Rust Family Foundation: Archaeology Grants Program
Excavating the fossil bearing strata at Pniel 6, lower Vaal River, South Africa
Principal Investigator: Michaela Ecker
Postdoctoral Fellow, Department of Anthropology, University of Toronto
The archaeological site of Pniel 6 is located c. 35 km outside of Kimberley, Northern Cape Province, South Africa (fig.1). It is an open-air site on the banks of the Vaal river, a few hundred meters from the remains of the former Berlin Missionary Society Mission Station (established 1845). The site dates to the earliest Middle Stone Age (c.300-100 ka, or thousand years ago), based on stone tool technology and species composition
of the faunal remains. This is the time period of the first
anatomically modern humans in Africa. However, organic preservation is
rare in the arid interior of southern Africa, limiting our knowledge of
the environments these early humans inhabited.Fig.1: Location of Pniel 6 in South Africa. Colored areas show environmental zones.
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Previous Research in the region
In the 1980s and 1990s, Peter Beaumont, then at the McGregor Museum in Kimberley, excavated at Pniel 6 recovering stone artefacts and faunal remains. However, there is little documentation of these excavations, missing photographs, drawings and notes.
2017 Funded Research Project (RFF-2017-33)
Goals:
In 2017, our team undertook a two-week pilot season at Pniel 6. Goals were to establish a modern research excavation, including the creation of a digital grid system at the site for use of a total station, conducting surveys on foot, and excavation of several test areas. All of these goals were achieved. The excavation is conducted with a South African Heritage Resources Agency (SAHRA) permit and in full collaboration with the McGregor Museum in Kimberley.
Methodology:
Eight datum points were established, allowing excavation at Pniel 6 with all trenches and finds recorded in three dimensions through the use of a total station. This also enabled us to create an initial topographic map of the area through transect measurements. Photogrammetry areas were used to record all profiles and surfaces. This, together with the spatial data on artefacts and the distribution of the sedimentological layers, will enables us to investigate site formation processes. Furthermore, the dip and orientation of all artefacts with one clear, long axis was recorded.
Three
areas were excavated (fig,2). Area 1 is adjacent to the old
excavation of Peter Beaumont. This test area was used to investigate
possible connections to the earlier excavation and to explore if there
was any material left. We encountered archaeologically sterile clay,
which was confirmed by several auger test holes in the vicinity. Fig.2: Plan of the Pniel 6 site, showing 2017 datum points and excavation areas.
Area 2 was in a small natural gully abutting the river bank. This provided us with the opportunity to rapidly create a profile. Area 2 yielded very distinct sand and clay layers over a gravel horizon containing artefacts and faunal remains.
Area 3 is set on the slope of a small hill, where artefacts could be seen eroding out onto the surface. This Area revealed a gravel horizon rich in lithic artefacts and well-preserved faunal remains, including complete teeth. As in Area 2, the gravel horizon was 10-15cm thick, slightly sloping, and overlaid sterile clay.
Findings:
We exposed stone tools and associated faunal remains in distinct lenses. All together 317 lithics and 22 faunal fragments were three-dimensionally recorded using the total station. The majority of lithic artefacts are weathered, but not rolled. Main raw material used was andesite, hornfels and chert (fig.3) Both areas include a large percentage of ‘other’ raw material, most of which is derived from river cobbles and spans a variety of fine-grained materials. There is no trend in the dip and orientation of the artefacts which would have suggested sorting through movement.
Lithics are dominated by detached pieces (n=183, flakes, large blades and points), with few cores (n=5), chunks/debitage (n=120) and some broken river cobbles. Further analysis is under way. Faunal remains and lithics are clearly associated and spread evenly throughout the find horizon. All excavated buckets were sieved and the remaining residue sorted by hand. This added 147 lithics and 27 faunal remains to the assemblage.
Fig.3: Lithic artifacts and faunal remains from 2017 testing (a: point, b: point; c: blade; d: bovid tooth; e: flake fragment; f: core; g: point).
In general, the description of the stratigraphy by previous excavators of grey and beige silts overlying andesite clasts in a sand-grit matrix with abundant lithic artefacts and faunal remains was confirmed. To answer remaining questions concerning the vertical and horizontal extent of the layers, the nature of the layers of pure sand we discovered, and the nature of deposition, a river geomorphologist will be consulted. Sediment samples were taken from all levels and shipped to Canada for further analysis. Further post-excavation work included washing of all lithic artefacts, entering of lithic and faunal descriptions and measurements into the site database, as well as taking photographs of artefacts. All finds were archived in the McGregor museum, Kimberley.
There are currently no absolute dates available for the site, and our exposure in the pilot was not deep enough below the surface for OSL sampling. An extended field season in 2018 will enable us to open deeper trenches and to have an OSL specialist assess the sampling strategy on site.
We conducted a one-day foot survey, walking in lines from Pniel 6 along the river bend to Pniel 1, which marks the property boundary to the neighboring farm. Additionally, we walked a transect from Pniel 6 inland to the old Pniel mission station. In both surveys, all occurrences of lithics or faunal remains on the surface were documented with photos, descriptions and GPS coordinates. Auger holes were sunk in the most promising sites. This survey revealed several gravel horizons, helped us in our understanding of the landscape, and to plan for future field seasons.
Conclusions:
We confirmed the appearance of Early Middle Stone Age lithic artefacts associated with preserved fauna in discrete lenses at Pniel 6. This makes Pniel a rare site because of its organic preservation in an open-air context in the arid interior of southern Africa.
The 2017 season will serve as a starting point to a long-term project at Pniel, which will include extended excavations and environmental analysis to reconstruct the landscape of the earliest modern humans in southern Africa and their use of the local resources. Our long-term research objectives going forward are to focus on landscape use of hominids during the Mid-Pleistocene at the lower Vaal river. After establishing the depositional nature and analysis of the lithic industry the focus will move to environmental reconstruction, using stable isotope analysis on the recovered faunal remains as well as phytolith analysis to create a terrestrial proxy record.
References:
Updates on the Pniel project will be periodically posted on the homepage of the Principal Investigator:
michaelasecker.com
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