Physical Geography of Africa South of the Sahara

Chapter 20

1. The LandKnown for extraordinary physical

geographyVery diverse

LandformsMI: Africa south of Sahara is a region of

plateaus, mountains and rift valley in eastMassive region covers 9.5 million square

miles

The Great Rift ValleyRuns from Syria in SWA to Mozambique in SE

AfricaRift valley – large depression in Earth’s surface,

formed by tectonic plate movementVolcanic mountains at it’s edges, deep lakes Includes Mt. Kilimanjaro, one of largest mtns. in

worldLake Tanganyika, one of deepest and longest

freshwater lakes in world, lies on western branch of GRV

Lake Malawi, more than 2300 ft deep

Mountains and PlateausSeries of plateaus, rise in elevation from

coast inlandPlateaus range in elevation from 500 ft to

8000 ftEdges lined by escarpments, steep jagged

cliffs, and cataracts, or waterfallsLargest mountains include Kilimanjaro and

Mt. Kenya

Water SystemsMI: Landforms and physical processes have

influenced the regions water systems (lakes, waterfalls, rivers)

Lakes/rivers, located in basins, formed by tectonic activity

Rivers start at high elevations, make their way to the sea

Land of LakesMost lakes near Great Rift Valley, E AfricaLake Victoria, largest freshwater lake in

Africa, second largest in world behind Lake Superior

Lake Chad, W. Africa, shrinking due to irrigation, desertification, global warming

Desertification – long periods of drought and land use destroy vegetation

Human Made LakeLake Volta, W. Africa (Ghana), among

largest HM lake in the worldCreated in 1960’s by damming Volta RiverDam built for hydroelectric power in Ghana

River BasinsNiger River, main river in W. Africa2600 miles longImportant for agriculture and

transportation in regionForms Niger Delta upon entering Atlantic

Ocean, 200 miles wideDelta – a triangular section of land formed

by sand and silt carried downriver

River BasinsZambezi River, S. Central Africa2200 miles longHeadwater near the Zambia-Angola border,

flows to Indian OceanAt border of Zambia and Zimbabwe,

Zambezi falls 355 feet, forming Victoria Falls

River BasinsCongo River, Central AfricaAbout 2,900 miles longReaches sea through an estuary, or

passage where freshwater meets seawater

Natural ResourcesMI: Mineral resources and water are

among the region’s most abundant natural resources

Oil – Nigeria, Angola, Gabon, Congo and Cameroon

4 percent of world oil in Sub-Saharan Africa

South Africa – half of worlds goldUranium – South Africa, BotswanaWater is abundant, but irregular and

unpredictable, difficult to control for irrigation and hydroelectric power

2. Climate and VegetationMI: Rain helps determine:climatevegetation growth

Tropical Climates

Causes of variation in climate and vegetation:

rainfallocean currentsprevailing windselevationlatitude

Tropical WetMap of p. 516TW Zone located near equatorMore than 60 inches of rain per yearProduces variety of vegetationRainforest levels:Low: ferns, moss, shrubsMid: Trees, palmsCanopy: leafy trees, max height of 150 ftSoil not fertileHeavy rains leach, or dissolve and carry

away, nutrients from soilCrops grown: bananas, pineapples, cocoa,

tea, coffee, timber, cotton

Tropical DrySavanna, or grassland with scattered

trees, covers half of AfricaAlternating wet and dry seasons35-45 inches annual rainfallHot, dry air from Sahara, called harmattan, affects TDZone

Cool, humid air from SW affect TDZoneCombination at times forms tornadoesAnimals: zebras, gazelles, hyenas, lions,

giraffes and cheetahs

Dry ClimatesMI: Dry climates of Sub-Saharan Africa

located in the north and south, away from the equator

SteppeTransition zone between tropical dry

savanna and desertNorthern steppe called the Sahel, from

Senegal to Sudan4-8 inches annual rainfall

DesertificationSahel, undergone desertification over past

50 yearsMay be caused by climate changeMay be caused by human activities, animal

grazing, logging, farming, etc.

DesertNamib Desert, Atlantic coast of NamibiaKalahari, eastern Namibia, Botswana and

part of South AfricaDaily temps in Kalahari vary widely, from

50 dg., night, to 120 dg., day

MidlatitudeCoastal areas of South Africa, humid

subtropical climatesHighland East Africa, moderate climates,

adequate rainfall for farming, some snow at high elevations