The bipolar technique in southern Africa: a replication experiment

Bipolar flaking is a technique with a long ancestry, widely distributed across southern Africa. Artefacts of bipolar origin occur in assemblages from the Upper Pleistocene through the Holocene andfrom the southern Cape to eastern Zaire, but the bipolar technique and the conditions under which it occurs remain largely unexamined in southern Africa. This paper presents the results of an experiment designed to replicate the stages of bipolar reduction and to determine the factors which favour the use of this technique. The replication experiment produced a distinct set of debitage and the results suggest that bipolarflaking is a response to constraints posed by raw material texture, morphology and availability. * Received December 1986 Introduction Artefacts showing evidence of bipolar flaking have been reported in Middle Stone Age assemblages (e.g. Mehlman 1976; Beaumont 1978) as well as from numerous Later Stone Age sites in southern Africa (e.g. Clark 1950, 1958; Schoute-Vanneck & Walsh 1961; Miller 1969; Van Noten 1971, 1977; Sampson 1974; Davies 1975; H. J. Deacon 1976, 1978; Phillipson 1976, 1977; J. Deacon 1978, 1982, 1984a, b; Beaumont 1981; Thackeray 1981; Schweitzer & Wilson 1982; Musonda 1984; Parkington 1984 Walker & Wadley 1984; Peters 1985). These artefacts are generally classified as pieces esquill~es, outils ecailles and core reduced pieces. All three types are morphologically similar being quadrilateral in plan view, and lenticular in profile with opposed striking platforms that are chisel-like in profile. Bifacial flake removal is also a common feature. The distinctions between these types are usually based on differences of edge morphology and assumed function. Pieces esquillres are identified by the presence of secondary crushing, possibly due to use, on their slightly curved striking platforms (J. Deacon 1982, 1984a). Outils 6cailles, in contrast, derive their straight chisel-like edge from deliberate flaking rather than from use (Thackeray 1981). Core reduced pieces are simply exhausted cores with straight chisel-like striking platforms which show little secondary crushing (J. Deacon 1982, 1984a). The present study results from difficulties in applying these distinctions to the analysis of Holocene assemblages from Siphiso (Mlawula) rock shelter in eastern Swaziland (Fig. 1). Pieces esquillees, outils ecailles and core reduced pieces occur at Siphiso along with intermediate forms characterized by a mixture of edge attributes. The latter forms are difficult to classify in terms of edge morphology. A single piece may have one curved platform with secondary crushing in opposition to another which is straight with little crushing. Is this a partial piece esquillee, a used outil ecaill6 or a used core reduced piece? The general morphological similarity between the intermediate and standard forms suggets a common technological origin. The replication experiment was designed to examine the possibility that pieces esquillees, outils ecailles, core reduced pieces and intermediate forms are all the products of bipolar flaking.