Going the distance: Mapping mobility in the Kalahari Desert during the Middle Stone Age through multi-site geochemical provenancing of silcrete artefacts

Abstract

This study utilises geochemical provenancing of silcrete raw materials, in combination with chaîne opératoire analyses, to explore lithic procurement and behavioural patterns in the northern Kalahari Desert during the Middle Stone Age (MSA). New data from the sites of Rhino Cave, Corner Cave, and ≠Gi in northwest Botswana, combined with earlier results from White Paintings Shelter, reveal that the long distance transport of silcrete for stone tool manufacture was a repeated and extensively used behaviour in this region. Silcrete was imported over distances of up to 295 km to all four sites, from locations along the Boteti River and around Lake Ngami. Significantly, closer known sources of silcrete of equivalent quality were largely bypassed. Silcrete artefacts were transported at various stages of production (as partially and fully prepared cores, blanks, and finished tools) and, with the exception of ≠Gi, in large volumes. The import occurred despite the abundance of locally available raw materials, which were also used to manufacture the same tool types. On the basis of regional palaeoenvironmental data, the timing of the majority of silcrete import from the Boteti River and Lake Ngami is constrained to regionally drier periods of the MSA. The results of our investigation challenge key assumptions underlying predictive models of human mobility that use distance-decay curves and drop-off rates. MSA peoples in the Kalahari appear to have been more mobile than anticipated, and repeatedly made costly choices with regard to both raw material selection and items to be transported. We conclude that (i) base transport cost has been overemphasised as a restrictive factor in predictive models, and (ii) factors such as source availability and preference, raw material quality, and potential sociocultural influences significantly shaped prehistoric landscape use choices.3

Heat treatment as a universal technical solution for silcrete use? A comparison between silcrete from the Western Cape (South Africa) and the Kalahari (Botswana)

“…The samples from Botswana were collected in primary position at two sites along the Boteti River, close to the village of Samedupi, and are representative of drainage-line silcrete, the most widespread variety of non-pedogenic silcrete found in the Kalahari [26]. Silcrete from the Boteti River is known to have been used as a raw material source by the peoples who occupied MSA sites in the Tsodilo Hills [27, 28], and, to a lesser extent, the MSA site at #Gi [28–31]. Sample numbers and petrographic descriptions (one standard thin-section was cut from each sample) are summarised in Table 1.…”

Ecological risk, demography and technological complexity in the Late Pleistocene of northern Malawi: implications for geographical patterning in the Middle Stone Age

“…through heating or mixing) have also been argued to reflect an underlying system of symbolically mediated cultural transformations (Wadley, ). Extensive preferential acquisition of raw materials from distant sources is known from eastern Africa by at least ∼200 ka (Blegen, ), and after ∼100 ka in the southern African MSA (Nash et al ., ), potentially indicating expansion of social networks (Ambrose, ).…”

Integrated Geophysical Techniques for the Archaeological Investigation of LbDt-1, a Paleo-Inuit Lithic Quarry Site in the Interior of Southern Baffin Island, Nunavut, Canada

“…These activities create a baseline for interpreting lithic reduction sequences, which archaeologists use to trace the circulation of toolstone, and by extension, people across landscapes (Andrefsky, 2008(Andrefsky, , 2009. Thus, quarries are unique nexus points that link sites throughout a region (Nash et al, 2016). While archaeologists recognize their analytical importance, quarries remain understudied and poorly understood .…”

“…Arguably, archaeologists are ambivalent about studying quarries because they are spatially massive and comprise mixed reduction episodes often spanning millennia; they are devoid of stratigraphy, lack temporally diagnostic tool types and other datable materials, yield voluminous assemblages dominated by lithic debris and shatter, and are logistically challenging to excavate Daniel, 2001;Gopher & Barkai, 2014;Sykes et al 2017; see Milne 2016a) Yet, by avoiding investigation of these sites because of the noted challenges they present, archaeologists cannot accurately reconstruct human mobility and settlement using lithic technology as a proxy since they cannot "anchor" the beginning of reduction sequences Nash et al, 2016, see Milne 2016a).…”