The Eloise Cu-Au deposit is 60 km SE of Cloncurry in NW Queensland
and has a current indicated reserve of 3.2 Mt @ 5.8 per cent Cu, 1.5gA Au
and I9g/t Ag. It is hosted by metasediments and metabasic rocks that
underwent amphibolite facies metamorphism at 550-600C and less than
3.5 kb. Peak metamorphism coincided with the regional D2 event which
produced an S2 foliation with north-south strike and variable sub-vertical
to steep east or west dip. The deposit is associated with several major
shear zones parallel to the S2 foliation. The lodes form part of a large alteration system that is localised by the
retrograde shear zones. Homblende-biotite-quartz with minor sulphides
occur early in the alteration paragenesis which is overprinted by
chlorite-muscovite-pyrrhotite-chalcopyrite calcite+nagnetite. The later
assemblage replaces the earlier Fe-K alteration as well as Fe-rich
metamorphic assemblages such as homblende, biotite and staurolite
indicating a post peak metamorphism timing for ore formation. Although
replacive textures are the most common, the alteration can display open
space infill and brecciation as well as durchbewegung and mylonite
textures indicating that mineralisation occurred during ongoing ductile
deformation. All these features are crosscut by a later brittle phase of
calcite-chlorite-quartzpyrite alteration.