Geology and Geomorphological Landscapes of Eritrea

The landscape of Eritrea is highly variable and reflects the complex geological history of the area, which is only partially shared with the other regions of the Horn of Africa. The structural geomorphology of Eritrea was investigated through field surveys, literature reviews and a few topographic profiles oriented east–west across the country. The information collected led to the production of a new schematic geological map. The older crustal deformations controlled the orientation of the main fluvial systems, whereas later tectonic events affected their upstream drainage networks. The geological history of Eritrea is very long as it started in the Neoproterozoic, though it was punctuated by a few, more or less long intervals of quiescence. The modern landforms derive from the combined effects of the powerful uplift, to which the whole Horn of Africa was subjected throughout the Cenozoic, and the present arid climate. Fluvial erosion resulted in the accumulation of clastic deposits, a few thousands of meters thick, which gave rise to the coastal belt. In spite of an average denudation rate of 30 mm/ka (a value similar to those inferred for the upper Blue Nile and other areas with a similar structural setting), hard rocks such as the laterites, formed on top of old peneplain surfaces, are still preserved and their present-day elevation along east–west profiles witnesses an impressive upwards dislocation of about 2500 m associated with the impingement of the Afar Plume. In Eritrea, the emplacement of Trap basalts is spatially rather limited, especially if compared with the impressive expansion all across the neighboring Ethiopia. Most of volcanic activity of Eritrea is recent (Quaternary) and associated with the very last phases of the Danakil depression formation. Presently, arid conditions and a volcanic morphology provide the Eritrean Danakil with a unique and fascinating landscape.