Tuesday, 24 March 2009

Blombos Cave

Blombos Cave (BBC) is located near Still Bay on the southern Cape coast in South Africa. It is 100m (330ft) from the coast and 35m (115ft) above sea-level. The site was discovered by Christopher Henshilwood in 1991 and has been excavated regularly since.

The site is notable for the discovery of two pieces of ochre, 73,000 years old, engraved with abstract designs; 75,000 year old tick shell (Nassarius kraussianus) beads; 70,000 year old bone tools; and evidence of shellfish collection and possibly fishing 140,000 years ago. All of these are considered to be markers of modern human behaviour, emerging millennia before the so-called “human revolution” 50,000 years ago.

Three MSA phases have been excavated; these are separated from overlaying the LSA by wind-blown sediments. The phases, from top to bottom, are known as M1, M2 and M3. Dating by Optically Stimulated Luminescence (OSL) and Thermoluminescence (TL) methods has yielded dates of c. 73,000 years for the M1 Still Bay phase (oxygen isotope stage OIS-5a/4); c. 77,000 years for the M2 Still Bay phase (OIS-5a); c. 80,000 years for the M2 low density (hiatus) phase (layers CGAA, CGAB, CGAC); and c. 125-140,000 years for the M3 phase (OIS-5e/6). The M1 layer is separated from the more recent LSA deposits by a hiatus layer of sterile aeolian (wind-blown) sand; M2 and M3 are also separated by a hiatus layer. M1 comprises layers CA, CB, CC, CD and CE; M2 comprises CFA, CFB/CFC and CGA; M3 comprises CGB/CH, CI, CJ, CK, CL, CM, CN, CO and CP. These occupation layers are generally less than 10cm thick, suggesting sporadic, brief periods of occupation punctuated by long periods when the cave was not in use (Henshilwood, 2007; Henshilwood et al, 2001; Jacobs et al, 2006; Tribolo et al, 2006).

All three phases of occupation have evidence of extensive exploitation of aquatic resources including large fish, shellfish, seals and dolphins. Land mammals were extensively hunted, with mole-rats making a frequent appearance on the menu (Henshilwood et al, 2001; Henshilwood, 1997).

All three phases have wood-ash scattered indicating regular use of fire for cooking purposes.

Still Bay technology:
Bifacial foliate points associated with the Still Bay tradition were recovered from the M1 and upper M2 phases of Blombos. Earlier phases contain lithic artefacts that do not fit into existing MSA 1 typographic traditions. They represent an earlier phase of the MSA (Henshilwood, 2007, citing Soressi & Henshilwood, 2004, unpublished paper).

Still Bay points are soft hammer worked points, predominantly made on
silcrete. They are typically bifacially retouched, narrowly elliptic to lanceolate shaped tools, with two sharply pointed apices. There is a distinct preference for silcrete as a raw material. Increased use of finer-grained stone, relative to earlier MSA phases, is a characteristic of the Still Bay (Henshilwood et al, 2001). The small, highly-standardised bifacial Still Bay stone points are a marker of behavioural change (Klein, 1999).

Bone tools:
Bone tools are known from the M1 and upper M2 phases, corresponding to the Still Bay complex. The tools include points and awls. The majority are shaped on bone fragments or splinters removed from long bone shafts although in some cases the whole bone is shaped. Bovid bone is most widely used but marine mammal bone and a single bird bone were also employed.

Morphology and use-wear patterns suggest most MSA bone tools (85%) were used to perforate fairly soft material such as well-worked hides, possibly during the manufacture of clothing and other items, probably being used as awls. However three artefacts have been interpreted as projectile points, being visually similar to bone projectile points from various LSA and ethnographic collections. These are symmetrical both at the tip and in overall shape, are worked on the entire surface and tend strongly toward a circular cross-section. In contrast, awls are often asymmetrical in shape, may be incompletely worked and mostly have an elliptical cross-section. Blombos cave bone tools interpreted as awls conform to their LSA counterparts. One of the putative projectile points shows signs of hafting; probably all three were.

MSA bone tools at Blombos Cave were extensively used after manufacture, in many cases re-used even after tip breakage, suggesting that tools were maintained at the site. Tools were probably discarded when the breakage occurred nearer the midpoint, rather than the tip, making the tool too small to hold for further use. Projectile points were probably discarded when they broke in the haft.

One question is that if the people of the African MSA possessed the cognitive ability to make bone tools, why have so few been found in the archaeological record in comparison to Upper Palaeolithic Europe? One possibility is that MSA people only worked bone infrequently. African hardwoods are also suitable for the manufacture of tools such as awls and points, are easier to work than bone and may thus have been used in preference. Wood is rarely preserved in MSA sites, so such tools would be absent from the archaeological record. Another possibility is that bone tools in the MSA may have served specific, time limited functions within small populations that were relatively isolated, in contrast to the demographic picture the Upper Palaeolithic in Europe.

Bone tool use in Africa may have been the exception rather than the rule and purely practical considerations may also be a factor. Though generally bone fares better than wood, taphonomic factors do still dictate against its preservation at many MSA sites. In addition, many MSA sites were excavated before modern recovery techniques became available and much evidence may have been lost.

There is currently a lack of consensus on the evolutionary significance of bone tool technology. It is not known why humans began to produce bone tools or the incidence and consequence of their manufacture in and use in prehistoric societies. Consequently we do not know whether bone tool technology represents one attribute of cultural modernity or that it results from punctuated cultural adaptations that have little evolutionary significance. The association of formal or elaborate bone artefacts and the Upper Palaeolithic in Europe has been used to argue that bone technology is allied with cultural modernity, anatomically modern humans and a package of other euro-centrically derived modern cultural behaviours, but what is observed in one region does not necessarily constitute a general paradigm

Bone tools from Blombos cave may also reflect symbolic behaviour. The techniques used to manufacture objects in many societies are more often a reflection of their symbolic rather than utilitarian function. The careful deliberate polishing of the Blombos MSA bone artefacts interpreted as projectile points has no apparent function and seems to be a technique used to give a distinctive appearance and/or an ‘‘added value’’ to this category of artefacts.

In contemporary hunter-gatherer societies a consequence of the symbolic value of hunting weapons is that they are produced and handled solely by men. The differences in the manufacturing techniques between the projectile points used for hunting and awls used domestically may well reflect the different symbolic functions of these activities; differences that must have been linguistically transmitted (Henshilwood, 2007; Henshilwood et al, 2001).

More than 2000 pieces of ochre have been recovered from the M1 and M2 phases. Two pieces (AA 8937 and AA 8938) from the M1 phase have been unequivocally engraved. Both pieces have a cross-hatched pattern. On AA 8938 this is bounded top and bottom by parallel lines, with a third parallel line running through the middle. The choice of raw material, the situation and preparation of the engraved surface, engraving techniques and final design for both pieces are similar, indicating a deliberate sequence of choices and intent. They are not isolated occurrences or the result of idiosyncratic behaviour (Henshilwood, 2007). Fully syntactical language is arguably an essential requisite to share and transmit the symbolic meaning of beadworks and abstract engravings such as those from Blombos Cave (Henshilwood et al, 2004).

More than 65 “tick” shell (Nassarius kraussianus) beads have been recovered from the MSA levels at Blombos Cave. These shells occur only in estuaries and were probably brought to the site from the Duiwenhoks and Goukou rivers, located around 20km from the cave. This distance rules out the shell having been deposited at the cave by non-human predators. While it is possible that the tick shells were collected as food, the time taken to extract the modest quantities of nutrient available per shell makes this unlikely given the availability of larger shellfish and fish.

All the shells are adult, indicating deliberate selection for size, and arguing again against their presence being the result of non-human agency. All are perforated dorsally with 88 percent having a medium sized perforation near the lip, confirming the perforations to be man-made and deliberate rather than the result of some natural process. A sharp tool, elliptical in section, was most likely used to make the perforations.

The beads show signs of wear from threading with cord or gut and contact with human skin, suggesting they were worn as bracelets or necklaces for a considerable period of time. Traces of ochre suggest possible colouring of beads, though it could also have come from body-paint. Beads were found in groups displaying similar size, colour, perforation type and use-wear pattern, suggesting such groups represented single beadwork items. Wearing of personal ornaments implies a comprehension of self-awareness or self-recognition. As with the engraved ochre, the existence of syntactic language is arguably implied (Henshilwood et al, 2004; d’Errico et al, 2005; Henshilwood, 2007).


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Francesco d’Errico, Christopher Henshilwood, Marian Vanhaerend, Karen van Niekerke (2005): Nassarius kraussianus shell beads from Blombos Cave: evidence for symbolic behaviour in the Middle Stone Age, Journal of Human Evolution 48 (2005) 3-24.

Frederick E. Grine, Christopher S. Henshilwood and Judith C. Sealy (2000): Human remains from Blombos Cave, South Africa: (1997–1998 excavations), Journal of Human Evolution (2000) 38, 755–765.

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C. S. Henshilwood (1997): Identifying the Collector: Evidence for Human Processing of the Cape Dune Mole-Rat, Bathyergus suillus, from Blombos Cave, Southern Cape, South Africa, Journal of Archaeological Science (1997) 24, 659–662.

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Christopher S. Henshilwood, Francesco d’Errico, Curtis W. Marean, Richard G. Milo, Royden Yates (2001): An early bone tool industry from the Middle Stone Age at Blombos Cave, South Africa: implications for the origins of modern human behaviour, symbolism and language, Journal of Human Evolution (2001) 41, 631–678.

Christopher S. Henshilwood, Francesco d’Errico, Royden Yates, Zenobia Jacobs, Chantal Tribolo, Geoff A. T. Duller, Norbert Mercier, Judith C. Sealy, Helene Valladas, Ian Watts, Ann G. Wintle (2002): Emergence of Modern Human Behavior: Middle Stone Age Engravings from South Africa, Science 295, 1278 (2002).

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Zenobia Jacobs, Geoffrey A.T. Duller, Ann G. Wintle, Christopher S. Henshilwood (2006): Extending the chronology of deposits at Blombos Cave, South Africa, back to 140 ka using optical dating of single and multiple grains of quartz, Journal of Human Evolution 51 (2006) 255-273.

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C. Tribolo, N. Mercier, M. Selo, H. Valladas, J.-L. Joron, J.-L. Reyss, C. Henshilwood, J. Sealy and R. Yates (2006): TL dating of burnt lithics from Blombos Cave (South Africa): further evidence for the antiquity of modern human behaviour, Archaeometry 48, 2 (2006) 341–357.

© Christopher Seddon 2009

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