Isotopic investigations of the Nova-Bollinger Ni–Cu–Co deposit in the Fraser Zone, Albany-Fraser Orogen, Western Australia

The Fraser Zone of the Albany-Fraser Orogen Western Australia contains an extensive suite mafic and mafic–ultramafic intrusions. This includes Nova-Bollinger intrusions (ca 1300 Ma), which host economic Ni-sulfide mineralisation, a prime example magmatic sulfide liquids emplaced into deep crust under ambient granulite facies conditions. Sulfur, Sr Sm–Nd isotopes, trace elements have been used to evaluate role crustal contamination parental magmas other sulfide-bearing bodies within gabbro suite. All ore types ?34S values between +1.6 +8.0‰ VCDT with positively skewed distribution median value +2.3‰ VCDT, anomalous relative uncontaminated mantle near 0‰ VCDT. No significant ?33S anomalism was observed. initial 87Sr/86Sr 147Sm/143Nd ratios most igneous rocks age formation Ma, is similar those CHUR1300Ma record limited by lower continental material. country Snowys Dam Formation, locally enriched in iron sulfur, are likely candidates as contaminants. These metasedimentary sulfides show ranges for both ores, but their isotopic range greater than observed at sampled Bollinger globular ?Sr 63.1 144.5 ?Nd ?5.7 ?1.8 suggestive localised from adjacent wall rock marbles, otherwise high do not appear dominant Bulk assimilation rocks, modelled silicate portions system, up 30% primitive melt siliceous gneisses, would sufficient produce degree recorded more regionally gabbros. Beyond indications that S crustally derived, it possible identify specific source, sediments likely. There no compelling evidence Archean unsurprisingly given mid-Proterozoic age. It much magma generation liquid took place during lateral flow through linked sill complexes deeply buried metasediments, prior emplacement form orebodies.KEY POINTSNova-Bollinger Ni–Cu–Co ores metasediments. Values consistent equilibration xenomelts R factors 200–700.There detectable mass-independent fractionation ?33S ores.The Ma CHUR1300 material.Unusual indicating marble; however, this pervasive orebody. orebodies.