Do heavy minerals and detrital zircons in sandstone tell the same story? A method study based on continental sandstones from South Africa
Heavy mineral studies and detrital zircon geochronology are two commonly applied complementary methods used to study and track the provenance of clastic sediments.
In these MSc projects, the important question to be answered is: Will shifts in provenance indicated by changes in U-Pb and Lu-Hf isotope characteristics of detrital zircon populations also be reflected by changing heavy mineral assemblages?
The research targets are two continental sedimentary sequences in South Africa, each of which is suitable for an MSc project:
- Neoproterozoic sandstones from western South Africa (Gariep Belt, Saldania Belt, Nama Group), where detrital zircon studies suggest a significant change in provenance from a regime dominated by recycling of older (late Palaeoproterozoic to Mesoproterozoic) cover deposits to one of input of material from Neoproterozoic sources.
- The late Palaeozoic to Mesozoic Karoo Supergroup in KwaZulu-Natal, South Africa, where provenance is dominated by recycling of Neoproterozoic sedimentary rocks, but where a distinct component of Permian to Carboniferous, volcanogenic zircons is present in Triassic to Jurassic formations.
The theses will be based on samples in existence at the Department of Geosciences, which have previously been used for detrital zircon studies.
Laboratory work will include sample preparation, conventional mineral separation, microscopy (optical and SEM), X-ray diffraction, and possibly major and trace element analysis of minerals by electron microprobe and laser-ablation ICPMS.