Rich, attractive and extremely dense: A geophysical review of Australian IOCGs

Summary

Most Iron Oxide Copper-Gold deposits were initially discovered through regional magnetic and gravity targeting, but there have been few published investigations of their geophysics as a deposit class. This study investigates the magnetic and gravity anomalies associated with several IOCGs and assesses their variability as a function of their physical characteristics. 3-D magnetic and gravity inversion and forward modelling are used to generate 3-D bodies, whose physical characteristics are then modified to assess the utility of magnetic and gravity data to IOCG exploration. The hypothesis that IOCGs form as fault and/or pipe bound hydrothermal breccias is consistent with their geophysical signatures. These modelling experiments highlight that gravity data is a more robust tool for IOCG exploration than magnetics, and that high resolution gravity data is critical to the identification of IOCG deposits in the Gawler and Mount Isa provinces.

Key words::

• Iron-Oxide Copper-Gold
• IOCG
• Magnetics Gravity
• Susceptibility
• Density
• Forward Modelling.