In
2005, Glass Earth Limited (GEL) commissioned two large area detailed airborne
geophysical programmes in the Taupo Volcanic Zone (TVZ). In the first survey
Bell Geospace Ltd of Scotland
conducted an Air-FTG (airborne Full Tensor Gravity Gradiometry) survey covering
2338km2 at 300m line spacing. The second survey by UTS Geophysics, Australia included detailed airborne
magnetic, radiometric and digital terrain data capture covering 5341km2 at 150m
line spacing.

From
the detailed geophysical data collected it is possible to identify major deeply
penetrative crustal structures within the TVZ, as well as define subsurface
geological features, such as intrusive bodies and alteration zones. These major
deep crustal structures are thought to have a controlling influence on the
distribution of epithermal gold mineralising systems, and along the corridors
defined by these deep crustal zones, the chances of discovery of an economic
epithermal gold discovery are greatly increased.

In
this paper GEL gives some examples of the application of its integrated data
driven approach to exploration in the TVZ at both regional and project scale.
The paper focuses on how GEL identifies regional scale highly prospective deep
crustal structures. Then, using the Horohoro epithermal gold system as an
example, we show how GEL applies innovative geological and geophysical data
processing to model and understand detailed subsurface geology, focusing
subsequent exploration to ensure the best opportunity for a new economic
epithermal gold discovery.