Magmatic sulphide deposits form in a variety of geodynamic tectonic settings where sulphide ores are typically hosted by mafic-ultramafic silicate magma. Many Ni–Cu-platinum group element (PGE) sulphide breccia deposits are associated with an assortment of poorly sorted mafic-ultramafic rocks that are suggestive of dynamic emplacement and rapid crystallisation. The Munali Ni–Cu–PGE deposit is a complex brecciated orebody situated within the Zambezi Belt in southern Zambia, a region that has undergone periodic tectonism since the Neoproterozoic (De Waele et al. 2008). Located along a major structural lineament, Munali consists of an unmineralised central gabbro unit (CGU) surrounded by a complex heterogeneous mafic-ultramafic breccia unit (MUBU) that is host to the ore. The MUBU is made up of a range of maficultramafic rocks that include poikilitic gabbro, olivine-gabbro, dolerite, magnetite-olivinite (Cr-poor dunite), wehrlite and phoscorite (apatite-magnetiteolivine cumulate rock).

Mineralisation is characterised by an unusual carbonate-rich apatite-magnetite-sulphide assemblage predominately present as a semi-massive to massive sulphide ore. Carbonate within the ores shows intimate relationships with sulphide and micro-macro textures signifying the presence of carbonate melts. Although the intrusive complex is enveloped almost entirely within a unit of marble, C and O isotope analyses of carbonate at Munali have revealed clear mantle signatures for some of the carbonate associated with sulphide, suggesting the interaction of carbonated mantle melts. Macroscale underground mapping has aided in deconstructing the relationships of the dynamic magmatic emplacement and deformation events that formed the chaotic nature of the MUBU. Previous dating of the CGU (the most voluminous unit) and ultramafics of the MUBU (Holwell et al. 2017) has provided time constraints for initial magmatism of the intrusive complex, which intruded into carbonaceous sediments during continental rifting at∼ 860 Ma. In comparison