Understanding Geological Agents and Their Impact on Relief

Geological Agents:

Geological agents act on the relief and change it, including the sea, glaciers, rivers, and wind. External geological agents are activated by solar energy and gravity. The actions they take are called external geological processes. In contrast, internal geological processes are originated by thermal energy inside the Earth.

Factors That Determine the Shape of Relief

Relief modeling is the process by which the Earth's surface acquires a certain shape. The diversity of relief is due to the following factors:

• Type of Rock: Each rock is modeled differently because it has specific characteristics.
• Climate: The type of agent that prevails in the external geological area is determined by the weather.
• Structure of Materials: Rocks can be folded or fractured, which provides initial conditions for modeling.
• Antiquity of Relief: External geological agents remove materials from one place and deposit them in another, causing relief to change over time. A young relief is different from an old one.

The differences between the relief of some areas and others are due to climate, rock type, and the structure of materials, emphasizing the antiquity of each place. Rocks are the material that shapes the land relief.

Lithology and Its Impact

The lithology, or rock type, present in every location conditions the form that relief takes. The most characteristic rocks that cover most of Spain's surface are clay, limestone, and granite.

Clay

Clay sediments and sedimentary rocks are consistent and impermeable, with pores that are easily eroded. Humid climates result in low relief plains and gentle slopes.

Badlands

Badlands are characterized by a very dense network of gullies and ravines caused by torrential rains, which can lead to poor land conditions.

Limestones

Limestones are a type of sedimentary rock formed by calcium carbonate. They are coherent, permeable, and resistant to physical weathering. Limestones can dissolve in water if it carries a certain amount of carbonic acid. The formation of this acid is a frequent process because rainwater incorporates carbon dioxide from the air, which enhances its ability to dissolve limestone.

Karst Relief

Karst relief is formed by the dissolution of limestone or other similar rocks.