Angola is located on the western Atlantic Coast of Southern Africa between Namibia and the Republic of the Congo. It also is bordered by the Democratic Republic of the Congo and Zambia to the east. The country consists of a sparsely watered and somewhat sterile coastal plain extending inland for a distance varying from 50 to 160 km (31 to 99 mi). Slightly inland and parallel to the coast is a belt of hills and mountains and behind those a large plateau. The total land size is 1,246,700 km2 (481,400 sq mi). It has an Exclusive Economic Zone of 518,433 km2 (200,168 sq mi).
There are three regions of rock formations in Angola: the littoral zone, the median zone formed by a series of hills more or less parallel with the coast, and the central plateau.[2]
The central plateau consists of ancient crystalline rocks with granites overlain by non-fossiliferoussandstones and conglomerates of Paleozoic age. The outcrops are largely hidden under laterite. The median zone is composed largely of crystalline rocks with granites and some Palaeozoic unfossiliferous rocks. The littoral zone contains the only fossiliferous strata. These are of Tertiary and Cretaceous ages, the latter rocks resting on a reddish sandstone of older date. The Cretaceous rocks of the Dombe Grande region (near Benguela) are of Albian age and belong to the Acanthoceras mamillari zone. The beds containing Schloenbachia inflata are referable to the Gault. Rocks of Tertiary age are met with at Dombe Grande, Moçâmedes and near Luanda. The sandstones with gypsum, copper and sulfur of Dombe are doubtfully considered to be of Triassic age. Recent eruptive rocks, mainly basalts, form a line of hills almost bare of vegetation between Benguela and Moçâmedes. Nepheline basalts and liparites occur at Dombe Grande. The presence of gum copal in considerable quantities in the superficial rocks is characteristic of certain regions.[2]
The geology and outline of the west coast of Angola is related to the opening of South Atlantic that started in the Early Cretaceous and continued until the Eocene, which is reflected in the invertebrate and vertebrate fossil fauna.[3] The diamond mine of Catoca preserved unexpected ancient dinosaur, mammal and crocodylomorph tracks with 128 Million years.[4]
Like the rest of tropical Africa, Angola experiences distinct, alternating rainy and dry seasons. In the north, the rainy season may last for as long as seven months—usually from September to April, with perhaps a brief slackening in January or February. In the south, the rainy season begins later, in November, and lasts until about February. The dry season (cacimbo) is often characterized by a heavy morning mist. In general, precipitation is higher in the north, but at any latitude it is greater in the interior than along the coast and increases with altitude. Temperatures fall with distance from the equator and with altitude and tend to rise closer to the Atlantic Ocean. Thus, at Soyo, at the mouth of the Congo River, the average annual temperature is about 26 °C or 79 °F, but it is under 16 °C or 61 °F at Huambo on the temperate central plateau. The coolest months are July and August (in the middle of the dry season), when frost may sometimes form at higher altitudes.[5]
Examples
Climate data for Luanda (1961-1990, extremes 1879-present)
Angola has four principal natural regions: the arid coastal lowland, stretching from Namibia to Luanda and characterized by low plains and terraces; green hills and mountains, rising inland from the coast into a great escarpment; a large area of high inland plains of dry savanna, called the high plateau (planalto), which extends eastward and south-east from the escarpment; and rain forest in the north and in Cabinda.[13][5] The highest point in Angola is Morro de Môco, at 2,620 m. Elevations generally range from 910 to 1,830 m (3,000 to 6,000 ft).
Coastal lowland
The coast is for the most part flat, with occasional low cliffs and bluffs of red sandstone. There is but one deep inlet of the sea – Great Fish Bay (or Baía dos Tigres). Farther north are Port Alexander, Little Fish Bay and Lobito Bay, while shallower bays are numerous. Lobito Bay has water sufficient to allow large ships to unload close inshore.[2] The coastal lowland rises from the sea in a series of low terraces. This region varies in width from about 25 kilometres (16 mi) near Benguela to more than 150 kilometres (93 mi) in the Cuanza River Valley just south of Angola's capital, Luanda, and is markedly different from Angola's highland mass. The Atlantic Ocean's cold, northwardflowing Benguela Current substantially reduces precipitation along the coast, making the region relatively arid or nearly so south of Benguela (where it forms the northern extension of the Namib Desert), and quite dry even in its northern reaches. Even where, as around Luanda, the average annual rainfall may be as much as fifty centimeters, it is not uncommon for the rains to fail. Given this pattern of precipitation, the far south is marked by sand dunes, which give way to dry scrub along the middle coast. Portions of the northern coastal plain are covered by thick brush.[5]
Hills and mountains
The approach to the great central plateau of Africa is marked by the west-central highlands, a series of irregular escarpments and cuestas parallel to the coast at distances ranging from 20 to 100 kilometres (12 to 62 mi) inland. The Cuanza River divides the mountain zone into two parts. The northern part rises gradually from the coastal zone to an average elevation of 500 metres (1,600 ft), with crests as high as 1,000 to 1,800 metres (3,300 to 5,900 ft). South of the Cuanza River, the hills rise sharply from the coastal lowlands and form a high escarpment, extending from a point east of Luanda and running south through Namibia.[5] The highest peak is Mount Moco (2,620 m or 8,600 ft),[citation needed] and the escarpment is steepest in the far south in the Serra da Chella mountain range.[5] In Benguela Province other high points are Loviti (2,370 m or 7,780 ft), in 12° 5' S., and Mount Elonga (2,300 m or 7,500 ft). South of the Cuanza is the volcanic mountain Caculo-Cabaza (1,000 m or 3,300 ft).[2]
High plateau
The high plateau, with an altitude ranging from 1,200 to 1,800 m (3,900 to 5,900 ft), lies to the east of the hills and mountains and dominates Angola's terrain. The surface of the plateau is typically flat or rolling, but parts of the Benguela Plateau and the Humpata Highland area of the Hufla Plateau in the south reach heights of 2,500 metres (8,200 ft) and more. The Malanje Plateau to the north rarely exceeds 1,000 metres (3,300 ft) in height. The Benguela Plateau and the coastal area in the immediate environs of Benguela and Lobito, the Bie Plateau, the Malanje Plateau, and a small section of the Hufla Plateau near the town of Lubango have long been among the most densely settled areas in Angola.[5]
Drainage
The Zambezi River and several tributaries of the Congo River have their sources in Angola.[13] A large number of rivers originate in the central uplands, but their patterns of flow are diverse and their ultimate outlets varied. A number flow in a more or less westerly course to the Atlantic Ocean, providing water for irrigation in the dry coastal strip and the potential for hydroelectric power, only some of which had been realized by 1988.[needs update] Two of Angola's most important rivers, the Cuanza (Kwanza) and the Cunene (Kunene), take a more indirect route to the Atlantic, the Cuanza flowing north and the Cunene flowing south before turning west. The Cuanza is the only river wholly within Angola that is navigable—for nearly 200 kilometers from its mouth—by boats of commercially or militarily significant size. The Congo River, whose mouth and western end form a small portion of Angola's northern border with Zaire, is also navigable.[5]
North of the Lunda Divide the Kwango and many other streams flow north from the tableland to join the Kasai River (one of the largest affluents of the Congo), which in its upper course forms for fully 300 mi (480 km) the boundary between Angola and the Congo.[2] South of the divide some rivers flow into the Zambezi River system and thence to the Indian Ocean, others to the Okavango River (as the Cubango River is called along the border with Namibia and in Botswana) and thence to the Okavango Swamp in Botswana. The tributaries of the Cubango River and several of the southern rivers flowing to the Atlantic are seasonal, completely dry much of the year.[5]
Natural hazards: locally heavy rainfall causes periodic flooding on the plateau[1]
Environment—current issues
Current environmental issues include overuse of pastures and subsequent soil erosion attributable to population pressures; desertification; deforestation of tropical rain forest, in response to both international demand for tropical timber and to domestic use as fuel, resulting in loss of biodiversity; soil erosion contributing to water pollution and silting of rivers and dams; and inadequate supplies of potable water.[1]
Both flora and fauna are those characteristic of the greater part of tropical Africa. As far south as Benguela the coast region is rich in oil palms and mangroves. In the northern part of the province are dense forests. In the South towards the Kunene are regions of dense thorn scrub. Rubber vines and trees are abundant, but in some districts their number has been considerably reduced by the primitive methods adopted by native collectors of rubber. The species most common are various root rubbers, notably the Carpodinus chylorrhiza. This species and other varieties of carpodinus are very widely distributed. Landolphias are also found. The coffee, cotton and Guinea pepper plants are indigenous, and the tobacco plant flourishes in several districts. Among the trees are several which yield excellent timber, such as the tacula (Pterocarpus tinctorius), which grows to an immense size, its wood being blood-red in colour, and the Angola mahogany. The bark of the musuemba (Albizzia coriaria) is largely used in the tanning of leather. The mulundo bears a fruit about the size of a cricket ball covered with a hard green shell and containing scarlet pips like a pomegranate.[2]
Angolan montane forest-grassland mosaic, the inland slopes of the central highlands which are covered in grassland and contain the remaining patches of mountain woodland;
^Jacobs, L. L., Polcyn M. J., Mateus O., Schulp A. S., Gonçalves A. O., & Morais M. L. (2016). Post-Gondwana Africa and the vertebrate history of the Angolan Atlantic Coast. Memoirs of Museum Victoria. 74, 343–362.
^Mateus, O., Marzola, M., Schulp, A.S., Jacobs, L.L., Polcyn, M.J., Pervov, V., Gonçalves, A.O. and Morais, M.L., 2017. Angolan ichnosite in a diamond mine shows the presence of a large terrestrial mammaliamorph, a crocodylomorph, and sauropod dinosaurs in the Early Cretaceous of Africa. Palaeogeography, Palaeoclimatology, Palaeoecology.
^"Klimatafel von Luanda, Prov. Luanda / Angola"(PDF). Baseline climate means (1961-1990) from stations all over the world (in German). Deutscher Wetterdienst. Archived(PDF) from the original on 12 May 2019. Retrieved 11 June 2016.
^"Station Luanda" (in French). Meteo Climat. Retrieved 11 June 2016.
