Geoscience Australia (GA) has initiated a program of Airborne Electromagnetic (AEM) acquisition under the Australian Government's Energy Security Initiative (2007 - 2011), to provide new data in geological provinces relevant for uranium exploration. The focus of this acquisition is directed at geologic architecture indicative of unconformity-related and paleochannel-hosted uranium potential. Three regional-scale projects have been established, Paterson, Pine Creek, and Frome Embayment-northwest Murray Basin.
The Paterson project is centred on the Kintyre uranium deposit, and covers much of the surrounding exposed and near surface Proterozoic. Kintyre is hosted by Paleoproterozoic Rudall Complex which is unconformably overlain by Neoproterozoic sediments of the Yeneena Basin. Approximately 28 000 line km of TEMPEST data were acquired at line spacings of between 200 and 6000 m. Preliminary interpretation indicates contrasts in AEM response between outcropping Rudall Complex and formations of the Yeneena Basin. Interpretation of inverted AEM data will seek to map the unconformity in the sub surface. Gamma ray data indicate that the Rudall Complex and regionally extensive ferruginous duricrust contain above background uranium (>7 ppm U). Erosion and weathering of these sources has possibly moved substantial uranium into younger paleovalleys, some of which are evident in the acquired AEM data. These valleys have potential to host sandstone uranium and calcrete uranium deposits.
The Pine Creek project is directed at AEM characterisation of Paleoproterozoic rocks, particularly graphitic units adjacent to Archean granite domes, and tracing these in regions of cover (e.g., the Woolner Granite area). The project will also attempt to map key sub-surface unconformities, and structures that may have controlled mineralisation. Acquisition for Geoscience Australia in the project area is at line spacings of 1.66 km and 5 km. VTEM acquisition in the east over the Pine Creek Orogen and overlying Kombolgie Subgroup has been completed. Acquisition of TEMPEST data farther west should be completed by mid June 09.
The Frome Embayment - Murray Basin project will provide regional AEM data over a large area (80 000 km2) including known paleochannel-type uranium at the Beverley, Four Mile and Honeymoon deposits. Proposed infill flying at 1.66 km will be undertaken over the NW Murray Basin to test whether similar channel settings occur south of high-uranium granites and uranium occurrences in the Olary Province. The infill area also plans to map strand lines of the Murray Basin which may be prospective for thorium rich heavy mineral sands.
