A reconnaissance study on the magmatic Cu-Ni-PGE sulphide potential of the Tete Complex, Mozambique

Abstract

The Tete Complex of Mozambique is a composite mafic-ultramafic intrusion that consists largely of pyroxenites and gabbros, with lesser amounts of coarse-grained troctolitic and anorthositic rocks reminiscent of massif-type anorthosites. The Complex thus may have potential to host reef-type PGE ores and/or massive Ni-Cu sulphides analogous to those found in the gabbro-troctolite hosted Voisey’s Bay deposits. We analysed 8 isotopically and mineralogically well-characterized samples of anorthosite, leucotroctolite, clinopyroxenite, gabbro, olivine melagabbro, dolerite, and a pegmatitic orthopyroxenite for major and trace elements, including PGE. The samples show little evidence for significant crustal contamination and are mostly undepleted in PGE relative to Cu, and to a lesser degree, Ni. If the samples are representative of the intrusion, this may indicate that the Complex has limited potential to host economic Ni-Cu sulphide ores. The potential for reef-type PGE ores remains less clear, in view of the occurrence of such ores in seemingly uncontaminated intrusions elsewhere (e.g. the Great Dyke).