Loess accumulation and soil formation in Kaokoland (Northern Namibia) as indicators of Quaternary climatic change

In the basins and broad valley bottoms located in central and northern Kaokoland, fine-grained sediments have been cut by gullies. They allow insight into the stratigraphical and palaeopedological formation of the Younger Quaternary at the zone of transition between the Namib desert and the savanna. After fieldwork and laboratory analysis, it is possible to distinguish between poorly sorted aeolian deposits at the hanging wall of fluviatile series, and well sorted desert margin loess near Opuwo. On top of the poorly sorted aeolian sediments, a cambic aridisol with a mighty Cca horizon containing numerous calcite nodules developed, presumably during the transition period between the Middle and Younger Holocene, and was finally covered by desert margin loess. A relatively humid period during the Younger Holocene is documented by another brown soil, which has developed on top of younger aeolian sediments and is itself covered beneath recent sands in the basin of Omungunda. The intercalation of soils in finely elastic aeolian deposits do express climatic oscillations with characterizing impacts on the landscape, and a connected shift of the desert margin. (C) 2000 Elsevier Science B.V. All rights reserved.