Thermal and Fluid Dynamics of Komatiitic Lavas Associated with Magmatic Fe- Ni-Cu-(PGE) Sulphide Deposits

The most important examples of magmatic ore deposits in volcanic rocks are Fe-Ni-Cu-(PGE) sulphides associated with Archean and Proterozoic komatiitic lava channels (Lesher, 1989). Komatiitehosted ores contain ~25% of the world’s nickel sulphide resource (≥ 0.8% Ni), including significant amounts of copper and platinum group elements (Ross and Travis, 1981). Field, experimental, and theoretical studies of komatiite lavas (e.g., Nisbet, 1982; Lesher et al., 1984; Huppert et al., 1984; Huppert and Sparks, 1985a,b; Jarvis, 1995; Greeley et al., 1998; Williams et al., 1998) suggest that they had thermal and physical characteristics that made them particularly capable of thermally eroding their substrates. Because thermal erosion is considered to have played a fundamental role in the formation of komatiite-hosted sulphide deposits (Lesher, 1989; Lesher and Campbell, 1993), understanding the physical dynamics of komatiitic lavas is essential to understanding the dynamics of sulphide generation and segregation processes in high temperature, volcanic ore-forming systems.