Geographic Information Systems (GIS) are ideal tools for understanding
regional geological controls of mineralisation in a province. Primary
digital layers that can be incorporated for metallogenic analysis include
geology (rock types, structure), geophysics (gravity, magnetics,
gamma-ray spectrometric data), satellite images (SPOT, Landsat thematic
mapper (TM) or Multi-Spectral Scanner (MSS)), mineral deposits, rock
and surficial geochemistry. From these primary data sets, a series of
derivative layers can be developed including solid geology, geological
provinces, basement tectonic elements, metamorphic grade and rock
geochemical maps. The individual geological units from the map can
also be used as a basis for further data integration by classifying the units
according to their age, dominant lithology and the proportions of the
metallogenically reactive minerals present (K-feldspar, carbonates,
magnetite, hematite, graphite, sulphide, etc). Interactive models can be
developed for highlighting potential areas for most major ore deposit
types by using two methods. The first involves determining which
geological parameters are essential for their formation, and then utilising
the GIS to determine which areas meet these criteria. The second method
examines known areas of mineralisation within the GIS, and then
determines the specific geoscientific expression of the ore deposit (eg
magnetic signature, geochemical anomaly, proximity to faults etc).