Geomorphic Processes

1. Introduction to Geomorphic Processes

• Geomorphic processes are the natural mechanisms that shape the Earth’s surface.
• These processes are driven by endogenic (internal) and exogenic (external) forces.
• The Earth’s surface is constantly changing due to these processes.

2. Endogenic Processes

• Processes originating from within the Earth’s interior.
• Types:
  • Diastrophism: Large-scale deformation of the Earth’s crust.
    • Orogenic Processes: Mountain-building processes.
    • Epeirogenic Processes: Uplift or depression of large land areas.
  • Volcanism: Movement of magma toward or onto the Earth’s surface.
    • Intrusive Volcanism: Magma solidifies below the surface (e.g., batholiths, laccoliths).
    • Extrusive Volcanism: Magma erupts onto the surface (e.g., lava flows, volcanic cones).
  • Earthquakes: Sudden shaking of the Earth’s crust due to tectonic activity.
    • Focus: The point inside the Earth where the earthquake originates.
    • Epicenter: The point on the Earth’s surface directly above the focus.

3. Exogenic Processes

•  Processes originating from outside the Earth’s surface.
• Types:
  • Weathering: Breakdown of rocks in situ.
    • Mechanical Weathering: Physical breakdown (e.g., frost action, thermal expansion).
    • Chemical Weathering: Chemical alteration (e.g., oxidation, hydrolysis, carbonation).
    • Biological Weathering: Breakdown by living organisms (e.g., roots, burrowing animals).
  • Erosion: Removal of weathered material by agents like water, wind, ice, and waves.
  • Mass Movement: Downslope movement of material under gravity.
    • Examples:  Creep, slump, landslide, avalanche.
  • Deposition: Accumulation of eroded material in new locations.

4. Gradation

• The process of leveling the Earth’s surface by erosion and deposition.
• Agents of Gradation:
  • Running Water: Forms valleys, gorges, floodplains, deltas.
  • Glaciers: Create U-shaped valleys, moraines, drumlins.
  • Wind: Forms sand dunes, loess deposits.
  • Waves: Create sea cliffs, beaches, spits.
  • Groundwater: Forms caves, sinkholes, stalactites, stalagmites.

5. Landforms and their Evolution

• Fluvial Landforms: Created by running water (e.g., meanders, oxbow lakes, alluvial fans).
• Arid Landforms: Shaped by wind and water in deserts (e.g., yardangs, zeugens, inselbergs).
• Glacial Landforms: Formed by glacial activity (e.g., cirques, aretes, fjords).
• Coastal Landforms: Shaped by wave action (e.g., sea caves, arches, stacks).
• Karst Landforms: Formed by the dissolution of limestone (e.g., karst valleys, poljes).

6. Soil Formation

•  The process of soil development from the weathering of rocks.
• Factors Influencing Soil Formation:
  • Parent Material: The original rock from which soil is formed.
  • Climate: Temperature and precipitation affect weathering rates.
  • Topography: Slope and elevation influence drainage and erosion.
  • Biological Activity: Plants and animals contribute organic matter.
  • Time: The duration over which soil-forming processes operate.

7. Significance of Geomorphic Processes

• Landform Development: Shapes the Earth’s surface into mountains, valleys, plains, etc.
• Resource Formation: Creates fertile soils, mineral deposits, and groundwater reservoirs.
• Hazard Mitigation: Understanding processes helps in managing natural disasters like earthquakes, landslides, and floods.

8. Human Impact on Geomorphic Processes

• Deforestation: Accelerates soil erosion and alters river courses.
• Urbanization: Increases surface runoff and reduces groundwater recharge.
• Mining: Causes land subsidence and alters landscapes.
• Agriculture: Leads to soil degradation and changes in landforms.

9. Conclusion

• Geomorphic processes are fundamental to understanding the dynamic nature of the Earth’s surface.
• Both endogenic and exogenic processes play crucial roles in shaping the landscape.
• Human activities can significantly alter these natural processes, leading to environmental changes.