Targeted Exploration Initiative, South Australia (TEiSA)
Minerals Project Summary

Year 4 projects
2001 - 02

Eleven contracts were awarded (value in excess of $2 300 000) for geophysical surveys, drilling, research and development, geochemical data compilation, report scanning, landscape evolution and regolith, ortho-imagery and geochemical analysis.

GRAVITY PROGRAMS

Gawler Craton
Approximately 2400 stations were acquired in the Mount Woods gravity survey to augment the various high-resolution surveys that were concurrently being obtained in the region by explorers. The survey was completed in June 2002 with stations being acquired at 1x2 and 1x1 km spacings. The new data highlight a number of important crustal structures that may be related to the location of Prominent Hill.

AIRBORNE GEOPHYSICAL SURVEYS

Musgrave Block
The survey was designed to facilitate mineral and petroleum exploration in the AP and Maralinga Tjarutja lands along the southern half of the Musgrave Block and northern margin of the Officer Basin. The data acquired included magnetic, radiometric and topographical elevation.

The data are now being used by both mineral and petroleum explorers to identify possible mineralised targets and stratigraphic traps. The survey area is immediately south of the previously completed Mann, Woodroffe and Alberga Airborne Geophysical Survey. Preliminary data have generated great interest throughout the exploration industry, displaying geological structural features more clearly than previous surveys. The acquisition of these data sets is timely due to the increased interest in the Musgrave Block following the nickel discovery made by WMC on its Western Australian Musgrave Block tenements. Many different stakeholder groups will use the data, with the radiometric and elevation data also having land-use planning and management applications.

The final data set is now available and can be obtained by contacting Miles Davies.

DRILLING PROGRAM

Musgrave Block
Broad-spaced reconnaissance RC percussion and diamond core drilling was conducted along roads and tracks across the MANN 1:250 000 map area. The objective was to target different magnetic signatures from the recent airborne geophysical survey and drill until fresh basement was intersected. Approximately 200 holes for a total of 5000 m were planned but, as the cover was deeper and the drilling much slower than planned, 46 holes were drilled for a total of 2282 m RC and 304 m NQ diamond core. Whole-rock and trace element geochemical analysis and petrology will be conducted on bottom of hole samples (fresh basement), and petrophysical data have been recorded to aid interpretation of the geophysics. The cover sequences and weathered basement was scan-sampled for economic elements. Where significant groundwater flows were intersected, a sample was taken to determine water quality and the hole was left open to enable use as a water bore if required.

Information on the drillhole locations and results is available from Miles Davies.

Gawler Craton
The Greenstone Drilling Project Phase 1 commenced in May 2001 and was designed to test the ultramafic–mafic–BIF sequences in the Lake Harris, Hopeful Hill and Talia Hill – Mullina Well regions.

In conjunction with this project, two other geophysical surveys were funded to enhance the geological understanding of the region;

• A regional gravity survey
• An AEM survey with detailed aeromagnetics

This first phase of drilling established a framework stratigraphy for the greenstone belt, allowing dating on the sequence and groundtruthing of the geophysics. Approximately 4952 m of aircore and open hole percussion, and 951 m of diamond core, have been completed in 131 holes. The program confirmed the existence of substantial komatiitic lavas, which have potential for nickel deposits.

The Greenstone Drilling Project Phase 2 has been incorporated in the ‘TEiSA 2020’ initiative.

For further information on the Greenstone Drilling Project contact Marc Davies.

DATA MANAGEMENT AND DELIVERY

Geoscientific Information Management Program

Statewide Surface Geochemical Database
This project involved the compilation of open file surficial geochemistry from regional investigations and company exploration throughout South Australia. In particular, digital data collected during 1995–2001 were combined with analogue data from targeted regions considered highly prospective, for example, parts of the Gawler Craton and Curnamona Province. The digital data set includes sample location coordinates, sample type, analysis values, analytical methods, mesh size, date collected, and position in the landscape if known. At the beginning of the project only 5000 sample sites were recorded in the database but at completion over 50 000 sites will be recorded, primarily over the Gawler Craton and Curnamona Province.

Company exploration (minerals) report scanning
Exploration companies must submit technical data for permanent storage in accordance with South Australia’s mining and petroleum legislation. Storage and maintenance of these data must also conform to the State Records Act 1997. As data are in their original form and no duplicates exist, these items are not only unique but comprise a highly valuable data set. Their digital capture will not only ensure preservation of data integrity, but also ensure long-term data availability, minimise the risk of data loss, and facilitate the efficient provision of data to future explorers. Digital copies in PDF format will then be made accessible to stakeholders via SAMREF, online in SARIG. On completion of this project, ~2 000 000 items will be available for search and download. The target for 2001–02 was 100 000 pages of open file analogue reports, maps, and figures converted to digital PDF. At 30 June 2002, 130 000 pages had been converted to digital format and made available through SAMREF.

Musgrave Block ortho-imagery
The need for a modern, accurate spatial database has been satisfied by acquisition of spatially registered aerial photography, which will be the basis of accurate ortho-imagery and DTM for the entire Musgrave Block in South Australia. PIRSA was in partnership with the Geological Survey of Western Australia in the project. The mineral industry is not the sole beneficiary, as the data set is available to the Pitjantjatjara, Yankunyatjatjara, and Ngaanyatjarra Peoples, and for other uses such as land management.

For further information on the above data contact Miles Davies.

LANDSCAPE EVOLUTION AND REGOLITH

Gawler Craton
The Greenstone regolith project involves detailed regolith mapping of selected areas of the Harris Greenstone Belt along with detailed regolith subsurface modelling based on drillhole data. The Harris Greenstone Belt is covered by thin surficial sediments and has been affected by moderate to deep weathering (<10–>100 m). To undertake efficient geochemical exploration over the greenstones, relationships between geochemical dispersion patterns, weathering processes and evolutionary stages of regolith and landform development needed to be studied. The Landscape Evolution Project will characterise the regolith within the greenstone belt and allow comparisons with regolith development in more established geochemical exploration regions in Western Australia.

Preliminary results show a high variability in the depth of weathering and extent of preserved weathering profile. A good correlation has been established between depth of weathering and response to airborne electromagnetics. Samples have been submitted for geochemical analysis, with results expected in the near future. This will allow the dispersion effects of selected elements within the regolith to be studied in more detail.

For further information contact Malcolm Sheard.

The Kingoonya Palaeochannel Project

A sedimentological study of the main palaeochannel crosscutting the Archaean greenstones and adjacent Proterozoic goldfields in the central Gawler Craton. The aim is to better define the palaeochannel systems developed across the Harris Greenstone Belt and define target areas within these systems with the potential for placer deposits (gold, diamonds, uranium and heavy minerals) or to aid in determining mineralisation in the basement. The study will enhance the understanding of the area’s landscape evolution, groundwater resources and regolith development, and allow a better understanding of the results from exploration geochemistry.

Relogging of existing drillholes is complete, allowing a better interpretation of true depth to basement and palaeochannel dynamics. Preliminary interpretation of geophysical and remote sensing data is underway and has already revealed previously unrecognised palaeochannel systems. Five holes have been drilled into palaeochannels as part of the phase 2 drilling to determine the physical parameters of these systems.

For further information contact Baohong Hou.

Curnamona Province
This project involves assessment of the sedimentary and regolith cover of the northern Murray Basin, Callabonna Sub-basin and Willyama Inliers. It includes reassessment of current geological information, the potential for sedimentary uranium, heavy mineral sands and other commodities, and will investigate the effect of cover or regolith on exploration of the underlying basement.

Outputs will include compilation of existing data for the northern Murray Basin, a summary report on the Northern Murray Basin Drilling Program (2000–01), and a preliminary compilation of data and palaeochannel map for the Callabonna Sub-basin.

Further information is available from Adrian Fabris.

GEOLOGICAL MAPPING

Curnamona Province
This project is focused on Palaeo- and Mesoproterozoic rocks of the Curnamona Province in the Willyama Inliers, Benagerie Ridge and Mt Painter Inliers, and was funded through year 4 of the TEISA program. The project includes detailed outcrop mapping, re-appraisal and incorporation of existing mapping, interpretation of covered areas, geochronology, and studies of the intrusive, tectonic, metamorphic and metallogenic history of the region. The aim is to produce key geoscientific data sets and concepts to facilitate efficient, targeted exploration.

Outputs completed in 2001–02 include mapping in the Mingary area (Radium Hill North and South maps), Coppertop and Outalpa Inliers, and in the Billeroo South area; an isotope and geochemical study of granites and metasediments in the western Willyama Inliers; several summary technical reports and MESA Journal articles.

Digital maps and data are available from Stuart Robertson.

DELAMERIAN OROGENY

TEiSA is contributing to a three-year SPIRT study (January 2001–04) by Dr Martin Hand, University of Adelaide, on the timing of deformation and syn-metamorphic mineralisation in the Delamerian Orogeny. An honours project on Kangaroo Island has pointed to a more complex history for the Delamerian Orogeny than previously known.

MINERAL EXPLORATION RESEARCH

Curnamona Province
This project aims to examine the secondary dispersion of indicator minerals from the Pine Creek Kimberlite to assist exploration for diamonds across the state through a better understanding of the relationship of indicator anomalies to source. Regolith mapping, RC drilling, trenching and loam sampling are underway to test the primary dispersion of diamond indicator minerals. The Pine Creek Kimberlite was chosen because of its large area, indicator minerals and suitable topography.

Contribution to a three-year AMIRA Project (P544) by CODES and other researchers commenced in 2000, studying Proterozoic sedimentary copper. The study specifically includes factors that influence copper transport, concentration and deposition, as well as possible remobilisation during basin evolution, and definition of possible vectors that indicate ore both on a deposit scale and a district scale. Comparison between the Neoproterozoic Southern African copper belt and Australian Neoproterozoic, particularly the Adelaidean rocks in South Australia, are being made such that better exploration models may be developed.

This project reached a major milestone in April with a workshop held in Adelaide and a field workshop in the Willouran Ranges to transfer new ideas that have come from the study. The Adelaide Geosyncline is well known for stratiform copper prospects and its gross similarity to the world’s largest copper resource terrain in the Southern African Copper Belt.

It is hoped that TEISA investment in this project will provide new approaches to the search for stratiform copper in South Australia.