Scientists at the University of the Witwatersrand’s School of Geosciences have proposed an explanation for a phenomenon that has long puzzled geologists. The researchers are Professor Rais Latypov and Dr Sofya Chistyakova and their research has been published in the journal Geology. The puzzle has been the fact that some magmatic rocks have a mineral composition that is not normal. Usually, magmatic rocks are composed of fixed proportions of different minerals. Thus, one such rock would comprise 90% of one mineral and 10% of another. But some magmatic rocks were composed of minerals which were in totally random proportions.