Elevated fluorine and chlorine contents of metasomatic fracture-fill and wallrock replacement biotite in relation to gold mineralisation in western and central Tanami gold deposits/prospects indicate possible magmatic hydrothermal fluid contributions.
Gold grains enclosed by fluorine rich biotite intergrown with K-feldspar filling fracture crossing wallrock and dislocating early peak metamorphic/metasomatic quartz veining (location 1 above) 300 microns field of view.
Gold/electrum grains intergrown with fluorine rich biotite and K-feldspar filling fractures traversing early peak metasomatic wallrock arsenopyrite (location 2 above). 300 microns field of view.
In some eastern Tanami locations magmatic hydrothermal contributions to mainly metamorphic metasomatic fluid flow are indicated by the presence of chlorine-rich metasomatic biotite.