2013 Honorary LecturerSponsored by Shell

Pacific South

Dave Isles

Perth, Australia

Aeromagnetics–A Driver for Discovery & Development of Earth Resources

 
Abstract

Dave Isles

Aeromagnetic surveys are very commonly under-interpreted. The potential value, captured during acquisition, is all too often unrealised at the interpretation and ‘action' stages of a project. This presentation illustrates the fundamentals of robust aeromagnetic interpretation using telling case studies.

The two keys to astute interpretation are:
1. Understanding and full integration of local geology
2. Adequate time applied to observation and interrogation of the aeromag

These tasks are very largely qualitative and simple (in a geological context), but they do take time. Fancy hardware and software is no substitute for incisive geological reasoning, and such reasoning cannot occur without time-consuming observation and data integration.

The four studies presented will be:

  1. The Kalgoorlie district, where scant outcrop in an 80Moz goldfield can be integrated with semi-detailed aeromagnetics to produce geological maps that accurately guide exploration.
     
  2. The Amadeus Basin, where again, patchy outcrop and almost no gravity or seismic data limit assessment of the exploration potential. Aeromagnetic data here provides a platform for understanding both basin and basement architecture, and a reliable guide to seismic planning.
     
  3. The Galmoy – Lisheen carbonate-hosted Zn-Pb district, where (yet again) superficial cover is a major barrier to effective exploration. Aeromagnetics in this hitherto ‘non-magnetic' environment maps both structure and stratigraphy and becomes a driver for on-ground prospecting.
     
  4. The Golden Dyke district. This is perhaps the most informative study.  It is a very small area with very good outcrop that is very well mapped. The integration of modest quality aeromagnetics unveils a coherent structural picture and directly points to potential alteration systems. The extraordinary return for a very modest investment in aeromagnetics is a salutary lesson that the method often achieves its best results in areas where we (think we) know a great deal about the geology.