HyMap of Broken Hill – imaging spectrometry for rock and mineral abundance mapping

Abstract

Imaging spectrometry (hyperspectral imagery) has been acquired for the Broken Hill Block. The data were acquired using the HyMap scanner on behalf of the New South Wales Department of Primary Industries (former Department of Mineral Resources). Interpretation of the imagery for selected test sites demonstrates the capability to map a wide range of lithologies and minerals. Minerals mapped include iron oxides, garnets, micas, clay minerals, and amphiboles. Lithologies mapped include all the lithologies present in the region, and the surficial sediments. HyMap is also able to map certain lithologies critical to mineral exploration in the region, such as gahnite-bearing quartz, manganese-bearing garnetiferous rocks, and sodium-rich micas indicative of likely mineral alteration. The mapping capabilities of the HyMap scanner are demonstrated using selected test sites, but the lithology and mineral mapping has also been extended to cover a whole 1:25 000 map sheet area. It is suggested that the HyMap-derived information will form the vital surficial component in a three-dimensional view of the crust provided by geophysical data including gravity, magnetic, radiometric, and imaging spectrometry data.