February 2018

A monthly online newsletter with product news, data releases and project highlights relating to the minerals and energy exploration industries.

1. Geoscience Australia Minerals Forum presentations available online
2. Geoscience Australia at the 2018 AEGC (Australasian Exploration Geoscience Conference)
3. New geochronology reports and data available
4. Geophysical estimates of cover thickness: two new case studies available
5. Update on geophysical data release
6. About Minerals Alert

1. Geoscience Australia Minerals Forum presentations available

The Minerals Systems Branch delivered a series of presentations at a public forum in Canberra on 12 December 2017. Those presentations are now available online for download. The presentations cover the themes: (i) Cover, (ii) 3D architecture, (iii) 4D geodynamics, and (iv) Mineral Systems Footprints and Toolkits. As well as covering a range of current activities within the Mineral Systems Branch, the presentations emphasise new projects arising from the Australian Government's four year Exploring for the Future Programme, which commenced in 2016.

2. Geoscience Australia at the 2018 AEGC (Australasian Exploration Geoscience Conference)

Geoscience Australia will be at the First Australasian Exploration Geoscience Conference (AEGC) in Sydney at the International Convention Centre from 18-21 February 2018. The Conference is being jointly organized by the Australian Society of Exploration Geophysicists Ltd, the Australian Institute of Geoscientists Ltd and the Petroleum Exploration Society of Australia Ltd. Presentations, both oral and poster, will be given on the various geoscientific programs conducted by Geoscience Australia and will include results from the Exploring for the Future initiative and recent geophysical surveys in Australia that have collected passive seismic, magnetotelluric, ocean-bottom seismometer, airborne electromagnetic, magnetic, radiometric, gravity and seismic datasets. If you are in Sydney at this time please come and visit the Geoscience Australia booth (Numbers 75 & 76) in the exhibition hall for more information about the numerous geoscientific activities at Geoscience Australia.
The presenters, their topics and presentation schedule are available from the conference website at www.aegc2018.com.au.

3. New geochronology reports and data available

• Northern Territory Geological Survey Record 2017-011 by Kositcin and McGloin reports new SHRIMP U-Pb zircon ages from two granite samples from the Aileron Province, Northern Territory.
• Northern Territory Geological Survey Record 2017-012 by Kositcin, Munson and Whelan reports new SHRIMP U-Pb detrital zircon ages from 11 sedimentary samples from the greater McArthur Basin, Northern Territory.
• Geoscience Australia Record 2017/16 by Kositcin and Carson reports new SHRIMP U-Pb detrital zircon ages from 9 sedimentary samples from the Birrindudu and Victoria Basins, Northern Territory. These results complement those previously presented in Carson, 2013, Australian Journal of Earth Sciences 60, 175-196, and provide an understanding of the evolving sedimentary provenance through the Proterozoic in this part of northern Australia.
• Geoscience Australia Record 2017/20 by Lewis reports new SHRIMP U-Pb detrital zircon ages from 9 samples from the GSWA Harvey 1 drill-hole in the southern onshore Perth Basin, Western Australia.
• Geological Survey of South Australia Report Book 2015/0003 by Jagodzinski and Reid reports U-Pb SHRIMP and LA-ICPMS, and 40Ar/39Ar results from over 30 samples from a range of minerals and energy prospects across South Australia.
• Geological Survey of Western Australia Report 161 by Maidment reports new SHRIMP U-Pb zircon ages, as well as associated whole-rock geochemistry Sm-Nd isotopic results, from 15 samples from the Rudall Province, Western Australia.

In each of these studies, U-Pb results were acquired in Geoscience Australia's in-house SHRIMP laboratory, in some cases under National Collaboration Framework agreements  between Geoscience Australia and the relevant State or Territory geological survey. SHRIMP U-Pb Geochronology data presented and discussed in each of these Records are also available for download via Geoscience Australia's Geochron Delivery system.

• Geoscience Australia Record 2017/22 by Anderson et al. presents a compilation of available U-Pb SHRIMP and LA-ICP-MS ages from across Queensland, Northern Territory and parts of Western Australia and South Australia. More than 2200 age results were compiled in a consistent format in spreadsheet form to facilitate use in GIS layers, and example thematic age maps are presented in the Record. This work was conducted as part of the Exploring for the Future programme, a four-year initiative funded by the Australian Government to better understand the mineral, energy and groundwater resources in northern Australia and parts of South Australia.
• Bowden, B. et al. 2017. Mineralium Deposita 52, 863-881. This study presents new U-Pb and 40Ar/39Ar age results from the Prominent Hill iron-oxide copper-gold (IOCG) deposit in South Australia.
• Cross, A. J. & Williams, I. S., in press. Chemical Geology. This study presents a new method for correction of so-called matrix effects during SHRIMP geochronology analyses of the mineral xenotime (YPO4).

For further information on geochronology at Geoscience Australia, please email: geochronology@ga.gov.au.

4. Geophysical estimates of cover thickness: two new case studies available

Release of Geoscience Australia Record 2017/021: Estimating Cover Thickness in the Southern Thomson Orogen - Results from the pre-drilling application of refraction seismic, audio-magnetotelluric and targeted magnetic inversion modelling methods on proposed borehole sites.
This report details the acquisition, processing, modelling and interpretation of geophysics techniques used for estimating cover thickness at 16 proposed borehole sites throughout the southern Thomson Orogen in New South Wales and Queensland. A detailed discussion of the limits and uncertainties associated with each technique is also included. The cover thickness estimates presented in this report were used to lower the risks associated with the southern Thomson Orogen stratigraphic drilling program by reducing the uncertainty in intersecting the target stratigraphy at each of the proposed borehole sites, as well as allowing for better project and program planning. Successful completion of the stratigraphic drilling program in the southern Thomson Orogen will allow for each of these geophysical methods for estimating cover thickness to be benchmarked using actual cover thicknesses measured in the boreholes. The Southern Thomson Project is a collaboration between Geoscience Australia and its state partners the Geological Survey of New South Wales (GSNSW) and Geological Survey of Queensland (GSQ).

Release of Geoscience Australia Record 2017/19: Cover Thickness Estimates in the Coompana Province, South Australia: Benchmarking and results from the pre-drilling geophysics program - Magnetotellurics.  
A partnership between the Geological Survey of South Australia (GSSA) and Geoscience Australia was formed to undertake a regional drilling program in the Coompana Province, which is completely covered by Neoproterozoic to Cenozoic sediments with no known records of outcropping basement. The geophysical technique of magnetotellurics (MT) was applied to estimate cover thickness at the proposed drillhole sites as part of a pre-drilling geophysics field program. Comparison with historic drillhole results indicates that the MT method is capable of identifying major stratigraphic structures and providing cover thickness estimates with a reasonable accuracy (within 10%). Subsequently, estimates of cover thickness at eight proposed drillhole sites are derived from the MT data and are provided to assist the Coompana Drilling Program in April 2017. Details of MT data acquisition and processing, data inversion and preliminary interpretation of model results are presented in this report.

5. Update on geophysical data release

Geoscience Australia is managing the geophysical data acquisition programs in Western Australia, Victoria, New South Wales, Queensland, Tasmania and the Northern Territory on behalf of the state/territory geological surveys.

The current status of Geoscience Australia's geophysical survey data acquisition is available in a comprehensive table.

For further information, email clientservices@ga.gov.au or phone 1800 800 173.

6. About Minerals Alert

For more information, please email clientservices@ga.gov.au; or phone 1800 800 173.