Raw material quality and Oldowan hominin toolstone preferences: evidence from Kanjera South, Kenya David R. Braun a, * , Thomas Plummer b , Joseph V. Ferraro c , Peter Ditchfield d , Laura C. Bishop e a Department of Archaeology, University of Cape Town, Rondebosch 7701, Western Cape, South Africa b Department of Anthropology, Queens College, CUNY & NYCEP, 65-30 Kissena Boulevard, Flushing, NY 11367, USA c Department of Anthropology, Baylor University, One Bear Place #97173, Waco, TX 76798-7173, USA d Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford OX1 3QY, UK e Research Centre in Evolutionary Anthropology and Palaeoecology, School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool L3 3AF, UK article info Article history: Received 26 November 2008 Received in revised form 12 March 2009 Accepted 13 March 2009 Keywords: Oldowan Stone tools Transport Raw material quality Geoarchaeology Lithic technology abstract The role of raw material quality in Oldowan technology has not been fully explored. There are numerous studies suggesting Oldowan hominins preferred certain types of stone for artifact manufacture. Previous studies of the artifact assemblage from the early Pliocene Oldowan locality of Kanjera South (South Rachuonyo District, Kenya) show that raw material selection and transport was an important aspect of Late Pliocene hominin adaptations. Yet the exact properties of stones that hominins were selecting remain enigmatic. Two potentially important features of artifact raw material are durability and fracture predictability. We investigate fracture predictability through mechanical tests of stone and investigations of the affect of stone properties on fracture patterns in archaeological collections. We investigate stone durability with actualistic studies of edge attrition combined with further mechanical tests of various lithologies. Oldowan hominins at Kanjera appear to have selected raw materials based on their durability. The ability for a stone to fracture consistently does not appear to be as important in hominin toolstone preference as previously assumed. Hominins that produced the assemblages at Kanjera South appear to have incorporated an extensive understanding of various attributes of raw material in the transport and production of stone artifacts. When combined with previous research on the transport patterns at Kanjera, the results of this study provide evidence for a more complex raw material acquisition strategy than has previously been suggested for Late Pliocene Oldowan hominins. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction Early in the investigation of Oldowan hominin behavior, Isaac (1972) recognized that, despite the clear connection between the physical properties of stone and Oldowan hominin technology, there were surprisingly few formal systematic or experimental attempts to explain technological variation with this approach. More than 35 years later, the application of stone properties has yet to be fully explored in discussions of Oldowan technology (Braun, 2006; Harmand, 2004; Stout et al., 2005). Many archaeologists agree that raw material quality imposes serious technological constraints on artifact production and use (Andrefsky, 1994; Crabtree, 1967; Inizan et al., 1992; Kuhn, 1995, 1992; Luedtke, 1992; Roth and Dibble, 1998). It is assumed that the ability for a rock to fracture predictably will hamper the consistent production of large flake elements (Brantingham et al., 2000). In Middle and Late Pleistocene technological adaptations, raw mate- rial quality is a major factor in the organization of flaked stone industries (Andrefsky, 1994; Brantingham et al., 2000; Luedtke, 1992; Meignen and Bar-Yosef, 1988; Orton, 2008; Schiffer, 1979; Tavoso, 1984). Where significant variability in raw material quality exists, measures of the intensity of utilization (Geneste, 1985, 1988; Hiscock, 1981; Hiscock and Clarkson, 2005; Holdaway et al., 2008), and degree of raw material transport (Beck and Jones, 1990; Beck et al., 2002; Kuhn, 1991), track this variability. The affect of raw material quality variation on artifact morphology may be muted by the availability of suitable stone for artifact manufacture (Roth and Dibble, 1998). In contrast to the extensive literature on the inter- action between raw material quality and technological strategies in the Middle and Late Pleistocene, little is known about how (or if) lithic material properties influenced Oldowan hominin toolstone preference (but see Stout et al., 2005). Although Oldowan technology is often seen as a ‘‘least effort solution’’ to producing sharp edges (Isaac and Harris, 1997), it is * Corresponding author. Tel.: þ27 21 650 2350; fax: þ27 21 650 2352. E-mail address: david.braun@uct.ac.za (D.R. Braun). Contents lists available at ScienceDirect Journal of Archaeological Science journal homepage: http://www.elsevier.com/locate/jas 0305-4403/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.jas.2009.03.025 Journal of Archaeological Science 36 (2009) 1605–1614