Umhlatuzana is an important archaeological site for the study of the Middle and Pleistocene Later Stone Age in South Africa with a largely continuous occupation sequence spanning MIS 4-2 (~70,000 -... Show moreUmhlatuzana is an important archaeological site for the study of the Middle and Pleistocene Later Stone Age in South Africa with a largely continuous occupation sequence spanning MIS 4-2 (~70,000 - 10,000 BP). The main technocomplexes represented are Still Bay, Howiesons Poort, Sibudan, final MSA and Robberg (from old to young). Changing selection of raw materials is an important issue in the study of the Middle-to-Later Stone Age transition that appears characterised by a shift in raw material use in addition to a technological organisation. Umhlatuzana was first excavated in 1975 by Jonathan Kaplan who suggested that the lithic assemblage of the Pleistocene deposits consisted mainly of quartz (61%), hornfels (37.6%), and quartzite (1.4%) (Kaplan 1990). Renewed excavations at the site were conducted during 2018 and 2019. This campaign aims to clarify the site’s formation processes employing micromorphological analysis and other techniques (Reidsma et al. 2021, Sifogeorgaki et al. 2020). Micromorphology uses thin sections of undisturbed sediment samples for microscopic studies. The sections allow a petrological inspection of rock fragments embedded in the deposits. Rather unexpectedly, the Umhlatuzana thin sections yield different raw material determinations than Kaplan (1990). While quartz and hornfels are present (around 23% and 25% respectively), they represent a much less sizable proportion than previously reported. Instead, the most prominent raw material observed is a quartz arenite sandstone (42%). Quartzite fragments were not detected.We therefore initiated an in-depth mineralogical and elemental classification of the raw materials. We distinguish 6 raw material types based on the thin section analysis: sandstone, quartz, hornfels, dolerite, chert and diorite. We then determined the elemental composition of the raw material types of the micromorphology samples using p-XRF. Additionally, p-XRF analysis was conducted on c. 100 specimens from the 2018-2019 excavation lithic collection. This allowed us to determine elemental characteristics of the raw materials used during the Pleistocene occupation of the site. Subsequently, p-XRF analysis was systematically performed on a larger sample set of lithics from the site in order to correctly determine their raw material type. The combination of micromorphological and p-XRF analysis of the Umhlatuzana assemblages demonstrates that if only visual inspection is done, the variability of raw materials used may be misinterpreted and the relative frequency of different rock types in an assembly may be over- or underestimated. Future work will aim at re-visiting the raw material categorization of artefacts excavated during the 1975 excavations. Show less
Umhlatuzana rockshelter is an archaeological site with an occupational record spanning the last ~70,000 years, covering the Middle Stone Age (MSA), Later Stone Age (LSA), and Iron Age. The deposits... Show moreUmhlatuzana rockshelter is an archaeological site with an occupational record spanning the last ~70,000 years, covering the Middle Stone Age (MSA), Later Stone Age (LSA), and Iron Age. The deposits bearing Pleistocene archaeological assemblages at Umhlatuzana rockshelter appear homogeneous with no macroscopically visible stratigraphic boundaries. This means the integrity of the archaeological assemblages is difficult to ascertain. Moreover, the sedimentation rate, taphonomic history, and the environmental context across the sequence are unclear. This study aims to resolve these issues by integrating different geoarchaeological techniques in order to explore fine-resolution geochemical differentiations of the sediments that are macroscopically invisible. Samples were systematically retrieved from the western profile of the site following a grid-based sampling strategy and analysed for pH, elemental composition (XRF), and Magnetic Susceptibility. These methods were chosen because they provide insight into ‘invisible’ geoarchaeological dynamics, related to sediment input (geogenic and anthropogenic), taphonomy, and environmental conditions. Additionally, the results were integrated with preliminary micromorphological observations. Our study reveals a gradual change in the geochemistry of the deposits throughout the Pleistocene, related to a combination of environmental change and occupation intensity. Furthermore, the gradual change within the geochemical data indicates that no large-scale sediment mixing took place (contrary to previous suggestions), while small-scale mixing related to bioturbation is visible in the micromorphological thin sections. Our study offers a successful multi-proxy approach to systematically sample and analyse archaeological deposits at the macro and micro scale, integrating a variety of geoarchaeological techniques. The approach provides insight into the depositional and postdepositional history of the site, and allows questions of stratigraphic integrity, anthropogenic input, preservation, and environmental change to be addressed. Show less
In 2018 we initiated a geoarchaeological investigation of Umhlatuzana rock shelter. Our aim is to clarify the depositional environment of the Middle and Later Stone Age (MSA-LSA) assemblages (~70 –... Show moreIn 2018 we initiated a geoarchaeological investigation of Umhlatuzana rock shelter. Our aim is to clarify the depositional environment of the Middle and Later Stone Age (MSA-LSA) assemblages (~70 – 20 ka), in light of suggestions of post depositional sediment movement (Kaplan 1990). The Pleistocene sequence shows few visible stratigraphic boundaries. Sedimentological analysis allows us to evaluate the depositional environment. Show less
Umhlatuzana is an important site for the study of modern behavior during the Middle and Later Stone Age in South Africa. The site was excavated in the 1980s by Jonathan Kaplan, who observed a... Show moreUmhlatuzana is an important site for the study of modern behavior during the Middle and Later Stone Age in South Africa. The site was excavated in the 1980s by Jonathan Kaplan, who observed a complex Pleistocene stratigraphy and suggested that the sequence may have been impacted by sediment movement. The site formation is poorly understood with a lack of clear sedimentary boundaries in the Pleistocene deposits. In 2018, a high-resolution geoarchaeological study of the site was initiated. We re-excavated part of the site applying state-of-the-art methods and techniques designed to clarify the stratigraphy and the archaeological context. We present the results of our field observations, complemented by an evaluation of the recorded find density to reveal diachronic changes in the character of occupation. We suggest that the Pleistocene Later Stone Age occupations at the site may have been characterized by a low occupation intensity. With a clearer stratigraphic understanding of the site, we plan to study the archaeological materials and assess whether the existing collections are representative. Additional geoarchaeological analyses are underway to address outstanding questions on the stratigraphic integrity of the site. Show less
Umhlatuzana rock shelter is an important archaeological site for the study of the Middle and Later Stone Age in South Africa (~70,000 BP - 1,800 CE). The site was first excavated in 1985 by... Show moreUmhlatuzana rock shelter is an important archaeological site for the study of the Middle and Later Stone Age in South Africa (~70,000 BP - 1,800 CE). The site was first excavated in 1985 by Jonathan Kaplan within a limited timeframe and was reported to have a complicated stratigraphy. One of the main problems in comprehending the formation processes of the site was the lack of clear stratigraphic boundaries in the Pleistocene deposits. In 2018, a high-resolution geoarchaeological study of the site was initiated. We re-excavated part of the site applying state-of-the-art methods and techniques designed to clarify the stratigraphy and the archaeological context.Our stratigraphic assessment of the site is based on a combination of field observations with geospatial, sedimentological, and geochemical analyses. Specifically, we have conducted grain-size, pH, and Loss-on-Ignition analyses. Within the Holocene part of the sequence pH and Loss-on-Ignition analysis confirms the presence of combustion features. Within the lower part of the sequence, our results suggest differential preservation across the sequence, explaining the absence of faunal remains and charcoal in several units. In addition, based on our analysis of piece-plotted finds, we suggest that the Pleistocene Later Stone Age occupations at the site may have been characterized by a low occupation intensity. Additional geoarchaeological work including micromorphological analysis are underway to address outstanding questions on the stratigraphic integrity of the site. With a clearer stratigraphic understanding of the site, we plan to study the archaeological materials and assess whether the existing collections are representative. Show less
