Planation surfaces in Northern Ethiopia

摘要: Abstract Planation surfaces are an old-fashioned topic in geomorphology, but they nevertheless important where make up much of the landscape. Northern Ethiopia is largely a stepped topography, caused by differential erosion. Exhumation old planation that were preserved under sedimentary or volcanic cover process landscape evolution. The oldest surface early Palaeozoic age (PS1); second Late Triassic (PS2); and third Early Cretaceous (PS3). Oligocene Trap Volcanics buried (PS4) Tertiary age, which now widely exposed erosion as that, flat enough, exhumed surface. do not relate to supposed Africa-wide pediplain sequence King [King, L.C., 1975. upon highlands. Z. Geomorph. NF 20 (2), 133–148.], either mode formation age. Although region tropical, there scarce evidence deep weathering few indications could be regarded etchplains. These indicate eastern Africa underwent long episodes tectonic quiescence during processes able planate at altitudes too far from sea level. Only after onset rifting processes, uplift became active transformed vast lowland plain into present Ethiopian highlands, exceeding 2500 m a.s.l. Some hypotheses speculations on genesis these considered here.