Unit 1: Landforms of Africa

This unit explores the diverse physical features of the African continent, ranging from massive mountain ranges to vast desert systems. It examines the geological processes of internal and external forces that shape the Earth’s surface and create distinct physiographic divisions. Students will analyze the spatial distribution of these landforms and their significant impact on Africa’s climate and ecosystems.

1.1 Overview of the World’s Major Landforms

• Landforms are physical features on the Earth’s surface that form the terrain of an area.
• Major types of landforms include mountains, plateaus, and plains.
• Minor landforms include hills, gorges, valleys, and basins.
• Formation Processes:
  1. Internal processes: Tectonic plate movement and volcanic activities in the Earth’s interior create landforms by pushing up mountains and hills.
  2. External processes: Erosion by water and wind wears down land to create features like gullies, river valleys, and gorges.
• The world is divided into seven continents: Asia, Africa, North America, South America, Antarctica, Europe, and Oceania (Australia).
• Oceans cover 71% of the Earth and include the Arctic, Atlantic, Indian, Pacific (largest and deepest), and Southern Oceans.
• Coastal Features:
  • Island: A piece of ground completely surrounded by water (e.g., Greenland).
  • Peninsula: Land surrounded by water on three sides but connected to the mainland on the fourth (e.g., Italy, Florida).
  • Isthmus: A narrow strip of land with water on both sides connecting two larger landmasses (e.g., Isthmus of Panama).

1.2 Location and Related Features of Africa

• Boundaries: Africa is bounded by the Mediterranean Sea (North), Red Sea and Gulf of Aden (Northeast), Indian Ocean (East), and Atlantic Ocean (West).
• Size and Rank: Africa is the second-largest and second-most populous continent, covering 30.37 million $Km^2$ (6% of Earth’s total surface area).
• Position: The Equator divides the continent almost in half, creating a mirror image of climatic and physical conditions in the north and south.
• Political Structure: Africa is home to 54 recognized sovereign states.

1.3 Major Landforms of Africa

• Africa’s landforms are categorized into four significant regions containing eight physical regions.
• Ecological Importance: Landforms influence ecosystems, modify climate (macroclimate and microclimate), and determine the ecological potential of an area.

1.3.1 African Alpine System

• Atlas Mountains: A mountain range in North Africa extending from Morocco to Tunisia for over 2,000 kilometers.
• It forms a high divide between the Mediterranean Sea and the Sahara Desert and makes up the Maghrib region.

1.3.2 African Massif

• The Sahara Desert: The largest hot desert in the world ($9,200,000 Km^2$), encompassing parts of ten countries.
  • Erg: A great sand sea covered with reddish sand dunes.
  • Reg: A desert pavement of pebbles on top of vast flat-surfaced sheets of sand.
• The Sahel: A vast semiarid transitional zone south of the Sahara, stretching 5,000 kilometers from Mauritania to Somalia.
• The Savanna: A tropical grassland region with drought-resistant trees and shrubs that shed leaves during the dry season.
• The Tropical Rainforest: Found in the Congo Basin and other areas like Ghana and Madagascar.
  • Characterized by a thick continuous canopy (25–35 meters tall), high diversity of species, and rapid decomposition.

1.3.3 East African Highlands and Rift System

• The Rift Valley: A 5,600 km long feature formed by normal faulting where land splits apart.
• Graben: An elongated block of the Earth’s crust displaced downward between two faults in a Rift Valley.
• Ethiopian and Eritrean Highlands: A massive central highland complex divided by the deep Great Rift Valley.

1.3.4 Southern Africa Platform

• Drakensberg Escarpment: The most recognizable landscape in the region, averaging 3,000 m in altitude.
• Deserts:
  • Kalahari Desert: Lies mainly in Botswana; an arid mixture of grasslands and sand.
  • Namib Desert: Found along the west coast, formed partly by the cold Benguela ocean current.
• Highveld: An inland plateau in South Africa bounded by the Great Karoo, Kalahari, and Bushveld.

Key Terminology

• Atlas Mountains: A mountain range in North Africa extending from Morocco to Tunisia.
• Benguela: The cold ocean current affecting the formation of the Namib Desert.
• Canopy: A thick continuous layer formed by closely spaced trees in a rainforest.
• Congo Basin: A major region of tropical rainforest in central Africa.
• Continents: The largest landmasses in the world.
• Deserts: Arid regions with little or no rainfall.
• Ecosystems: A system consisting of all organisms and the physical environment they interact with.
• Equator: The imaginary line that divides Africa into two almost equal parts.
• Erg: A desert surface characterized by a great sea of sand.
• External processes: Natural forces like erosion that create minor landforms.
• Graben: An elongated block of crust lying between two faults.
• Great Escarpment: A major geological feature in Southern Africa.
• Great Karoo: A region bounding the Highveld to the south.
• Highveld: The portion of the South African inland plateau.
• Internal processes: Tectonic and volcanic activities creating major landforms.
• Island: A piece of land completely surrounded by water.
• Isthmus: A narrow strip of land connecting two larger land pieces.
• Landforms: Physical features on the Earth’s surface.
• Macroclimate: The climate of a large geographical area.
• Maghrib: The North African region meaning “west” in Arabic.
• Microclimate: The climate of a small, specific area.
• Mountains: The largest elevated landforms with steep sides and high peaks.
• Oceans: Large areas of salt water between continents.
• Peninsula: Land surrounded by water on three sides.
• Plain: Large areas of flat low land.
• Plate tectonics: The movement of Earth’s plates that creates landforms.
• Plateaus: Large areas of raised land that are flat on top.
• Reg: A desert surface covered with pebbles and gravel.
• Rift Valley: A long rupture in the Earth’s crust.
• Sovereign state: A recognized independent political entity.
• Surface area: The total area of the Earth’s surface covered by a continent.
• The Sahara: The largest hot desert in the world.
• The Sahel: A semiarid region forming a transitional zone south of the Sahara.
• The Savanna: A tropical grassland region.
• Tropical rainforest: A diverse, wet forest found near the equator.
• Volcanic activities: Internal processes involving the release of lava that form landforms.