Magma Flow Directions in Ferrar Intrusive Rocks using Anisotropy of Magnetic Susceptibility Methods

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9711722 Grunow Abstract This award supports an exploratory program to measure the anisotropy of magnetic susceptibility (AMS) on existing samples of the Ferrar intrusive rocks to provide preliminary magma flow directions. The AMS method represents one of the few techniques available capable of determining magma flow directions and hence, constrain magma emplacement models. The Ferrar province (4000km long), along with the Karoo province in South Africa, represents the most significant flood basalt province associated with Gondwana break-up. Various models have been proposed in which the Ferrar magmas are thought to have emanated from a point source beneath South Africa, beneath the Dufek massif, or from multiple point sources. The AMS method provides a direct test of these models. Very little AMS work has been done on the Ferrar province and so it is uncertain whether the Ferrar rocks will yield any magma dlow information. Ferrar samples (75 cores) from a 3000 km segment of this province are presently available and more will be collected in the upcoming field season and made available to this project. These samples will be analyzed at the University of Michigan paleomagnetism laboratory. Results will demonstrate the viability of the method on Ferrar province rocks and may also provide preliminary constraints on Ferrar plume versus multiple source emplacement models.