Assemblage variability and bifacial points in the lowermost Sibudan layers at Sibudu, South Africa

摘要

Building on the important work of Lyn Wadley at Sibudu, archeologists from the University of Tubingen have excavated the upper stratigraphic units of the Middle Stone Age (MSA) sequence down to the Howiesons Poort (HP). Here, we present the main results from lithic analyses of the lowest part of the Sibudan sequence to assess its overall variability and taxonomic status. Based on the new findings, we also discuss the implications for archeological systematics and the cultural evolution of modern humans in MIS 3 from a more general perspective. The Sibudan deposits encompass over 20 archeological horizons that span a 1.2-m-thick, well-stratified sequence whose base and top have been dated to similar to 58 ka (MIS 3). In contrast to the upper stratigraphic units, the lower Sibudan assemblages that we analyzed here show much higher use of local sandstone, quartz, and quartzite. These older units are characterized by frequent use of expedient core reduction methods, bipolar reduction of locally available quartz and quartzite, less retouch of blanks, and lower find densities. Tongati and Ndwedwe tools, which feature abundantly in the upper part of the Sibudan sequence, are entirely absent, as are unifacial points. Instead, notched and denticulated tools are common. Surprisingly, knappers manufactured small bifacial points, mainly made from quartz, by means of alternating shaping in the course of the oldest occupations. The results highlight the great diversity of human technological behavior over even short periods during the MSA, raising important questions about the mechanisms of behavioral change, cultural taxonomy, appropriate scales of lithic analyses, and the relationship between the HP and the Sibudan. Our findings further erode the old idea that bifacial technology in southern Africa is limited to the Still Bay. Research is increasingly showing that bifacial points come and go in different forms and contexts of African Late Pleistocene technology, impeding their use as chrono-cultural markers.