, Semeniuk, Vic1,2

1Notre Dame University, Fremantle, Australia, 2V & C Semeniuk Research Group, ,

Patina is an ultra-thin crust of silica or silica and carbonate that is developed on glass and, while it best developed on anthropogenic glass, it provides important information on products and processes associated with weathering of glasses in general.  It is common in modern environments, though variable in expression dependent on environmental setting, and it has been recorded on pre-Mediaeval and Mediaeval artefacts.  Anthropogenic glass is geochemically unstable and, as such, it corrodes relatively rapidly (within years), generating a variety of weathering crusts of different thicknesses, and various internal structures.  The type of patina that is developed depends on the glass composition, the type of soil it is embedded in, the hydrochemistry of the soil water, climate setting, and whether the glass is located in an inland vadose zone or phreatic zone, a maritime coastal zone, or a submarine environment. The patina crusts are < 10 µm up to 100 µm, thickening with age. The solutional relationship of the patina to the glass varies from straight, undulating, irregular, to cuspate and, internally, shows structures of colloform to undulating lamination, parallel lamination, massive to mottled patterns, micro-brecciation, shrinkage cracks, and infiltrated dust-sized minerals, all reflecting and recording a history of solution and precipitation, and variation in climate. For vadose environments, the main agents in the patination is alternating wet and dry vadose conditions, and alternating acid and alkaline vadose conditions that result in precipitation of an amorphous silica ‘gel’ that forms silica laminae, its layer-parallel shrinkage, and the precipitation of calcite laminae.  While modern patina and historic patina have been documented from the various climate, hydrochemical, and pedogenic environments, the results are widely applicable to understanding and unravelling the weathering of natural materials such as obsidian, chert, and volcanic glasses – in this context, it conforms to the geoheritage category of ‘modern processes’ and provides a record of modern processes and products in the weathering of natural glass and glass-like materials.


Vic Semeniuk is a Director of VCSRG, a Research & Development Corporation. Awarded a PhD from the University of Sydney, a UWA Postdoctoral Fellowship, and the Queens Postdoctoral Fellowship in Marine Science, as a multi-disciplinary research scientist, Vic has over 160 peer-reviewed publications in the geology, geomorphology, and geoheritage, as well as in coastal science, environmental science, and conservation ecology (estuaries, mangrove, wetland, coastal dunes, soldier crabs). Vic arrived in Western Australia 50 years ago, initially with a position at The University of Western Australia, and continues to teach and supervise postgraduate students as an Adjunct Professor at the University of Notre Dame and Murdoch University. Vic is a founding member in 2019 of Geoheritage Australasia, and in 1999 of the Wetlands Research Association. Inc.

Recognising and preserving mineral diversity: An updated catalogue of type mineral specimens in Victoria’s State collections

Lindenmayer, Oskar1

1Museums Victoria, Melbourne, Australia

Type mineral specimens are designated by the International Mineralogical Association (IMA) as the physical standards by which newly discovered mineral species are defined. They represent the benchmarks against which the word’s mineral diversity can be recognised and studied. Each type mineral specimen is a globally significant element of movable natural heritage and forms an irreplaceable resource for researchers in the fields of mineralogy, crystallography and materials science. Despite their importance, the management of these specimens has historically lacked transparency.

Museums Victoria holds approximately half of the type mineral specimens in Australian institutions. The most recent edition of the global catalogue of type mineral specimens, prepared under the direction of the IMA Commission on Museums, lists 98 specimens as lodged with Museums Victoria, of which 45 are from Australian localities and 53 are from overseas localities. This catalogue also lists the whereabouts of 12 specimens from Australian localities as unknown. In contrast to the global catalogue, Museums Victoria’s internal catalogue includes 125 type mineral specimens, of which 59 are from Australian localities and 66 are from overseas localities. There are also a number of discrepancies between the two catalogues for specimens that appear on both, including type status (ie. whether the specimen is a holotype, cotype or neotype) and registration number.

To resolve these issues, a review of the information available in publications, Museums Victoria records and correspondence, and minutes from meetings of IMA Commissions has been undertaken for each specimen. Where necessary and practical, authors of new mineral descriptions have been contacted for further information. A methodology has been developed to identify legitimate type specimens and appropriately categorise them by their type status. In a departure from previous attempts to document type mineral specimens in Victoria’s State collections, areas of uncertainty or missing information for specimens are flagged and explicitly discussed.

The sources of the majority of the discrepancies between the global and internal catalogues were found to be either publically undocumented transfers from other institutions or incomplete information having been given in the original publications of new mineral descriptions. Amongst the discrepancies resolved was the identification of Museums Victoria as the lodging institution for five of the type specimens listed as having unknown whereabouts in the global type catalogue. In the absence of a formal mechanism for reviewing details or reporting transfers of type mineral specimens, periodical review and publication of catalogues by the institutions that hold them is necessary for the ongoing management of these most significant parts of mineral collections. It is hoped that by undertaking this review in a transparent manner, and making the results and methodology publically available, other institutions will be encouraged to do the same.


As Collection Manager, Geosciences, at Museums Victoria, Oskar is responsible for managing Victoria’s State collections of minerals, gemstones, rocks, meteorites, and tektites.

This involves preserving and organising the collection, maintaining and improving the digital collection database and facilitating access of the collections for the purposes of research, education, and exhibition.

A geoheritage treasure – a case study of the Hornsby Diatreme

Semeniuk T A1,2

1Western Sydney University, The College, Quakers Hill, Australia.  email: t.semeniuk@westernsydney.edu.au

The quarrying for bluestone at the Hornsby Quarry Site exposed a > 40 m-deep cross-section of a volcanic diatreme, showing a volcanic neck extruding through Sydney Basin sediments, complete with volcanic features visible at many scales, with post-volcanic features related to magma and gas extrusion at various depths, and with different host rocks. Globally, there are very few instances of such excellent exposure, revealing a full range of macroscale to microscale features in three dimensions. It is arguable that this exposure alone, makes it a site of international geoheritage significance.  Using the Geoheritage Tool-kit, applied at various scales shows that this diatreme is internationally to nationally significant.  For example, at the macroscale, there dish beds in all orientations of the quarry walls are visible, giving a three-dimensional picture of its structure, reflecting its volcanic accretion and later caldera collapse.  At the mesoscale, where breccia beds, bombs, and surge layers are visible, these show how the magma interacted with various host rocks and other post-volcanic processes that occurred prior to solidification.  Finally, at the microscale, lapilli (including accretionary lapilli), chilled margins and carbon-rich xenoliths are evident in hand specimen.  As such, this Quarry is a unique site worldwide. In fact, the Quarry, exposing the volcanic pipe of the Hornsby Diatreme, offers a snapshot in time of the Sydney Basin, preserving its volcanic and post-volcanic history on the quarry walls.


Trudi Semeniuk is a multidisciplinary scientist in the fields of general geology, metamorphic geology, geoheritage, wetland-, mangrove-, foraminiferal-, and tidal-flat sedimentology and ecology.  Her work experience is manifold ranging from fieldwork for VCSRG (a Research & Development Corporation), and a Research Officer for ANU, CSIRO, and Kings Park Botanical Gardens. More recently Trudi has focused on reviewing sites of geoheritage significance listed on, the now archived, Register of the National Estate (NSW) and work as a scientific editor.  Trudi was awarded a PhD from the Institute of Mineralogy and Petrography, ETH Zurich in 2003 in a study of Alpine mylonites, and completed a Postdoctoral Fellowship in 2004-2006 in aerosol chemistry at Arizona State University.  Trudi is active in Geoheritage, and is the co-convenor for the NSW Division for Geoheritage in the Geological Society of Australia.

The status of geoheritage and geoconservation in Australia

Creswell, Ian1

1University of Newcastle, Callaghan, Australia

The protection of Australia’s natural heritage has been ongoing since the 1870s in every state and territory, however, efforts to identify and conserve important sites of geoheritage significance have had limited success.  This presentation reviews the policies and legislation governing geoheritage and geoconservation in all Australian jurisdictions and shows that there are inconsistencies and inadequacies in the processes to identify and protect areas of geoheritage significance.  Each state and territory has differing emphases on geoconservation and different degrees of success in achieving geoconservation goals.  In 2015 the Australian Government released the Australian Heritage Strategy as the overarching framework for the identification, management, and protection of Australia’s heritage across all levels of government and community.  While in recent years there have been a few ad hoc successes related to national heritage or to state heritage, it is not clear the strategy is working.  There is an urgent need for a nation-wide systematic approach to identifying representative geoheritage sites, and to enact processes for their protection.


Dr Cresswell is the co-Chair of the national State of the Environment report, and Chair of the Western Australian Biodiversity Science Institute. He has extensive experience working in environmental science in biodiversity conservation and discovery, oceans governance, fisheries management, wildlife regulation, and protected areas, including geoheritage. He has led major programs in CSIRO both in marine science and terrestrial and freshwater ecology science. Previous to this Ian worked within the Australian Government leading oceans management, sustainable fisheries assessments, international wildlife management, and the Australian Biological Resources Study. In collaboration with the V & C Semeniuk Research Group, Ian has studied coastal systems, including coastal dunes, estuaries, mangroves systems, and tidal flats, towards their management and assessing their geoheritage values.  In relation to geoheritage, Ian has a strong interest in geoconservation, policy, and legislation, and maintains an ongoing research interest in multiple-use management and coastal systems.

Geoheritage values of Beenyup Swamp, in the Yellagonga Regional Park, Western Australia

Unno, Joy1

1V & C Semeniuk Research Group

Beenyup Swamp in the southern part of Yellagonga Regional Park on the Swan Coastal Plain in Western Australia is a Holocene wetland with geoheritage values.  It is part of the chain of linear wetlands belonging to the Yanchep Wetland Suite that is located between limestone ridges of the Spearwood Dunes near the boundary of the quartz-sand-dominated Bassendean Dunes.  Instead of being dominated by calcilutite as are other wetlands in this Suite, Beenyup Swamp is a basin stratigraphically dominated by peat. As such, in contrast to other basins in the Yanchep Wetland Suite that are mostly calcilutite-filled, Beenyup Swamp has a stratigraphy of thick homogeneous peat, with stratigraphic evidence of fire scarring including buried lumps of charcoal, and ubiquitous diagenetic products of acidic groundwater.  The sequence of peat in this region of the Yanchep Wetland Suite dates back to 8000 years BP and contains a diagenetic record of plant organic matter grading from fibrous peat to organic gel.  The stratigraphy, the Holocene fire history, the acidic water diagenesis providing a model of peat accumulation and peat diagenesis at Beenyup Swamp is a geological ensemble of geoheritage significance.


Joyleen Unno (MSc) is a wetland scientist with over 20 years of experience studying coastal and inland wetlands (mangroves, inter-tidal flats and estuaries, and inland basins) in Australia in conjunction with the V & C Semeniuk Research Group in Perth, Western Australia; In recent years, Joyleen has become involved in the geoheritage aspect of wetlands, whereby wetlands may be conserved for their significant on-going geological processes and their stratigraphic value to scientific knowledge. Joyleen also is a founding Committee Member of the Wetlands Research Association Inc.

Geoconservation of ancient Pilbara stromatolite fossils as a multifunctional landscape

Fletcher, Clare1, Van Kranendonk, Martin J.2, Metternicht, G.3, Walter, M. R4.

1University of New South Wales, Sydney, Australia, 2Australian Centre for Astrobiology, Sydney, Australia, 3University of New South Wales School of Biological, Earth and Environmental Science, Sydney, Australia, 4Emeritus Professor, Macquarie University, Sydney, Australia

The ancient (3.48 billion year old) stromatolite fossils of Western Australia’s Pilbara region constitute the oldest convincing evidence of life on Earth found to date. These fossils offer a unique insight into the origin of life on Earth and elsewhere in the universe. There are six key sites for ancient life in the Pilbara, mostly concentrated around the North Pole Dome geological region. Since the discovery of such ancient and well-preserved stromatolite fossils in 1980, they have become a sought-after item for indiscriminate collectors to the point where the original site (Dunlop) no longer exists. 

Due to this indiscriminate collection, various methods of conservation have been recommended over the years. In 1987 a Geological Survey of WA report recommended that the North Pole Dome fossils were placed on the Register of National Estate (henceforth RNE) (now the National and Commonwealth Heritage Lists). The site was also placed on an indicative list for UNESCO World Heritage listing in 1996. Whilst the sites of Buick and Awramik were registered on the RNE, the Register was closed in 2007, and so the legal conservation status of these sites was lost, and they were once again left unconserved.

Currently the six sites are State Geoheritage Reserves vested in the Minister for Mines and Petroleum. While this affords some protections such as requiring approval before visiting these sites, it has not prevented collection of material from the sites. Mining licenses can also be granted for the collection of materials from these sites. The conservation of these sites is complicated by the surrounding lands being either Crown Land or pastoral lease (depending on the site). Other stakeholders include the Nyamal people, the community of Marble Bar, NASA, the European Space Agency, the Japanese Space Agency, and others.

The vision for these sites is both geoconservation and on-the-ground management that prevents further theft of the fossils and facilitates learning and tourism in the area. We have petitioned the Department of Biodiversity Conservation and Attractions to add the North Pole Dome sites to Meentheena for consideration under the WA Government’s Plan For Our Parks initiative which works concurrently with an Indigenous Ranger program. Our vision also includes a combined scientific research and ranger station, that can be used for site visits by space agencies, universities, schools, and potentially become a visitor information and discovery centre combining science on the origin of life and Indigenous history and tellings.

The type of conservation effort to be pursued is yet to be determined. While both National Heritage listing and World Heritage listing are appropriate for the site because of its universal importance, the timeframe of achieving either of these as well as the additional legal protections afforded need to be considered before committing to either effort. Public-private partnerships are also to be considered alongside conservation efforts. While different conservation avenues are being explored public-private partnerships will allow for the vision for geoconservation of the North Pole Dome stromatolite fossils to be realised. 


Clare Fletcher is an MPhil student at UNSW researching the best method of conserving the North Pole Dome stromatolite fossils.

Martin Van Kranendonk and Graciela Metternicht are both supervisors on this project. Malcolm Walter was one of the people who originally described the stromatolite fossils.


About the GSA

The Geological Society of Australia was established as a non-profit organisation in 1952 to promote, advance and support Earth sciences in Australia.

As a broadly based professional society that aims to represent all Earth Science disciplines, the GSA attracts a wide diversity of members working in a similarly broad range of industries.