Morphoclimatic Systems, Structural and Coastal Modeling: Landforms Explained

Morphoclimatic Systems

The Earth's surface presents forms of relief that result from the balance between external and internal geological processes occurring in each environment.

A) Glacial Morphoclimatic System

Found in high-altitude areas and at the poles, with very low temperatures and scarce precipitation. The most important agent is ice.

• Glaciers: masses of ice in movement that spread in all directions (ice sheets) or descend through valleys in some mountain ranges.

B) Periglacial Morphoclimatic System

Periglacial areas have low temperatures and processes linked to freezing and thawing of ice.

C) Temperate Morphoclimatic System

Characterized by processes of washing and runoff caused by rainwater.

• Rain that falls intensely or is scarce causes fine particles to be dragged away.
• Sheet runoff: water flows without a fixed channel and causes erosion on soft earth, forming gullies and heterogeneous ravines (barrancos).
• In some cases, the earth is eroded into earth pyramids.

Linear Erosion

Linear erosion is carved out by rivers, water courses that flow over a surface along a fixed channel. It is divided into three sections:

• Upper section: near the river source, with steep slope; erosion and transport predominate, forming V-shaped valleys.
• Middle section: the slope decreases, velocity is lower, and transport predominates; valleys are less V-shaped and more open.
• Lower section: gentle slope, low velocity, and sedimentation prevails.

Relief Forms Produced by River Erosion

Fluvial valleys, gorges, waterfalls, rapids, and meanders.

Relief Forms Produced by River Sedimentation

Fluvial terraces and deltas.

D) Desert Morphoclimatic System

Desert areas receive less than 200 mm of precipitation per year and have high aridity. Types include tropical, continental, and coastal deserts.

Structural Modeling

The main agent is relief in sedimentary basins or regions, and relief in volcanic areas.

Littoral Modeling

The littoral is the natural zone where the terrestrial and marine environments converge and interact. Littoral processes are zonal, although climatic influences on land can also act on them.

• Mechanical action: the impact of water (waves, tides, and marine currents) on the coast.
• Chemical weathering: salts dissolved in water promote the dissolution of rocks.
• Biological weathering: marine life exerts mechanical and chemical actions.

A) Erosion Forms from Mechanical Action

Erosion forms on the coastline include cliffs, abrasion platforms, and caves.

B) Sedimentation Forms

Beaches, wetlands, and deltas.

C) Evolution of Coasts

A coast is the border between land and sea. There are two types:

• Submergence coasts: the land sinks beneath the sea.
• Emergence coasts: the land rises above the sea when an elevation of the land occurs.