Regional geology of the Dogu’a Tembien massif

The Dogu’a Tembien Massif is located on the western margin of the Mekelle Outlier, a nearly circular hilly area (8000 km2) with an average elevation of ~2000 m (Fig. 2.1) and elevations ranging between 1200 and 2850 m (Fig. 2.1a). The landscape, although deeply incised by rivers, is characterized by four planation surfaces (Palaeozoic, Triassic, Cretaceous, and Tertiary in age) that can be observed in the area northwest of Mekelle. They represent wide surfaces formed during long periods of tectonic quiescence when longstanding erosion shaped a gently rolling landscape down to almost sea level (see chapter 11). This chapter presents the regional geography of Dogu’a Tembien. Most geological formations, as well as planations and later dissection of the massif are detailed in the next chapters.