Dissertation work by Dr Kath Silva on the geochemistry on a complete komatiite sequence through the Belingwe Greenstone Belt has been used to place constraints on how this greenstone belt was formed. Examples of the well preserved Belingwe komatiites. Spinifex texture from the upper part of the flows on the left and the texture of the cumulate zones from the lower part of the flows on the right. The current hot topic about komatiites is do they represent hot dry magmas or do they represent less hot, wet, possibly subduction zone magmas . Dr Mary Gee is currently measuring water contents in melt inclusions from the Belingwe Komatiites using FTIR methods.
Initial results reveal very low water contents.
Dave Sparks has developed 3-D numerical models of the temperature distribution within mantle plumes. We use these models, along with parameterisations of the temperature and pressure dependence of the chemistry of mantle melts, to predict the composition of melts produced by different mantle plumes. We ve investigated the effects of varying mantle temperature, the variation in lithosphere thickness, and are now attempting to introduce the effect of water on melting. The work has been used to predict the mantle conditions required for the generation of komatiites, and has led to predictions of Archaean mantle temperatures. Box depth corresponds to the depth of the upper mantle.