Integrated stratigraphic-structural-hydrothermal alteration and mineralisation model for the Kangaroo Caves zinc-copper deposit, Western Australia

The Kangaroo Caves volcanic-hosted massive sulfide deposit is located in the Archean Panorama district in the northern Pilbara Craton, Western Australia. The deposit contains an indicated and inferred mineral resource of 6.3 Mt at 3.3% Zn, 0.5% Cu and 12.1 g/t Ag. The Kangaroo Caves area is characterised by predominantly tholeiitic volcanic rocks of the ca 3240 Ma Kangaroo Caves Formation, which is overlain by turbiditic sedimentary and volcanic rocks of the Soanesville Group. Zinc-copper mineralisation is hosted mainly by the regionally extensive Marker Chert, the uppermost unit of the Kangaroo Caves Formation, and structurally controlled by D1 synvolcanic faults. The upper area of the deposit is characterised by quartz-sphalerite ± pyrite ± barite ± chalcopyrite, whereas the lower area contains mainly chlorite-pyrite-quartz-carbonate-sericite ± chalcopyrite ± sphalerite.Laser-ablation inductively coupled-plasma mass-spectrometry analyses show that pyrite in the Marker Chert is enriched in Zn, Ag, Pb and Sb when compared with dacite from the Kangaroo Caves Formation, Paddy Market Formation, and Dalton Suite. Pyrite from the Marker Chert also displays a negative correlation between Zn and As, i.e. with increasing Zn levels As is decreasing. The Co/Ni ratios in pyrite are significantly greater in the upper, Zn-rich area (median ratio = 0.4) of the deposit than the lower, Zn-poor area (median ratio = 5). Copper is low irrespective of the host rocks. Sphalerite displays low Fe (