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Geophysical Studies of Mineralised Terrains in Western Australia

Western Australia

State-of-the-art methods for regional exploration targeting place much emphasis on mapping major structures, in particular suture zones between major crustal blocks, in the deep crust and mantle.  

These features are considered important because of their ability to act as conduits to the upper crust for metal-bearing hydrothermal brines and magma originating deeper in the crust and in the mantle. At the same time there is general acceptance amongst mineral explorers that future exploration will be directed at targets at increasingly greater distances below the surface. These two factors require the best possible ‘pictures’ of the geology at depth, which only geophysical methods can provide. Research in the characterisation of mineralised terrains is currently concentrated in Western Australia where we are working with the Geological Survey of Western Australia (GSWA) on a major project funded by the Western Australian Government’s Exploration Incentives Scheme (EIS).

This work involves studies of selected terrains in Western Australia which are considered to be poorly understood and, as a consequence, under explored. The terrains that will be studied during this project are the Arunta Orogen, Musgrave Province, Capricorn Orogen and Kimberley Province. Each area is considered on a case-by-case basis but common components of the analysis include:

1.      Determination of the 3D architecture and 4D  geological evolution of the area based on the integration and synthesis of geological and geophysical data. This work may include magnetotelluric surveys, the creation of a petrophysical database, interpretation of geophysical imagery, forward and inverse modelling of gravity and magnetic data in 2D and 3D and, if available, interpretation of seismic data. Future work may involve the acquisition and interpretation of passive seismic data. Particular emphasis is placed on indentifying major faults. 2.      Based on the known geology and 3D and 4D studies the terrain is then subject of a commodity review (involving all available CET staff) to identify which commodities/deposit types are mostly likely to occur in the terrain and to define geological criteria that are potential indicators of geologically favourable conditions for deposit formation. 3.      A mineral systems based analysis using fuzzy logic in a GIS environment the spatial distribution of favourable geological circumstances in the study area is compiled and a series of regional prospectivity maps are produced of the area.