New research on the Holocene settlement and environment of the Chad Basin in Nigeria

Three sites in northeast Nigeria carry Breunig, Neumann and Van Neer's account of Holocene settlement and environmental change in the Chad Basin. Dufuna provides evidence of early water transport, Konduga of pottery production before food production, and Gajiganna A and B of village settlement, domestic animals and local environments. The sites belong to a longer-term research project that combines excavation with archaeobotanical and archaeozoological study.

The evidence

At Dufuna a dugout lay in deposits of clay and sand with no associated archaeological finds. Two radiocarbon dates are given for the boat, together with its dimensions, wood species, likely tools and setting near the Komadugu Gana and Mega-Chad (pp. 116–117).

At Konduga, surveys and excavation in a sand quarry on the Bama Ridge recovered pottery, charcoal and a small assemblage. Sherd condition and decoration are assessed, charcoal identifications serve to reconstruct local vegetation, and a discrepancy between radiocarbon and thermoluminescence dates for the pottery is noted (pp. 119–121).

Excavations in two mounds at Gajiganna produced pollen, charcoal, animal bones, pottery, stone and bone artefacts, and human burials. Radiocarbon dates distinguish upper and lower cultural layers. The faunal study covers aquatic species, wild animals and domesticates, and the charcoal and pollen inform the reconstruction of vegetation and water conditions (pp. 124–128, 131, 135, 140–141).

The argument

Breunig, Neumann and Van Neer argue that the Dufuna boat and the Konduga pottery push evidence of human activity in the region beyond the previously recognised 3000 B.P. threshold. Water transport and the former Mega-Chad shoreline, they propose, supported movement along the southern margin of the Sahara.

They describe the Dufuna canoe as among the oldest known boats in the world and suggest that it indicates water transport in the early and middle Holocene, when the nearby lake and flooded areas could have supported fishing and movement. The Konduga assemblage is presented as evidence for pottery-making around 5500–5000 BC, before firm evidence for food production in the region, and its position on the Bama Ridge gives a direct date for the former shoreline. The Saharan-style decoration and the charcoal are read as pointing to a wooded environment at the site (pp. 116–120).

Gajiganna they interpret as part of a broad colonisation of land exposed by retreating lake waters, with domestic animals present from the earliest documented village phase. Cattle are the most numerous domestic animal remains, alongside fish and other aquatic species, wild animals and gathered fruit. Without evidence of crops, the authors propose a pastoral economy using wild plants, and suggest that drying conditions or human effects may have contributed to the abandonment of the settlements (pp. 128, 131–132).

Dating

Radiocarbon dates are presented for all three sites. Dufuna's boat dates to around 6000 BC in the calibrated ranges given, and Konduga's pottery is associated with dates around 5500–5000 BC. At Gajiganna the calibrated dates indicate an upper cultural layer around 1200–900 BC and a lower layer around 1500–1200 BC. The authors also note an earlier settlement phase in the Gajiganna region, around 3700 B.P., outside the excavated assemblages described (pp. 116, 119, 125, 138).