The concentric elliptical structure of feeder sites to the Bushveld Complex and possible economic implications.

The layered mafic component of the Bushveld Complex crops out in four discrete compartments. Each compartment possesses at least one supposed feeder, as determined by gravity data. There are seven feeders, which, together with the main Bushveld satellitic intrusions, fall on two concentric elliptical traces, each of which possibly originated by large-scale conical fracture of the crust. These ellipses are, in turn, broadly concentric to the supposed margins of the Transvaal basin, and their locus falls on the 'Bushveld-Great Dyke lineament'. It is proposed that the location of the feeders along these ellipses was controlled by the regional grain of the basement. The size and location of individual right inverted conical magma chambers sited above these feeders were major influences on the shape of the compartments. Possible sites for exploration activity are suggested at the intersection between elliptical traces and certain regional lineament trends.-Authors