Earth's Landforms: Shaping Forces and Types

Forces Shaping Earth's Relief

Other agents also contribute to the shaping of relief. These agents are water, wind, extreme temperatures, and the action of human beings.

Water

Water in seas and oceans shapes coastal relief. Water in rivers and streams shapes fluvial relief. Water in contact with rocks causes erosion (by wearing down or breaking) or rock dissolution, forming karst relief.

Wind

Wind erodes rocks and transports sand and dust, which accumulate to form dunes (small hills of sand).

Temperatures

Extremely high or low temperatures cause rocks to crack. When heat (which makes rocks expand) and cold (which makes rocks contract) alternate, rocks break into pieces.

Human Action

Human beings have always changed large areas of land for their own use. Quarries, mines, tunnels, and roads are all examples of the impact of human activity on the landscape.

Types of Relief on Earth

There are different kinds of relief:

Continental Relief

• Mountains: Elevated relief with steep slopes. The highest part of a mountain is called a summit or a peak.
• Mountain Ranges: A series of mountains connected to each other.
• Depressions: Wide, low areas with gentle slopes, surrounded by higher areas.
• Valleys: Low areas between mountains, smaller than a depression.
• Plains: Low, flat areas of land.
• Plateaus: Large, raised plains.

Coastal Relief

• Peninsula: A piece of land surrounded by water on all sides except one.
• Isthmus: Connects a peninsula to a continent.
• Cape: A part of the coast which extends into the sea.
• Gulf: A large area of a sea or ocean partially enclosed by land.
• Bay: A small gulf.
• Island: An area of land surrounded by water on all sides.
• Archipelago: A group of islands.
• Beach: Accumulation of sand and gravel on low areas of the coast.
• Cliff: A steep rock formation in high coastal areas.

Oceanic Relief

• Continental Shelf: An extension of the continent below the water.
• Continental Slope: A sharp descent at the end of the continental shelf.
• Ocean Ridges: Large mountain ranges which rise from the ocean floor.
• Ocean Trenches: Large, deep depressions in the ocean floor.