Mapping Middle Stone Age human mobility in the Makgadikgadi Pans (Botswana) through multi-site geochemical provenancing of silcrete artefacts

Making Points: The Middle Stone Age lithic industry of the Makgadikgadi Basin, Botswana

“…The raw material groups were continually refined and reassessed during the entire analysis and refitting process, as many blocks displayed similar characteristics (for an overview, see the Supplementary Online Material in Staurset et al, 2022). These groups were later used as the basis for selecting samples for geochemical provenancing (see Nash et al, 2022).…”

“…Importantly, analyses of trace element composition has made it possible to provenance archaeological Kalahari silcrete to original source areas (Nash et al, 2013a;Nash et al, 2013b;Nash et al, 2016), providing possibilities for the reconstruction of MSA movement patterns. This facet of Makgadikgadi MSA behaviour is further discussed in Nash et al (2022). Silcrete outcrops occur regularly within and along the current edges of the Makgadikgadi pans (Nash et al, 2022 and references therein).…”

“…To the best of our knowledge this is the first time sites have been excavated on Ntwetwe Pan, meaning we had no prior knowledge of the vertical aspect of the sites (also see Coulson et al, 2022). Through the excavations we aimed to acquire enough archaeological data to 1) classify and understand the predominant MSA industry; 2) investigate the technology and techniques used in its production; 3) determine whether these factors varied greatly from site to site; 4) provide lithic samples for geochemical provenancing reflecting the material chosen for prehistoric production (as reported in Nash et al, 2022); 5) represent sites associated with different landscape features in the pan environment; and 6) determine the timing of site deposition and its relation to palaeohydrological conditions in the basin via optically-stimulated luminescence (OSL) dating (see Burrough et al, 2022). To achieve these goals, we began by excavating four smaller sites (MAK2, MAK14K, MAK14O and MAK15) and, based on experience with the uncovering of these, moved on to incorporate one large site (MAK33, location of all sites shown in Fig.…”

“…We also prioritized sites where several stages of lithic production were evidently present. To address goal 5, we factored in sites associated with dune edges, hardened clay areas and silcrete outcrops, and, for goal 6, those with higher potential for dating (see Burrough et al, 2022;Nash et al, 2022;Thomas et al, 2022). OSL dating at MAK14K, MAK14O, MAK15 and MAK33 (reported in detail by Burrough et al, 2022), revealed that the lithic industry at these sites was deposited during dry periods following palaeolake high stands dating to c.128e81 ka and c. 72e57 ka.…”

“…This outer surface tended to be partially preserved also on the finished tools. The natural blanks and products from these were limited to a small number of raw material groups, mostly comprising very fine-grained, well cemented silcrete in light to white colours (also see Nash et al, 2022). This is likely the result of these particular types of silcrete forming in thin enough layers that they form natural blanks, and could be exploited directly by bifacial reduction for point production.…”