Abstract This study assesses the potential of chlorite, white mica, and garnet chemistry, coupled with hyperspectral data, as vectoring tools in metamorphosed volcanic-hosted massive sulfide (VHMS) deposits. Samples were collected from the King Zn deposit of the Eastern Goldfields superterrane, Yilgarn craton, which was metamorphosed to the amphibolite facies. In situ chlorite-white mica chemical trends match the shifting positions of the 2,200W and 2,250W absorption features obtained by short-wave infrared (SWIR) spectroscopy. These include a shift from muscovite to Na muscovite in the felsic footwall approaching mineralization, to phengite in the hanging wall, and mostly mixed Fe-Mg chlorite compositions with shifts to Mg-rich chlorite in the Mg-metasomatized felsic footwall. Fluorine (up to 2,500 ppm) and Mn (up to 1.1 wt %) contents of chlorite increase systematically through the footwall of the deposit toward the massive sulfide but drop sharply in the hanging wall—a trend mirrored in F contents in white mica (up to 2,500 ppm) and Mn in garnet (up to 17 wt %). These variations are attributed to premetamorphic footwall metasomatism and can trace hydrothermal up-flow zones in metamorphosed VHMS systems. Thermal infrared (TIR) signatures (11,100W and 11,300DW) correlate negatively with almandine and positively with spessartine contents in garnet, while rare earth element (REE) profiles of garnet further aid in the assessment of VHMS prospectivity. Positive Eu anomalies and downward-dipping heavy rare earth element (HREE) profiles in garnet enriched in the almandine end member distinguish mineralization-related garnet from those of barren metamorphic or igneous origins. Several elements, including Sr-Ba-Rb contents in white mica, Al in chlorite, and Ca-Mn with positive Eu anomalies in garnet, also differentiate footwall from least altered hanging-wall units. This study highlights the effectiveness of integrating chlorite, white mica, and garnet chemistry with hyperspectral data for regional VHMS exploration in high-grade metamorphic terranes.
Dana et al. (Wed,) studied this question.