Sub Saharan Africa

PHYSICAL NOTES

A. SECOND LARGEST CONTINENT

B. Known as "The Plateau Continent"

1. Interior is a gigantic plateau (highest in the east and south/drops sharply at the coast). A plateau is an elevated area of high, flat or gently rolling land.
2. Africa: almost entirely surrounded by a low, narrow coastal plain. The sharp rise or steep cliff that separates the coastal plain from the elevated plateau is called an escarpment.
3. The steep slope marking the edge of the continental plateau in South Africa is called the Great Escarpment.
4. Africa as a continent has the highest overall elevation of all continents (averages 1,000+ above sea level).
5. Mountains: individual mountains/not chains/mainly in the east. Most are volcanic mountain. Elevation is the key to their temperature.
6. Africa's rivers contain many cataracts (multiple waterfalls at the edge of steep escarpments).

C. GREAT RIFT VALLEY

1. One of the world's natural wonders
2. 4,000+ miles long (approximately)
3. Begins in Syria (Southwest Asia), goes through the Red Sea, extends southward through East Africa, and ends in Mozambique (Southern Africa).
4. Valley is a rift fault caused over millions of years ago when two of the earth's Continental plates moved apart.
5. Can be up to 40-50 miles wide.
6. Sides can be up to about 1 mile high.
7. Valley Floor: often barren/many extinct volcanoes and a surface covered with volcanic lava and ash. Makes soil very fertile.
8. There is a large string of long and deep natural lakes throught the valley (Lakes Albert, Edward & Tanganyika). Tanganyika is the longest lake in the world (over 400 miles long)
9. Not part of the Great Rift Valley Lakes: Lake Victoria (largest lake in Africa/located east of the Great Rift Valley).

D. CLIMATE & VEGETATION

1. Similar bands of climate & vegetation stretch across Africa north and south of the equator.
2. Vegetation along the Equator-10% Rain forest (hot and wet/one season and shrinking more each year.)
3. 65% Grasslands (also called savanna)-located north and south of the rainforests; usually long & short and widely scattered trees; hot all year round with two seasons: long, dry seasons separated by wet seasons.
4. 25% Desert (semi-arid & arid)-usually have 10 inches or less of rain per year; in the north, Sahara and the Sahel (means "shore of the desert"/borders south side of the Sahara Desert);in the south: Kalihari Desert; in the southwest: Namib Desert.
5. Mediterranean Coastal Plain: along the north coastal edge of Africa. Also: there is Mediterranean Coastal Plain in the far southern coast of Africa also.

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• Most of Africa is hot (temperature) all year long.
• Elevation can affect the temperature as much as latitude.
• Rainfall varies greatly/amounts vary with the distance away from the equator.
• The closer to the Equator the more rainy; the further away, the less rain (EXCEPT at the coast where a Mediterranean Climate can prevail).

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The longest crack in the earth's surface is the Great Rift Valley. Millions of years ago, the shift of tectonic plates tore a rift in the earth's crust, splitting the Arabian Peninsula away from Africa (creating the Red Sea) and forming numerous canyons in eastern Africa, many of which are filled with deep, long lake. Along its 4,000+ mile length, extending north to Syria & Jordan in the Middle East, the rift is concealed by erosion, mountains and plateaus. At various sites along the valley, fossil evidence of the earliest humans have been discovered.

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E. NARROW COASTAL PLAIN on the Mediterranean Sea (Mediterranean Climate)

F. THE SAHARA

1. 3.5 million square miles (nearly the size of the U.S.)
2. Largest hot desert in the world.
3. Most of the region gets less than 10 inches of rain per year.
4. Atlas of Morocco & Algeria (West coast of Africa) prevent moisture from the Atlantic Ocean from reaching North African region.
5. Little moisture or humidity in desert air so no clouds form.
6. Sun's rays beat directly on land in day...high temperatures and no clouds/can reach temperatures of 125 degrees+ in the day.
7. Drop as low as 40 degrees fahrenheit at night (because there are no clouds to prevent daytime heat from rising from the earth).
8. Extreme temperatures & little rainfall make it hard for life to survive...life forms must adapt or die.

G. PEOPLE OF THE SAHARA

1. Most are Muslims who speak Arabic.
2. Majority live along the Mediterranean Sea in crowded cities.
3. Inland (in Sahara), people are Bedouins (Desert Dwellers).
4. In early times, tradres crossed desert in caravans for safety.
5. Many trade routes between North Africa and west coastal countries (salt from the north and gold, ivory, and slaves fromt the south).

H. ANIMALS

1. Camels: brought by Romans from Central Asia. Have adapted to dry climate & can survive for long periods without food or water.
2. Bedouins often have goats & sheep for food, clothing, and trade.

I. WIND

1. Powerful force in desert. Shape region's terrain/carries loose sand paricles which can form sand dunes (ERGS). Many are huge and permanent.
2. The surface that is left when sand blows away is a thin surface of pebbles, gravel & boulders called desert pavement.

J. WATER

1. The most important resource in North Africa. Found in a few underground springs that force their way up to the surface & form oases (singular=oasis)- can support life in barren land. Sahara has approximately 90 oases (widely scattered/some are centuries old).
2. Dry river beds (wadis). Sharp gullies that are temporary reservoirs/collect run-off water if there is rain...can even be rain in far off regions that rushes through the wadi/dry up quickly/subject to flash flooding.
3. Rivers: Most important source of water because they are the most consistent source of water (example: Nile River in Egypt)
4. The Nile is fed from mountains in East Africa. Water flows northward from the White Nile in Uganda and the Blue Nile in Ethiopia and merge into the Nile River that flows across Egypt northward for 4184 miles to empty miles to empty into the Mediterranean Sea.