The Nature Of The Deep Crust Of The Kaapvaal Craton

In this paper the geophysical properties and signatures of the crust<br>of the Kaapvaal craton are discussed. Particular attention is paid<br>to observed increased levels of magnetisation, continuity thereof<br>and correlation with other geophysical signatures. It is proposed<br>that the higher levels of magnetisation, comparable or even greater<br>than those reported for lower crustal sections exposed elsewhere,<br>arise as a result of the recrystallisation of iron to magnetite in a<br>granite-gneissic basement. The controls for this phenomenon<br>include the presence of fluids and elevated oxygen fugacity ac<br>depth. The higher magnetisation manifests itself as regional<br>magnetic anomalies, providing an excellent means for mapping<br>crustal structure.