2. Mountains
1. A mountain is a landform or area of the earth’s surface that are higher then the
surrounding land.
2. Mountains cover about one-fifth (1/5) of the lithosphere and are found in every part
of the world.
3. They are most often formed by movement of the tectonic plates in the Earth’s crust.
4. Types of Mountains: There are four main types of mountains:
1) Fold Mountains
2) Block Mountains
3) Dome Mountains
4) Volcanic mountains.
3. Fold Mountains:
Fold Mountains are formed when two tectonic or continental plates run into
each other or collide. This force causes the Earth’s crust to crumple, fold and
buckle.
The up-fold is called ‘anticline’ and the down-fold is called ‘syncline’
Some example are: The Andes, Himalayas, and the Rockies.
4. Block mountains are formed when the Earth’s crusts fractures (cracks open)
and pulls apart breaking into blocks or chunks.
Some large blocks of rock are forced upwards while others are forced
downwards. The one lifted above the surrounding area are called ‘Block
mountains’.
Examples: The Sierra Nevada (N. America) and Harz Mountains(Germany)
Fold Mountains:
5. Dome Mountains are formed when the molten magma below the Earth’s
surface pushes up the rock layer above it creating a dome on the Earth’s
surface. This magma cools and forms hardened rock forming a circular
mountain called dome mountains. Examples : The Sierra Nevada (N.
America)
Dome Mountains
7. Plateaus
A plateau is a huge mass of level land or flat land that rises abruptly
from surrounding areas.
It usually has a steep slope on one or more sides and its surface
has a wave-like appearance. It is also known as a tableland.
Basically, a plateau is a small or large raised area of flat land which
is separated from the rest of the surrounding land. These plateaus
have sloped lands on either side of it.
8. Formation of Plateaus
Plateaus are formed due to reasons like :
❖The erosion of surrounding areas by rivers, flooding, and glacier
activities .
❖The pressure from the large magma chamber under the rocks can
result in the uplifting the ground.
❖3.Over several years plateaus are formed due to repeated lava flows.
❖ 4th
point from textbook.
❖5.The tectonic plates of the earth’s crust collide and plateaus are
formed.
9. DO NOT WRITE
Plateaus are formed when thick lava in some places, through tiny fissures and
cracks on the earth's surface, pours out and covers those areas. These areas form
layers of lava sheets. These areas are called volcanic plateaus. The Deccan
Plateau (India) and the Snake Plateau (USA) are examples of volcanic plateaus.
•Many plateaus form as magma deep inside the Earth pushes toward the surface
but fails to break through the crust. Instead, the magma lifts up the large, flat,
impenetrable rock above it.
10. Plateau formed due to Endogenic forces:
Three kind of plateaus are formed due to the Endogenic forces of
the Earth:
1. Intermontane Plateau
2. Piedmont Plateau
3. Continental Plateau
(Complete the notes from the textbook as instructed)
11. Importance of Plateau
• Low plateaus are generally suitable for farming.
• High plateaus are important suitable for rearing livestock (animals)
• Some plateaus are rich in minerals like copper, iron, manganese, coal, gold
and diamond.
• It is suitable for habitation (living) as its climate is cooler than the
surrounding areas.
• The rivers flowing down the plateaus are used to generate hydro-electricity.
12. Plains
• Plains are broad and generally flat areas of land in the form of
grasslands, forests, shrub lands and barren lands.
• Plains are formed by deposition of lava, sediments and sand.
• They are also sometimes fomed due to erosion of high lands.
• The types of plains are:
1) Coastal Plains
2) Alluvial Plains
3) Lava Plains
4) Glacial Plains
13. Types Of Plains
1. Coastal Plains:
A coastal plain is a flat, low-lying piece of land next to the sea. Coastal plains are separated from
the rest of the interior by nearby landforms, such as mountains or plateus.
Example: The Konkan coast The Coromandal coast
2. Alluvial Plains:
An alluvial plain is a largely flat landform created by the deposition of sediment over a long period of time
by one or more rivers coming from highland regions, from which alluvial soil forms. This plain is very fertile due
to the fresh alluvium soil which is periodically added.
Example: The Indo-Gangetic plain of India
14. 3. Lava Plains:
(Write from page 182)
4. Glacial Plains:
Are formed by the movement of glaciers under the force of gravity.
When a portion of glacier gets detached from the main body of a
glacier and melts in place depositing the sediments it carries it forms
glacial plains.
Examples: The Ladhakh plain in India
15. Importance of Plains
Give Reason:
Q.1 90% of the world's population lives in plain lands. Why?
Plains are low-lying areas and are one of the most important landforms for the humans to
live. They are mostly populated because:
• They mostly consist of fertile lands, which are ideal for agriculture and related activities.
• Easy availability of water near river plains is a reason for the settlement of people there.
• The flat surfaces facilitate the construction of houses, roads, industries, etc.
• It has grasslands which are required for feeding of livestock (domestic animal).
• They are suited for road and rail transportation
