Abstract:
The lakes of the eastern Africa Rift often contain great thicknesses of sediment that may provide
continuous records of environmental change over decadal to million-year timescales. However interpretation
of these changes is greatly compromised without a reliable chronology. Luminescence dating
has not been used extensively in lacustrine settings; instead previous studies have often relied upon
radiocarbon dating, using extrapolation beyond the upper limit of that technique, and employing
opportunistic sampling of tephra and palaeomagnetic signatures where possible. This study from Lake
Tana, Ethiopia, demonstrates that recent advances in luminescence methodology can provide long
chronologies for lake sediments that are not dependent on the intermittent presence of dateable material,
as is the case for radiocarbon and tephra-based methods. Specifically, this study generates luminescence
ages that agree with independent chronology based on radiocarbon dating in the upper part of
the core, and extends significantly beyond the range of radiocarbon dating to provide one of the longest
independently dated lacustrine sediment records in eastern Africa, thus demonstrating the tremendous
potential of luminescence for constructing lacustrine sediment chronologies over 100,000 year
timescales.
