14 
PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 65, Supplement II 
Luanda Norte, Lunda Sul and the northern parts of Moxico, is drained by the Casai-Congo Basin, 
the eentral areas of the Angola, and especially the east and southeast, are drained by the Zambezi, 
Cuando, Cuito, and Cubango rivers. The Cuvelai-Etosha Basin extends from northern Namibia to 
parts of Cunene and Huila provinces, whereas the Kunene Basin dominates most of Huila Province 
with the main river bordering Namibia along the southern edges of Namibe and Cunene provinces. 
Finally, the Kwanza, an exclusively Angolan river, starts in Bie and makes a turn to the west in 
Malanje Province, passing through Kwanza Norte, Kwanza Sul, Bengo and Luanda provinces 
where it meets the sea. A large part of the west coast of Angola, including the provinces of Zaire, 
Bengo, Luanda, Kwanza Sul, Benguela, Namibe and Huila, is drained by smaller, sometimes inter¬ 
mittent, coastal rivers. 
Geology.— Angolan geological history is complex, shaped by different events, with rocks 
from different geological eras scattered across the country, and a considerable diversity of soils 
(Schluter 2006). While a large part of the metamorphic rocks of the country derive from the Congo- 
Kasai Craton, there is a considerable diversity of more recent sedimentary and igneous rocks 
(Schluter 2006). Coastal areas of Angola are divided by three main basins: the Congo, the Kwan¬ 
za and the Namib marine coastal basins. These first developed during the Lower Cretaceous and 
are dominated by sedimentary rocks (both carbonate and non-carbonate) with some areas of sand¬ 
stone and limestone sands in the southwest (Namibe Province), as well as some alluvial sands, such 
as those at the mouth of the Congo River at the northwestern border of the country (Schluter 2006; 
Fig. 4). Sedimentary rocks dominate almost all of eastern Angola, which is largely covered by 
sands and related Aeolian sediments of the Kalahari Group (Schluter 2006). The main river basins 
and depressions contain alluvial and colluvial deposits in the form of sands, clays, rubbles and 
gravels, with the exception of the Cuvelai Basin, which contains saline soils (Schluter 2006; Fig. 
4). The more central areas of the country are characterized by a mix of metasedimentary, magmat¬ 
ic, to metamorphic (metaigneous) rocks (Schluter 2006). The Bie Escarpment area is dominated by 
silica rich soils, originating from volcanic activity, while some intrusive volcanic rocks occur in 
Huila, Cunene, and Moxico (Schluter 2006; Fig. 4). A considerable area of the escarpment border 
is limited by metaigneous rocks, possibly from the old Congo-Kasai Craton, which are also pres¬ 
ent in some areas in the northeast of the country (Lunda Sul and Lunda Norte provinces; Schluter 
2006; Fig. 4). 
Climate.— Most of Angola lies wit hin the zone of intertropical trade winds and has a hot wet 
summer and a warm dry winter (Huntley 1974). The local climates within Angola reflect combi¬ 
nations of elevation, latitude, and distance to the coast. Generally, the coastal and southern areas of 
the country are hotter (although coastal areas in the Namib are cooler than those further north) 
whereas temperature tends to diminish with higher latitude and elevation, and especially at higher 
elevations in the central area of the country (Fig. 5). The variation of mean monthly temperatures 
is more extreme in the southeast and less pronounced in the north and northeast (Huntley 1974). 
Annual rainfall in Angola increases in a roughly southwest to northeast direction, with coastal 
areas south of Mo 9 amedes City, Namibe Province) being extremely dry and most central/northeast 
areas of the country, as well as Cabinda, having an annual rainfall of 1200-1400 mm (Fig. 6). Most 
of the southern and coastal areas have a less humid climate (Fig. 6). Rainfall is seasonal through¬ 
out Angola, with the northeast rainy season being from March to May and that of the southwest 
being shorter and occurring some time between December and March (Huntley 1974). The north¬ 
west experiences a short dry period (pequeno cacimbo) in January and February (Huntley 1974). 
Biomes and Vegetation Zones. — Due to its geographic placement, Angola supports a 
considerable diversity of biomes and vegetation types, from more tropical evergreen and semi- 
deciduous rainforests in the north to true desert in the extreme southwest. This enormous habitat 
