Earth's Geological Processes: Weathering, Erosion, and Deposition

1. Weathering and Atmospheric Agents

Weathering is the widespread deterioration and breakdown of rocks caused by atmospheric agents. The resulting fragments are called clasts, which accumulate, often on the slopes of mountains.

Clasts

Clasts are rock fragments of any size and origin.

Causes of Rock Splitting

Rocks are split by atmospheric agents, including:

• Rain and snow
• Temperature changes
• Gelifraction (Frost Wedging): Water freezing in rock fissures, causing them to split.

Definition of Weathering

Weathering is the set of processes caused by atmospheric agents that break down rocks.

2. Weathering Processes

There are three primary types of weathering:

1. Mechanical Weathering

   Physical breakdown of rocks resulting from dilation and contraction, collisions, and gelifraction (frost wedging).

2. Chemical Weathering

   Rocks are split because chemical reactions change some of their constituent minerals.

3. Biological Weathering

   The splitting of rocks caused by the activity of living organisms (e.g., plant roots).

Weathering Factors

The primary factors influencing weathering are:

• Temperature
• Humidity

3. Geological Modeling Processes: Erosion, Transport, and Sedimentation

Geological agents are responsible for wearing down materials, transporting them, and depositing them.

Erosion (Wear)

Erosion is the removal of materials from their original location.

Transport

Transport is the movement of materials from one place to another. This occurs through two main types:

1. Bedload Transport: Materials are transported along the ground surface.
2. Suspension Transport: Materials are transported without touching the ground (suspended in the medium).

Sedimentation (Deposition)

Sedimentation occurs when a geological agent loses energy, causing the transported material to be deposited in a specific location.

4. Geological Agents

The primary geological agents are:

• Wind
• Water (River, Groundwater, Sea, Torrential)
• Glaciers
• Life (Biological Agents)

6. Glaciers

Glaciers are moving masses of ice formed in places where snow accumulates and turns into ice rather than melting.

7. Torrential Surface Water

Torrential water is a high-capacity geological modeling agent, especially in dry climate areas. It forms when heavy, intermittent rains occur.

8. Rivers

A river is a permanent body of flowing water. Smaller streams often meet to form major rivers, which generally flow into the sea.

9. Groundwater

Aquifers are underground accumulations of water that can be exploited through wells.

Karst Modeling

Karst modeling is the set of surface and underground landforms created by the dissolution of soluble rocks (like limestone) by groundwater.

10. Marine Processes

Marine processes involve the action of waves, currents, and tides:

• Waves

  Waves are caused by wind and erode the steep edges of the coastline.

• Sea Currents

  Currents are caused by differences in water temperature and salinity, carrying small materials over long distances.

• Tides

  Tides are the movement of large masses of water caused by the gravitational pull of the Sun and Moon. Tidal areas experience increased wave activity.

11. Sedimentary Basins

A sedimentary basin is a surface depression where sediments concentrate. The basin floor gradually subsides as layers of sediment accumulate.