Chapter 7 – Landforms and Their Evolution
- What are landforms?
Landforms are natural physical features of Earth’s surface, created and modified by geomorphic processes like erosion, weathering, and deposition. Examples include mountains, valleys, plateaus, plains, and dunes. - What are exogenic processes in landform formation?
Exogenic processes like weathering, erosion, transportation, and deposition shape Earth’s surface from the outside and are influenced by agents such as rivers, glaciers, wind, and sea waves. - What are endogenic processes in landform development?
Endogenic forces originate within Earth—like tectonics, earthquakes, and volcanism. They uplift, fold, fault, or break rocks to create landforms such as mountains, rift valleys, and plateaus. - How do rivers shape landforms?
Rivers erode, transport, and deposit materials—forming features like valleys, waterfalls, meanders, floodplains, ox-bow lakes, and deltas depending on the stage and speed of the river. - What are landforms created by glaciers?
Glaciers erode landscapes through plucking and abrasion, forming features like U-shaped valleys, cirques, moraines, drumlins, and fjords. They also deposit sediments as they retreat. - What is a waterfall and how is it formed?
A waterfall forms when a river plunges over a steep slope or resistant rock layer, creating vertical drops. Continuous erosion may lead to its retreat upstream. - What is an ox-bow lake?
It’s a crescent-shaped lake formed when a river meander is cut off from the main channel due to erosion and deposition, leaving a free-standing water body. - What are floodplains?
Flat areas beside a river that get flooded during heavy rainfall. They are formed by repeated deposition of alluvium and are very fertile for agriculture. - What is a delta?
A delta is a fan-shaped deposit of sediment at a river’s mouth where it meets a sea or lake. Famous examples include the Ganga-Brahmaputra Delta. - How do sea waves create landforms?
Waves erode coastlines and deposit materials, forming cliffs, sea caves, arches, stacks, beaches, and spits through hydraulic action, abrasion, and deposition. - What is a sea arch?
A sea arch forms when waves erode both sides of a headland, creating a hole that becomes an arch. Continuous erosion may collapse it into a stack. - What is a sea stack?
A sea stack is an isolated vertical column of rock left after the collapse of a sea arch due to continuous wave erosion. - How does wind create landforms?
In arid regions, wind erodes and deposits materials, forming features like mushroom rocks, sand dunes, loess plains, and yardangs through deflation and abrasion. - What are sand dunes?
Sand dunes are hills of sand formed by wind deposition. Their shape and size vary based on wind direction, speed, and sand availability. Example: Barchans in deserts. - What is a mushroom rock?
A mushroom rock is a landform shaped by wind erosion, with a narrow base and a wider top, resembling a mushroom—common in deserts. - What is a loess plain?
It is a flat area covered with fine, wind-blown silt deposits, highly fertile for agriculture. Found in parts of China and the USA. - What are depositional landforms?
These are formed when transporting agents like rivers, wind, or glaciers lose energy and deposit sediments. Examples: deltas, beaches, sand dunes, moraines. - What are erosional landforms?
They result from the wearing away of Earth’s surface by agents like water, wind, or ice. Examples: waterfalls, sea cliffs, U-shaped valleys, mushroom rocks. - What is a meander?
A meander is a winding curve or bend in a river formed due to lateral erosion and deposition on outer and inner banks, respectively. - What are moraines?
Moraines are accumulations of glacial debris (till) left behind by retreating glaciers. Types include lateral, medial, terminal, and ground moraines. - What is plucking in glacial erosion?
It’s the process where moving glaciers freeze onto rock surfaces and pull away fragments, contributing to landform modification in cold regions. - What is abrasion in erosion?
Abrasion occurs when rocks and sediments carried by wind, water, or ice grind against surfaces, wearing them down over time. - What is deflation in wind erosion?
It refers to the lifting and removal of loose particles from the ground by wind, common in dry and sandy regions. - How do landforms evolve over time?
Landforms undergo continuous changes due to weathering, erosion, deposition, tectonics, and climatic variations, transitioning through stages of youth, maturity, and old age. - What are karst landforms?
Formed in limestone regions by chemical weathering (carbonation), they include caves, sinkholes, stalactites, and stalagmites. Karst topography is common in humid climates. - What is a sinkhole?
A sinkhole is a depression or hole formed by the collapse of a cave roof or by water dissolving underlying rock layers like limestone. - What are stalactites and stalagmites?
They are mineral formations in limestone caves—stalactites hang from ceilings, while stalagmites rise from the floor. Formed by dripping water rich in minerals. - What are badlands?
Highly eroded, barren landscapes with deep gullies and steep slopes—common in semi-arid regions with soft sedimentary rocks. Example: Chambal valley in India. - What is a fjord?
A deep, narrow sea inlet between high cliffs, created by glacial erosion and later flooded by rising sea levels. Common in Norway. - Why is understanding landforms important?
It helps in disaster planning, agriculture, infrastructure, water resource management, and understanding Earth’s geological and climatic history for sustainable development.