Assessing four AEM systems; throughout their capacity to deliver target geometry and character

In the Musgrave Province of South Australia, local scale airborne electromagnetic data sets are being employed to build pre-competitive data bases and to develop hydrogeological conceptual models in support of the minerals industry and for regional scale water resources assessment. The work has required the re-processing of historical TEMPEST and VTEM data sets and acquisition of SkyTEM508 and SPECTREM2000 airborne EM (AEM) data. For a more precise assessment we have processed and inverted the AEM data using a same model parameterization (fixed 30 layer thicknesses) and one common inversion kernel. We inverted data from all systems using Geoscience Australia's LEI algorithm, and inverted each sample independently. The capacity to resolve targets of a different nature resides mainly on system design and its nose levels, whilst the ability to accurately model the system and account for the processing that occurs post acquisition enables a more accurate inversion of the data. Applying a common procedure to the estimate of noise-levels, tries to deliver a less bias system comparison. Data for two distinct areas containing 1) an anomaly with some of the characteristics of a mineralization target and 2) another with contrasting hydrogeology and significant sedimentary character; indicate the complex evolution of the landscape. The systems employed resolve similar structures despite their different noise-levels, geometries, induction waveforms, transmitted current, and footprints. Not surprising is the ability of certain systems to detect and resolve a more complex near-surface aquifer variability features.