Mountains and Plateaus

Mountains

Part of land > 900 mts height
With slope ~ 25 – 30*
Mainly of four types viz.

Fold Mountains

Block Mountains

Volcanic Mountains

Residual / Dissected / Relict Mountains

Fold Mountains

Formed by folding of geosyncline sediments under compressible tectonic forces
For Ex. Himalaya, Alps, Rockies, Andes, Alapchhian, Ural, Aravalis
Since the rock strata have been elevated to great heights, Fold Mountains are also called mountains of elevation
Are closely associated with volcanic activities.
Contains many active volcanoes, especially in circum Pacific fold mountain system
Are rich in mineral resources such as Tin, Copper, Gold & Petroleum

Block Mountains

Formed due to faults caused by tension or compression forces which lengthen or shorten earth’s crust
It causes a section of it to subside or rise above the surrounding level
For Ex. Vosges (France), Black Forest (Germany)
Faulting results in formation of Block Mountains & their counterparts in rift valleys
In general, large scale Block Mountains & rift valleys are due to tension rather than compression.

Volcanic Mountains

Also known as mountains of accumulation
Formed due to accumulation of thick lava as a result of volcanic eruption
Common in circum pacific belt
For Ex. Fuji Yama (Japan), Mt. Popa (Myanmar), Mt. Mauna loa (Hawai), Mt. Mayon (Phillipines), Mt. Agung (Bali), Mt. Merapi (Sumatra) & Mt. Catopaxi (Euador)

Residual / Dissected / Relict Mountains

Formed due to waning of previously existing elevated regions by erosion
For Ex. Nilgiris, Parshavnath, Hills of Peninsula India, Mt. Manodnock (USA)
Mountains evolved by denudation, where the general level of land have been lowered by agents of denudation; also known as mountains of denudation

Plateaus

An elevated area compared to its surroundings, having a large almost flat top area (Also known as tableland)
Like all highlands, Plateaus are also subjected to erosional processes, as a result their original characteristics are highly altered
According to their mode of formation & their physical appearance, plateaus may be divided into 3 types viz.

Tectonic Plateaus

Formed by earth movements which causes uplift, of a considerable size with fairly uniform altitude
For ex. Deccan plateaus, Mesera plateau (tilted of central Iberia) & Harz plateau (Faulted of Germany)

When plateaus are surrounded by mountains they are known as inter-montane plateaus for ex. Tibetian plateau, Bolivian Plateau

When plateaus are surrounded by sea or plains they are known as Continental Plateaus For ex. Deccan plateau, Greenland plateau, South Africa plateau

Volcanic Plateau

Molten lava from the volcanic eruption may solidify to form successive sheets of basalatic lava, known as Lava plateau
For ex. Antrim Plateau of Northern Island, NW part of Deccan Plateau & Columbia Snake Plateau (Biggest one)