MAGNETIC FABRIC IN THE UMVIMEELA DYKE, SATELLITE OF THE GREAT-DYKE, ZIMBABWE

Anisotropy of magnetic susceptibility (AMS) has been determined for 22 locations from the 500-km-long gabbroic Umvimeela Dyke of Zimbabwe. A MS is controlled by the presence of multi-domain magnetite grains whic h appear to have preserved a variety of magnetic fabrics related to ma gma movement at the time of dike emplacement. Three locations along th e Umvimeela Dyke have been identified as feeder points at which magma flowed into the dike from below. Lateral flow away from these points s upplied the rest of the dike system. The presence of several foci of i gneous activity along the Umvimeela Dyke parallels the development of the neighbouring contemporaneous Great Dyke layered complex, which con sists of a line of contiguous subchambers. Individual feeder points to the Umvimeela Dyke may be directly related to activity in adjacent su bchambers.