Research Projects

Diagenetic minerals in South African archaeological caves and rockshelters: An inventory and review
Susan M. Mentzer (1,2,3), Thomas Beard (4), Christoph Berthold (3), Magnus Haaland (5,6), Peter Kloos (3), Christopher E. Miller (1,2,3,5)

1 Geogenomic Archaeology Campus Tuebingen, Germany
2 Senckenberg Centre for Human Evolution and Palaeoenvironment, Germany
3 Department of Geosciences, University of Tuebingen, Germany
4 Department of Evolutionary Anthropology, University of Vienna, Austria
5 SapienCE, University of Bergen, Norway
6 Museum of Archaeology, University of Stavanger, Norway

Secondary minerals that form in archaeological sites can be used to understand post-depositional processes. In open air sites, most secondary minerals form due to pedogenesis and groundwater activity. In caves and rockshelters, a wider variety of secondary minerals can form due to a range of dripwater and groundwater compositions as well as the presence of initial sedimentary components that are unique to these settings (e.g. bat guano). Benchmark studies of mineral diagenesis in archaeological caves in the Levant and Mediterranean have linked the formation of certain minerals or mineral suites to specific chemical micro-environments within the sites. This paper provides an overview of more than 20 secondary minerals that have been identified in South African caves and rockshelters. Many of these minerals were identified during the course of geoarchaeological studies conducted by researchers and students at the University of Tuebingen using a combination of optical properties, elemental analysis, Fourier transform infrared spectroscopy, and x-ray diffraction, while others are reported in the literature (e.g. Montagu Cave, Waterfall Bluff, the Pinnacle Point sites). The minerals presented in this paper include: anhydrite, apthitalite, ardealite, bassanite, bloedite, brushite, calcite, epsommite, gypsum, halite, hydroxylapatite, kutnohorite, leucophosphite, niter, nitratite, sveite, sylvite, syngenite, taranakite, whewellite, and whitlockite. Additional compounds identified are amorphous silica/opal and tricalcium phosphate, while other crystalline substances have been documented but not fully identified. In reviewing the occurrences of all of these minerals, several suites corresponding to specific environments, animal occupation, and human activities can be identified.

This presentation was given on the SASQUA Congress 2024 in Cango Valley, South Africa.

A micromorphological and mineralogical study of Holocene stabling deposits in Boomplaas Cave, South Africa
Susan M. Mentzer (1,2,3), Thomas Beard (4), Ani Hristonova (1,3), Justin Pargeter (5,6)

1 Geogenomic Archaeology Campus Tuebingen, Germany
2 Senckenberg Centre for Human Evolution and Palaeoenvironment, Germany
3 Department of Geosciences, University of Tuebingen, Germany
4 Department of Evolutionary Anthropology, University of Vienna, Austria
5 Department of Anthropology, New York University, USA
6 Palaeo-Research Institute, University of Johannesburg, South Africa

The uppermost Holocene deposits in Boomplaas Cave (Cango Valley, Klein Karoo) are both the youngest and least-studied from an archaeological perspective. The surface CBM Member, which has been removed the central area of the site, is white in color, and was described by Hillary Deacon as broadly “calcined,” having formed as a result of stabling of animals within the cave and periodic burning of the resulting dung. Occupation features such as hearths were also present. The underlying DGL member formed under similar conditions and also contained dung and the remains of both wild and domesticated animals. The deposits are currently exposed in two scarps, one in the northern area of the site and another along the eastern wall. These were sampled for geoarchaeological analysis during the 2022 field season. Six blocks were collected for micromorphological analysis, and more than 50 loose samples of the sediment and visible secondary mineral crusts and nodules were collected for mineralogical analysis. Fourier transform infrared spectroscopy was conducted on site and in the field laboratory. Minerals identified within the CBM and DGL members included calcite, aphthitalite and niter, and the deposits are overall enriched in phosphorus, sodium, and potassium. The micromorphological analyses of the deposits revealed fibrous microlaminations containing secondary mineral encrustations. The deposits are significant for the geoarchaeological study of pastoralism in that they provide a southern hemisphere example of fumier, which is a type of burned stabling deposit more frequently associated with Neolithic and younger sites located in caves in the Mediterranean basin.

This poster has been presented on the SASQUA Congress 2024 in Cango Valley, South Africa.

Cave or rock shelter? Landscape evolution in the Lone Valley of the Swabian Jura as seen from the perspective of small mammals

Elisa Luzi (1) & Nicholas J. Conard (1-3)

1 Department of Geosciences, University of Tuebingen, Germany
2 Geogenomic Archaeology Campus Tuebingen, Germany
3 Senckenberg Centre for Human Evolution and Palaeoenvironment, Germany

Langmahdhalde is a rock shelter located in the Lone Valley (Swabian Jura, SW Germany). Excavation at the site began in 2016 and is still ongoing. The team from the University of Tübingen uncovered an archaeological sequence spanning from Middle Paleolithic to the Neolithic, including sediments dating to the Last Glacial Maximum, which is unique in this region (Conard et al., 2023; Schürch et al., submitted). Analysis of the taphonomy conducted on first lower molars of voles indicates a change in the main agents of the accumulation of the small mammal assemblages. In the upper part of the sequence (GHs 4 to 17), the main accumulators were predators of category 3-4. In the last two GHs studied (GH 18-19) the accumulators shifted to category 2-3 (follow Fernández-Jalvo et al.2016). Diurnal raptors that prefer to roost and nest in cliffs and trees while avoiding caves count among the predators of category 4. The absence of diurnal predators in the lower part of the sequence suggests that the current shelter was a cave before the Last Glacial Maximum. We carried out direct dating of the small mammal remains to gain better control of the stratigraphy and of the timing of this transformation. Ongoing studies of micromorphology will further clarify the geological history of Langmahdhalde and will facilitate an improved understand of the use of the site by human groups during the Paleolithic. The Middle Paleolithic occupation recognized in GHs 24-28 during the last two years and the rich Magdalenian occupation in GHs 4-9 might have taken place, not just under different climatic and environmental conditions, but also in different settings in the landscapes with different landmarks and spatial organization.

This poster has been presented on the 65th Annual Meeting of the Hugo Obermaier Society in Weimar.