| The stratigraphic record of fluvial and infilled valley deposits in the area of Adwa (Northern Ethiopia) allowed the description and identification of three main episodes of soil formation (between ca.50 ka – ca.10 ka yrs BP), related to wetter climatic conditions in the area, which constitute the oldest soil formation episodes described in northern Ethiopia. The oldest soil formation episode ca 50 ka yr BP correlates in time with a high lakes phase further south in the Ethiopian rift area (Abhé II). A second important episode of soil formation took place during the oldest gemorphological and sedimentary record of past active karst processes in the Adwa area, affecting the carbonaceous rock layers of the Tambien formation (Work Amba Surface), ca 30-35 ka yr BP. The preserved record of soil formation phases also register, interbedded, thick coluvial deposits units, corresponding to periods of rapid incision and erosion in the catchment area. |