Heritage Cases

This project is for the excavation and sampling of Mwulu's Cave. This is an archaeological site excavated by P. Tobias in the 40'. The site contains Middle Stone Age remains and have been broadly assigned to the Pietersburg. I would like to make a new archaeological profile for this site and take archaeological, OSL, micromorphology and pollen samples. Moreover, my plan is to publish the old lithic collection (which is stored at the Origins center) excavated by Prof. Tobias and complete it with the new lithic material. Excavation of Mwulu’s Cave, a Middle Stone Age site in Limpopo Summary of Research Mwulu’s Cave, located in Limpopo Province, was excavated in the 1940s by Phillip Tobias, who assigned the entire stratigraphic sequence to the Pietersburg industry. This industry is one of the few regional variants within the Middle Stone Age (MSA) of southern Africa, and its definition and our understanding of it are not good, mostly because other techno-traditions have received more attention. Mwulu’s Cave is an interesting site because it offers the opportunity to understand multiple occupation levels assigned to this vague entity. I plan to direct an archaeological excavation at this site, in order to give a stratigraphic context to the material excavated by Tobias, and to new archaeological finds. I plan to refresh the profiles and describe in detail the site stratigraphy by means of drawings, photogrammetry and studying the micromorphology. Sediment samples will be taken for Optically Stimulated Luminescence dating, pollen and phytolith analyses, and archaeological material will be curated at the n the Archaeology Collection, University of the Witwatersrand. My study of the lithic technology, together with contemporaneous climatic indicators and first radiometric ages for the deposits, hold great promise for better understanding MSA cultural adaptation in this culturally rich and poorly documented region of southern Africa. Rationale The MSA (300 000-40/20 000 before present (BP)) covers the first appearance of Homo sapiens sapiens and its subsequent cultural development. The original definition of the term MSA was merely typological, so the objects ascribed to it were simply ordered in a diachronic sequence. The MSA is understood now to be far more complex, but still it is generally depicted with a monotonous evolution in terms of lithic technology. Apart from the Howiesons Poort and the Still Bay technocomplexes, the remaining pre and post development is implicitly conceived of as quite uniform in terms of technological variability, which is sometimes translated (tacitly) into lower cognitive capabilities in comparison to the Later Stone Age. Particularly, Pre-Still Bay assemblages are very seldom described, and their development is defined by a lack of certain typological implements, rather than by their own idiosyncrasy. Moreover, most of the sites excavated so far in this southernmost part of the continent are located along the west coast. Even if the MSA has been considered by some researchers as a period of high cultural variability (Shea, 2012), the MSA of southern Africa seems to have, from a typological point of view (Wurz, 2013), an apparent uniform development in lithic technology; and not many regional distinctions have been pointed out, the Pietersburg industry being one of them (Sampson, 1974). Different sites of the former Northern Transvaal were also attributed to the Pietersburg by Mason (1957): Mwulu’s Cave, Olieboompoort, Rufus, Kalkbank, Aasvoëlkop, Rooirand, Border Cave, Bushman Rock Shelter and Koedoesrand. The excavation of Mwulu’s Cave is part of a bigger research project planned for my postdoctoral fellowship next year, in which I intend to compare the chrono-stratigraphy and lithic technology of Mwulu’s Cave with other Pietersburg assemblages, specifically from Bushman Rock Shelter and Border Cave. Aims of Research The first aim of the proposed research is to expose a stratigraphic profile, by cutting a small section into the old one from Tobias’s excavation (approximately 50 cm into the profile and along 2 m). This will allow me to refine the stratigraphy and understand it in detail, particularly because several micromorphology blocks will be taken for analysis. Moreover, a complete 3D photogrammetry model will be compiled for the purpose of fully documenting the exposed section. My second aim is to take several sediment samples for dating using optically stimulated luminescence (OSL), at least two samples for each of the layers identified. The reason being that the samples will be sent to two independent dating laboratories. My primary aim, possible only if the first two are achieved, is to contribute to a new technological definition of the so-called Pietersburg industries, by conducting a technological comparative study of newly excavated material, and the existing lithic collection made by Tobias (stored in the Archaeology section of the Origins Centre, University of the Witwatersrand). Mwulu’s cave does not have organic preservation as it lies in a quarzitic area that does not allow for macro-plant or bone preservation. However, once the stratigraphy is refined a pollen column and sediment samples for phytolith analysis will be taken as palaeoenvironmental proxies. Materials & Methods Archaeology The excavation will follow the geological stratigraphic layers defined by a geoarcheologist in the field. All sediment removed will be sieved through 2 mm mesh, and the volumes of deposit removed will be recorded. All the buckets of sediment removed and the sediment samples for the different analyses will be plotted in using a total station theodolite (EDM reference). All the archaeological material and features like hearths will be mapped using an EDM. This will provide a 3-dimensional reference for all the finds. Moreover, 3D plotting will allow me to make a spatial analysis of the densities of finds per layer, and correspond this with features and geological stratigraphic layers. ArcGis software will be used for this purpose. Photogrammetry Two photogrammetry models are planned; one to record the whole site and another to document the new profile unveiled by the new excavation. Agisoft software will be used for this purpose. Geoarchaeology The preservation of complex micro- and macro-stratigraphy, which in the case of some South African rock shelters, potentially preserve high resolution evidence of early modern human behaviour require dedicated geoarchaeological study to help identify primary and secondary site formation processes, and their impact on the archaeological record (e.g. Karkanas & Goldberg, 2010). This work has become standard in MSA archaeology and applies a range of geochemical, sedimentological and spatial analyses at various scales to interrogate the context of the archaeological assemblages. Geoarchaeological investigations should be a priority for initial investigations, and include bulk and micromorphological sampling in order to establish a stratigraphic and contextual framework for the site, deposits or area of interest. At least five micromorphology blocks will be taken in order to study the entire stratigraphic sequence. Moreover, sedimentological analyses are also planned to be performed at the School of Archaeology, Geography and Environmental Studies, University of Witwatersrand (collaboration with Dr. Dominic Stratford). Petrography of rock types A thin section will be cut for all the main rock types identified by eye during excavation. The thin section will be prepared following standard techniques, and examined using a transmitted light microscope at the School of Geosciences, University of Witwatersrand. Petrographic examination will include mineral identification, mineral shape, textures, and distinction between larger clasts and groundmass. The final classification into rock type will be based on petrographic observations. Optically Stimulated Luminescence (OSL) dating Sediment cores will be removed for OSL dating. This dating method is favoured because, based on preliminary typological information, the industry appears to be a Pre-Still Bay assemblage. It is therefore likely that the chronology is in excess of 30,000 BP. Ideally two OSL cores will be taken per layer. This protocol will allow for independent results from two laboratories: the University of Washington OSL Laboratory and the OSL Laboratory at the University of the Witwatersrand. Phytoliths and pollen Sediment samples of all the layers will be taken for analysis of phytoliths. Moreover, a full pollen sequence will be taken by an archaeobotanist. Owing to the fact that the site does not preserve organic remains, because of the well vegetated acidic conditions where the cave is located, these highly informative plant remains are very important as they will inform us about climate change, and the effects, or not, on local cultural adaptation/behaviour in the interior of southern Africa.