Chapter 6 – Geomorphic Processes
What are geomorphic processes?
They are natural processes responsible for shaping Earth’s surface through physical and chemical actions like weathering, erosion, transportation, and deposition, operating over time to form landforms.
What is endogenic force?
Forces originating inside the Earth. They cause movements like earthquakes, volcanism, folding, and faulting, leading to the creation of major landforms like mountains and rift valleys.
What is exogenic force?
Forces acting on the Earth’s surface due to atmospheric elements like wind, water, and temperature. These processes break down and reshape landforms through erosion and weathering.
What is weathering?
The mechanical and chemical breakdown of rocks at or near Earth’s surface without movement. It prepares material for erosion and helps in soil formation.
What is physical weathering?
Also called mechanical weathering, it breaks rocks into smaller fragments without changing their chemical composition. Examples: freeze-thaw, thermal expansion, exfoliation.
What is chemical weathering?
It involves decomposition of rocks due to chemical reactions with water, oxygen, carbon dioxide, or acids. It alters the rock’s chemical structure. Example: rusting of iron minerals.
What is biological weathering?
It occurs when plants, animals, or microorganisms break down rocks. Tree roots growing into cracks or burrowing animals contribute to physical and chemical weathering.
What is mass movement?
Also called mass wasting, it refers to the downslope movement of soil or rock under gravity. Includes landslides, soil creep, and rockfalls.
What factors influence weathering?
Rock type, climate, topography, vegetation, and time affect the rate and type of weathering in a region.
What is exfoliation?
A type of physical weathering where outer layers of rock peel off due to expansion and contraction from temperature changes—common in desert areas.
What is block disintegration?
It occurs when rocks split along joints or cracks due to temperature variations, especially in rocks like granite.
What is frost wedging?
A mechanical weathering process where water enters rock cracks, freezes, expands, and breaks the rock apart—common in cold climates.
What is oxidation in chemical weathering?
It occurs when minerals react with oxygen, forming oxides. Iron-bearing rocks rust and disintegrate due to oxidation.
What is carbonation?
When rainwater reacts with carbon dioxide to form carbonic acid, it dissolves limestone and chalk rocks—common in karst topography.
What is solution weathering?
It involves dissolving of minerals in water. Salts like halite (rock salt) easily dissolve, leading to chemical weathering.
What is soil creep?
A slow, imperceptible form of mass movement where soil particles move downhill due to gravity, wetting and drying, or freezing and thawing.
What is landslide?
A sudden and rapid mass movement of rock and soil down a slope, triggered by rainfall, earthquakes, or human activity.
What are the types of mass movement?
Creep (slow), flow (mudflows), slide (landslides), and fall (rockfall) are the main types based on speed and material involved.
What is erosion?
The process of wearing away rocks and soil by agents like rivers, glaciers, wind, and waves. It shapes landscapes by transporting material from one place to another.
What are the agents of erosion?
Running water, glaciers, wind, waves, and groundwater are natural agents that cause erosion and deposition on Earth’s surface.
What is deposition?
It is the laying down of eroded material when an agent loses its energy. Rivers deposit sediments in plains and deltas, forming depositional landforms.
What is the significance of geomorphic processes?
They constantly modify Earth’s surface, forming valleys, mountains, deltas, deserts, and shaping habitats and ecosystems.
What is the difference between erosion and weathering?
Weathering breaks down rocks in place without movement. Erosion involves the transportation of weathered material by natural forces.
What is a slope?
A slope is an inclined surface of land. Its gradient affects the rate of erosion, deposition, and mass movements.
What is gravity’s role in geomorphic processes?
Gravity drives mass movement, causes rockfalls and landslides, and helps in transporting material downslope in all exogenic processes.
What is heaving?
The lifting of soil or rocks due to frost action or swelling from moisture, which contributes to soil creep and weathering.
What is sheet erosion?
A form of water erosion where a thin layer of topsoil is removed evenly over a large area by rain or surface runoff.
What is gullying?
Formation of deep channels or gullies in soil due to concentrated runoff, common in regions with loose soil and heavy rainfall.
How do humans influence geomorphic processes?
Construction, mining, deforestation, and agriculture accelerate erosion, trigger landslides, and disturb natural mass movement and weathering patterns.
Why are geomorphic processes important for geography?
They explain landform development, soil formation, and landscape evolution, helping in planning, hazard mitigation, and sustainable development.