ABSTRACT
This paper reports new oxygen, carbon and sulphur isotopic data on ultramafic-mafic rocks and ore of the Bruvann Ni deposit, in order to understand contamination processes of the magmatic system by graphite-sulphide-schist and to determine the role of schist in the ore deposition. Carbon and sulphur isotopes show the complexity of the contamination mechanisms, and strongly suggest a disconnection of the magma and volatile phases during the cooling of the magmatic system. Oxygen isotopes give evidence of a large-scale contamination operated by a low assimilation of schist material and also by isotopic exchanges between magma and schist via a fluid phase.
