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B1c. Topography and GeologyA low-lying (0-200 m) undulating coastal belt stretches from Cabinda to the southernborder with Namibia (Exhibit 3). This geomorphic unit, composed of sedimentary rocksand weakly consolidated sediments, ranges in width from 200 km south of Luanda toaround 10 km between Benguela and Namibe. To the east, a deeply incised stripseparates the coastal belt from the interior plateau and mountainous areas. Thistransitional geomorphic unit — etched on schists, arkoses, and quartzites — rangesfrom 200-500 m in altitude and from 60-250 km in width. Geomorphologically, it iscomposed of pediments in the arid south and residual hills and narrow valleys that gainaltitude as one moves inland. In its southern reaches, the transitional belt sportsinselbergs and massifs that tower 1,000 m above the regional base level.Exhibit 3. Topographic map of AngolaAltitude (in meters)0-200 200-500 500-1,000 1,000-1,500 1,500-2,000 |2,000-2,500An elevation bulge between 1,500 and 2,000 m located in the midwestern section of thecountry (Exhibit 3) is known as the “central plateau.” This is a rolling erosional surfaceunderlain mostly by basement complex rocks such as gneiss, granites, and migmatites.Considering southern Africa’s regional hydrology, the central plateau is an extremelyimportant land unit. It hosts the headwaters of the Cunene and Cubango rivers and feedssome of Angola’s principal rivers, such as the Kwanza, Cutato, and Cunhinga. TheCubango is the primary source of water for the Okavango River and its delta inBotswana.A number of important mountains separate the central plateau from the westerly slopingtransitional zone. These elevated points exceed 2,000 m and support afro-montane118/119 BIODIVERSITY AND TROPICAL FOREST ASSESSMENT FOR ANGOLA 7