Geomorphic Processes – CBSE NCERT Study Resources

Endogenic processes originate within Earth (e.g., volcanism), while exogenic processes (e.g., weathering) are surface-driven. Köppen’s Af climate accelerates exogenic actions.

• Endogenic: Himalayas’ uplift (ET climate)
• Exogenic: Thar Desert’s sand dunes (BSh)

Mass wasting is downhill movement of soil/rock under gravity. Our textbook shows GIS tracks landslides in Cwa (monsoon) zones.

• Increased rain in Cwa raises landslide risks (e.g., Assam).
• GIS predicts vulnerable zones using rainfall trends.

Fluvial erosion is river-driven land cutting. Aw climates (heavy rain) intensify it, as we studied in the Amazon.

• Youthful: Brahmaputra’s gorges (Cwb).
• Mature: Mississippi’s floodplains (Cfa).

Aeolian processes are wind-driven sand movements. BWh (hot desert) and BWk (cold desert) dominate, like Sahara and Gobi.

• Desert expansion (BWh to Csa).
• GIS tracks dune migration via satellite.

Chemical weathering alters rock composition (e.g., Cfb’s humidity), while mechanical weathering breaks rocks physically (e.g., Dfc’s frost).

• Chemical: Limestone caves in Cfb (Europe).
• Mechanical: Scree slopes in Dfc (Canada).

Endogenic processes originate from Earth's interior (e.g., plate tectonics), while exogenic processes are external (e.g., weathering).

In the Himalayas, endogenic uplift (Indian Plate collision) and exogenic erosion (Ganges River) interact.

Mass wasting is downhill movement of soil/rock under gravity. Our textbook shows types like landslides (rapid) and creep (slow).

In Cfb (temperate) Western Ghats, heavy rains trigger mudflows, damaging plantations. [Diagram: Slump structure]

Fluvial erosion involves river-driven landform changes. We studied vertical (downcutting) and lateral (meander) erosion.

Brahmaputra’s lateral erosion displaces 50,000/year (GIS data). [Diagram: Oxbow lake formation]

Physical weathering breaks rocks mechanically (e.g., frost), while chemical alters composition (e.g., carbonation).

In BWh (hot desert), physical weathering dominates (diurnal temperature swings).

Aeolian processes involve wind action, like deflation (removal) and abrasion (polishing).

Rising temperatures increase wind speed, accelerating aeolian erosion in Rajasthan (NCERT data).

Glacial landforms include U-shaped valleys (erosion) and moraines (deposition).

Himalayan glaciers (ET) retreat at 15 m/year vs. Antarctica’s (EF) stability. [Diagram: Arete formation]

Endogenic geomorphic processes are internal forces originating within the Earth that lead to the formation of major landforms. These processes are driven by the Earth's internal heat and include diastrophism and volcanism.

Diastrophism involves movements of the Earth's crust, such as:

• Folding: When compressional forces bend rock layers (e.g., the Himalayas).
• Faulting: When tensional forces break rock layers (e.g., the East African Rift Valley).

Volcanism includes the eruption of magma onto the surface, forming features like volcanoes (e.g., Mount Fuji) and lava plateaus (e.g., Deccan Traps).

These processes shape the Earth's surface by creating mountains, plateaus, and rift valleys, altering the landscape over millions of years. They also trigger earthquakes and tsunamis, impacting human settlements.

Weathering is the breakdown of rocks in situ due to atmospheric or biological factors. It plays a crucial role in landform development by weakening rock structures, making them susceptible to erosion and deposition.

Physical weathering involves mechanical disintegration without chemical change, such as:

• Frost action: Water freezes in cracks, expanding and breaking rocks.
• Exfoliation: Peeling of rock layers due to temperature changes (e.g., granite domes).

Chemical weathering alters rock composition through reactions like:

• Oxidation: Rocks with iron rust (e.g., laterite soil formation).
• Carbonation: Limestone dissolves in acidic water (e.g., karst landscapes).

Weathering prepares rocks for erosion, contributing to soil formation and sculpting landforms like tors and regolith-covered plains.

Endogenic processes are internal forces that originate within the Earth's crust and are driven by the Earth's internal energy. These include:

• Diastrophism: Large-scale deformation of the Earth's crust, e.g., folding (Himalayas) and faulting (East African Rift Valley).
• Volcanism: Movement of magma to the surface, e.g., volcanic mountains like Mt. Fuji.

• Weathering: Breakdown of rocks, e.g., chemical weathering in limestone regions.
• Erosion: Wearing away of landforms, e.g., river valleys formed by fluvial erosion.

Weathering is the breakdown of rocks in situ due to physical, chemical, or biological processes. It prepares rocks for erosion and contributes to landform evolution:

• Physical weathering: Freeze-thaw action creates scree slopes.
• Chemical weathering: Limestone dissolves to form karst landscapes (e.g., caves).

• Slow movement: Soil creep causes tilted fences.
• Fast movement: Landslides block valleys (e.g., Kedarnath disaster).

Exogenic geomorphic processes are external forces that originate from the Earth's atmosphere or surface and are responsible for the continuous reshaping of the landforms. These processes include weathering, erosion, transportation, and deposition.

Weathering is the breakdown of rocks into smaller particles due to exposure to atmospheric conditions like temperature changes, water, and wind. For example, freeze-thaw action in cold regions causes rocks to crack and break apart.

Erosion involves the removal of weathered materials by agents such as rivers, glaciers, wind, and waves. A classic example is the formation of canyons by river erosion over millions of years.

Transportation refers to the movement of eroded materials by natural agents. Rivers transport sediments downstream, while wind carries sand particles in deserts, forming dunes.

Deposition occurs when these transported materials settle in new locations, creating features like deltas at river mouths or beaches along coastlines.

These processes work together to create diverse landforms, such as valleys, plains, and plateaus, making the Earth's surface dynamic and ever-changing.

Endogenic geomorphic processes are internal forces originating within the Earth that shape the Earth's surface. These processes are driven by the Earth's internal heat and include diastrophism (movement of Earth's crust) and volcanism (movement of molten rock).

Examples:

• Diastrophism: Includes folding (e.g., Himalayas formed by the collision of Indo-Australian and Eurasian plates) and faulting (e.g., East African Rift Valley).
• Volcanism: Formation of volcanic mountains like Mt. Fuji or shield volcanoes like Mauna Loa.

Contribution to landforms:
1. Mountains: Formed by folding, faulting, or volcanic activity.
2. Plateaus: Created by lava flows (e.g., Deccan Plateau) or upliftment.
3. Rift valleys: Result from tensional forces causing faulting.
4. Volcanic islands: Formed by magma solidifying underwater (e.g., Hawaiian Islands).

These processes are continuous and counteract exogenic processes, maintaining Earth's dynamic equilibrium.

The exogenic processes are external forces that shape the Earth's surface through weathering, erosion, and deposition. These processes are driven by atmospheric elements like wind, water, and ice. For example, rivers carve valleys through erosion, while wind shapes deserts by transporting sand.

These processes interact with endogenic processes (internal forces like tectonic activity and volcanism) to create diverse landforms. While endogenic forces build mountains and plateaus, exogenic forces wear them down over time. This dynamic balance results in features like:

• Himalayas: Formed by tectonic uplift (endogenic) and sculpted by glacial erosion (exogenic).
• River deltas: Created by deposition (exogenic) where rivers meet oceans, often in tectonically stable regions.

Understanding this interaction helps explain Earth's ever-changing topography.

Mass movements refer to the downhill movement of soil, rock, or debris under gravity. Major types include:

• Soil creep: Slow movement due to freeze-thaw cycles or wetting-drying.
• Landslides: Rapid movement triggered by earthquakes or heavy rain.
• Mudflows: Water-saturated debris moving swiftly down slopes.

Causes include:

• Natural factors: Steep slopes, heavy rainfall, earthquakes.
• Human activities: Deforestation, construction, mining (which destabilize slopes).

For example, the 2013 Uttarakhand floods were worsened by unchecked construction and deforestation, leading to catastrophic landslides. Proper land-use planning and afforestation can mitigate such risks.

The exogenic processes are external forces that shape the Earth's surface through weathering, erosion, and deposition. These processes are driven by solar energy and gravitational forces.

Types of Exogenic Processes:

• Weathering: Breakdown of rocks in situ. Example: Frost action creates talus slopes.
• Erosion: Removal of weathered material by agents like water, wind, or ice. Example: River erosion forms V-shaped valleys.
• Deposition: Accumulation of eroded material. Example: Wind deposition creates sand dunes.

These processes continuously modify landscapes, creating diverse landforms such as canyons, deltas, and moraines.

Endogenic processes are internal forces originating from Earth's interior, responsible for crustal movements and landform creation. They include diastrophism and volcanism.

Diastrophism refers to crustal deformation due to tectonic forces. Example: Folding forms Himalayan mountains.
Volcanism involves magma movement leading to eruptions. Example: Shield volcanoes like Mauna Loa.

Key Differences:

• Diastrophism is slow and results in folds/faults, while volcanism is rapid, producing lava landforms.
• Diastrophism affects large areas, whereas volcanism is localized.

These processes shape continents, create mountains, and trigger earthquakes, playing a vital role in Earth's dynamic nature.