Syenitic Group intrusions of the Archean Kurnalpi Terrane, Yilgarn Craton: Hosts to ancient alkali porphyry gold deposits?

Archean alkali-rich (Syenitic Group) intrusions in the Eastern Goldfields Superterrane, Yilgarn Craton, are chemically similar to intrusions associated with Phanerozoic alkali porphyry systems. High-temperature potassic and ferruginous alteration associated with the Yilgarn intrusions are also similar to those in Phanerozoic counterparts but these are generally not well mineralized. Disseminated and fracture-controlled gold mineralization associated with Syenitic Group intrusions is commonly hosted by mesothermal albite-carbonate-pyrite assemblages, the origin of which is ambiguous. This communication aims to stimulate discussion on the origin of gold in and around Syenitic Group intrusions and the apparent absence of significant gold or copper mineralization in associated high-temperature alteration. Gold associated with Syenitic Group intrusions in the Yilgarn Craton has many similar characteristics to disseminated gold deposits associated with syenitic intrusions in the Abitibi greenstone belt, Canada, and may be present in other Archean greenstone belts.