High-resolution geophysics in modern geological mapping

A modern geoscientific knowledge base developed through systematic mapping is a major component of sustainable development strategies, underpinning mineral resource assessment and exploration. High-resolution airborne magnetic and gamma-ray spectrometric surveys are fundamental to modern geoscientific mapping, providing cost-effective definition of structure and lithology in a diverse range of geological provinces and terrains. Magnetic (and gravity) data are particularly valuable in determining basement structure and continuity under cover. Gamma-ray spectrometric data provide geochemical (K, Th, U) maps that have proved valuable in mapping bedrock lithology and alteration, and for mapping regolith materials and activity, particularly in highly weathered (regolith-dominated) terrains. More than 3 million line kilometres of new high-resolution airborne geophysics have been acquired by the Australian Commonwealth, State and Northern Territory geological surveys, since the commencement of the National Geoscience Mapping Accord, in support of geological mapping in a wide range of provinces. These new data, coupled with other modern mapping technologies, notably geographic information systems, provide a means of rapid, cost-effective geoscientific mapping and analysis in a wide diversity of geological environments and terrains. New geological maps and other thematic maps based on these geophysical data enable better definition of mineral potential and contribute directly to more effective and efficient exploration. In all provinces, new high-resolution airborne magnetic and gamma-ray spectrometric data have resulted in better definition of both geological structure and lithological boundaries than indicated on previous maps. This paper shows, by examples, the usefulness of geophysical data over a wide range of mapping in support of the mineral industry. 47 refs., 12 figs