Faculty of Natural and Agricultural Sciences
School of Physical Sciences
Department of Geology
Selected Highlights from Research Findings
A crystal chemical and kinetic study of disintegration reactions in titania slags showed that there are three different oxidation reactions that take place on cooling of the tapped slag. The lowest temperature reaction is the most rapid and results in extensive disintegration. The determination of the kinetics of the reactions enabled the development of cooling methods to minimize the formation of unsuitable fine-grained material.
Electron microscopic investigations on the microstructure of electrolytic manganese dioxide showed wide variations in crystallite size and bridging between grains that could explain some of the conduction phenomena.
Contact person: Prof JPR de Villiers.
The first sedimentological model has been developed for the Silverton Formation, Pretoria Group, Transvaal Supergroup. The data suggest a low gradient epeiric sea in the Silverton-Magaliesberg epicontinental basin
Field work has allowed the establishment of an adequate field data base of the Soutpansberg Group, that enabled proper modeling of the relevant rocks as products of a rift basin.
Contact person: Prof PG Eriksson.
Research has proved a more widespread occurrence of the Rooihoogte Formation to the southeast of Pretoria. This allows safe residential development in areas previously considered unsuitable due to the high risk for sinkholes.
Contact person: Prof A van Schalkwyk.
Geochemical and petrological studies on the Jinchuan Intrusion, China, showed that the body was emplaced as a dense, viscous crystal mush consisting of olivine, orthopyroxene and chrome spinel, suspended in a mixture of high Mg basalt and exsolved sulfide liquid. These findings have an impact on exploration strategies.
Contact person: Prof SA de Waal.
Research on sulphur isotope data and composition of olivine in the Uitkomst Complex indicates that the intrusion formed from at least three compositionally contrasting magmas, and confirms the idea that sulphide segregation was most likely triggered by contamination with dolomite or Timeball Hill shale.
A detailed PGE study of the Merensky Reef suggests that the PGE were largely concentrated by primary magmatic sulphides in accord with the widely accepted models, but that some localized metal remobilization occurred during solidification. This implies that PGE can behave mobile in later magmatic environments.
Contact person: Prof WD Maier.
|
