Sedges as bedding in Middle Stone Age Sibudu

[摘要] Cyperaceae (sedge) nutlets dominate the archaeobotanical assemblage of fruits andseeds recovered from the Middle Stone Age deposits at the rock shelter Sibudu,KwaZulu-Natal, South Africa (Sievers 2006). My aim is to investigate theimplications of the nutlet presence in terms of human behaviour and to demonstratethat the nutlets were likely brought into the shelter on sedge culms (stems)deliberately harvested by people and informally placed on the shelter floor toprovide 'bedding”, a surface for working, resting or sleeping. I use variousempirical and experimental approaches to confirm the use of sedges for bedding atSibudu as early as ~77 000 years ago, almost 50 000 years earlier than anypreviously identified archaeological bedding. The bedding consists of the sedgesCladium mariscus subsp. jamaicense, Scleria natalensis, S. melanomphala, Cyperussp. and a panicoid grass, identified through Scanning Electron MicroscopyTo investigate repeated and deliberate burning of bedding at Sibudu, I useexperimental micromorphology and I compare the signatures of the Sibudusediments with burned fresh sedge and grass bedding. I undertake further fireexperiments, also in open air situations, to answer questions about burning sedgebeds and the taphonomic implications. Experimental sedge bedding fires are hot andbrief. The matrix beneath the fires affects the temperatures achieved both on thesurface directly under the fire, and at depths of 2 cm and 5 cm below the surface; anash matrix conducts heat more effectively than a matrix of 1–2 mm sized particlesand allows for carbonisation of buried nutlets. The burning of dry and green beddingindicates that once the bedding is burning, the temperatures are sufficient tocarbonise sedge nutlets below both dry and moist bedding.The methodological innovations I introduce are the use of experimentalmicromorphology to address an archaeobotanical question and the use of GIS-basedcoexistence analysis of southern African archaeobotanical data to makeinterpretations about past climate. The analysis develops previous palaeovegetationresearch in the area (Sievers 2006; Wadley et al. 2008) and provides anenvironmental context for people/plant activities at Sibudu.

[发布机构] University of the Witwatersrand