Geomorphic Processes
- Pratik Garg
- Mar 15
- 4 min read
1. Introduction to Geomorphic Processes
Definition: Geomorphic processes are natural mechanisms that shape the Earth's surface through the interaction of endogenic (internal) and exogenic (external) forces. These processes create and modify landforms over time.
Landforms: Physical features like mountains, valleys, plateaus, and plains are the result of these processes.
Example: The Himalayas (formed by endogenic forces) and the Grand Canyon (shaped by exogenic erosion).
2. Types of Geomorphic Processes
A. Endogenic Processes
Definition: Processes originating from within the Earth, driven by internal energy (radioactive decay and primordial heat).
Types:
1. Diastrophism:
Definition: Deformation of the Earth's crust leading to the formation of mountains, plateaus, and basins.
Types:
Orogenic Processes: Mountain-building through folding and faulting.
Example: Himalayas formed by the collision of the Indian and Eurasian plates.
Epeirogenic Processes: Vertical uplift or subsidence of large continental landmasses.
Example: Uplift of the Deccan Plateau in India.
2. Volcanism:
Definition: Movement of magma from the Earth's interior to the surface.
Types:
Intrusive Volcanism: Magma cools and solidifies below the surface (e.g., granite batholiths).
Extrusive Volcanism: Lava erupts onto the surface (e.g., shield volcanoes like Mauna Loa, Hawaii).
3. Earthquakes:
Definition: Sudden shaking of the Earth's crust caused by the release of energy along fault lines.
Example: 2001 Bhuj earthquake (India) caused by the subduction of the Indian Plate.
B. Exogenic Processes
Definition: Processes originating from outside the Earth, driven by solar energy and gravity.
Types:
1. Weathering:
Definition: The breakdown of rocks at or near the Earth's surface due to physical, chemical, or biological processes.
Example: Freeze-thaw cycles in the Alps (physical weathering).
2. Erosion:
Definition: The wearing away of the Earth's surface by natural agents like water, wind, ice, and waves.
Example: Ganga River eroding the Himalayas.
3. Transportation:
Definition: The movement of eroded materials by natural agents.
Example: Sediment carried by the Ganga River.
4. Deposition:
Definition: The accumulation of eroded materials in new locations.
Example: Formation of the Sundarbans delta by sediment deposition from the Ganga-Brahmaputra rivers.
3. Weathering
Definition: The breakdown of rocks at or near the Earth's surface due to physical, chemical, or biological processes.
A. Physical (Mechanical) Weathering
Frost Action:
Definition: Water freezes in rock cracks, expanding and breaking rocks.
Example: Tors (rock formations) in the Himalayas.
Thermal Expansion:
Definition: Rocks expand by day and contract at night, leading to cracking.
Example: Exfoliation domes in Yosemite National Park, USA.
Salt Crystallization:
Definition: Salt crystals grow in rock pores, causing disintegration.
Example: Arid regions like the Thar Desert.
B. Chemical Weathering
Oxidation:
Definition: Rocks react with oxygen (e.g., iron turns to rust).
Example: Red soil in Odisha (high iron content).
Carbonation:
Definition: Rainwater (CO₂-rich) dissolves limestone.
Example: Limestone caves in Mawsmai, Meghalaya.
Hydration:
Definition: Minerals absorb water and expand.
Example: Feldspar converting to clay.
C. Biological Weathering
Plant Roots:
Definition: Roots grow into rock cracks, causing splitting.
Example: Banyan tree roots splitting rocks in tropical regions.
Burrowing Animals:
Definition: Animals create pores in soil and rocks.
Example: Earthworms in agricultural fields.
4. Mass Movements
Definition: The downslope movement of material under the influence of gravity.
A. Slow Movements
Soil Creep:
Definition: Gradual movement of soil (1–2 mm/year).
Example: Bent tree trunks on slopes in the Western Ghats.
Solifluction:
Definition: Saturated soil flows over permafrost.
Example: Arctic tundra regions.
B. Rapid Movements
Landslides:
Definition: Sudden movement of rock and soil down a slope.
Example: 2013 Kedarnath landslide (Uttarakhand) triggered by heavy rain.
Mudflows:
Definition: Rapid flow of water-saturated soil.
Example: 1999 Vargas tragedy (Venezuela) caused by heavy rainfall.
5. Erosion and Deposition
Erosion:
Definition: Removal of surface material by natural agents like water, wind, ice, and waves.
Agents of Erosion:
Water: Rivers, rainfall, and ocean waves.
Example: Ganga River eroding the Himalayas.
Wind: Common in arid regions.
Example: Sandstorms in Rajasthan.
Glaciers: Ice erodes land by plucking and abrasion.
Example: U-shaped valleys in the Alps.
Waves: Coastal erosion.
Example: Cliffs in Dover, UK.
Deposition:
Definition: The laying down of eroded material in new locations.
Examples:
Deltas: Formed at river mouths (e.g., Sundarbans delta).
Sand Dunes: Formed by wind deposition (e.g., Thar Desert).
Glacial Moraines: Deposits of glacial debris (e.g., Himalayan moraines).
6. Significance of Geomorphic Processes
Landform Development: Creates mountains, valleys, plateaus, plains, etc.
Example: Himalayas (endogenic) and Grand Canyon (exogenic).
Soil Formation: Weathering of rocks contributes to soil formation.
Example: Laterite soil in Kerala.
Natural Hazards: Processes like earthquakes, landslides, and volcanic eruptions can cause disasters.
Example: 2004 Indian Ocean tsunami.
Ecological Balance: Influences ecosystems and biodiversity.
Example: River deltas supporting rich ecosystems.
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