The sediment-hosted Thompson Ni sulfide deposits are related to serpentinised dunite and peridotite intrusions. The pyrrhotite-pentlandite ores have a primary magmatic origin, but have been modified during deformation. Reformation of monosulphide solid solution and translocation of sulphide occurred during D1-2. Variations in Ni tenor of sulphide are co-linear with the axes of D3 deformation. Geochemical zonation of the ore system in the context of geology provides a guide to exploration.