2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 9
Presentation Time: 10:30 AM

Holocene Floodplain Paleosol Sequences: Natural Versus Anthropogenically Driven Environmental Change in Sub-Saharan Africa

STRONG, Nikki, National Center for Earth-surface Dynamics, Univ of Minnesota, St. Anthony Falls Laboratory, Mississippi River at 3rd Ave SE, Minneapolis, MN 55414, ESHETU, Zewdu, Forestry Research Center, Ethiopian Institute of Agricultural Research, Addis Ababa, 30708, Ethiopia, GEBRU, Tsige, Department of Earth Sciences, Addis Ababa University, Addis Ababa, P.O. Box 343, Ethiopia, WILLENBRING, Jane, Institut für Mineralogie, University of Hanover, Callinstraße 3, Hanover, D-30167, Germany, HUANG, Yongsong, Department of Geological Sciences, Brown University, 324 Brook Street, Providence, RI 02912 and TERWILLIGER, Valery, Faculté des Sciences et Techniques, Université François Rabelais de Tours, Parc Grandmont, Tours, F-37200, France, stro0068@umn.edu

The Northern Highlands of Ethiopia have a long history of human settlement including great migrations, an agricultural origin dating back to at least 7000 yBP, and the rise and collapse of several civilizations – all with incompletely understood links to land use and ecological change. Though the region was once home to a fertile agricultural center, today, the Highlands are highly degraded with frequent famine and some of the highest rates of soil erosion in the world. What happened? To what extent is the highly degraded landscape on which the Ethiopian highland farmers struggle to survive today a result of regional climate change or the land-use practices of past ancient societies? Using a combination of approaches – SOM stable isotope analysis, charcoal identification, soil and rock magnetism, paleo-hydraulic reconstructions based on exposed modern and ancient fluvial systems, digital terrain modeling, and carbon 14 dating, we reconstruct possible scenarios of how paleovegetation type and density, and rates of erosion (and deposition), changed throughout the Holocene in the Ethiopian Highlands in response to changes in climate and land-use.