Hyperspectral remote sensing for mineral mapping of structural related mineralizations around Mount Isa, Queensland, Australia

The present report demonstrates the possibilities and limitations of remote sens- ing, especially hyperspectral data, for mineral mapping purposes, using the example of the Mount Isa Inlier. This geological area is situated in Northern Queensland, Australia, and is known for its considerable ore deposits and consequent mining of predominantly copper, zinc, lead, silver and gold. Beside hyperspectral HyMap data, multispectral Landsat 8 and SRTM digital elevation data were analyzed. A three-week field study supported the investigations by data delivered from rock sampling and field spectral measurements. The observations were concentrated on four study areas and four main objectives: the location of orebodies near Mount Isa mine by mapping their altered outcrops, the targeting of critical elements at the Mary Kathleen U-REE deposit, the investigation of the dependency between the shear and fault-controlled vein-copper deposits of Mount Isa inlier and main deep-crustal faults and the testing of a fixed-wing drone for 3D-photogrammetry of geological features.
Throughout the study, mineral mapping using remote sensing data, especially hyperspectral data, turned out to deliver high qualitative results when it is supported by additional infor- mation. In situ investigation of the observed mineralizations for validation is important and can deliver such data, for instance by the investigation of rock samples or spectral measure- ments. Since mineralizations and alterations are often related to structures, their analysis and consideration can provide crucial hints. Without additional data it is very difficult up to impossible to create and interpret mineral mapping results accurately. The most significant result throughout the study was the determination of a new site of gossanous, silicified ridges south of the Mount Isa mining complex. They coincide with the outcrops of mineralized parts of the Urquhart Shale, which form the mined Pb-Zn-Ag deposits and are probably related to structures. Their occurrence was validated through fieldwork observations including rock sampling and spectral measurements. The gathered information additionally supported the mapping of those ridges using HyMap data, which confirmed the connection between the north-south trending ridges and the Mount Isa mine deposits.