Abhishek Mani Tripathi Geography Faculty

1. MajorLandforms

2. A mountain can be defined as an area of land that rises abruptly from the surrounding region. Mountains are significant relief features of the second
order on the earth surface.
First-order landforms :Con=nents Oceans
Second-order landforms: Mountains Plateaus Plains
Third-order landforms: Valleys Beaches Sand dunes
Classifica(on of Mountains: On the basis of origin
1. Fold Mountains
Fold Mountains are formed when two plates collide with each other and their edges crumbled, much the same way as a piece of paper folds when
pushed together. The upward folds are known as an=clines, and the downward folds are synclines. Examples of Fold Mountains include: Himalayan
Mountains in Asia, the Alps in Europe, the Andes in South America, the Rockies in North America, and the Urals in Russia etc.
Mountains

3. 1. Symmetrical: A fold in which two limbs are mirror images of each other.
2. Asymmetrical: A fold in which one limb dipsmore steeply than the other. It has irregular and unequal limbs.
3. Isoclinal:A fold in which two limbs are parallel
4. Recumbent: An overturned fold in which axial plane is virtually horizontal.
5. In extreme cases fracture may occur in the crust, so that upper part of the recumbent fold slides forward
over the lower part along the thrust plane, forming an overthrust fold, and over riding por=on is termed as
NAPPE.

4. 2. Fault-Block Mountains
When the earth crust bends folding occurs and when it cracks faul=ng takes place. Faul=ng may be caused by
tension or compression.
Earth movements generate tensional forces that tend to pull the crust apart and faults are developed. This may
also cause some blocks to rise and other blocks in the centre to subside. The upstanding block becomes horst
or block mountain with steep sides and level summit while the subsided por=on become the graben or riW
valley. e.g. the Vosges and Black Forest of the Rhineland, African RiW Valley system in East Africa.

5. Formation of block mountains and rift valley due to compressive forces.

6. 3. Volcanic Mountains
They are formed when molten rock (magma) deep within the earth, erupts, and piles upon the surface. When the ash
and lava cools, it builds a cone of rock.
Examples of volcanic mountains include: Mount St. Helens in North America, Mount Pinatubo in the Philippines,
Mount Kea and Mount Loa in Hawaii and mount Fujiyama in Japan
4. Residual Mountains
These are mountains Evolved by denuda=on where the general level of the land has been lowered by the agents of
denuda=on. Some very resistant Areas May remainAnd these form residual mountains. Residual mountains may also
evolve from plateau which have been dissected by rivers into hills and valleys. Examples Vindhyachal ranges, Aravallis,
Satpura etc.
Diagram

7. Plateau are elevated upland with extensive level surfaces with steep edges. Also called as tableland.
Plateau

8. The Yellowstone Plateau in the United States, the Massif Central in France, and the Ethiopian Plateau in Africa
are prominent examples of thermal expansion.
Tibetan Plateau is an example of crustal shortening. It is intermont plateau between the Himalayas and the kunlun mt.
Deccan Traps/ Deccan plateau is an example of Volcanic plateau. The volcanic eruptions that produce lava plateaus
tend to be associated with hot spots. For example, the basalts of the Deccan Traps, which cover the Deccan plateau in
India, were erupted 60–65 million years ago when India lay in the Southern Hemisphere, probably over the same hot
spot that presently underlies the volcanic island of Reunion.

9. Dissected Plateau
Through continuous process of weathering and erosion plateaus are gradually worn down, surface made irregular and deep
valleys are formed in the plateau. Such plateau are termed as Dissected Plateau.
Mesas are generally found in arid regions with horizontal layers of sedimentary rock that makes up the cliffs. The top of the
mesa is called the caprock, this upper layer is often harder and more resistant to weathering or erosion.
Buttes generally still have the caprock intact, but eventually this also begins to wear away so that you might see buttes with
more rounded or pointed tops.

10. Plain is an area of lowland, either level or undulating. There may be low hills which will give it a typical rolling topography.
Rolling topography is any land formation that is not high enough to be considered a mountain. Rolling topography is
formed by erosion or some other force in nature like glaciers.
Types of plains:
1. Structural Plains: Structurally depressed, make up natural lowlands. Formed by horizontally bedded rocks relatively
undisturbed by crustal movements of earth. Examples Great Plains of USA, central lowlands of Australia.
2. Depositional Plains: alluvial plains, flood plains by rivers, outwash plain by glaciers, coastal plains by waves, loess plain by
winds e.g. Pampas in Argentina.
3. Erosional Plains: peneplains by rivers with monadnocks, peneplains by winds with inselberg. They are low, undulating, gentle
sloping plains.
Plains