Abstract:
Garba Guracha is a cirque lake located at 3950 m altitude in the Bale Mountains National Park, Ethiopia, at the boundary between the Afro-alpine and sub-alpine Ericaceous vegetation belts. Jean-Jacques Tiercelin and Mohammed Umer cored its sediments in about 2002, leading to publication of one of the longest, best-dated, and most continuous Late Pleistocene-Holocene palaeoenvironmental records from above 3000 m in Africa. Their 2007 and 2008 papers document the vegetation and deglaciation history of the Bale Mountain plateau, which supports the most extensive area of Afro-alpine vegetation on the planet, and an exceptionally rich endemic biodiversity. However, those publications revealed little about human exploitation of the Bale Mountain environment.
We again cored Garba Guracha (‘Black Lake’ in the Oromo language) in February 2017, as part of a major DFG-funded research unit (“The Mountain Exile Hypothesis - How humans benefited from and re-shaped African high altitude ecosystems during Quaternary climate changes”) that aims to test the hypothesis that human settlement of the Bale Mountains dates from at least the late Pleistocene. We also drilled cores from seven other sites in the area in early 2018, in partnership with archaeological, glacial geological and pedological investigations. Here we attempt an early synthesis of the results of ?XRF geochemistry, stable isotope, biomarker, pollen and charcoal analyses of the Garba Guracha sediments with a new age model based on radiocarbon and 210Pb ages, and suggest an initial interpretation of anthropogenic impact on the Bale Mountains.
