Mapping non-magnetic, talc-bearing ultramafic rocks in the Kalgoorlie region using airborne hyperspectral data

Abstract

Previously unrecognised ultramafic units in the Kalgoorlie-Kanowna area have recently been discovered using airborne hyperspectral sensing. Some of these units are up to 1 km in length and 200 m in width and were identified through airborne mineral mapping of talc. These areas lack significant magnetic expression, have little or no outcrop or subcrop and comprise a surface dominated by talc-bearing soil pediment. Exploration drill spoil in these areas confirms the presence of weathered talc schists underlying the soils. These results suggest that even in well mapped areas of deeply weathered greenstone belts, airborne hyperspectral sensing can complement traditional geophysical data by mapping non-magnetic, talc-bearing ultramafic rocks, which may be potential hosts to massive nickel and base metal mineralisation.