Roelofse, FrederickGauert, ChristophKeet, Jarlen Jocelyn2023-08-232023-08-232022http://hdl.handle.net/11660/12137Thesis (Ph.D. (Geology))--University of the Free State, 2022Historically, research on the Bushveld Complex (BC) in the northern limb mainly focused on the near surface Platreef. The Platreef is well-known for being complicated and erratic due to significant degrees of country rock assimilation and contamination along strike. A correlation of the disrupted magmatic stratigraphy of the Platreef to the Upper Critical Zone of the western and eastern limbs has thus proven difficult. The discovery of the Flatreef, the down-dip, sub-horizontal extension of the Platreef, on the farms Turfspruit and Macalacaskop, opened new avenues for enquiry. The proportion of assimilated country rock within the Flatreef is significantly less than in the near surface Platreef, with a stratigraphy that is less disrupted and affected by footwall interaction than the Platreef, such that Bastard Reef and Merensky Reef correlates may be identified in the Flatreef stratigraphy. In this study Sr, Nd and S isotopic compositions across the stratigraphic units of the Flatreef as intersected by drill hole UMT-393 on the farm Macalacaskop, and to a lesser extent, drill hole UMT-276 on the farm Turfspruit is reported. The initial ⁸⁷Sr/⁸⁶Sr ratio (Sri) (also indicated as ⁸⁷Sr/⁸⁶Sri) results show a significant shift from about 0.706 to 0.707 in the immediate footwall, to values > 0.709 near the top of the Main Reef. This isotopic shift matches the isotopic shift described for the Merensky Reef of the eastern and western BC. The mineralized units of the Flatreef, namely the Main Reef and Upper Reef, have 𝛿³‏⁴S values ranging between -0.2 to 1.5‰ (with the exception of three outliers), and 0.52% and 11.2‰ in UMT-393, respectively. The S-isotope data for UMT-276 are lighter with 𝛿³‏⁴S values ranging between -0.96 and 2.24‰ for the Main Reef and 3.19‰ was recorded for an Upper Reef sample. These near-mantle 𝛿³‏⁴S values fall within the range of about 0 to 3‰ reported for the Merensky Reef in the eastern and western BC.enThesisUniversity of the Free State