Plants, people and fire: Phytolith and FTIR analyses of the post- Howiesons Poort occupations at Border Cave (KwaZulu-Natal, South Africa)

Acknowledgements IE has received funding from the postdoctoral fellowship programme Beatriu de Pinós (2019 BP00247), funded by the Secretary of Universities and Research (Government of Catalonia) and by the Horizon 2020 programme of research and innovation of the European Union under the Marie Skłodowska-Curie grant agreement No. 801370. Laboratory materials for sample processing at the University of Barcelona were funded by the Ministerio de Ciencia e Innovaci on - PID 2020-119773 GB-I00. Visit to the site for sampling collection for this study was sponsored by a NRF Y-Rated Research Grant (No. 116358) to DS. PdlP was supported by a Poroulis grant through Cambridge University. PdlP thanks the action PID 2019- 1049449 GB-I00 funded by Spanish FEDER/Ministry of Science and Innovation. LB was funded by a National Geographic Explorer grant (NGS-54810R-19), DSI-NRF Centre of Excellence in Palaeosciences (Genus) grant (CEOOP 2020-1), and NRF African Origins Platform grant (No. 98824). Research by FdE is funded by the Research Council of Norway (SFF Centre for Early Sapiens Behaviour- SapienCE-project 262618), the Talents program of the University of Bordeaux (n. 191022_001), and the program “Human Past”, funded by the same university.We are grateful to Amafa for issuing us with the excavation permit (SAH 15/7645), and to SAHRA for an export permit (CaseID 15987).We thank two anonymous reviewers for their helpful comments that significantly improved the manuscript.Supplementary data to this article can be found online at https://doi.org/10.1016/j.quascirev.2022.107898.Border Cave is a well-known South African Middle and Early Later Stone Age site located in KwaZulu-Natal. The site has exceptional plant preservation, unparalleled in the African Middle Stone Age archaeological record. This study focuses on the phytolith and FTIR analysis of two Members (2 BS and 2 WA) of the under-documented post-Howiesons Poort occupations dating to ∼60 ka. These members contain complex successions of vertically overlapping, interdigitating light brown sediments, plant bedding and combustion features of various sizes. The complexity and distinctiveness of these deposits provide an excellent opportunity for the study of plant exploitation strategies and their associated human behaviour. Our taphonomic assessment inferred, through the variability of phytolith properties and minerals composing archaeological layers, that specific occupations suffered more physical weathering than others, for example in the form of trampling. The preservation of fragile and highly soluble phytoliths (eudicot leaf phytoliths) and the high frequencies of articulated phytoliths indicates that some bedding deposits experienced little disturbance after their deposition. Not all bedding layers dating to ⁓60 ka show, from a phytolith perspective, the same plant composition, which could be explained in terms of changes in human preference for the use of plants over time to construct bedding or because distinct types of living floors are represented. Finally, the systematic application of phytoliths and FTIR to the complex archaeological sequence of Border Cave confirm these analyses can be used in the future to identify bedding deposits not visible to the naked eye, and behavioural patterns obscured by diagenetic or biased processes during sampling.Programme Beatriu de Pinós (2019 BP00247), funded by the Secretary of Universities and Research (Government of Catalonia)Horizon 2020 programme of research and innovation of the European Union under the Marie Skłodowska-Curie grant agreement No. 801370Ministerio de Ciencia e Innovación - PID 2020-119773 GB-I00NRF Y-Rated Research Grant (No. 116358)Action PID 2019- 1049449 GB-I00 funded by Spanish FEDER/Ministry of Science and InnovationNational Geographic Explorer grant (NGS-54810R-19)DSI-NRF Centre of Excellence in Palaeosciences (Genus) grant (CEOOP 2020-1)NRF African Origins Platform grant (No. 98824)Research Council of Norway (SFF Centre for Early Sapiens Behaviour- SapienCE-project 262618)Talents program of the University of Bordeaux (n. 191022_001)Program “Human Past” University of BordeauxSAH 15/7645CaseID 1598