Veget Hist Archaeobot (2000) 9:239-249 VegetationHistory and Archaeobotany 9Sprmger-Verlag 2000 Pollen analysis of Iron Age cow dung in southern Africa Jos6 S. Carri6n l, Louis Scott 2, Tom Huffman 3 and Cobus Dreyer 4 i Departamento de Biologfa Vegetal, Universidad de Murcia, E-30100 Espinardo, Murcia, Spain 2 Department of Botany and Genetics, University of the Orange Free State. Bloemfontein 9300, South Africa 3 Department of Archaeology, University of the Witwatersrand, Johannesburg, Wits 2150 South Africa 4 National Museum. Bloemfontein 9300. South Africa Received October 27, 1999 / Accepted May 16, 2000 Abstract. Thick accumulations of consolidated cow dung occur in ancient kraals (byres or corrals)in the bushveld and highveld areas of Zimbabwe, Botswana, and South Africa dating from the last 2000 years. They originated from long-term cattle herding by Iron Age people. The "vitrified" or baked dung deposits are thought to be a product of the burning of cow dung as fuel, either for do- mestic purposes or for iron smelting. In order to establish the palaeoecological potential of this material, 36 samples of cow dung from archaeological sites within the present-day savanna and grassland biomes were analyzed for pollen and other microfossils. Of the samples, 29 con- tained pollen together with other microfossils that support a faecal origin of the material such as sordariaeeous ascospores, Thecaphora, Gelasinospora, and Chaeto- mium, and eggs of the intestinal parasite Trichuris. Simi- lar microfossils were also found in recent fresh cow dung from the same study areas. The presence of pollen grains and spores in most of the Iron Age samples lead to the assumption that they survived the burning because fire temperatures were not high enough to destroy them. Pol- len in these cow dung pieces is apparently sealed and can be preserved under open-air'conditions at sites under which pollen in other deposits like soils, will decay away. Good pollen preservation and palynomorph diversity were found with mainly Poaceae, and secondly Chenopo- diaceae and Cyperaceae as the most important pollen types, while trees and shrubs indicating savanna are rare. In the case of the samples that came from the subtropical savanna biome the latter result is unexpected and suggests that the cattle were kept in more open vegetation than the woody environments of today. Recent cow dung samples reflect the composition of present-day vegetation by showing considerably higher proportions of tree pollen than the fossil assemblages. Key words: Palynology - Cow dung - Holocene - Iron Age - Southern Africa Correspondence to: Josd S. Carridn (email: carrion@um.es) Introduction For several decades, archaeologists have attributed a di- versity of solid slag-like materials associated with Iron Age finds in southern Africa to metal smelting slag (Dart 1931), while uncertainty prevailed about their origin. At present, however, there seems to be consensus that the silicon-rich material is the product of the burning of cow dung, a traditional fuel of African people (Dreyer 1997). Although it is possible that the slag-like finds may have formed during iron smelting, most were not formed during this process. Stanley (1934) analyzed the chemical and physical properties of some material and concluded that it could not be metal smelting slag. Friede et al. (1982) sug- gested that these finds should not be attributed to smelting unless they were found in the context of furnaces. EDX (energy dispersive X-ray) analysis of dung material from Winburg, Doornpoort in the Free State, indicated a high silicon content but no sign of smelted metal. The material had probably been derived from organic materials and consisted mainly of silica residues of phytoliths in Iron Age cow dung. Although in some cases they came from ancient kraals', deposits were probably produced in a spe- cial way, that is, as far as we know, not practised on a large scale by traditional communities any more. The first Iron Age settlements south of the river Limpopo in southern Africa arrived before 400 A.D. from north of this river, where their presence was reported sev- eral hundred years earlier (Vogel 1995). The Iron Age set- tlement pattern seems to have been influenced by fluctuat- ing climate cycles as defined by Tyson and Lindesay (1992), and Huffman (1996). Wet, warm periods show an increase in Iron Age activity while cool dry phases like the Little Ice Age (A.D. 1675-1780) show a lack of settle- ment (Table 1). With our aim of finding more direct evi- dence of environmental change during Iron Age times in southern Africa, this paper investigates the palaeoeco- logical potential for pollen analysis of burnt or "vitrified" cow dung from different phases listed in Table 1. To find pollen in dry open-air sites in the corrosive environment of soils is virtually impossible, but burnt or vitrified cow dung pieces can apparently seal their contents from the