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N. Cleghorn (University of Texas at Arlington) (link is external), Z. Jacobs (University of Wollongong, Australia) (link is external), P. Karkanas (Ephoreia of Paleoanthropology-Speleology, Greece) (link is external), J. Lee-Thorp (Oxford University, UK) (link is external), H. Cawthra (Council for Geoscience, South Africa)
The archaeological data in Project 5 also directly addresses the pace of technological innovation, such as heat treatment and microlithic technology.
This project focuses on the environmental conditions for behavioral variation during the time of the origin of the modern human lineage. It will test the proposal that coastal locations were the ideal environments for the evolution of complex cognition and cooperation. This project will span the three foci of human uniqueness (cognition, cumulative culture, and cooperation) and link to the evolution of locally adaptive technology (e.g., Project 7) and the mechanisms sustaining large-scale cooperation (Projects 10, and 11).
Despite the consensus that the modern human lineage originated in Africa before 100 ka, there is debate as to when cultural and cognitive characteristics typical of modern humans first appeared and the role these played in the expansion of modern humans out of Africa. Scientists typically rely on symbolically specific proxies, such as artistic expression, to document the origins of complex cognition. Advanced technologies with elaborate chains of production are also proxies for complex cognition since these often demand high-fidelity transmission and thus language. At Pinnacle Point (South Africa) site PP13B the IHO research team showed that early humans had discovered the relation between lunar phases and tidal return rates so that they could develop a coastal adaptation by ~110 ka, and perhaps as early as ~162 ka. We recently documented the earliest evidence of stone tool heat treatment (~162 ka)—a complex chain technology that requires language for high fidelity transmission—and the origin of microlithic technology at ~71 ka. Rarely found before 40 ka, microlithic technology, dominated by the production of small bladelets (microliths) primarily from heat-treated stone, is widely believed to have been used to create composite tool components as part of advanced projectile weapons (atlatls and bows). These results demonstrate continuity of this technology over 11,000 years from ~71 to 60 ka.
A fundamental component of the effort to understand the origins of human uniqueness is conducting the fieldwork that allows accurate placement of new evidence on the timeline and to integrate these findings with ideas about cultural evolution from the study of modern traditional societies. To that end we propose to expand our fieldwork at Pinnacle Point, and initiate new fieldwork at two strategically placed localities, Knysna and Pondoland, where we have identified sites of outstanding potential, under the direction of two project collaborators (Cleghorn and Fisher, respectively). These sites, given their environmental differences and similarities to Pinnacle Point, will allow testing of the idea that coastlines formed refugia during glacial maxima, and create a deeper understanding of the significance of coastal adaptations to the expression of modern human behavioral complexity.
IHO-led research in South Africa has focused on the Pinnacle Point locality, specifically the sites PP13B and PP5-6. Together, these two sites provide the longest continuous sequence (160-90 ka at PP13B, and 90 to 50 ka at PP5-6) for modern human origins study of any locality yet discovered in Africa. Pinnacle Point documents the earliest evidence for coastal adaptations, as well as continuous shifts in reaction to environmental changes over that prolonged period of time. During marine isotope stage 6 (MIS6; 195-125 ka), the genetic record shows that human populations were tiny and the archaeological record is consistent with this. It has been argued that when populations were small they focused their settlement on the coast, following it as its position shifted with changing sea levels. With the beginning of MIS5 at about 125 ka, populations grew but remained focused on the coast. New results from PP5-6 show that with the next glacial at ~74 ka to 60 ka, a completely different pattern is evident –populations enlarge rather than diminish. Abundant sites across the Cape attest to intensified occupation, suggesting that human populations developed a resilience to glacial phases. This is a fascinating result but one that requires a better sample of well-dated and excavated sites to test.
Of the many research problems arising from prior work at Pinnacle Point, several require a geographically broader perspective. First, is the Pinnacle Point pattern an anomaly not represented at other sites? Second, would we see similar temporal patterning in an area with a similar climate, but a very different resource base such as a coastal estuary? And third, if we are correct to hypothesize that people followed the coast when populations were small during MIS6, then we should see continuous coastal occupations at a locality where the sea was never far away. New recently discovered localities allow us to examine these propositions.
The IHO team will conduct field work in two separate regions to probe the consistency of this pattern and study the impacts of coastline distance, varying vegetation, differing climates, and presence and absence of estuaries on the origins and development of key early modern human adaptations, technological complexity, and cognition.
Sites around the modern town of Knysna, located about 80 km east of Pinnacle Point, provide an outstanding test case. It is environmentally different in two key ways. First, backed up on the landward side of the coastal cliffs is a large and rich estuary, the Knysna Lagoon. It is a rich source of fish, birds, and estuary-specific marine life that is absent at Pinnacle Point. Similar to Pinnacle Point, the caves are clustered in the ocean-facing cliffs near mollusk-rich rocky inter-tidal zones, with sandy beaches located within the typical 10 km daily foraging radius of hunter-gatherers. During glacial periods when sea level was significantly lower and the coastline too distant for significant tidal contributions, the Knysna Lagoon would have been totally fresh water and almost certainly a rich inland lake, or perhaps a river valley. Second, the Knysna region’s rich Afro-Montane forest vegetation, so different from the environment of Pinnacle Point, dates back at least to the Pleistocene, and was in evidence even during peak glacials such as the Last Glacial Maximum. Like Pinnacle Point, the coastal platform here is gradual and thus coastline retreat would be fast and dramatic with changing sea levels.
This project will be under the direction of Naomi Cleghorn, assistant professor at the University of Texas at Arlington. With the support of our base at Mossel Bay, Cleghorn has conducted several reconnaissance, survey, and mapping trips to Knysna and developed an excellent relationship with local authorities and stake holders. Cleghorn discovered several large caves in close proximity to the lagoon and coast, and one cave (KEH-1) has a floor at ~+25 masl. This height is crucial as the MIS5e high sea stand at ~120 ka is at +5 masl, and we have determined that sites below +10 masl typically have been washed clean of sediments older than 125 ka. This site has rich MSA deposits with well-preserved hearth features, MSA tools, and fossil fauna. It is an outstanding context to begin to test and fill out the patterns we have identified at Pinnacle Point, and funds from this grant will be used to commence excavations and study. An excavation permit is in hand and excavations will commence in January 2015.
Pondoland provides the opportunity to investigate a region where the coast was never more than 5 km from the caves on the modern coast. The research region is Eastern Pondoland—between the Umzimvubu River at Port St. Johns and the Mtamvuna River, south of Port Edward. It is outside the Cape Floral Region, receiving much higher rainfall and temperatures, nearly 100 percent summer rain compared to the stronger bimodal rainfall of Pinnacle Point and Knysna, with a tropical flora and fauna. The offshore platform is narrow and steep, meaning that the modern coast is close to the warm Agulhas current, there is a much different coastal ecology, and even during maximum sea level lows the coast would have always been within 5 km of the modern coast. If our hypothesis is correct that people targeted the coastal zone for settlement during periods of lowered population density during MIS6, then what we should see in Pondoland is early and constant human occupation from MIS6 through MIS3 with a coastal emphasis. MIS6 sites in Africa are extremely rare and date to the origin point of our lineage—Pondoland provides an outstanding probability of increasing our sample of these very rare sites.
This project will be under the direction of Erich Fisher. Fisher, currently a research professor at ASU, conducted three weeks of intensive survey in 2011 with an NGS/Waitt Foundation grant. His results, just published in the journal Paleoanthropology, highlight the discovery of over two dozen promising open air and cave/rock shelter sites. Funds from awarded in this grant will be used to test excavate some of these sites, and then begin major excavations at the site determined to be most appropriate for this study.