New government geophysics from the Onshore Energy Security Program

Summary

As part of the recently completed Onshore Energy Security Program, Geoscience Australia has delivered new types of pre-competitive data to as well as the more familiar government pre-competitive data types such as aeromagnetics. These new data provide industry with additional information for assessing the geological prospectivity of a region and making targeting decisions.

The visionary AWAGS continental airborne magnetic and radiometric survey enabled the first ever national merging of all radiometric surveys to produce the Radiometric Map of Australia. The rigorously calibrated data supports quantitative normalisation of uranium anomalies against rock-type, and hence identification of zones of uranium enrichment, at either a prospect or regional scale.

Geoscience Australia also undertook three large AEM surveys (>50,000km2) to map regional scale geological structures important for uranium deposition. These surveys were effective in imaging depth of regolith, geological unconformities, shale units and fault zones. Often these features are not apparent in regional magnetic or gravity data.

MT data are now acquired along all deep crustal seismic transects to image the deep conductivity structure. These data are highly complementary to the structural information interpreted from the seismic sections. MT can also detect conductivity features in the non-reflective crust below the Moho.

Key words::

• pre-competitive
• radiometrics
• magnetotellurics
• airborne electromagnetics
• geological mapping