VEGETATION HISTORY OF THE SAVANNA CORRIDOR BETWEEN THE GUINEAN AND THE CONGOLIAN RAIN-FOREST DURING THE LAST 150,000 YEARS

Pollen and spores from a deep-sea core located west of the Niger Delta record an uninterrupted area of lowland rain forest in West Africa fr om Guinea to Cameroon during the last Interglacial and the early Holoc ene. During other: periods of the last 150 ka, a savanna corridor betw een the western - Guinean - and the eastern - Congolian - part of the African lowland rain forest existed. This so-called Dahomey Gap had it s largest extension during Glacial Stages 6, 4, 3, and 2. Reduced surf ace salinity in the eastern Gulf of Guinea as recorded by dinoflagella te cysts indicates sufficient precipitation for extensive forest growt h during Stages 5 and 1. The large modern extension of dry forest and savanna in West Africa cannot be solely explained by climatic factors. Mangrove expansion in and west of the Niger Delta was largest during the phases of sea-level rise of Stages 5 and 1. During Stages 6, 4, 3, and 2, shelf areas were exposed and the area of the mangrove swamps w as minimal.