OSTRACODE-INFERRED LAKE-LEVEL HISTORY OF LAKE TANGANYIKA, EAST AFRICA, FOR THE PAST 2500 YEARS

Species-abundance data for ostracode assemblages were used to reconstruct lake-level history at decadal to centennial timescales during the late Holocene at Lake Tanganyika, East Africa. The ostracode-based lake-level curves for several sediment cores resemble both each other and the only previously published lake-level record of comparable resolution for Lake Tanganyika during this interval. Collectively, these ostracode-inferred records successfully reconstruct known highstands, improve the chronology of known lowstands, and contribute new information on late Holocene lake-level variability at this important tropical African location. In agreement with other late Holocene records from East Africa, the surface level at Lake Tanganyika reflects predominantly arid conditions throughout this interval, interrupted by relatively brief episodes of higher precipitation and lake level. The most pronounced lowstand in the record occurs at 200–0 BC, with other significant lowstands dating to the intervals 200–500 AD, 700–850 AD, the Medieval Warm Period (1050–1250 AD at Lake Tanganyika), and the latter part of the Little Ice Age (1550–1850 AD). The most important wet intervals in the lake-level record are centered on 500 AD, 1500 AD, and 1870 AD. The highstands and lowstands reported here for Lake Tanganyika appear to be fairly coherent with other records of rainfall throughout East Africa during the Medieval Warm Period and the Little Ice Age. Prior to the Medieval Warm Period, paleoclimate records are apparently less coherent, although this may be a reflection of the resolution and abundance of recent paleoclimatic data available for this climatically complex region.