Bulk rock geochemistry and SWIR reflectance spectroscopy are widely used by companies for rapid and cost-effective exploration of volcanic-hosted massive sulfide (VHMS) deposits. However, few studies have integrated bulk-rock geochemistry with hyperspectral reflectance spectroscopy in greenstone belts that have undergone high-grade metamorphism. Here we present an extensive dataset combining bulk-rock geochemistry with chlorite and white mica SWIR spectral reflectance from the amphibolite-grade King VHMS deposit of the Yilgarn Craton, Western Australia. At King, the footwall stratigraphy is dominated by tholeiitic mafic rocks overlain by a sequence of calc-alkaline intermediate-felsic metavolcanic rocks. The hanging-wall stratigraphy is characterized by a thin metaexhalite layer, overlain by thick succession of interbedded metasedimentary and metavolcanic rocks. Chlorite spectral signatures are more Fe-rich in mafic lithologies and Mg-rich in felsic rocks, particularly where intense Mg-metasomatism occurred before metamorphism. In all units, Fe/Mg ratios of chlorite are strongly tied to bulk rock Fe/Mg ratios. White mica in the footwall is primarily muscovitic, with minor amounts of phengite in deep Fe-rich mafic rocks. By contrast, the hanging-wall sequence is dominated by phengitic signatures in both the Fe-rich metaexhalite, and weakly Ca-Mg altered volcanic rocks. This study concludes that chlorite SWIR reflectance is largely influenced by the bulk Fe/Mg composition of the host rock, whereas white mica reflectance correlates with the type and intensity of hydrothermal alteration prior to metamorphism. These findings underscore the potential of using chlorite and white mica spectral signatures to understand hydrothermal alteration patterns and detect new orebodies in metamorphosed VHMS systems.

公司广泛使用块状岩石地球化学和 SWIR 反射光谱法，以快速、经济高效地勘探火山承载的块状硫化物 （VHMS） 矿床。然而，很少有研究将块状岩石地球化学与经历高品位变质作用的绿岩带中的高光谱反射光谱相结合。在这里，我们提供了一个广泛的数据集，将块状岩石地球化学与来自西澳大利亚 Yilgarn Craton 的角闪岩级 King VHMS 矿床的绿泥石和白色云母 SWIR 光谱反射率相结合。在 King，下盘地层以钙镁铁质岩为主，上面覆盖着一系列钙碱性中长英质变质火山岩。上壁地层的特点是薄薄的变质喷出岩层，上面覆盖着厚厚的连续互层变质沉积岩和变质火山岩。绿泥石光谱特征在镁铁质岩性中更富铁，在长英质岩中更富镁，特别是在变质作用之前发生强烈 Mg 交代作用的地方。在所有单元中，绿泥石的 Fe/Mg 比率与块状岩石的 Fe/Mg 比率密切相关。下盘的白色云母主要是白云母，在富含铁的深层镁铁质岩石中含有少量的铁云母。相比之下，上壁层序在富含 Fe 的变质岩和弱 Ca-Mg 蚀变的火山岩中以 phengitic 特征为主。本研究得出结论，绿泥石 SWIR 反射率在很大程度上受主岩块体 Fe/Mg 成分的影响，而白色云母反射率与变质作用前热液蚀变的类型和强度相关。 这些发现强调了使用绿泥石和白色云母光谱特征来了解热液蚀变模式和检测变质 VHMS 系统中新矿体的潜力。