Mapping porphyry-skarn alteration at Yerington, Nevada, using airborne hyperspectral VNIR-SWIR-TIR imaging data

The alteration mineralogy of a porphyry-skarn system near Yerington, Nevada, was mapped using combined airborne hyperspectral HyMap and SEBASS data. The VNIR-SWIR HyMap data provided information about the abundance and levels of Tschermak substitution in white micas, as well as mapping the Mg-Fe chemistry of chlorite. The TIR SEBASS data provided unique information about the abundance and Fe-Al chemistry of garnet and Na-Ca chemistry of plagioclase feldspar. Both wavelength regions mapped calcite, dolomite, amphibole and epidote. The derived mineral maps were validated through spectral, mineralogical and chemical analyses of associated field samples. From these mineral maps, the geometry and physicochemistry of porphyry-skarn hydrothermal system becomes apparent, including the sites for Cu mineralization.