Stratigraphy and palaeoenvironment of the Carboniferous Jurassic Karoo Supergroup in the Lebombo-Tshipise basin

Clayton, Katherine E
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The Karoo Supergroup represents a highly complete sedimentary succession that was deposited in several basins throughout southern Africa during the late Palaeozoic and Mesozoic (Carboniferous-Jurassic). While research in the Lebombo-Tshipise Basin of southern Africa has largely focused on lithological description of Karoo sediments or structural features of the basin, little effort has been made to describe the palaeoenvironments recorded in the sediments, or the basin fill’s response to major tectonic or climatic events. To address palaeoenvironmental reconstruction, lithostratigraphic analysis resulted in defining 11 facies associations from the Tshidize, Madzaringwe, Mikembeni, Fripp, Solitude, Elliot and Clarens Formations in the Pafuri sub-basin of the Lebombo-Tshipise Basin. Twenty boreholes drilled in Kruger National Park by the Council for Geoscience in 1979 record largely stable and consistent deposition of the Tshidize, Madzaringwe and Mikembeni Formations during the Permian. The Mikembeni Formation thins dramatically southwards, whereas the overlying Triassic successions tend to wedge out to the east. Late Triassic and Jurassic sediments directly overlie Precambrian basement in the southernmost boreholes. Significant thickness differences between the western and eastern boreholes indicate a large fault, which likely represents a rift shoulder. The palaeoenvironments in this basin are similar to those of the Main Karoo Basin, but quantitative analyses suggest a more humid environment in the Late Triassic Elliot Formation. Sauropodomorph fossils validate assignment of formerly mapped Solitude Formation as actually being the Elliot Formation. Palaeosols in the Elliot are consistent with either Oxisols or Argillisols. Wet desert conditions, evidenced by burrows produced by invertebrate communities, and tectonic activity, suggested by seismites, persist into the Early Jurassic Clarens Formation.
A dissertation presented to the Faculty of Science, University of the Witwatersrand, in partial fulfillment of the requirements for the degree of Master of Science. August, 2017
Clayton, Katherine Elisabeth, (2017) Stratigraphy and palaeoenvironments of the Carboniferous-Jurassic Karoo Supergroup in the Lebombo-Tshipise basin, University of the Witwatersrand, Johannesburg,