Geological Agents and Earth Surface Processes Explained

1. Who are the active geological agents and why are they named so?

Driven by solar energy and gravity, they are called external geological agents.

2. Can badlands originate in an area with abundant vegetation? Why?

No. The vegetation holds the soil with its roots, while stems and leaves slow down water, thus reducing its transport capacity.

3. What is karst relief and how is a column formed?

Karstic reliefs are landscapes caused by the dissolution of limestone or similar rocks. Columns are formed when a stalactite meets a stalagmite.

4. What is the dual effect of relief evolution?

• Arenization: Chemical weathering causes residual gravel to form between blocks.
• Formation of boulders: Granite blocks reduce their volume and acquire rounded forms.

5. Geological agents and climates

• Surface water: The dominant agent in temperate and tropical climates.
• The sea: Plays a role in oceanic areas and along the coast.
• The wind: An important geological agent in arid climates and coastal areas.
• Glaciers: The dominant agent in glacial and periglacial climates.

6. Types of gravitational processes

• Detachment: Material in freefall.
• Gliding: Movement of materials in blocks that slide on a surface.
• Flow: Mass movement of poorly cohesive materials moving as a viscous flow.
• Creeping: Downslope movement of loose material that affects the topsoil.

7. Why is a river valley in a medium or low section much wider than the space occupied by water?

Due to the flooding of the river and the lateral effect of water streams.

8. What is a glacier and what are its parts?

A glacier is a mass of ice that creeps on the Earth's surface, consisting of:

• Cirque: The highest part where snow accumulates and becomes ice.
• Tongue: The mass of ice that runs down the valley.
• Terminal area: Where ice melts, depositing the materials it was transporting.

9. Do rivers, glaciers, and wind transport materials similarly?

Generally no, because the wind cannot drag the same heavy materials as rivers or glaciers, and the wind can also transport materials from low areas to high elevations.

10. What are antiforms and synforms?

An antiform is a fold that is convex upward, while a synform is a fold that is concave upward.