Pastoral Neolithic 'pillar sites' of northwestern Kenya

In northwestern Kenya, at least seven megalithic monumental sites lie near the palaeoshores of Lake Turkana. 'Pillar sites', as they are called by archaeologists, are distinguished by columnar basalt of up to 2 m in height, or smaller sandstone pieces, set in constructed platforms of up to 30 m in diameter. Some sites have additional cairns and stone circles. Recent research by the Later Prehistory of West Turkana (LPWT) research team has clarified the chronology of and contexts for the creation of the pillar sites. Pillar site construction and use began ca. 5000-4000 years ago when the first pastoralists in eastern Africa arrived in northwest Kenya, a landscape already home to hunter/gatherer/fisher communities. At this time, Lake Turkana was shrinking dramatically as the African Humid Period came to an end. Most of the pillar sites served as cemeteries: excavations at Lothagam North pillar site, for example, have revealed a mortuary cavity of more than 100 m² containing an estimated minimum of 580 burials. In this chapter, we synthesize research on all known pillar sites around Lake Turkana, with special attention to the sites that the LPWT team has studied on the western side of the lake. We explore the implications of new dates for longstanding debates about the possible archaeoastronomical significance of the sites and renew discussion about the pillars themselves. We review the location of pillar sources, the transport necessary to move them from source to installation, and the implications of their spatial distribution within the sites. We also review possible regional antecedents to and descendents of this tradition and observe that megalithism in northwest Kenya was an isolated phenomenon in both time and space. Why did ancient pastoralists construct these sites? We have previously argued that building the pillar sites may have served to create socially symbolic, fixed landmarks for herders in a dynamic physical landscape. Processes of construction and use may likewise have helped to solidify social networks at a time of dramatic environmental and social change. We also discuss other possibilities, and emphasize that interpretations of monumentality within mobile pastoralist societies must depend on contextualizing local and regional data rather than on recycling models developed elsewhere for settled agriculturalist peoples.