The 1980s witnessed a major revolution in the application of airborne
geophysics to mineral exploration. The now commonplace term `high
resolution aeromagnetics' (HRA) evolved from advances in survey
specifications, instrumentation, data processing and imaging techniques
which greatly improved the quality and geological information content of
the final maps. Although initially HRA was successfully applied in `hard
rock' basement terrains, eg the Archaean Yilgarn Craton of Western
Australia, the technique along with the radiometric and electromagnetic
techniques is now gaining wide acceptance in all geological terrains
including inaccessible sedimentary rock dominated mountain belts such
as New Guinea for mineral and petroleum exploration. It is also being
used in more and more diverse roles away from exploration, such as
environmental monitoring. The main reason for this acceptance is of course the very cost-effective
surface and sub-surface mapping capabilities of the various airborne
techniques. Although the three main techniques (magnetic, radiometric
and electromagnetic) have been in use for some time, they are
continuously being improved. Recent developments include: better navigational positioning using real-time GPS systems
(Geographic Positioning Systems) such as Picodas Navigation Systen
(PNAV); the use of magnetic gradiometer systems; improved sensitivity and sampling rate of magnetometers; increased use of ultra detailed low level (<50 m) magnetic surveys for>
instance using heli-mag systems; improved spectrometer systems for environmental monitoring of
nuclear waste; improved EM systems designed to look both deeper and shallower
(<50 m) within the earth's surface. shallower-looking em systems>
have been developed to help combat Australia's growing salinity
problems (SALTMAP system).