Differentiation of Mafic and Ultramafic Rocks in the Pilbara of WA, Using Remote Sensing Techniques

The Filbara region of northwestern Western Australia contains several known occurrences of mafic/ultramafic rock assemblages which may host platinum group element (POE) mineralisation. This paper deals with occurrences at Munni Munni and Andover. The Munni Munni complex is of particular interest because it is known to contain PGE mineralisation and is currently undergoing active exploration. The US/Australia Joint Scanner Project of October 1985 collected airborne scanner data for the BMR over Munni Munni. Such an ultramafic-mafic complex had not been previously researched with advanced remote sensing instrumentation. Extensive investigation of data from the NSOO1 (Thematic Mapper Simulator) scanner resulted in successful differentiation of gabbroic and ultramafic rocks, and also subdivision within the ultramafies. Similar differentiation could not be achieved using conventional Landsat MSS imagery and aerial photography. Encouraged by those results and in support of BMR field research into the mafic-ultramafic suites of the region, data from the Landsat Thematic Mapper (TM) instrument were investigated to attempt differentiation of the ultramafic and mafic rocks in the Andover complex some 50 km to the northeast of Munni Munni.