TY - JOUR
T1 - High-resolution sedimentary record of the last deglaciation from a high-altitude lake in Ethiopia
AU - Tiercelin, J. -J.
AU - Gibert, E.
AU - Umer, M.
AU - Bonnefille, R.
AU - Disnar, J. -R.
AU - Lézine, A.-M.
AU - Hureau-Mazaudier, D.
AU - Travi, Y.
AU - Keravis, D.
AU - Lamb, H. F.
N1 - Funding Information:
This research was conducted as part of the ERICA (Environmental Research for Intertropical Climate in Africa) Project initiated by R. Bonnefille. The coring operation (MUM, DH, JJT) and laboratory analyses were funded by the INSU-CNRS “Corne de l’Afrique” Program. The Earth Sciences Department of the Addis Ababa University, the Cultural and Scientific Service of the French Embassy in Ethiopia and the Bale Mountains National Park provided facilities and field assistance. Special thanks are due to INSU-CNRS for having supported MUM as Research Associate at UMR CNRS/UBO 6538 “Domaines Océaniques”, Institut Universitaire Européen de la Mer (IUEM), Plouzané, France. The authors would like to thank Welde Selassie Gebrehiwot and Hailu Dibabe from Addis Ababa University and the guide Hajii from Bale Mountains National Park for their invaluable help when coring in the field. Special acknowledgements are also due to J. Cotten for geochemical analyses, D. Williamson for discussion on magnetic susceptibility data, M. Benoit and P. Huntsman-Mapila for interpretation of geochemical data and the reviewers for their constructive comments.
PY - 2008/3/1
Y1 - 2008/3/1
N2 - Sedimentological and geochemical studies conducted on a 15.82-m long core collected from Lake Garba Guracha (Ethiopia) associated with a precise AMS-14C time-scale document a unique record of the sedimentary processes linked to the progressive retreat of a high-altitude glacier in the Bale Mountains since 17,000 yr cal BP. Lake sedimentation is interpreted as the result of discharges of meltwater and glaciogenic sediment which progressively filled the accommodation space generated by glacier retreat within the basin. Monogenic sediment originated from glacial erosion of the trachytic tuff forming the cirque floor. Ice melting ended progressively between 12,600 and 11,800 cal BP, as suggested by the decrease in sedimentation energy followed by a sharp change in sedimentary facies. From 11,800 cal BP, the lake reached its maximum development and clastic input was replaced by organic-rich sedimentation. This relates to a major increase of lake productivity, which lasted up to 4500 cal BP. From this period, a lowering in productivity reflects the widespread dryness which occurred throughout the East African tropics.
AB - Sedimentological and geochemical studies conducted on a 15.82-m long core collected from Lake Garba Guracha (Ethiopia) associated with a precise AMS-14C time-scale document a unique record of the sedimentary processes linked to the progressive retreat of a high-altitude glacier in the Bale Mountains since 17,000 yr cal BP. Lake sedimentation is interpreted as the result of discharges of meltwater and glaciogenic sediment which progressively filled the accommodation space generated by glacier retreat within the basin. Monogenic sediment originated from glacial erosion of the trachytic tuff forming the cirque floor. Ice melting ended progressively between 12,600 and 11,800 cal BP, as suggested by the decrease in sedimentation energy followed by a sharp change in sedimentary facies. From 11,800 cal BP, the lake reached its maximum development and clastic input was replaced by organic-rich sedimentation. This relates to a major increase of lake productivity, which lasted up to 4500 cal BP. From this period, a lowering in productivity reflects the widespread dryness which occurred throughout the East African tropics.
UR - http://www.scopus.com/inward/record.url?scp=40849106664&partnerID=8YFLogxK
UR - http://hdl.handle.net/2160/6114
U2 - 10.1016/j.quascirev.2007.11.002
DO - 10.1016/j.quascirev.2007.11.002
M3 - Article
SN - 0277-3791
VL - 27
SP - 449
EP - 467
JO - Quaternary Science Reviews
JF - Quaternary Science Reviews
IS - 5-6
ER -