PhD - Science / Analysis of charcoal from Middle Stone Age layers at Sibudu Cave, KwaZulu-Natal,
shows evidence of environmental change during the Last Glacial. Layers analysed
encompass the end of the cold stadial, Oxygen Isotope Stage (OIS) 4, and the warmer
interstadial, OIS 3. Layers are divided – on the basis of lithic industry associations
and taxonomic content – into the Howiesons Poort (HP) (dated to ca. 61 000 years
ago), and the early, middle and late post-HP assemblages (ca. 60-55 000, 55-50 000
and 50-33 000 years ago respectively). This project aims to identify evidence for
environmental change, characterise this change using qualitative and quantitative
analyses, and compare the results to evidence from other proxies at Sibudu Cave and
elsewhere in South Africa.
HP layers (GS, GR, GR2) are dominated by evergreen forest taxa, including
Podocarpus spp., Buxus sp., Brachylaena sp., Sapium/Spirostachys and Ptaeroxylon
obliquum. Kirkia sp. suggests a warm, woodland savanna habitat grew beyond the
forest vegetation. Early post-HP layers (Eb, SPCA, BSp) contain taxa from
evergreen, riverine forest communities, including Erica spp., Leucosidea sericea, and
Rapanea melanophloeos. Some of the taxa in these layers suggest a shift in
vegetation, possibly related to the marine regression of the Last Glacial, bringing taxa
currently found further inland towards the site. Fewer evergreen forest components,
and more bushveld taxa, are present in the middle post-HP (RSp, OMOD, MOD) than
in the previous layers. Some of the taxa are only found in northern South Africa in
regions that are significantly drier than modern KwaZulu-Natal. These layers also
contain more Acacia spp. and other Fabaceae taxa and fewer Erica spp. than the
samples from the early post-HP. This may be a result of environmental change, a
change in wood selection, charcoal fragmentation, or sampling bias. Layer Bu, within
the late post-HP, contains evergreen and deciduous taxa many of which are found in
KwaZulu-Natal today. Kirkia sp. again provides evidence for a dry habitat not
iv
currently found in the region. Many Types were defined in Bu, which may indicate a
vegetation community for which there is currently no reference material.
Temperature and moisture indices produced using the Factor Analysis suggest warm
and moist conditions during the HP layers. During the early post-HP conditions
became cooler with intermediate moisture levels. Subsequently, conditions were
warm and dry (middle post-HP) and then warm with a little more moisture indicated
(late post-HP).
Good fuelwoods were routinely collected during the post-HP. In contrast, the HP
layers are dominated by Podocarpus spp. and many of the good fuelwoods, such as
Acacia spp. and Erica spp., are absent. This pattern may be a result of changes in the
environment, sample bias or a development of awareness of wood properties between
the HP and post-HP occupations.
The charcoal results corroborate palaeoenvironmental interpretations provided by
seeds and macrofauna from Sibudu Cave. When the Sibudu Cave data are combined
with data from other sites it is apparent that, although conditions in the summer
rainfall region during the Last Glacial were generally dry, there is evidence for
localised variation in vegetation and climate.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/156 |
| Date | 02 February 2006 |
| Creators | Allott, Lucy Fiona |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 80500 bytes, 56229 bytes, 2964175 bytes, 469597 bytes, 34742 bytes, 34762 bytes, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf, application/pdf |
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