Investigating Changes in Middle Stone Age Hunter-gatherer Mobility and Resource Utilisation in Response to Coastline Migration using Archaeological Lithic Provenance in the southern Cape Region, South Africa 2.

Context of study

Anatomically modern humans (hereafter AMH) emerged and spread across the African continent during early MIS 6 (200 ka) (Lombard et al., 2012; McDougall et al., 2005; Stewart & Jones, 2016). Their material culture attest to important adaptations to the diverse environments of Middle Stone Age (200-50 ka, hereafter MSA) Africa and the development of cultural modernity. Cultural modernity refers a suite of behaviours that are thought to distinguish AMH from earlier and contemporary species of human (e.g., Neanderthals) and continue to be exhibited by us today. The components that potentially characterise this critical development in human evolution are not yet fully understood and continue to be debated (McBreaty & Brooks, 2000; Scerri & Will, 2023; Shea, 2011). Among them are a greater exploitation and reliance on marine and coastal resources. The occupation of new econiches was possibly enabled by changes to their mobility and technology.

Mobility is a fundamental aspect of the human experience and is a defining feature of hunter-gatherers (Kelly, 1992; Kuhn, 2020; Kuhn et al., 2016). It presents at several scales, referring to the movement of populations over time, groups throughout the year, and individuals as they forage. It is important to understand the mobility patterns exhibited by a hunter-gatherer society because they have implications for survival, as they are typically a means of mitigating environmental stress (Collard et al., 2013; Hitchcock, 1982), such as a reduction in resources. Mobility is inextricably linked to interaction among groups, subsistence strategies, and the organisation of technology. It is often investigated through reconstructions of resource procurement strategies (Kuhn, 2020), such as those used for stone tools. Stone tools are a major component of hunter-gatherer sites during the Pleistocene and often the means by which they are identified (Potts, 1991). These implements enabled hominins to cope with their environments for the past 2.5 million years and, for archaeologists, provide high resolution evidence of behavioural change throughout human evolution. Procurement encompasses the suite of decisions and activities involved in the acquisition of raw material (Wilson, 2007), which have implications for the subsequent reduction, transport, utility, and longevity of the tools. The variability and distribution of natural resources, both terrestrial and marine, often force hunter-gatherers to confront decisions regarding the nature of procurement and their mobility.

The southern Cape Region in South Africa provides a significant opportunity in which to investigate the relationship between hunter-gatherer mobility and coastal subsistence. It encompasses high plant biodiversity and landscape variability, including an exposed rocky coastline on the south Atlantic Ocean with multiple caves and shelters. Several of these caves were occupied during the MSA. One important site, Klipdrift Rockshelter, has been excavated and studied by Prof. Christopher Henshilwood (now of the SapienCE group from the University of Bergen, Norway) and contains MSA layers dating from 69-50 ka BP.

The lowering of sea level opened up a large geographic area (today submerged) off the southern coast of Africa, known as the Palaeo-Agulhas Plain (Marean et al., 2020). The proximity to marine resources, predominantly shellfish (De Vynck et al., 2020), is reflected in the nature of the ecocultural niches of the sites. In particular, occupation at Klipdrift Rockshelter occurs while the coastline was still many kilometres away to the south (Cawthra et al., 2020). Consequently, it is becoming clearer that the shifting coastlines of southern Africa had a noticeable impact on the nature of subsistence in the region (d’Errico et al., 2017), and further begs inquiry into which other aspects of human behaviour were affected.

The lithic assemblage from Klipdrift Rockshelter contains tools and debitage made from a variety of lithologies, including quartz, quartzite, cryptocrystalline silicates, and silcrete. Klipdrift Rockshelter contains layers with the Howiesons Poort techno-tradition, signalled by blade technology and small backed tools. Howiesons Poort tradition has been discovered at other MSA sites throughout South Africa, indicating their likely importance for subsistence, networking, and regional identity. For hominins congregating in a region with shifting coastlines, the development of effective foraging and lithic procurement strategies was essential to their survival. The procurement of raw materials, specifically silcrete which is not found locally, likely required hunter-gatherer groups to be mobile across the landscape, especially during sea level regression. A reconstruction of raw material procurement strategies will lend insight into critical questions regarding the nature of hunter-gatherer mobility and the ecocultural niches that humans occupied during the MSA in the southern Cape Region.

Questions and objectives

The research will be guided by the following questions:

1) Where are the lithological sources from which the stone tools at Klipdrift Rockshelter are manufactured? What sources might have been available during the MSA in what are now in offshore regions, such as the Palaeo-Agulhas Plain?

2) What are the specific marine-related signatures that can be identified when investigating patterns of hunter-gatherer mobility and resource utilisation at coastal and inland sites during the MSA and can these be identified and correlated with changes in raw material types?

3) What evidence is there for connections among MSA sites of the southern Cape, western Cape, and the Karoo interior, and can these be related through past mobility patterns, particularly in relation to marine resources?

The corresponding objectives of this project are threefold:

1) Investigate the provenance of lithic materials at Klipdrift Rockshelter, through linkages to potential terrestrial and marine sources.

2) Reconstruct patterns of resource utilisation and movement across the terrestrial and coastal landscape of the southern Cape Region and Palaeo-Agulhas Plain during the MSA.

3) Situate the mobility of hunter-gatherers with the corresponding econiches during each econiche, particularly in reference to sea regression and transgression.