Undercover at Mt Isa
10 January 2007
Geoscientists from the Australian and Queensland Governments have just completed the data acquisition phase of a major deep crustal seismic survey of the Mount Isa and Cloncurry region of the North West Queensland mineral province.
The survey was carried out in a joint venture involving Geoscience Australia, the Geological Survey of Queensland within the Department of Mines and Energy, the Predictive Mineral Discovery Co-operative Research Centre, and Zinifex Limited. ANSIR, the National Research Facility for Earth Sounding, used specialised vibrator trucks to look under cover and obtain information about the region’s crustal architecture up to 65 kilometres below the surface.
The Chief Executive Officer of Geoscience Australia, Dr Neil Williams, and the Director of the Geological Survey of Queensland, Mr David Mason, said the region targeted in the survey represents one of the world’s most important base-metal mineral repositories, and that a better understanding of the principal basin-forming structures is required to assist predictive mineral discovery in the region.
Mr Mason said almost 900 kms of survey line information was obtained in a series of transects that included close to 137 kms from around Lawn Hill, more than 120 kms south of Gunpowder mine, almost 200 kms from north west of Cloncurry to McKinlay, and almost 450 kms extending from south west of Dajarra to Cannington and north west of McKinlay. Reults of the new survey will add to and complement an earlier seismic study carried out in 1994.
"The lines were located to cross major crustal structures which may have acted as conduits for fluids during times of known mineralisation," Mr Mason said.
"The survey targets areas of known mineralisation in the Leichhardt River Fault Trough, Lawn Hill Platform, and Mount Isa/Cloncurry mineral province, and will provide images of the Earth’s crust down to depths beyond the region’s known surface geology based on outcropping rock," he said.
Mr Mason said that recent mineral discoveries made under cover in the Mount Isa Inlier had encouraged further exploration beyond the outcropping areas.
When processed, the data gathered will help resolve some of the complexities of the regional geology and structure so that the tectonic evolution of the region and its influence on mineralisation can be better understood. The information gathered also will provide vital input to the onshore component of the Australian Government’s $135 million energy security initiative and the Queensland Government’s $20 million Smart Exploration initiative.
Dr Williams said that establishing the architecture of major faults and shear zones to determine their influence on known mineralisation also could provide a guide to locating similar, as yet unidentified, ore bodies.
"By combining the results of the new and older surveys, a comprehensive 3-D model of the whole region ultimately will substantially improve pre-competitive information to encourage mineral exploration and provide more certainty for exploration and mining operations in the region".
"The project highlights the importance of regional-scale integrated geoscience programs undertaken as cooperative ventures by Geoscience Australia in partnership with State instrumentalities to better define Australia’s resource potential," Dr Williams said.
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