School of Geosciences (ETDs)

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    Late Quaternary Palynological Studies at Lake St Lucia, KwaZulu-Natal
    (University of the Witwatersrand, Johannesburg, 2023-08) Effiom, Angela Charles; Neumann, Frank; Bamford, Marion
    Palynological studies were done on lacustrine sediments deposited during the last ~6300 and about ~2000 cal yrs BP in Mkhuze Swamp, which drains into the most northern part of Lake St Lucia located in the Indian Ocean Coastal Belt Biome of KwaZulu-Natal, eastern South Africa. The aim was to reconstruct the past vegetation and to infer past climate fluctuations as well as human disturbances to complement growing evidence from other disciplines about these questions in the area. Following standard palynological methods, samples from two cores Mkhuze River Delta (MKD-1, long core) and Mkhuze swamp (MK24-1, short core) were extracted and analyzed. Palynological results for both cores show a dominance of Poaceae (20-90%) suggesting a strong influence of grassy woodland savanna. Spirostachys pollen dominated the arboreal spectra of the pollen profile in MK24-1, but it dominated the arboreal pollen spectra for the last 2600 cal yrs BP in MKD-1 as Podocarpus pollen dominated the arboreal spectra from 6300-2600 cal yrs BP indicating a change from a forested environment to a more open woodland environment. The results also show that the mid Holocene was humid with high precipitation and high sea level while the late Holocene was warm, dry with Marine influence (more sea water flowing into the lake due to high evaporation and low fresh water supply caused by drought). Similar pollen fluctuations were observed in records from Lakes Eteza and Sibaya also located within the Indian Ocean Coastal Belt Biome. The presence of Pinus pollen at the top of the profiles suggests the onset of European settlement when pines were introduced for timber production. Other published pollen records from the region in the last ~7000 cal BP show a general trend from a mesic forested environment towards an open woodland environment with grasses which is due to climate change.
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    Palaeoclimate Reconstruction Using Charcoal from a Mid-Holocene Stratum 4b, Wonderwerk Cave, South Africa
    (University of the Witwatersrand, Johannesburg, 2024-06-18) Hlophe, Busisiwe; Bamford, Marion
    Caves are often sources for palaeoenvironmental information in the dry interior regions of southern Africa. The Wonderwerk Cave, located in Northern Cape, is a national heritage site with a well-preserved, nearly complete record of the local Holocene LSA techno-complexes and past environmental indicators. Hence, it has the potential to provide valuable insights into past human behaviour as well as the local palaeoclimate and vegetation. This study examined wood charcoal from stratum 4b, Excavation 1 of the Wonderwerk Cave. The aim was to evaluate the taxonomic composition and the physiognomy of the charcoal to understand the environment around the cave 6.9-5.9 ka. The study also investigated the modern uses of the vegetation to infer how humans may have utilized the woody plants around them during that period. The results indicate the landscape cover included woody plants adapted to dry conditions and summer rainfall. However, the archaeological taxa identified also included two species that thrive in moist environments, Halleria lucida and Olinia ventosa, suggesting fluctuations in climate. The taxonomic composition also suggests an environment similar to the modern bushveld found near the cave. The low conductivity capacity as well as vulnerability and mesomorphy indices of the woods support the implication that the vegetation was adapted to low water availability or aridity. The cave's inhabitants likely used the identified plants for firewood, magical and medicinal purposes, and more between 6.9 and 5.9 ka.