Africa - Chapter 2: The Physical Environment

Front 1

Plate Tectonics

Back 1

Theory suggesting that the crust of the earth is split up into seven large plates and a few smaller plates all of which are able to move around.

Front 2

Continental Drift

Back 2

Theory that over 180 million years ago the supercontinent Pangea began to break up due to "continental drift".

Front 3

Sea-floor Spreading

Back 3

Theory provided scientific clues to the mechanisms by which the rigid earth's plates moved. i.e. folding, faulting, mountain building, volacnism, and formation of new crustal materials

Front 4

Rift Valley

Back 4

Major fault valley or graben, with walls between 15 and 100 miles apart averaging 25 to 30 miles apart.

Front 5

Pangea

Back 5

Supercontinent once connecting all seven of today's present continents.

Front 6

Continental Shelf

Back 6

Part of an ocean that extends from the shore to the transition zone (demarcating the open ocean) where depths increase rapidly.

Front 7

Gondwanaland

Back 7

Section of Pangea containing Africa, South America, and parts of Asia.

Front 8

Escarpment

Back 8

Narrow coastal belt in High Africa with higher elevation.

Front 9

Subtropical High Pressure

Back 9

Dictates surface wind patters and also influences rainfall and temperature regimes in Africa (along 30 degree N and S latitudes).

Front 10

Intertropical Convergence Zone

Back 10

Dictates surface wind patters and also influences rainfall and temperature regimes in Africa (along equator). Al so known as the zone of transition where the STHP winds meet.

Front 11

Harmattan Winds

Back 11

As the ITCZ move southward, the influence of the dry northeasterly airmass prevails over west Africa. These trade winds knows as the "Harmattan winds" or north east trades. They blow across the Sahara and bring dusty hazy conditions to most of west central Africa.

Front 12

Ocean Currents

Back 12

Moce warm water poleward and cold water toward teh equator, thereby exerting a modifying influence on temperature.

Front 13

Lake Effect

Back 13

Lakes have a modifying effect on temperature and rainfall as moisture from the lake is carried by prevailing winds to the land.

Front 14

Tropical Rain Forest

Back 14

All forest in the humid and semi-humid areas of Sub-Saharan Africa. Characterized by lush vegetation, high temperatures, and heavy rainfall.

Front 15

Savanna Grassland

Back 15

A vegetation zone where herbaceous plants and grasses dominate the landscape.

Front 16

Sahel

Back 16

Area constitutinga trasitione between the Sudanian grassland region and the Sahara desert.

Front 17

Montane Vegetation

Back 17

Develops over isolated elevated regions of Sub-Saharan Africa and is affected by local temperatures, rainfall, and soil conditions.

Front 18

Maritime Effect

Back 18

Proximity to large bodies of water has a modifying effect on the climate. Land generally heats and cools faster than the oceans explaining the extreme temperatures.

Front 19

Northeast Trades

Back 19

Also known as the Harmattan Winds.

Front 20

Southeast Trades

Back 20

Originate from the sounth sub-tropical highs and meets with the northeast trades to create the ITCZ.

Front 21

Biome

Back 21

An extensive unit of vegetation cover, together with its associated animal life, and it usually corresponds iwth particular climatic and soil types.

Front 22

Oxisols

Back 22

Type of soil which forms in the intensely weathered moist equatorial beslt and underlie areas between western Congolia and the east African coast.

Front 23

Vertisols

Back 23

Type of soil confined to the subhumid to arid areas of southeast Sudan and western Ethiopia.

Front 24

Inceptisols

Back 24

Type of soil that is young but has a relatively well-developed soil profile compared with entisols. They usually develop in humid regions as well as regions iwth significant glacial, wind, and volcanic ash deposits.