Quaternary Research Copyright © University of Washington. Published by Cambridge University Press, 2020. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. doi:10.1017/qua.2020.75 Geoarchaeological investigation of occupation deposits in Blombos Cave in South Africa indicate changes in site use and settlement dynamics in the southern Cape during MIS 5b-4 Magnus M. Haalanda,b* , Christopher E. Millerb,c,d, Ole F. Unhammera, Jerome P. Reynarde, Karen L. van Niekerka,b, Bertrand Ligouisg, Susan M. Mentzerc,d, Christopher S. Henshilwooda,b,f aDepartment of Archaeology, History, Cultural Studies and Religion, University of Bergen, N-5020 Bergen, Norway bCentre for Early Sapiens Behaviour (SapienCE), University of Bergen, N-5007 Bergen, Norway cInstitute for Archaeological Sciences, University of Tübingen, 72070 Tübingen, Germany dSenckenberg Center for Human Evolution and Paleoenvironment, University of Tübingen, 72070 Tübingen, Germany eSchool of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, WITS 2050, South Africa fEvolutionary Studies Institute, University of the Witwatersrand, 2050 Johannesburg, South Africa gLaboratory for Applied Organic Petrology (LAOP)–Institute for Archaeological Sciences, University of Tübingen, 72070 Tübingen, Germany *Corresponding author at: E-mail address: [email protected] (M.M. Haaland). (RECEIVED July 12, 2019; ACCEPTED July 28, 2020) Abstract The archaeological assemblage recovered from the Middle Stone Age (MSA) levels in Blombos Cave, South Africa, is central to our understanding of the development of early modern humans. Here, we demonstrate that the cultural and technological innovations inferred from the Blombos Cave MSA record also correlate with significant shifts in site use and occupational intensity. Through a comprehensive geoarchaeological investigation of three MSA occupation phases, we identified distinct diachronic trends in the frequency of visits and the modes of occupation. During the earliest phases (ca. 88–82 ka), humans inhabited the cave for more extended periods, but cave visits were not frequent. During the later phases (ca. 77–72 ka), the cave was more regularly visited but for shorter periods each time. We argue that these changes in local occupational intensity, which also coincide with shifts in vegetation, sea levels, and subsistence, can best be explained by broader changes in hunter- gatherer mobility strategies and occupation patterns. Fundamental changes in regional settlement dynamics during Marine Oxygen Isotope Stages 5b-4 would have significantly affected the nature and frequency of social interaction within and between prehistoric populations living in the southern Cape, a scenario that ultimately may explain some of the social and technological advances that occurred there during this time frame. Keywords: Geoarchaeology; Micromorphology; Taphonomy; Middle Stone Age; Site formation processes; Settlement dynamics INTRODUCTION Kandel and Conard, 2012; McCall and Thomas, 2012;d’Er- rico et al., 2017). It is, however, likely that variation in the Currently, we do not fully understand how environmental fl availability of marine and terrestrial resources affected subsis- uctuations may have affected the residential mobility and tence strategies, hunting technology, and site use (e.g., Klein, settlement patterns of Middle Stone Age (MSA) hunter- 1976; Volman, 1978; Binford, 1984; Thackeray, 1988; Klein gatherer populations in southern Africa (Compton, 2011; and Cruz-Uribe, 2000; Henshilwood et al., 2001b; Fisher et al., 2010; Marean et al., 2010, 2020; Reynard and Henshil- Cite this article: Haaland, M. M., Miller, C. E., Unhammer, O. F., wood, 2017). Some researchers have hypothesized that shift- Reynard, J. P., van Niekerk, K. L., Ligouis, B., Mentzer, S. M., ing access to natural resources during the MSA may have led Henshilwood, C. S. 2021. Geoarchaeological investigation of occupation to a fundamental restructuring of hunter-gatherer societies, deposits in Blombos Cave in South Africa indicate changes in site use and settlement dynamics in the southern Cape during MIS 5b-4. Quaternary affecting not only their mobility strategies and settlement pat- Research 100, 170–223. https://doi.org/10.1017/qua.2020.75 terns, but also impacting the nature and frequency of social 170 Downloaded from https://www.cambridge.org/core. IP address: 170.106.202.8, on 29 Sep 2021 at 20:49:23, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/qua.2020.75 Geoarchaeology of Blombos Cave, South Africa 171 interaction within and across different hunter-gatherer groups investigation of the cave deposits has so far been published (McCall and Thomas, 2012; Mackay et al., 2014;d’Errico (but see Tærud, 2011). Yet, throughout multiple excavation et al., 2017). Such a restructuring could have stimulated the seasons, more than 40 micromorphological block samples adoption of more complex social behaviors, in particular (ca. 90 thin sections) and associated bulk sediment samples those involving more elaborate communication strategies, have been collected. By combining archaeological micromor- for example, the adoption of personal ornaments, engraved phology and microspectroscopy with 3D and high-resolution ostrich eggshells, and systematic use of ochre pigments field documentation, we have selected 13 of these blocks to (e.g., Henshilwood et al., 2002, 2018;d’Errico et al., 2005; specifically track patterns of site use and occupational inten- Mackay and Welz, 2008; Texier et al., 2010). sity in three discrete and laterally extensive MSA occupation While some regional comparisons of southern African phases: M3 CI phase (88 ka), the Upper M2 phase (77 ka), MSA assemblages appear to support a correlation between and the M1 phase (72 ka). Based on thin section observations behavioral innovation and changes in population movement of these occupation phases, we use an archaeological microf- and interaction (Jacobs et al., 2008), testing this hypothesis acies approach (Courty, 2001; Goldberg et al., 2009; Villag- on a local scale requires an analytical framework capable of ran et al., 2011; Miller et al., 2013; Karkanas et al., 2015)to robustly documenting short-term site use and subtle changes classify distinct human campsite activities and to map the lat- in occupational intensity. At most MSA sites, this type of eral and vertical distribution of these activities across the site high-resolution analysis has not been carried out systemati- and through the MSA sequence. Finally, we discuss how the cally. However, faunal taphonomic studies at Klipdrift Shel- observed microstratigraphic indicators of site use and occupa- ter (Reynard et al., 2016b) and Blombos Cave (Reynard and tion intensity allow us to assess continuity and shifts in site Henshilwood, 2018) have linked trampling marks on bones to use during the MSA at Blombos Cave, and we contextualize variations in human occupational activity. Additionally, at our new sediment-based results within the taphonomic, pale- both Pinnacle Point (Karkanas et al., 2015) and Sibudu (de oenvironmental, and archaeological framework already la Peña and Wadley, 2017), a combination of sediment-based established at the site. studies and archaeological artifact analyses led to a better understanding of the nature and variation of episodic human activities during the MSA. Assessing prehistoric site use and occupational However, many key MSA sites are located in caves and intensity from multiple proxies rock shelters where the recurrent use of space has led to the destruction of the original prehistoric site configuration and In previous studies of prehistoric campsites, researchers has instead caused the formation of deep sedimentary have applied several strategies to evaluate residential sequences that are exceedingly difficult to decipher. Geoarch- mobility and settlement patterns (e.g., Parkington et al., aeological and micromorphological investigations of such 1992;Conard,2004 and references therein). One common MSA contexts have demonstrated that their sedimentary approach has been the study of physical site structure and sequences often are composed of centimeter- to millimeter- campsite configurations (Wadley, 2001; Henshilwood, thick laminations, many of which were formed through fre- 2005;Stiner,2009) and the assessment of changes in site quent interactions between cultural and natural processes use and occupational intensity over time (Munro, 2004; (Goldberg et al., 2009; Karkanas and Goldberg, 2010; Wad- Conard, 2011). Multiple ethnographic and archaeological ley et al., 2011; Miller et al., 2013, 2016). Because of the dep- studies show that hunter-gatherer mobility patterns often ositional complexities involved in the formation of MSA reflect the way these groups use, maintain, and physically deposits, the application of geoarchaeological methods to organize their campsites (e.g., Yellen, 1977; Brooks and study the local archaeostratigraphy in high resolution has Yellen, 1987; Hitchcock, 1987;Kelly,1992; Koetje, been central in refining the nature, order, and scale of prehis- 1994;Binford,1998;Kent,1998). Consequently, if signifi- toric depositional events, as well as characterizing the envi- cant changes in occupation intensity